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WO2018173553A1 - Film de revêtement, procédé de production de film de revêtement, et dispositif électroluminescent organique - Google Patents

Film de revêtement, procédé de production de film de revêtement, et dispositif électroluminescent organique Download PDF

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WO2018173553A1
WO2018173553A1 PCT/JP2018/005024 JP2018005024W WO2018173553A1 WO 2018173553 A1 WO2018173553 A1 WO 2018173553A1 JP 2018005024 W JP2018005024 W JP 2018005024W WO 2018173553 A1 WO2018173553 A1 WO 2018173553A1
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organic
particle size
layer
coating film
formula
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Japanese (ja)
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昇 関根
拓己 倉田
勇作 田中
伊藤　博人
小西　敬吏
北　弘志
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Konica Minolta Inc
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Konica Minolta Inc
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  • the present invention relates to a coating film, a manufacturing method of the coating film, and an organic electroluminescence element, and in particular, an object thereof is to provide a coating film having a small particle size of organic compound particles in the film and a manufacturing method thereof, It is to provide an organic electroluminescence device excellent in luminous efficiency and durability using the coating film.
  • organic electronic device prevalence and current problems Electronic devices using organic compounds, such as organic electroluminescent elements (also referred to as “OLEDs”, “organic EL elements”), organic photoelectric conversion elements, and Various electronic devices such as organic transistors have been developed, and are spreading in various industrial and market fields along with their technological progress.
  • organic EL elements which are typical examples of organic electronic devices, have begun to be used in various fields such as displays, lighting, and indicators, and have already entered the current life together with liquid crystal displays and light emitting diodes (LEDs). From now on, we are about to enter a period of dramatic expansion.
  • problems remain to be solved in the research and development process.
  • various problems resulting from the use of organic compounds remain common or unique to various organic electronic devices. It can be said that these problems to be solved are ultimate problems directly connected to further improvement in performance such as quantum efficiency and light emission lifetime and further improvement in productivity, that is, cost reduction.
  • An organic EL element has an electron and a hole in a light emitting material (generally also referred to as “dopant”) present in a light emitting layer which is one of organic functional layers.
  • a light emitting material generally also referred to as “dopant”.
  • the basic principle is that the exciton produced when the recombination occurs and emits light when returning to the ground state. As the name suggests, this exciton is a very active chemical species that is in an excited state, so it easily reacts with water molecules and oxygen molecules, causing chemical changes or state changes such as decomposition and denaturation, and has a light-emitting property. It will decrease. That is, it is one of the factors that reduce the light emission lifetime.
  • an organic functional layer such as a light emitting layer
  • the existence state of an organic compound that constitutes a light emitting layer is not a crystal but an amorphous (amorphous) condition. Therefore, in order to form a homogeneous amorphous film, it is desired that the molecular state (amorphous state) of the organic compound and the surrounding environment are constant during the film formation.
  • the deposition method for the organic functional layer of the organic EL element exhibiting good performance so far is the vacuum deposition method, for the reasons such as prevention of harmful effects due to moisture and oxygen and the necessity of making the organic compound amorphous. It was due to.
  • the vapor deposition method is employed as a method for forming the organic functional layer.
  • Organic electroluminescence is self-luminous, and the luminescent color is uniquely determined by the luminescent material constituting the luminescent layer, so basically red (Red: R), green (Green: G), blue (Blue: B)
  • red Red
  • Green Green
  • Blue B
  • a method RGB side-by-side method in which organic EL elements of respective emission colors are formed for each pixel and arrayed to form a display has been adopted.
  • the RGB side-by-side method it is necessary to form a different light-emitting layer for each pixel, and in order to perform this in a large area, there is a method of forming each pixel while shifting the shadow mask for each pixel. It is common.
  • the formation (film formation) method of the light emitting layer or the like is a vacuum vapor deposition method, there is a decisive problem that the shadow mask is thermally expanded by the radiant heat from the vapor deposition source and causes pixel displacement. Due to this critical problem, small to medium-sized displays for smartphones are produced in hundreds of millions of panels per year using the RGB side-by-side method. The production yield originated from the thermal deformation of the shadow mask is low, and large-scale production is not performed.
  • a method for reproducing full color a method (color filter method) in which white light obtained from an organic EL element is color-divided into RGB by passing through a color filter (color filter method) is employed.
  • a large display that has already been mass-produced is an array of organic EL elements that emit white light for each pixel, and a shadow mask is not required for the color filter method, thereby improving the yield.
  • the color filter method has a problem in that the advantages and characteristics of the organic EL element that can obtain light with high contrast with independent pixels cannot be fully exhibited.
  • the organic functional layer constituting the organic EL element has a laminated structure of about 4 to 7 layers, and the total layer (film) thickness is about 100 to 200 nm. It is. If it is too thin, the anode and the cathode are partially short-circuited due to the surface roughness of the electrode serving as the underlayer, and a current leakage phenomenon occurs. If the thickness is larger than this, the charge conduction mechanism of the organic EL element is different from Ohm's law, and is a space charge limited current (SCLC) according to the child law. Since it is inversely proportional to the third power of, a significant drive voltage rise occurs, resulting in a problem of increased power consumption.
  • SCLC space charge limited current
  • the organic functional layer of an organic EL device is generally deposited by depositing a low molecular compound, but instead of the low molecular compound, a ⁇ -conjugated polymer such as polyphenylene vinylene or polyfluorene is used for carrier movement and light emission. There is also a method using a light emitting polymer (LEP) utilized for both. Since the polymer material cannot be formed by vapor deposition, the organic functional layer is produced by a wet coating method (wet film formation method, wet coating method) such as spin coating, die coating, flexographic printing, and inkjet printing.
  • a wet coating method such as spin coating, die coating, flexographic printing, and inkjet printing.
  • Patent Document 1 it is disclosed that the generation of microcrystals can be suppressed by combining a plurality of host materials and dopant materials, but the generation of microcrystals is controlled in a thin film made of a single kind of material. Whether or not is disclosed.
  • the present invention has been made in view of the above-mentioned problems and situations, and the problem to be solved is that even when a single type of material is used, there are few microcrystals, in other words, the particle size of the organic compound particles in the film ( It is to provide a coating film having a small domain size), a coating film manufacturing method for manufacturing the coating film, and to provide an organic electroluminescence device excellent in luminous efficiency and durability using the coating film. It is.
  • the present inventor in the process of examining the cause of the above-mentioned problem, is a coating film composed of at least a single kind of organic compound molecule, and molecules or aggregates obtained from small-angle X-ray scattering measurement.
  • a coating film having an organic compound having at least one maximum peak in a diameter distribution curve and satisfying a specific relational formula, and having a small particle size of organic compound particles in the film, and a method for producing the coating film the present inventors have found that an organic electroluminescence element excellent in luminous efficiency and durability can be provided, and have reached the present invention. That is, the said subject which concerns on this invention is solved by the following means. 1.
  • a coating film comprising at least a single organic compound, Having at least one maximum peak in the particle size distribution curve (horizontal axis: particle size, vertical axis: frequency distribution) of the molecule or aggregate obtained from the small angle X-ray scattering measurement, and
  • Formula (1): R ⁇ 15r [In Formula (1), R represents the particle size corresponding to the maximum peak which shows a particle size with the smallest particle size among the maximum peaks of the particle size distribution curve obtained from a small angle X-ray scattering measurement.
  • the molecular radius of the organic compound r (A ⁇ b) represents 1/2 . ]
  • R represents a particle size corresponding to a maximum peak having the largest frequency distribution among the maximum peaks of the particle size distribution curve.
  • R ′ and r are films formed by solidifying a coating solution containing an organic compound that satisfies the relationship represented by the following formula (3), according to any one of items 1 to 6 Coating film.
  • Formula (3): R ′ ⁇ 6r [In formula (3), R ′ is the particle size corresponding to the maximum peak indicating the smallest particle size among the maximum peaks of the particle size distribution curve obtained from the small angle X-ray scattering measurement of the coating solution. To express. r is synonymous with r in the formula (1). ]
  • Formula (3): R ′ ⁇ 6r [In formula (3), R ′ is the particle size corresponding to the maximum peak indicating the smallest particle size among the maximum peaks of the particle size distribution curve obtained from the small angle X-ray scattering measurement of the coating solution. To express. r is synonymous with r in the formula (1). ]
  • the organic electroluminescent element which has the coating film as described in any one of Claim 1- 7 in at least 1 layer of an organic functional layer.
  • the organic compound is preferably a low molecular compound (a high molecular compound is not preferable).
  • the film forming method is preferably a coating method (a vapor deposition method is not preferable).
  • the solvent in the coating solution is preferably a general-purpose solvent (an expensive dehydrated high-purity solvent is not preferred).
  • the dissolution is preferably in a monomolecular state (a microcrystalline dispersion is not preferred).
  • Adsorption-desorption equilibrium is preferably used for purification of the compound (thermal equilibrium is not preferred).
  • Examples of the method for dispersing the solute aggregate in the solution include chromatography, ultrasonic or microwave irradiation, and electrophoresis. Also, in the drying step, it is preferable to use a solvent having a solubility of solute of 5% by mass or less in order to suppress the interaction force between the solute and the solvent to a certain range or less and make the driving force for drying entropy. I found.
  • the expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.
  • the present inventors have studied focusing on the material state from the application of the coating solution in which the material is dissolved until the film is formed.
  • the solute contained in the coating solution forms a film
  • what kind of state the solute is in the solution state of the coating solution and how it is solidified (coating) It is.
  • solid molecules are transformed into a gas phase by being heated in a vacuum, and the molecules move to the element substrate due to a thermal gradient. It is considered that a film is formed by transformation from a gas to a solid, and as a result, an amorphous film is formed.
  • a solute molecule forms a cluster in which several to several tens of tens of molecules gather in a coating solution.
  • the clusters trigger the formation of microcrystals. Specifically, as shown in FIG. 1, a solute molecule 20 forms a cluster 22 in which several molecules to several tens of molecules are gathered, and a large number of solvent molecules 21 exist around the cluster 22.
  • molecules are highly dispersed at the coating liquid stage, that is, as shown in FIG. 11, a single solute molecule 20 (diameter 2r) is surrounded by a large number of solvent molecules 21, thereby forming a film. It is presumed that an amorphous film is formed by eliminating the cluster in the formation process.
  • Schematic diagram of one solute molecule present in the solvent A graph showing an example of particle size distribution curves for conventional deposited films and coated films The graph which shows an example of the particle size distribution curve in the coating film of this invention and a comparative example Schematic diagram of equipment using packed column in supercritical or subcritical chromatography
  • Schematic diagram showing an example of a display device composed of organic EL elements Schematic diagram of display part A Schematic showing the pixel circuit
  • Schematic diagram of passive matrix type full color display device Sectional drawing which shows the solar cell which consists of an organic photoelectric conversion element of a bulk heterojunction type
  • Sectional drawing which shows the solar cell which consists of an organic photoelectric conversion element provided with a tandem type bulk heterojunction layer
  • the coating film of the present invention is a coating film composed of at least one kind of organic compound, and is a particle size distribution curve of molecules or aggregates obtained from small angle X-ray scattering measurement (horizontal axis: particle size, vertical axis: frequency distribution). ) Contains at least one maximum peak, and R and r below contain an organic compound satisfying the relationship represented by the following formula (1).
  • Formula (1): R ⁇ 15r [In Formula (1), R represents the particle size corresponding to the maximum peak which shows a particle size with the smallest particle size among the maximum peaks of the particle size distribution curve obtained from a small angle X-ray scattering measurement.
  • the R represents a particle size corresponding to a maximum peak having the largest frequency distribution among the maximum peaks of the particle size distribution curve. It is preferable in that it increases, that is, the homogeneity in the film increases.
  • the frequency distribution of the maximum peak satisfying the formula (1) is 0.4 or more in that the degree of dispersion of the particle size in the coating film is high, that is, the homogeneity in the film is high. preferable.
  • Formula (2) R ⁇ 8r [In Formula (2), R and r are synonymous with R and r in said Formula (1). ]
  • the half width of the maximum peak satisfying the formula (1) is in the range of 0.3 to 3.0 nm from the viewpoint of uniform device characteristics.
  • R ′ and r are films formed by solidifying a coating solution containing an organic compound that satisfies the relationship represented by the following formula (3), so that no cluster exists in the film forming process. And a coating film having a smaller particle diameter can be obtained.
  • Formula (3): R ′ ⁇ 6r [In formula (3), R ′ is the particle size corresponding to the maximum peak indicating the smallest particle size among the maximum peaks of the particle size distribution curve obtained from the small angle X-ray scattering measurement of the coating solution. To express. r is synonymous with r in the formula (1). ]
  • the method for producing a coating film of the present invention includes a step of preparing a coating solution containing an organic compound in which R ′ and r below satisfy the relationship represented by the following formula (3), and a step of drying and solidifying the coating solution It is characterized by having.
  • R ′ is the particle size corresponding to the maximum peak indicating the smallest particle size among the maximum peaks of the particle size distribution curve obtained from the small angle X-ray scattering measurement of the coating solution.
  • r is synonymous with r in the formula (1).
  • the coating film of this invention is used suitably for the organic electroluminescent element which has in at least 1 layer of an organic functional layer. Moreover, it is preferable that the organic functional layer is a light emitting layer from the viewpoint of light emitting element lifetime and light emitting efficiency.
  • ⁇ is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
  • the ratios such as “%” and “ppm” are based on mass.
  • the coating film of the present invention is a coating film composed of at least one kind of organic compound, and is a particle size distribution curve of molecules or aggregates obtained from small-angle X-ray scattering measurement (horizontal axis: particle size, vertical axis: frequency distribution). ) Contains at least one maximum peak, and R and r below contain an organic compound satisfying the relationship represented by the following formula (1).
  • Formula (1): R ⁇ 15r [In Formula (1), R represents the particle size corresponding to the maximum peak which shows a particle size with the smallest particle size among the maximum peaks of the particle size distribution curve obtained from a small angle X-ray scattering measurement.
  • the molecular radius of the organic compound r (A ⁇ b) represents 1/2 . ]
  • the organic compound is preferably a low molecular compound (a high molecular compound is not preferable).
  • the film forming method is preferably a coating method (a vapor deposition method is not preferable).
  • the solvent in the coating solution is preferably a general-purpose solvent (an expensive dehydrated high-purity solvent is not preferred).
  • the dissolution is preferably in a monomolecular state (a microcrystalline dispersion is not preferred).
  • Adsorption-desorption equilibrium is preferably used for purification of the compound (thermal equilibrium is not preferred).
  • high-performance liquid chromatography HPLC
  • column chromatography with low purification efficiency low theoretical plate number
  • column chromatography can be used as a method for purifying low-molecular compounds.
  • the purification is performed by repeatedly performing a reprecipitation method using a good solvent and a poor solvent, and the low-molecular compound is more easily purified.
  • the polymer compound is a ⁇ -conjugated polymer compound, it is necessary to use a metal catalyst or a polymerization initiator for causing a polymerization reaction, and a reactive active substituent remains at the polymerization terminal. This is one of the reasons why low molecular weight compounds can be made more pure.
  • Light emitting polymer is a ⁇ -conjugated polymer when the molecular weight is increased, so that it is conjugated to stabilize the molecule.
  • the energy level difference between the excited state of the singlet or triplet and the ground state also referred to as “energy level gap” or “band gap”
  • blue light emission becomes difficult.
  • the light emitting polymer in blue phosphorescence requiring a higher energy level (large energy level difference) than fluorescent blue light emission, it is structurally difficult for the light emitting polymer to form a transition metal complex serving as the light emitting substance.
  • a light-emitting polymer is used as a host, it is difficult to obtain a compound having high triplet energy (abbreviated as “high T 1 compound”) due to the extension of the ⁇ -conjugate.
  • the low molecular weight compound there is no necessity to connect the ⁇ -conjugated system, and the aromatic compound residue that becomes the ⁇ -conjugated system unit is necessary, but they can be arbitrarily selected, and further, they can be substituted at an arbitrary position. Therefore, in low molecular weight compounds, the highest occupied orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and the triplet (T1) energy level can be intentionally adjusted easily. It is possible to make a blue phosphorescent substance, to use it as a host, and to construct a compound that causes the TADF phenomenon. As described above, the degree of expandability capable of intentionally designing and synthesizing an arbitrary electronic state and an arbitrary level is a factor of the second advantage of the low molecular weight compound.
  • the low molecular weight compound has no limitation on the molecular structure that can be synthesized as compared with the light emitting polymer (LEP).
  • LEP light emitting polymer
  • the main chain of a light-emitting polymer is ⁇ -conjugated, the applicable skeletons and synthesis methods are limited.
  • new functions are added and physical properties are adjusted (Tg, melting point, solubility, etc.). It is relatively easy to achieve by structure, and this is the third advantage of low molecular weight compounds.
  • the equivalent circuit of the organic EL element includes a series connection of a diode and a resistor. Become. That is, it is also known that Joule heat is generated inside the organic EL element that is being energized and light emission, and that heat is actually generated at 100 ° C. or more inside the element, particularly in the light emitting layer where recombination occurs.
  • the organic layer thickness of the entire organic EL element is an extremely thin layer of about 200 nm, heat is conducted between the layers (films), and not only the light emitting layer but all layers continue to be in a high temperature state. become.
  • Tg glass transition point
  • This crystal grows gradually, and when it exceeds several tens of nm, the thickness of the compound exceeds the thickness, and functional separation by the layer as the organic EL element becomes impossible, resulting in a decrease in luminous efficiency. Will do.
  • the low molecular weight compound of the organic EL element is a molecule that does not have a bulky non-aromatic substituent and has a glass transition point (Tg) exceeding 100 ° C. or higher (preferably 150 ° C. or higher). I have to.
  • the ⁇ -conjugated system is usually enlarged or the aromatic group is simply linked.
  • the compound formed in the usual case has extremely low solubility in a solvent, and coating Even if it cannot be formed into a liquid or can be applied, crystal precipitation or uneven distribution of substances will occur.
  • the inventors of the present invention have improved the molecular structure of low molecular weight compounds in accordance with the guidelines described above and optimized the drying conditions in the production of organic EL elements by a wet coating method. A dramatic improvement was achieved, with 95% of the device and 90% emission lifetime. As a result, even for devices using phosphorescent dopants, especially blue phosphorescent dopants, which are said to be the most difficult to improve their lifetime, the basic characteristics of coating film deposition methods are almost comparable to conventional deposition methods. Have found out that However, many problems still remain in the organic EL element with improved performance.
  • Examples of such problems include removal of purity of low molecular weight compounds, trace moisture adhering to the surface of the compound, oxygen content of solvent used, water content, and the like.
  • sublimation purification is performed after column chromatography and recrystallization in order to achieve the best performance, and an organic compound is used or In storage, after passing through a vacuum state, it is used after being replaced with a nitrogen atmosphere.
  • the coating method is attracting attention. If the method is performed under such strict control, the productivity is lower than the vapor deposition method and the cost is increased.
  • the reason why the sublimation purification method is employed in organic compounds for organic EL is mainly due to the fact that the manufacturing process of the organic EL element employs a vacuum deposition method. If even a very small amount of solvent is contained in the organic compound, the solvent in the organic compound volatilizes and lowers the degree of vacuum when placed under vacuum in the vapor deposition apparatus. This makes continuous production impossible and becomes a manufacturing problem. For this reason, a sublimation purification method in which the solvent is completely removed during purification is employed. Therefore, when the production method of the organic EL element is changed from the vapor deposition method to the coating method, the purification of the organic compound by the sublimation purification method is not essential for the reason described above.
  • purifying the compound A to be purified by recrystallization can be rationally explained by considering as follows.
  • A is dissolved at a high temperature in a solvent called B which can dissolve A
  • B which can dissolve A
  • entropy ( ⁇ S) is extremely large.
  • T ⁇ S applied with the absolute temperature T becomes smaller than before the cooling. At that time, in order to keep the cast free energy ( ⁇ G) constant before and after cooling, the enthalpy ( ⁇ H) must be increased.
  • the entropy term (T ⁇ S) first decreases with a decrease in temperature, and the enthalpy ( ⁇ H) increases due to crystallization to compensate for this, and the entropy term further decreases due to the decrease in the number of components. Recrystallization is accomplished by repeating the thermodynamic equilibrium in which ⁇ S decreases with decreasing ⁇ S and crystallization occurs accordingly. However, it is necessary to pay attention to the interaction between the solute A and the solvent B. Since the solute A dissolves by being solvated with the solvent B, A does not dissolve in B unless the interaction between AB is large. However, if the interaction is too large, the distance between A and A cannot be shortened enough to overcome the decrease in the entropy term that decreases due to cooling (because B intervenes between A and A). ), Resulting in no recrystallization.
  • the purification method by recrystallization can be applied only when the interaction force between AA and the interaction force between AB can be adjusted to the conditions under which recrystallization occurs.
  • a recrystallization purification method a large amount of purification of several hundred kg or more is possible at a time, and this method has been used for a long time in the chemical industry.
  • column chromatography (hereinafter also referred to as “chromatography”) will be considered.
  • the most typical place of column chromatography is to use fine particle silica gel as a stationary phase, adsorb compound A on the silica gel, and gradually elute it with a mobile phase (B) called an eluent.
  • B mobile phase
  • A is an adsorption-desorption equilibrium between the silica and the mobile phase B.
  • the purification efficiency by the chromatographic method is proportional to the length of the stationary phase and also to the passing speed of the mobile phase. Proportional to the surface area of the stationary phase. This is achieved by high-performance liquid chromatography, which is widely used for component analysis and quality assurance of organic compounds. It is a rare technique that can realize a high number of theoretical plates backed by this theory. This is due to the fact that
  • the interaction between A and the mobile phase B ′ is greater than the interaction between A and the silica gel. If the action is strong, the number of reciprocations of adsorption-desorption equilibrium is drastically reduced and the purification effect is lowered. That is, in order to enhance the purification effect, it is necessary to mix a large excess of the poor solvent C in addition to the good solvent B ′ to increase the number of reciprocations of adsorption-desorption equilibrium.
  • the solution of the compound A purified and collected contains a large excess of C, and the biggest problem is that it must be concentrated.
  • the mixing ratio of the good solvent B ′ and the poor solvent C needs to be about 1:99 to 10:90, and generally the poor solvent C of about 10 L to 100 L is required. It becomes necessary. Therefore, although HPLC fractionation is applied to research and development, it is not used for mass production.
  • a means for solving the problem of poor solvent concentration is HPLC using supercritical carbon dioxide.
  • Supercritical carbon dioxide is carbon dioxide converted to a supercritical fluid at high temperature and high pressure, and other substances can be made into such a supercritical fluid. Therefore, carbon dioxide is exclusively used for chromatography and extraction.
  • This supercritical carbon dioxide has different characteristics from ordinary fluids and liquids. That is, by changing the temperature and pressure, the polarity can be continuously changed in accordance with the polarity of the one to be dissolved. For example, this supercritical carbon dioxide is used to selectively extract docosahexaenoic acid contained in fish heads, and sebum dissolves and adheres to cleaning special clothing that uses adhesives.
  • the agent is achieved by making supercritical carbon dioxide, which does not dissolve, under temperature and pressure control.
  • supercritical carbon dioxide can have various polarities as described above, the polarity of supercritical carbon dioxide formed in a region of relatively low temperature and pressure is about cyclohexane or heptane.
  • this degree of polar supercritical carbon dioxide is produced in the apparatus, mixed with a good solvent, and entered into the column. Purification is performed.
  • the HPLC system using supercritical carbon dioxide it enters the detector after passing through the column, but normally, the high temperature and high pressure state is maintained until that stage, and carbon dioxide also exists as a supercritical fluid. Thereafter, carbon dioxide becomes a gas until it is separated at room temperature and normal pressure, and it escapes itself from the solution at the time of separation. Therefore, it is not necessary to concentrate the poor solvent.
  • the coating solution is a dispersion of fine crystals of organic EL compound, it looks like it is completely dissolved, but the actual state of the resulting thin film is
  • the thin film is a collection of microcrystals. Therefore, for example, the level of HOMO or LUMO is not that of a single molecule, but that of a stacked aggregate (microcrystalline state), which may cause a decrease in performance.
  • the microcrystals become nuclei and grow into coarse crystals, which not only makes it impossible to separate the functions between layers, but if the crystals become large crystals that short-circuit the anode and cathode, There is a big problem of generating spots.
  • FIG. 2 shows a particle size distribution curve (horizontal axis: particle size (nm), vertical axis: frequency distribution) of fine particles of a compound constituting a thin film prepared by a vapor deposition method, and a solid line indicates a thin film prepared by a coating method. It is a particle size distribution curve of fine particles of a constituent compound. Since both use the same compound, they can be directly compared.
  • the particle size at the position corresponding to the maximum peak is about 2 nm, which is close to monodispersion. Since this is the size of one or two molecules, this means that an amorphous film is formed by arranging almost single molecules at random in vapor deposition.
  • the particle size at the position corresponding to the maximum peak is about 4.5 nm, which is wider than the particle size distribution in the vapor deposition film formation.
  • the original crystallinity and cohesiveness of the compound are the same, and this difference is due to the molecular dispersion state in the state of the coating liquid, It is presumed that it was a dispersion of 5 to 10 molecules of microcrystals, not a single isolated molecule.
  • this coating solution is a so-called clear solution, we have misunderstood a dispersion of several molecular crystallites, which is found to be analyzed by X-ray, as a dissolved solution.
  • the organic EL element has a basic function of a phenomenon in which light is emitted when the light emitting material in an excited state returns to the ground state. Further, it is necessary to transport electrons and holes through the hopping phenomenon between the electrode and the light emitting layer.
  • an excited state for example, in the case of an organic EL element doped with a light emitting material having a concentration of 5%, in order to continuously emit light at a luminance of 1000 cd / m 2 , simply calculate, One dopant needs to be about 1 billion excitons. At this time, if the exciton reacts with the water molecule only once, it becomes a compound different from the original molecule.
  • the coating film of the present invention is a coating film composed of at least one kind of organic compound, and is a particle size distribution curve of molecules or aggregates obtained from small angle X-ray scattering measurement (horizontal axis: particle size, vertical axis: frequency distribution). ) Contains at least one maximum peak, and R and r below contain an organic compound satisfying the relationship represented by the following formula (1).
  • Formula (1): R ⁇ 15r [In Formula (1), R represents the particle size corresponding to the maximum peak which shows a particle size with the smallest particle size among the maximum peaks of the particle size distribution curve obtained from a small angle X-ray scattering measurement.
  • the molecular radius of the organic compound r (A ⁇ b) represents 1/2 . ]
  • a general-purpose device such as a nanoscale X-ray structure evaluation device NANO-Viewer manufactured by Rigaku Corporation may be used, and preferably a high energy accelerator research mechanism Utilizing large synchrotron radiation facilities such as Synchrotron Radiation Research Facility (Photon Factory), SPring-8 (Super Photoring-8 GeV), Saga Prefectural Kyushu Synchrotron Light Research Center (SAGA-LS), Aichi Synchrotron Light Center
  • Synchrotron Radiation Research Facility Photon Factory
  • SPring-8 Super Photoring-8 GeV
  • SAGA-LS Saga Prefectural Kyushu Synchrotron Light Research Center
  • Aichi Synchrotron Light Center A small-angle X-ray scattering apparatus can be used. The measurement conditions are shown below.
  • a sample is put into a capillary for X-ray diffraction sample (manufactured by WJM-Glass / Muller GmbH) to obtain a measurement sample.
  • the sample is irradiated with a wavelength of 0.1 nm.
  • a multi-axis diffractometer manufactured by HUBER is used, the X-ray incident angle ⁇ is fixed at 0.2 °, and the sample is irradiated. I do.
  • the particle size / hole size analysis software NANO-Solver manufactured by Rigaku Corporation is used for analysis of the obtained small angle X-ray scattering data.
  • a part is scattered by an electron cloud of each atom constituting the X-ray.
  • the scattering vector q is generally used instead of the scattering angle ⁇ . q is given by the following formula (A1).
  • Formula (A1): q (4 ⁇ / ⁇ ) sin ⁇
  • ⁇ represents the wavelength of X-rays
  • ⁇ represents the scattering angle.
  • the small region of q is called the Guinier region
  • the large region is called the Porod region. From the former, larger spatial information, particle dispersion state and long-period structure, from the latter, smaller region information, high It is possible to obtain molecular polymerization state, surface shape of dispersed particles, protein structural analysis, and the like.
  • the area that shows a sharp decrease in the scattering intensity due to the increase in the scattering angle is the small-angle scattering area, and the width of the central peak is almost inversely proportional to the size of the nonuniform density area, that is, the radius of inertia of the primary particles. . Therefore, if the scattering intensity increase / decrease behavior is applied to, for example, the Funkuchen method, tangent lines are drawn in order from the right end of the Guinier plot, and the inertia radius and the scattering intensity are calculated from the gradient of each tangent line, the primary particles are calculated from the intensity ratio. The relative ratio of the distribution of inertia radii can be obtained.
  • the particle diameter / hole diameter analysis software NANO-Solver manufactured by Rigaku Corporation is used, and the hole and particle diameter analysis fitting is performed assuming that the particle geometric shape is a sphere.
  • numerator or aggregate which originate in the organic compound in a coating film were calculated
  • the X-ray small angle scattering method reference can be made to, for example, the X-ray diffraction handbook 3rd edition (issued in 2000 by Rigaku Corporation).
  • the particle size distribution curve according to the present invention is prepared based on the measurement and analysis method of the small-angle X-ray scattering, and the horizontal axis is the axis representing the particle size and the vertical axis is the axis representing the frequency distribution. Is obtained by plotting the measured values of the frequency distribution against and plotting each plot.
  • frequency distribution also simply referred to as“ distribution ” refers to the ratio (ie, frequency) of the relative number of particles of a specific particle size to the total number of particles measured (ie, relative to 1 / nm. Value).
  • the coating film of the present invention has at least one maximum peak in the particle size distribution curve (horizontal axis: particle size, vertical axis: frequency distribution) of molecules or aggregates obtained from small angle X-ray scattering measurement.
  • FIG. 3 an example of the particle size distribution curve about the coating film of this invention is shown.
  • R is the particle size at the position corresponding to the maximum peak.
  • the particle size distribution curve of the coating film of the present invention may have a plurality of maximum peaks, but the particle size R corresponding to the position of the maximum peak indicating the minimum particle size is the above formula (1). If the relationship is satisfied, the effect of the present invention can be obtained.
  • the particle size R represents the particle size corresponding to the maximum peak having the largest frequency distribution among the maximum peaks of the particle size distribution curve.
  • the particle size R corresponding to the position of the maximum peak with the largest frequency distribution satisfies the above formula (1), the degree of dispersion of the particle size in the coating film increases, that is, the homogeneity in the film increases. The effects of the invention can be obtained effectively.
  • the “maximum peak” in the particle size distribution curve means a peak having a maximum value with a half width of 10 nm or less and a frequency distribution of 0.05 or more. That is, even if it is a peak having a maximum value in the particle size distribution curve, when the half-value width exceeds 10 nm due to variation in the particle size distribution, or when the frequency distribution is less than 0.05, It does not fall under the maximum peak of the present invention.
  • the molecular radius r of the organic compound obtained by density functional theory calculation according to the present invention will be described.
  • the molecular radius r in the present invention is calculated by DFT calculation (density functional theory calculation), the long axis length obtained in the optimized structure is 2a (nm), and the short axis length is 2b.
  • the geometric mean value r (a ⁇ b) 1/2 .
  • the basis function is 6-31G * and the exchange correlation functional is B3LYP.
  • the major axis length and the minor axis length are obtained based on this molecular structure.
  • the coating film of the present invention more preferably satisfies the following formula (2).
  • the frequency distribution of the maximum peak satisfying the formula (1) is preferably 0.4 or more, more preferably 0.5 or more, and further preferably 0.6 or more.
  • a large maximum value is considered to indicate that the degree of dispersion of the particle size in the coating film is high, and is preferable because the homogeneity in the coating film is high.
  • the particle size value of the maximum peak satisfying the formula (1) is preferably 10.0 nm or less, more preferably 6.0 nm or less, and further preferably 4.5 nm or less.
  • the smaller the maximum peak particle size value the smaller the number of molecules contained in the aggregate, indicating that they are highly dispersed, and the device characteristics are more uniform.
  • the maximum peak particle size is preferably 4.0 nm or more. The reason for this is not clear yet, but is estimated as follows.
  • the ⁇ - ⁇ plane of the molecule is close inside the aggregate and the intermolecular distance is close, so that the charge transport rate in the aggregate is improved. It is presumed that between the aggregates, the frequency of inhibition of charge transport at the interface of the aggregates decreases because the bonding area between the aggregates increases.
  • the full width at half maximum of the maximum peak satisfying the formula (1) is preferably in the range of 0.3 to 3.0 nm, more preferably in the range of 0.5 to 2.0 nm, More preferably, it is in the range of ⁇ 1.5 nm.
  • the narrower the half-value width the more the number of molecules contained in the aggregate is shown, and the device characteristics are more uniform, which is preferable.
  • the coating film of the present invention is a film formed by solidifying a coating solution containing an organic compound in which R ′ and r below satisfy the relationship represented by the following formula (3). It is preferable in that it can be in a non-existing state and can be a coating film having a smaller particle size.
  • R ′ represents the particle size corresponding to the maximum peak indicating the smallest particle size among the maximum peaks of the particle size distribution curve obtained from the small angle X-ray scattering measurement of the coating solution. . r is synonymous with r in the formula (1).
  • the small-angle X-ray scattering of the coating solution can be measured in the same manner as the small-angle X-ray scattering of the coating film described above.
  • a means for obtaining a coating solution containing an organic compound satisfying the above formula (3) will be described in a coating film manufacturing method (coating solution preparation step) described later.
  • the coating film of the present invention may be a coating film containing only one type of organic compound satisfying the relationship represented by the above formula (1) of the present invention, or may be a coating film containing a plurality of types of organic compounds. May be.
  • the coating film containing a plurality of types of organic compounds it is sufficient that at least one type of organic compound satisfies the relationship represented by the above formula (1) of the present invention. It is preferable that the relationship represented by the above formula (1) is satisfied, and it is more preferable that all kinds of organic compounds contained in the coating film satisfy the relationship represented by the above formula (1) of the present invention. preferable.
  • the plurality of components of the solute include, for example, the organic compound according to the present invention and at least one other organic compound other than the organic compound when considered thermodynamically as described in JP-A-2009-505154.
  • ⁇ G mix RT ⁇ (X n ln (X n ))
  • R represents a gas constant.
  • T represents an absolute temperature.
  • Xn represents a ratio in all components.
  • ⁇ X n 1, 0 ⁇ X n ⁇ 1, and ln (X n ) ⁇ 0, ⁇ G mix ⁇ 0. Therefore, when multiple types of solute are contained, it is thought that the effect that preservability becomes high will be acquired.
  • the organic compound used in the present invention is not limited to a compound of a specific type and a specific structure, but is preferably a compound used for various electronic devices from the viewpoint of the effect of the present invention.
  • the organic compound is preferably a material for organic electroluminescence (hereinafter also referred to as “organic EL material”).
  • the organic EL material refers to an organic compound that can be used for an organic functional layer (also referred to as “organic EL layer” or “organic compound layer”) formed between an anode and a cathode described later.
  • an organic EL element a light-emitting element composed of an organic functional layer including these anode, cathode, and organic EL material. Examples of compounds used as the organic EL material will be described later.
  • the organic compound is preferably a p-type organic semiconductor material or an n-type organic semiconductor material. Examples of compounds used as these p-type organic semiconductor materials and n-type organic semiconductor materials will be described later.
  • the organic solvent contained in the coating liquid for forming a coating film means the liquid medium which consists of an organic compound which can melt
  • the liquid medium for dissolving or dispersing the organic EL device material according to the present invention includes ketones such as methylene chloride, methyl ethyl ketone, cyclohexanone, fatty acid esters such as ethyl acetate, normal propyl acetate, isopropyl acetate, isobutyl acetate, chlorobenzene, di- Halogenated hydrocarbons such as chlorobenzene, 2,2,3,3-tetrafluoro-1-propanol (TFPO), aromatic hydrocarbons such as toluene, xylene, mesitylene, cyclohexylbenzene, cyclohexane, decalin, dodecane, etc.
  • ketones such as methylene chloride, methyl e
  • the solubility of the organic compound is about 0. It is preferable to use an organic solvent in the range of 001 to 5% by mass. Generally, a solvent with high solubility is used to dissolve the solute, but a solvent with high solubility generally has a high boiling point such as chlorobenzene or glycerin, and a large amount of energy is required to dry the solvent. It is. Furthermore, the high solubility indicates that the interaction with the material that is the solute is large, and the drying load is further increased because the interaction force between the solute and the solvent is large even during drying.
  • the solvent is not removed unless the interaction between the solute and the solute overcomes the interaction between the solute and the solvent, and the enthalpy is inevitably dried with a strong intermolecular interaction enthalpy.
  • the intermolecular interaction force is very strong, tends to be a film having a large particle size, and aggregates are observed when the intermolecular interaction force is remarkable.
  • the solubility of the organic compound within the range of 0.001 to 5% by mass, the interaction force between the organic compound and the organic solvent can be kept below a certain range, and the driving force for drying is controlled by entropy.
  • a coating film containing an organic compound satisfying the above formula (1) of the present invention can be obtained.
  • an organic solvent among the organic solvents described above, an ester solvent, an ether solvent, or the like is preferably used.
  • the coating film of the present invention is formed by a coating method, and the particle diameter in the film is reduced, and the particle diameter in the film is reduced.
  • the method for producing a coating film of the present invention includes a step of preparing a coating solution containing an organic compound in which R ′ and r below satisfy the relationship represented by the following formula (3), and drying and solidifying the coating solution. And a step of performing.
  • R ′ represents the particle size corresponding to the maximum peak indicating the smallest particle size among the maximum peaks of the particle size distribution curve obtained from the small angle X-ray scattering measurement of the coating solution.
  • . r is synonymous with r in the formula (1).
  • the measurement of the small angle X-ray scattering of a coating liquid can be performed about a coating liquid similarly to the X-ray small nucleus scattering measurement of the coating film mentioned above.
  • a coating liquid preparation process is a process of obtaining the coating liquid containing the organic compound which satisfy
  • the organic compound described above can be used as the organic compound, and the organic solvent described above can be used as the organic solvent.
  • the method for dispersing the organic compound in the solution include chromatography, ultrasonic or microwave irradiation, electrophoresis, and the like.
  • the chromatography include column chromatography, high performance liquid chromatography, supercritical or subcritical chromatography, gel permeation chromatography and the like, and supercritical or subcritical chromatography is particularly preferable.
  • the coating film of the present invention is preferably produced using a coating solution obtained by mixing the organic compound and the organic solvent using a supercritical or subcritical chromatography method.
  • a supercritical or subcritical chromatography method a packed column, an open column, or a capillary column can be used.
  • the column is not particularly limited as long as it has a separating agent capable of separating a target substance in a sample injected into a mobile phase.
  • the separating agent is selected from various separating agents according to the target substance.
  • the form of the separating agent is not particularly limited.
  • the column may be packed in a state of being supported on a particulate carrier, or may be stored in the column in a state of being supported on an integrated carrier accommodated in the column, or separated. It may be accommodated in the column as an integral molded product made of an agent.
  • a supercritical fluid 11 containing an organic solvent (including carbon dioxide), a pump 12, a modifier 13 if necessary, and an injector for injecting an organic compound to be separated 14, and a separation column 15, and if necessary, a detector 17 and a pressure regulating valve 18 can be used.
  • the temperature of the column 15 is adjusted in the column oven 16.
  • the filler can be appropriately selected from silica used in conventional chromatography methods or surface-modified silica.
  • the supercritical fluid is a substance in a supercritical state.
  • the supercritical state will be described.
  • Substances change between three states of gas, liquid, and solid due to changes in environmental conditions such as temperature, pressure (or volume), and this is determined by the balance between intermolecular force and kinetic energy.
  • a phase diagram shows the transition of the gas-liquid solid state with temperature on the horizontal axis and pressure on the vertical axis.
  • the three phases of gas, liquid, and solid coexist in this state.
  • the point at is called the triple point.
  • the pressure at this time is a saturated vapor pressure and is represented by an evaporation curve (vapor pressure line).
  • a fluid that is above the critical temperature and above the critical pressure is called a supercritical fluid, and the temperature / pressure region that gives the supercritical fluid is called the supercritical region.
  • a state satisfying either the critical temperature or higher or the critical pressure or higher is referred to as a subcritical (expanded liquid) state, and a fluid in the subcritical state is referred to as a subcritical fluid.
  • Supercritical fluids and subcritical fluids can be understood as high-density fluids having high kinetic energy, and exhibit liquid behavior in terms of dissolving solutes and gaseous characteristics in terms of density variability. Although there are many solvent properties of supercritical and subcritical fluids, it is important to have low viscosity, high diffusibility, and excellent permeability to solid materials.
  • the supercritical state is carbon dioxide
  • the critical temperature hereinafter also referred to as Tc
  • the critical pressure hereinafter also referred to as Pc
  • C, Pc 43.4 ⁇ 10 5 Pa
  • Pc 52.2 ⁇ 10 5 Pa
  • the fluid has a large diffusion coefficient and low viscosity. Since movement and concentration equilibrium are reached quickly and the density is high like a liquid, efficient separation becomes possible. In addition, recovery is quickened by using a substance that becomes a gas at normal pressure and room temperature, such as carbon dioxide. In addition, there are no various obstacles resulting from residual trace amounts of solvent that are inevitable in the purification method using a liquid solvent.
  • the solvent used as the supercritical fluid or subcritical fluid carbon dioxide, dinitrogen monoxide, ammonia, water, methanol, ethanol, 2-propanol, ethane, propane, butane, hexane, pentane and the like are preferably used. Among these, carbon dioxide can be preferably used.
  • a solvent used as a supercritical fluid or subcritical fluid can be used alone, or a so-called modifier (entrainer) for adjusting the polarity can be added.
  • modifiers include hydrocarbon solvents such as hexane, cyclohexane, benzene, and toluene, halogenated hydrocarbon solvents such as methyl chloride, dichloromethane, dichloroethane, and chlorobenzene, and alcohol solvents such as methanol, ethanol, propanol, and butanol.
  • hydrocarbon solvents such as hexane, cyclohexane, benzene, and toluene
  • halogenated hydrocarbon solvents such as methyl chloride, dichloromethane, dichloroethane, and chlorobenzene
  • alcohol solvents such as methanol, ethanol, propanol, and butanol.
  • Ether solvents such as diethyl ether and tetrahydrofuran (THF), acetal solvents such as acetaldehyde diethyl acetal, ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate and butyl acetate, formic acid, acetic acid and trifluoroacetic acid
  • Carboxylic acid solvents such as acetonitrile, pyridine, nitrogen compound solvents such as N, N-dimethylformamide, sulfur compound solvents such as carbon disulfide and dimethyl sulfoxide, water, nitric acid, sulfuric acid And the like.
  • the use temperature of the supercritical fluid or subcritical fluid is basically not particularly limited as long as it is higher than the temperature at which the organic compound according to the present invention is dissolved, but if the temperature is too low, the supercritical fluid or subcritical fluid of the organic compound is used.
  • the solubility in the fluid may be poor, and if the temperature is too high, the organic compound may be decomposed. Therefore, the operating temperature range is preferably 20 to 600 ° C.
  • the working pressure of the supercritical fluid or subcritical fluid is basically not limited as long as it is higher than the critical pressure of the substance to be used, but if the pressure is too low, the solubility of the organic compound in the supercritical fluid or subcritical fluid If the pressure is too high, problems may occur in terms of durability of the manufacturing apparatus, safety during operation, etc., so the working pressure should be in the range of 1 to 100 MPa. preferable.
  • a device using a supercritical fluid or subcritical fluid is limited as long as it has a function of dissolving an organic compound in contact with the supercritical fluid or subcritical fluid into the supercritical fluid or subcritical fluid.
  • a batch method using a supercritical fluid or a subcritical fluid in a closed system a distribution method using a supercritical fluid or a subcritical fluid circulated, a combined method combining a batch method and a distribution method, etc. Can be used.
  • the composition of the mobile phase may be changed, or the composition may be constant.
  • the step of changing the composition of the mobile phase is to change the composition of the mobile phase containing the supercritical fluid or subcritical fluid and the solvent.
  • the peak tailing decay can be accelerated.
  • the peak shows significant tailing particularly when a preparative operation for loading a relatively large amount of a compound to be separated is performed. If the next sample is injected before this tailing decays, the tailing component will be mixed into the peak component of the next injected sample, resulting in a decrease in the purity of the separated compound and inconvenience. Therefore, it is necessary to wait for complete tailing attenuation before the next sample is injected. Therefore, the timing of the next sample injection can be accelerated by increasing the decay of tailing.
  • the composition of the mobile phase is changed to promote the extrusion of the peak component from the column and the tailing. Can be accelerated.
  • Changing the composition in the mobile phase produces the same effect as the step gradient method in liquid chromatography, and accelerates the extrusion of the peak component from the column, thereby accelerating the tailing decay.
  • Supercritical fluid or subcritical chromatography uses a highly diffusive, low viscosity supercritical fluid or subcritical fluid, so the mobile phase has a high flow rate and the column equilibrates quickly. Therefore, even if the composition in the mobile phase changes temporarily, if the composition in the mobile phase is restored, the column will quickly return to the environment before the change. Can be injected. As a result, the amount of sample processed per hour can be increased, and the efficiency and productivity are improved.
  • the step of changing the composition of the mobile phase of the present invention may be performed by any technique as long as it can be performed by a supercritical or subcritical chromatography apparatus.
  • increasing the solvent ratio in the mobile phase can cause changes in the composition of the mobile phase, and significantly changing the pressure and column temperature can also change the CO 2 density in the mobile phase. Including these, the composition of the mobile phase is changed.
  • a solvent injection device is installed upstream of the column and downstream of the mobile phase generator to increase the solvent ratio in the mobile phase.
  • the solvent injection device can be, for example, a solvent injection device including a loop pipe for holding a solvent to be injected, a flow path switching valve, and a solvent injection pump.
  • the loop piping used for the solvent injection device is a tube having a predetermined volume. It is preferable to have a loop pipe because the quantitativeness of sample injection is improved and a larger amount of sample can be injected.
  • the volume of the loop pipe varies depending on conditions such as the type of column used in the supercritical fluid or subcritical chromatography apparatus, the inner diameter of the column, the type of the target substance, the composition of the mobile phase, etc. Therefore, it is necessary to inject a large amount of solvent into the loop piping of the solvent injection device, which is larger than the loop piping of the sample injection device and can hold a large amount of solvent.
  • the flow path switching valve used in the solvent injection device is not particularly limited as long as it is an openable / closable valve or cock provided in the mobile phase flow path.
  • a two-way valve or a butterfly valve may be used in combination, or a valve that switches the flow path of the mobile phase using a three-way valve may be used.
  • a high-pressure pump used for sample injection of a supercritical or subcritical chromatography device can be used.
  • the solvent injection device When the solvent injection device is used, the solvent is injected by switching the flow path switching valve and sending the solvent to the mobile phase of the column by the solvent injection pump. It is preferable that the solvent is injected instantaneously with a solvent larger than the injection volume of the sample, preferably 2 times or more, more preferably 5 times or more. As the upper limit value, it is preferable to inject a solvent of 30 times or less, preferably 20 times or less, more preferably 15 times or less the injection volume of the sample. By using such a solvent injection amount, the peak tailing decay is further accelerated.
  • the solvent injected from the solvent injection device is not particularly limited, and may be, for example, the same solvent as that contained in the mobile phase or a different solvent. Moreover, 1 type may be sufficient as the solvent inject
  • Both the step of changing the composition of the mobile phase and the step of returning the composition of the mobile phase to before the change are preferably performed instantaneously.
  • the instantaneous here may be a time sufficient to cause the change of the mobile phase.
  • the method of peak detection is not particularly limited, but the timing can usually be measured by a peak detected by a detector, such as an ultraviolet absorption spectrometer, included in a supercritical fluid or subcritical chromatography.
  • a detector such as an ultraviolet absorption spectrometer
  • the drying and solidifying step is a step of applying and drying and solidifying the coating liquid obtained in the coating liquid preparation step.
  • the coating method (coating film forming method) for the coating liquid include spin coating, casting, inkjet, spraying, printing, and slot coater methods. From the standpoint that a homogeneous film is easily obtained and pinholes are less likely to be generated, a coating method such as an ink jet method, a spray method, a printing method, a slot type coater method, or the like is preferable. The method is preferably used.
  • the ink jet head used in the ink jet method may be an on-demand method or a continuous method.
  • Discharge methods include electro-mechanical conversion methods (eg, single cavity type, double cavity type, bender type, piston type, shear mode type, shared wall type, etc.), and electro-thermal conversion methods (eg, thermal Specific examples include an ink jet type, a bubble jet (registered trademark) type, an electrostatic suction type (for example, an electric field control type, a slit jet type, etc.), and a discharge type (for example, a spark jet type).
  • any discharge method may be used.
  • a serial head method, a line head method, or the like can be used without limitation.
  • the volume of ink droplets ejected from the head is preferably in the range of 0.5 to 100 pL. A range of 2 to 20 pL is more preferable from the viewpoint of reducing coating unevenness and increasing the printing speed.
  • the volume of the ink droplet can be adjusted as appropriate by adjusting the applied voltage.
  • the printing resolution is preferably in the range of 180 to 10000 dpi (dots per inch), more preferably in the range of 360 to 2880 dpi, and can be appropriately set in consideration of the wet film thickness and the volume of the ink droplets.
  • the wet film thickness of the wet coating film at the time of inkjet application can be appropriately set, but is preferably in the range of 1 to 100 ⁇ m, more preferably in the range of 1 to 30 ⁇ m, and most preferably 1. In the range of ⁇ 5 ⁇ m, the effect of the present invention is more remarkable.
  • the wet film thickness can be calculated from the application area, printing resolution, and ink droplet volume.
  • Ink jet printing methods include a one-pass printing method and a multi-pass printing method.
  • the one-pass printing method is a method for printing a predetermined printing area by one head scan.
  • the multi-pass printing method is a method of printing a predetermined print area by a plurality of head scans.
  • a wide head having at least the width of each coating pattern may be used.
  • the interaction force between the solute (organic compound) and the solvent (organic solvent) is suppressed to a certain range or less, and the driving force for drying is entropy-dominated. It is preferable to use an organic solvent in the range of 0.001 to 5% by mass at normal temperature (25 ° C.).
  • the organic EL device of the present invention is characterized by having the coating film in at least one organic functional layer.
  • the organic functional layer include a plurality of organic functional layers such as an electron injection layer, an electron transport layer, a hole blocking layer, a light emitting layer, an electron blocking layer, a hole transport layer, and a hole injection layer.
  • the coating film of the present invention may be used for at least one of these organic functional layers, and is not particularly limited.
  • an electron transport layer, a hole blocking layer, a light emitting layer, an electron blocking layer It is preferably either a layer or a hole transport layer, and more preferably one or more of a hole blocking layer, a light emitting layer, and an electron blocking layer.
  • the light emitting layer is preferable from the viewpoints of light emission efficiency and durability.
  • the organic EL device of the present invention has an anode and a cathode and one or more organic functional layers (also referred to as “organic EL layer” or “organic compound layer”) sandwiched between these electrodes on a substrate. is doing.
  • substrate there are no particular limitations on the substrate that can be used in the organic EL device of the present invention (hereinafter also referred to as a substrate, a support substrate, a substrate, a support, etc.), and a glass substrate, a plastic substrate, and the like can be used. It may be transparent or opaque. When extracting light from the substrate side, the substrate is preferably transparent. Examples of the transparent substrate preferably used include glass, quartz, and a transparent plastic substrate.
  • the substrate has a thickness of 1 ⁇ m or more and a water vapor transmission rate of 1 g / (m 2 ⁇ 24 h ⁇ atm in a test based on JIS Z-0208. ) (25 ° C.) or less is preferred.
  • the glass substrate include alkali-free glass, low alkali glass, and soda lime glass.
  • Alkali-free glass is preferable from the viewpoint of low moisture adsorption, but any of these may be used as long as it is sufficiently dried.
  • the resin film used as the base material of the plastic substrate is not particularly limited.
  • polyester such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC) ), Cellulose acetates such as cellulose acetate butyrate, cellulose acetate propionate (CAP), cellulose acetate phthalate, cellulose nitrate, or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate , Norbornene resin, polymethylpentene, polyetherketone, polyimide, polyethersulfone PES), polyphenylene sulfide, polysulfones, polyetherimides, poly
  • organic / inorganic hybrid resin examples include those obtained by combining an organic resin and an inorganic polymer (for example, silica, alumina, titania, zirconia, etc.) obtained by a sol-gel reaction.
  • an organic resin for example, silica, alumina, titania, zirconia, etc.
  • norbornene (or cycloolefin-based) resins such as Arton (manufactured by JSR) or Apel (manufactured by Mitsui Chemicals) are particularly preferable.
  • Arton manufactured by JSR
  • Apel manufactured by Mitsui Chemicals
  • the plastic substrate that is normally produced has a relatively high moisture permeability and may contain moisture inside the substrate. Therefore, when using such a plastic substrate, it is preferable to provide a film (hereinafter referred to as “barrier film” or “water vapor sealing film”) that suppresses intrusion of water vapor, oxygen, or the like on the resin film.
  • a film hereinafter referred to as “barrier film” or “water vapor sealing film” that suppresses intrusion of water vapor, oxygen, or the like on the resin film.
  • the material constituting the barrier film is not particularly limited, and an inorganic film, an organic film, a hybrid of both, or the like is used.
  • a film may be formed, and the water vapor transmission rate (25 ⁇ 0.5 ° C., relative humidity (90 ⁇ 2)% RH) measured by a method according to JIS K 7129-1992 is 0.01 g / ( m 2 ⁇ 24 h) or less, and the oxygen permeability measured by a method according to JIS K 7126-1987 is preferably 1 ⁇ 10 ⁇ 3 mL / (m 2 ⁇ 24 h ⁇ atm), and a water vapor permeability of 1 ⁇ 10 ⁇ 5 g / (m 2 ⁇ 24 h) or less is preferable.
  • the material constituting the barrier film is not particularly limited as long as it has a function of suppressing the intrusion of elements that cause deterioration of elements such as moisture and oxygen, and examples thereof include metal oxides, metal oxynitrides, and metal nitrides.
  • An inorganic material, an organic material, a hybrid material of both, or the like can be used.
  • Metal oxide, metal oxynitride or metal nitride includes silicon oxide, titanium oxide, indium oxide, tin oxide, metal oxide such as indium tin oxide (ITO), aluminum oxide, metal nitride such as silicon nitride And metal oxynitrides such as silicon oxynitride and titanium oxynitride.
  • the barrier membrane had a water vapor permeability (25 ⁇ 0.5 ° C., relative humidity (90 ⁇ 2)% RH) of 0.01 g / (m 2 ⁇ 24 h) measured by a method according to JIS K 7129-1992.
  • the following barrier film is preferable, and further, the oxygen permeability measured by a method according to JIS K 7126-1987 is 10 ⁇ 3 mL / (m 2 ⁇ 24 h ⁇ atm) or less, and the water vapor permeability.
  • the film has a high barrier property of 10 ⁇ 5 g / (m 2 ⁇ 24 h) or less.
  • the method of providing the barrier film on the resin film is not particularly limited, and any method may be used.
  • Vapor deposition method sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma
  • a polymerization method, a CVD method chemical vapor deposition: for example, a plasma CVD method, a laser CVD method, a thermal CVD method, etc.
  • a coating method for example, a sol-gel method, or the like.
  • the method by plasma CVD treatment at or near atmospheric pressure is preferable from the viewpoint that a dense film can be formed.
  • the opaque substrate examples include metal plates such as aluminum and stainless steel, films, opaque resin substrates, ceramic substrates, and the like.
  • anode As the anode of the organic EL element, a material having a work function (4 eV or more) metal, alloy, metal electrically conductive compound, or a mixture thereof is preferably used.
  • the “metal conductive compound” refers to a compound of a metal and another substance having electrical conductivity, and specifically, for example, a metal oxide, a halide or the like. That has electrical conductivity.
  • an electrode substance examples include a conductive transparent material such as a metal such as Au, CuI, indium tin oxide (ITO), SnO 2 , and ZnO.
  • the anode can be produced by forming a thin film made of these electrode materials on the substrate by a known method such as vapor deposition or sputtering.
  • a pattern having a desired shape may be formed on the thin film by a photolithography method, and when the pattern accuracy is not so high (about 100 ⁇ m or more), a desired shape can be formed at the time of vapor deposition or sputtering of the electrode material.
  • a pattern may be formed through a mask. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%.
  • the sheet resistance as the anode is several hundred ⁇ / sq. The following is preferred. Further, although the film thickness of the anode depends on the material constituting it, it is usually selected in the range of 10 nm to 1 ⁇ m, preferably 10 to 200 nm.
  • the organic functional layer (also referred to as “organic EL layer” or “organic compound layer”) includes at least a light-emitting layer.
  • the light-emitting layer is a current flowing through an electrode composed of a cathode and an anode. Specifically, it refers to a layer containing an organic compound that emits light when an electric current is passed through an electrode composed of a cathode and an anode.
  • the organic EL device used in the present invention may have a hole injection layer, an electron injection layer, a hole transport layer, and an electron transport layer in addition to the light emitting layer as necessary, and these layers are cathodes. And the anode.
  • Anode / light emitting layer / cathode ii) Anode / hole injection layer / light emitting layer / cathode
  • Anode / light emitting layer / electron injection layer / cathode iv) Anode / hole injection layer / light emitting layer / electron Injection layer / cathode
  • anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode anode / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode etc.
  • a cathode buffer layer (for example, lithium fluoride) may be inserted between the electron injection layer and the cathode, and an anode buffer layer (for example, copper phthalocyanine) may be inserted between the anode and the hole injection layer. ) May be inserted.
  • anode buffer layer for example, copper phthalocyanine
  • the light emitting layer according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. May be the interface between the light emitting layer and the adjacent layer.
  • the light emitting layer may be a layer having a single composition, or may be a laminated structure including a plurality of layers having the same or different compositions.
  • the light emitting layer itself may be provided with functions such as a hole injection layer, an electron injection layer, a hole transport layer, and an electron transport layer.
  • an injection function capable of injecting holes from an anode or a hole injection layer and applying electrons from a cathode or an electron injection layer when an electric field is applied to the light emitting layer
  • a light-emitting function that provides a recombination field of electrons and holes inside the light-emitting layer and connects it to light emission.
  • a function may be added.
  • the light emitting layer may have a difference in the ease of hole injection and the ease of electron injection, and the transport function represented by the mobility of holes and electrons may be large or small. The one having a function of moving at least one of the charges is preferable.
  • the type of the light emitting material used for the light emitting layer is not particularly limited, and conventionally known light emitting materials for organic EL elements can be used.
  • a light-emitting material is mainly an organic compound, and has a desired color tone, for example, Macromol. Symp. 125, pages 17 to 26, and the like.
  • the light emitting material may be a polymer material such as p-polyphenylene vinylene or polyfluorene, and a polymer material in which the light emitting material is introduced into a side chain or a polymer material having the light emitting material as a main chain of the polymer. May be used. Note that, as described above, since the light emitting material may have a hole injection function and an electron injection function in addition to the light emission performance, most of the hole injection material and the electron injection material described later may be used as the light emitting material. Can be used.
  • the main component when the layer is composed of two or more organic compounds, the main component is called a host, the other components are called dopants, and the host and dopant are used in combination in the light emitting layer of the present invention.
  • the mixing ratio of the light-emitting layer dopant (hereinafter also referred to as light-emitting dopant) to the host compound as the main component is preferably 0.1 to less than 30% by mass.
  • the dopant used in the light emitting layer is roughly classified into two types, that is, a fluorescent dopant that emits fluorescence and a phosphorescent dopant that emits phosphorescence.
  • fluorescent dopants include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes.
  • a phosphorescent compound is a compound in which light emission from an excited triplet is observed, and is a compound having a phosphorescence quantum yield of 0.001 or more at 25 ° C.
  • the phosphorescence quantum yield is preferably 0.01 or more, more preferably 0.1 or more.
  • the phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence quantum yield used in the present invention only needs to achieve the above phosphorescence quantum yield in any solvent.
  • the phosphorescent dopant is a phosphorescent compound, and a typical example thereof is preferably a complex compound containing a group 8-10 metal in the periodic table of elements, more preferably an iridium compound or an osmium compound. , Rhodium compounds, palladium compounds, or platinum compounds (platinum complex compounds). Among them, iridium compounds, rhodium compounds, and platinum compounds are preferable, and iridium compounds are most preferable.
  • dopants are compounds described in the following documents or patent publications. J. et al. Am. Chem. Soc. 123, 4304-4312, International Publication Nos. 2000/70655, 2001/93642, 2002/02714, 2002/15645, 2002/44189, 2002/081488, JP 2002-280178.
  • Gazette 2001-181616, 2002-280179, 2002-181617, 2002-280180, 2001-247859, 2002-299060, 2001-313178 Gazette, 2002-302671, 2001-345183, 2002-324679, 2002-332291, 2002-50484, 2002-332292, 2002-83684 Publication, JP 2002-540572, JP 2002-117978, 2002-338588, 2002-170684, 2002-352960, 2002-50483, 2002-1000047 Gazette, 2002-173684 gazette, 2002-359082 gazette, 2002-17584 gazette, 2002-363552 gazette, 2002-184582 gazette, 2003-7469 gazette, special table 2002-525808.
  • Only one type of light emitting dopant may be used, or a plurality of types of light emitting dopants may be used. By simultaneously extracting light emitted from these dopants, a light emitting element having a plurality of light emission maximum wavelengths can be configured. For example, both a phosphorescent dopant and a fluorescent dopant may be added.
  • the light emitting dopants contained in each layer may be the same or different, may be a single type, or may be a plurality of types.
  • a polymer material in which the luminescent dopant is introduced into a polymer chain or the luminescent dopant is used as a polymer main chain may be used.
  • the host compound examples include those having a basic skeleton such as a carbazole derivative, a triarylamine derivative, an aromatic borane derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, and an oligoarylene compound. Transport materials and hole transport materials are also suitable examples.
  • the host compound When applied to a blue or white light emitting element, a display device, and a lighting device, the host compound preferably has a maximum fluorescence wavelength of 415 nm or less. When a phosphorescent dopant is used, the phosphorescence of the host compound is 0- More preferably, the 0 band is 450 nm or less.
  • a compound having a hole transporting ability and an electron transporting ability, preventing emission light from being increased in wavelength, and having a high Tg (glass transition temperature) is preferable.
  • the luminescent dopant may be dispersed throughout the layer containing the host compound or may be partially dispersed. A compound having another function may be added to the light emitting layer.
  • a light emitting layer can be formed by using the above-mentioned materials to form a thin film by a known method such as vapor deposition, spin coating, casting, LB, ink jet transfer, or printing.
  • the light emitting layer formed is particularly preferably a molecular deposited film.
  • the molecular deposition film refers to a thin film formed by deposition from the gas phase state of the compound or a film formed by solidification from the molten state or liquid phase state of the compound.
  • this molecular deposited film and a thin film (molecular accumulation film) formed by the LB method can be distinguished from each other by a difference in aggregated structure and higher order structure and a functional difference resulting therefrom.
  • the phosphorescent dopant and host compound which are said luminescent materials are said luminescent materials as an organic compound which concerns on this invention. That is, the light emitting layer is formed by applying a solution containing the phosphorescent dopant and the host compound and an organic solvent by spin coating, casting, ink jet, spraying, printing, slot coating, or the like. This is preferable because a light emitting layer made of a molecular deposited film can be formed.
  • the inkjet method is preferable from the viewpoints that a homogeneous film is easily obtained and pinholes are hardly generated.
  • the dissolved carbon dioxide concentration with respect to the organic solvent under an atmospheric pressure condition of 50 ° C. or less is set to 1 ppm to a saturated concentration with respect to the organic solvent.
  • a means for setting the dissolved carbon dioxide concentration within the above range a method of bubbling carbon dioxide gas in a solution containing a phosphorescent dopant and a host compound and an organic solvent, or a supercritical fluid containing an organic solvent and carbon dioxide is used. The supercritical chromatography method used is mentioned.
  • the coating solution it is preferable that at least one of the phosphorescent dopant and the host compound satisfies the relationship represented by the above (3). More preferably, in the coating solution, both the phosphorescent dopant and the host compound satisfy the relationship represented by the above (3). As such means, it is preferable to mix the phosphorescent dopant and the host compound and the organic solvent by using the supercritical chromatography method described above.
  • the hole injection material used for the hole injection layer has either a hole injection property or an electron barrier property.
  • the hole transport material used for the hole transport layer has an electron barrier property and a function of transporting holes to the light emitting layer. Therefore, in the present invention, the hole transport layer is included in the hole injection layer.
  • hole injection material and hole transport material may be either organic or inorganic.
  • triazole derivatives for example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives , Hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, porphyrin compounds, thiophene oligomers and other conductive polymer oligomers.
  • arylamine derivatives and porphyrin compounds are preferred.
  • aromatic tertiary amine compounds and styrylamine compounds are preferable, and aromatic tertiary amine compounds are more preferable.
  • aromatic tertiary amine compound and styrylamine compound include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl; N, N′-diphenyl-N, N ′.
  • the hole transport material of the hole transport layer preferably has a fluorescence maximum wavelength at 415 nm or less. That is, the hole transport material is preferably a compound that has a hole transport ability, prevents the emission of light from becoming longer, and has a high Tg.
  • the above-described hole injection material and hole transport material are known from, for example, a vacuum deposition method, a spin coating method, a casting method, an LB method, an ink jet method, a transfer method, and a printing method. This method can be formed by thinning the film.
  • the hole injection material and the hole transport material are preferably used as the organic compound according to the present invention.
  • a solution containing the hole injecting material and the hole transporting material and an organic solvent can be formed by applying a spin coat method, a cast method, an ink jet method, a spray method, a printing method, a slot coater method, or the like.
  • a spin coat method a cast method, an ink jet method, a spray method, a printing method, a slot coater method, or the like.
  • the inkjet method is preferable from the viewpoints that a homogeneous film is easily obtained and pinholes are hardly generated.
  • the thickness of the hole injection layer and the hole transport layer is not particularly limited, but is usually about 5 nm to 5 ⁇ m.
  • the hole injection layer and the hole transport layer may each have a single-layer structure composed of one or more of the above materials, or a laminated structure composed of a plurality of layers having the same composition or different compositions. Also good.
  • a positive hole injection layer and a positive hole transport layer although a different material is normally used among said materials, you may use the same material.
  • the electron injecting layer only needs to have a function of transmitting electrons injected from the cathode to the light emitting layer, and any material can be selected from conventionally known compounds.
  • Examples of materials used for this electron injection layer include heterocyclic tetracarboxylic acid anhydrides such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, naphthalene perylene, and carbodiimides. , Fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like.
  • a series of electron transfer compounds described in Japanese Patent Application Laid-Open No. 59-194393 is disclosed as a material for forming a light emitting layer in the publication, but as a result of investigations by the present inventors, electron injection is performed. It was found that it can be used as a material.
  • a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, or a quinoxaline derivative having a quinoxaline ring known as an electron-withdrawing group can also be used as an electron injection material.
  • metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (abbreviated as Alq 3 ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8- Quinolinol) aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc.
  • Alq 3 8-quinolinol aluminum
  • metal-free or metal phthalocyanine or those whose terminal is substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron injection material.
  • an inorganic semiconductor such as n-type-Si or n-type-SiC can also be used as the electron injection material.
  • the preferable compound used for an electron carrying layer has a fluorescence maximum wavelength in 415 nm or less. That is, the compound used for the electron transport layer is preferably a compound that has an electron transport ability, prevents emission of longer wavelengths, and has a high Tg.
  • the electron injection layer is formed by thinning the electron injection material by a known method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, an ink jet method, a transfer method, or a printing method. Can do.
  • the electron injection material is preferably used as the organic compound according to the present invention.
  • the solution containing the said electron injection material and an organic solvent by application
  • coating such as a spin coat method, the casting method, the inkjet method, the spray method, the printing method, the slot type coater method.
  • coating such as a spin coat method, the casting method, the inkjet method, the spray method, the printing method, the slot type coater method.
  • the inkjet method is preferable from the viewpoints that a homogeneous film is easily obtained and pinholes are hardly generated.
  • the thickness of the electron injection layer is not particularly limited, but is usually selected in the range of 5 nm to 5 ⁇ m.
  • the electron injection layer may have a single layer structure composed of one or more of these electron injection materials, or may have a laminated structure composed of a plurality of layers having the same composition or different compositions.
  • an electron carrying layer is contained in an electron injection layer.
  • the electron transport layer is also referred to as a hole blocking layer (hole blocking layer). Examples thereof include, for example, International Publication No. 2000/70655, JP 2001-313178 A, JP 11-204258 A, and the like. No. 11-204359, and “Organic EL devices and their industrialization front line (issued by NTT, Inc., November 30, 1998)”, page 237, and the like.
  • a buffer layer may be present between the anode and the light emitting layer or the hole injection layer, and between the cathode and the light emitting layer or the electron injection layer.
  • the buffer layer is a layer that is provided between the electrode and the organic layer in order to lower the driving voltage and improve the light emission efficiency. “The organic EL element and the forefront of its industrialization (issued on November 30, 1998 by NTS Corporation) ) ”, Chapter 2, Chapter 2,“ Electrode Materials ”(pages 123 to 166), which includes an anode buffer layer and a cathode buffer layer.
  • anode buffer layer Details of the anode buffer layer are also described in JP-A-9-45479, 9-260062, 8-28869, etc., and specific examples thereof include a phthalocyanine buffer layer represented by copper phthalocyanine, vanadium oxide. And an oxide buffer layer, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.
  • a metal buffer layer typified by strontium or aluminum examples thereof include an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, and an oxide buffer layer typified by aluminum oxide.
  • the buffer layer is desirably a very thin film, and depending on the material, the thickness is preferably in the range of 0.1 to 100 nm. Furthermore, in addition to the basic constituent layers, layers having other functions may be appropriately laminated as necessary.
  • the cathode of the organic EL element generally uses a metal having a low work function (less than 4 eV) (hereinafter referred to as an electron injecting metal), an alloy, a metal electroconductive compound, or a mixture thereof as an electrode material. Things are used. Specific examples of such electrode materials include sodium, magnesium, lithium, aluminum, indium, rare earth metals, sodium-potassium alloys, magnesium / copper mixtures, magnesium / silver mixtures, magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / Aluminum oxide (Al 2 O 3 ) mixture, lithium / aluminum mixture and the like.
  • the cathode may contain a Group 13 metal element. preferable. That is, in the present invention, as described later, the surface of the cathode is oxidized with oxygen gas in a plasma state to form an oxide film on the cathode surface, thereby preventing further oxidation of the cathode and improving the durability of the cathode. Can be made. Therefore, the electrode material of the cathode is preferably a metal having a preferable electron injection property required for the cathode and capable of forming a dense oxide film.
  • the electrode material of the cathode containing the Group 13 metal element include, for example, aluminum, indium, a magnesium / aluminum mixture, a magnesium / indium mixture, and an aluminum / aluminum oxide (Al 2 O 3 ) mixture. And lithium / aluminum mixtures.
  • the mixing ratio of each component of the said mixture can employ
  • the cathode can be produced by forming a thin film on the organic compound layer (organic EL layer) using the electrode material described above by a method such as vapor deposition or sputtering.
  • the sheet resistance as a cathode is several hundred ⁇ / sq.
  • the film thickness is usually selected from the range of 10 nm to 1 ⁇ m, preferably 50 to 200 nm.
  • Method for producing organic EL element As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode will be described.
  • a thin film made of a desired electrode material for example, an anode material is formed on a suitable substrate by a method such as vapor deposition or sputtering so as to have a thickness of 1 ⁇ m or less, preferably 10 to 200 nm, thereby producing an anode. To do.
  • an organic compound thin film of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a hole blocking layer, which are element materials, is formed thereon.
  • spin coating method there are spin coating method, casting method, ink jet method, spray method, vapor deposition method, printing method, slot coating method, etc. as methods for thinning these organic compound thin films, but a homogeneous film can be obtained.
  • the ink jet method is preferable because it is easy to be formed and pinholes are hardly generated, and the coating liquid according to the present invention can be used in the present invention. Different film formation methods may be applied for each layer.
  • the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 to 450 ° C., a vacuum degree of 10 ⁇ 6 to 10 ⁇ 2 Pa, a vapor deposition rate of 0.01 It is desirable to select appropriately within the range of ⁇ 50 nm / second, substrate temperature of ⁇ 50 to 300 ° C., and thickness of 0.1 nm to 5 ⁇ m.
  • a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a thickness of 1 ⁇ m or less, preferably in the range of 50 to 200 nm, and a cathode is provided.
  • a desired organic EL element can be obtained.
  • the organic EL element is preferably manufactured from the hole injection layer to the cathode consistently by a single evacuation, but it may be taken out halfway and subjected to different film forming methods. At that time, it is necessary to consider that the work is performed in a dry inert gas atmosphere.
  • the organic EL element sealing means is not particularly limited. For example, after sealing the outer periphery of the organic EL element with a sealing adhesive, a sealing member is provided so as to cover the light emitting region of the organic EL element. The method of arranging is mentioned.
  • sealing adhesive examples include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. Can be mentioned. Moreover, heat
  • a polymer film and a metal film can be preferably used from the viewpoint of reducing the thickness of the organic EL element.
  • inert gases such as nitrogen and argon, fluorinated hydrocarbons, and silicon oil are used. Inert liquids can also be injected. Further, the gap between the sealing member and the display area of the organic EL element can be evacuated, or a hygroscopic compound can be sealed in the gap.
  • the multicolor display device using the organic EL element of the present invention is provided with a shadow mask only at the time of forming a light emitting layer, and the other layers are common, so patterning such as a shadow mask is unnecessary, vapor deposition method, casting method, A film can be formed by a spin coating method, an inkjet method, a printing method, or the like.
  • the method is not limited, but a vapor deposition method, an inkjet method, and a printing method are preferable. In the case of using a vapor deposition method, patterning using a shadow mask is preferable.
  • the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order.
  • a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state.
  • the alternating current waveform to be applied may be arbitrary.
  • the multicolor display device can be used as a display device, a display, and various light emission sources.
  • a display device or display full-color display is possible by using three types of organic EL elements of blue, red, and green light emission.
  • the display device and the display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in a car.
  • the driving method when used as a display device for reproducing moving images may be either a simple matrix (passive matrix) method or an active matrix method.
  • Light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc.
  • the organic EL element according to the present invention may be used as an organic EL element having a resonator structure.
  • Examples of the purpose of use of the organic EL element having such a resonator structure include a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processing machine, and a light source of an optical sensor. It is not limited. Moreover, you may use for the said use by making a laser oscillation.
  • the organic EL device of the present invention may be used as a kind of lamp such as an illumination or exposure light source, a projection device that projects an image, or a display device that directly recognizes a still image or a moving image. (Display) may be used.
  • the driving method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, it is possible to produce a full-color display device by using two or more organic EL elements of the present invention having different emission colors.
  • FIG. 5 is a schematic diagram illustrating an example of a display device including organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.
  • the display 41 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, and the like.
  • the control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of the plurality of pixels based on image information from the outside.
  • the pixels for each scanning line are converted into image data signals by the scanning signal. In response to this, light is sequentially emitted and image scanning is performed to display image information on the display unit A.
  • FIG. 6 is a schematic diagram of the display unit A.
  • the display unit A includes a wiring unit including a plurality of scanning lines 55 and data lines 56, a plurality of pixels 53, and the like on a substrate.
  • the main members of the display unit A will be described below.
  • FIG. 6 shows a case where the light emitted from the pixel 53 is extracted in the direction of the white arrow (downward).
  • the scanning lines 55 and the plurality of data lines 56 in the wiring portion are each made of a conductive material, and the scanning lines 55 and the data lines 56 are orthogonal to each other in a lattice shape and are connected to the pixels 53 at the orthogonal positions (details are shown in the figure). Not shown).
  • the pixel 53 When a scanning signal is applied from the scanning line 55, the pixel 53 receives an image data signal from the data line 56, and emits light according to the received image data.
  • Full color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region that emit light on the same substrate.
  • FIG. 7 is a schematic diagram showing a pixel circuit.
  • the pixel includes an organic EL element 60, a switching transistor 61, a driving transistor 62, a capacitor 63, and the like.
  • a full color display can be performed by using red, green, and blue light emitting organic EL elements as the organic EL elements 60 for a plurality of pixels, and juxtaposing them on the same substrate.
  • an image data signal is applied to the drain of the switching transistor 61 from the control unit B (not shown in FIG. 7 but shown in FIG. 5) via the data line 56.
  • the switching transistor 61 When a scanning signal is applied from the control unit B to the gate of the switching transistor 61 via the scanning line 55, the switching transistor 61 is turned on, and the image data signal applied to the drain is supplied to the capacitor 63 and the driving transistor 62. Is transmitted to the gate. By transmitting the image data signal, the capacitor 63 is charged according to the potential of the image data signal, and the drive of the drive transistor 62 is turned on.
  • the drive transistor 62 has a drain connected to the power supply line 67 and a source connected to the electrode of the organic EL element 60, and the power supply line 67 changes to the organic EL element 60 according to the potential of the image data signal applied to the gate. Current is supplied.
  • the driving of the switching transistor 61 is turned off. However, even if the driving of the switching transistor 61 is turned off, the capacitor 63 holds the potential of the charged image data signal, so that the driving of the driving transistor 62 is kept on and the next scanning signal is applied. Until then, the organic EL element 60 continues to emit light.
  • the driving transistor 62 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 60 emits light.
  • the organic EL element 60 emits light by providing a switching transistor 61 and a driving transistor 62, which are active elements, for each of the organic EL elements 60 of a plurality of pixels, and a plurality of pixels 53 (not shown in FIG. 6) Each organic EL element 60 emits light.
  • a light emitting method is called an active matrix method.
  • the light emission of the organic EL element 60 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or on / off of a predetermined light emission amount by a binary image data signal. But you can.
  • the potential of the capacitor 63 may be held continuously until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.
  • FIG. 8 is a schematic view of a passive matrix display device.
  • a plurality of scanning lines 55 and a plurality of image data lines 56 are provided in a lattice shape so as to face each other with the pixel 53 interposed therebetween.
  • the scanning signal of the scanning line 55 is applied by sequential scanning, the pixel 53 connected to the applied scanning line 55 emits light according to the image data signal.
  • the passive matrix method there is no active element in the pixel 53, and the manufacturing cost can be reduced.
  • the coating film of the present invention is a coating film for producing a photoelectric conversion element
  • the organic compound may be a photoelectric conversion element material such as a p-type organic semiconductor material or an n-type organic semiconductor material.
  • the coating film can be suitably used as an organic functional layer constituting the photoelectric conversion element.
  • FIG. 9 is a cross-sectional view showing an example of a solar cell having a single configuration (a configuration having one bulk heterojunction layer) composed of a bulk heterojunction organic photoelectric conversion element.
  • a bulk heterojunction type organic photoelectric conversion element 200 has a transparent electrode (anode) 202, a hole transport layer 207, a bulk heterojunction layer photoelectric conversion section 204, an electron transport layer (or 208 and a counter electrode (cathode) 203 are sequentially stacked.
  • the substrate 201 is a member that holds the transparent electrode 202, the photoelectric conversion unit 204, and the counter electrode 203 that are sequentially stacked. In the present embodiment, since light that is photoelectrically converted enters from the substrate 201 side, the substrate 201 can transmit the light that is photoelectrically converted, that is, with respect to the wavelength of the light to be photoelectrically converted. A transparent member is preferred.
  • the substrate 201 for example, a glass substrate or a resin substrate is used.
  • the substrate 201 is not essential.
  • the bulk heterojunction organic photoelectric conversion element 200 may be configured by forming the transparent electrode 202 and the counter electrode 203 on both surfaces of the photoelectric conversion unit 204.
  • the photoelectric conversion unit 204 is a layer that converts light energy into electrical energy, and includes a bulk heterojunction layer in which a p-type semiconductor material and a n-type semiconductor material that are materials for photoelectric conversion elements are uniformly mixed. Is done.
  • the p-type semiconductor material functions relatively as an electron donor (donor)
  • the n-type semiconductor material functions relatively as an electron acceptor (acceptor).
  • the electron donor and the electron acceptor are “an electron donor in which, when light is absorbed, electrons move from the electron donor to the electron acceptor to form a hole-electron pair (charge separation state)”.
  • an electron acceptor which don't just donate or accept electrons like an electrode, but donates or accepts electrons by photoreaction.
  • the work function of the transparent electrode 202 when the work function of the transparent electrode 202 is larger than the work function of the counter electrode 203, electrons are transported to the transparent electrode 202 and holes are transported to the counter electrode 203. If the work function is reversed, electrons and holes are transported in the opposite direction.
  • the transport direction of electrons and holes can be controlled.
  • a hole blocking layer such as a hole blocking layer, an electron blocking layer, an electron injection layer, a hole injection layer, or a smoothing layer may be included.
  • a tandem configuration a configuration having a plurality of bulk heterojunction layers in which such photoelectric conversion elements are stacked may be used.
  • FIG. 10 is a cross-sectional view showing a solar cell composed of an organic photoelectric conversion element having a tandem bulk heterojunction layer.
  • the transparent electrode 202 and the first photoelectric conversion unit 209 are sequentially stacked on the substrate 201, the charge recombination layer (intermediate electrode) 205 is stacked, and then the second photoelectric conversion unit 206, Next, by stacking the counter electrode 203, a tandem structure can be obtained.
  • materials that can be used for the above layer include n-type semiconductor materials and p-type semiconductor materials described in paragraphs 0045 to 0113 of JP-A-2015-149483.
  • Examples of a method for forming a bulk heterojunction layer in which an electron acceptor and an electron donor are mixed include a vapor deposition method and a coating method (including a casting method and a spin coating method).
  • the coating method is preferable in order to increase the area of the interface where charges and electrons are separated from each other as described above and to produce a device having high photoelectric conversion efficiency.
  • the coating method is also excellent in production speed.
  • the photoelectric conversion portion (bulk heterojunction layer) 204 may be configured as a single layer in which an electron acceptor and an electron donor are uniformly mixed, but a plurality of the mixture ratios of the electron acceptor and the electron donor are changed. It may consist of layers.
  • the electrode which comprises an organic photoelectric conversion element functions as a battery in which positive and negative charges generated in the bulk heterojunction layer are respectively taken out from the transparent electrode and the counter electrode via the p-type semiconductor material and the n-type semiconductor material, respectively. It is.
  • Each electrode is required to have characteristics suitable for carriers passing through the electrode.
  • the counter electrode is preferably a cathode for taking out electrons generated in the photoelectric conversion unit.
  • the conductive material may be a single layer, or in addition to a conductive material, a resin that holds these may be used in combination.
  • the counter electrode material for example, known cathode conductive materials described in JP2010-272619A, JP2014-078742A, and the like can be used.
  • the transparent electrode is preferably an anode having a function of taking out holes generated in the photoelectric conversion part.
  • an electrode that transmits light having a wavelength of 380 to 800 nm is preferable.
  • known anode materials described in JP2010-272619A, JP2014-078742A, and the like can be used.
  • intermediate electrode As a material of the intermediate electrode required in the case of a tandem configuration, a layer using a compound having both transparency and conductivity is preferable.
  • the material for example, known intermediate electrode materials described in JP2010-272619A, JP2014-078742A, and the like can be used. Next, materials other than the electrodes and the bulk heterojunction layer will be described.
  • the organic photoelectric conversion device has a hole transport layer / electron block layer intermediate between the bulk hetero junction layer and the transparent electrode in order to more efficiently extract charges generated in the bulk hetero junction layer. It is preferable to have.
  • the material for the photoelectric conversion element constituting the hole transport layer for example, known materials described in JP 2010-272619 A, JP 2014-077872 A, and the like can be used.
  • the organic photoelectric conversion device more efficiently extracts charges generated in the bulk heterojunction layer by forming an electron transport layer, a hole blocking layer, and a buffer layer between the bulk heterojunction layer and the counter electrode. It is preferable to have these layers.
  • the electron transport layer for example, known materials described in JP 2010-272619 A, JP 2014-078742 A, and the like can be used.
  • the electron transport layer may be a hole blocking layer having a hole blocking function that has a rectifying effect so that holes generated in the bulk heterojunction layer do not flow to the counter electrode side.
  • a material for forming the hole blocking layer for example, a known material described in JP-A-2014-078742 can be used.
  • a structure having various intermediate layers in the element may be employed.
  • the intermediate layer include a hole block layer, an electron block layer, a hole injection layer, an electron injection layer, an exciton block layer, a UV absorption layer, a light reflection layer, and a wavelength conversion layer.
  • the substrate When light that is photoelectrically converted enters from the substrate side, the substrate is preferably a member that can transmit this photoelectrically converted light, that is, a member that is transparent to the wavelength of the light to be photoelectrically converted. .
  • the substrate for example, a glass substrate, a resin substrate and the like are preferably mentioned, but it is desirable to use a transparent resin film from the viewpoint of light weight and flexibility.
  • a transparent resin film There is no restriction
  • the organic photoelectric conversion element according to the present invention may have various optical function layers for the purpose of more efficient light reception of sunlight.
  • the optical functional layer for example, a light condensing layer such as an antireflection film or a microlens array, or a light diffusing layer that can scatter the light reflected by the counter electrode and enter the bulk heterojunction layer again can be provided. Good.
  • antireflection layer examples include known antireflection layers, light collecting layers, and light scattering layers described in, for example, JP2010-272619A, JP2014-078742A, and the like. Can be used.
  • Electrode There is no particular limitation on the method and process for patterning the electrode, the power generation layer, the hole transport layer, the electron transport layer, and the like according to the present invention.
  • JP 2010-272619 A, JP 2014-078742 A, etc. The known methods described can be applied as appropriate.
  • Solutions (B) to (M) were prepared in the same manner as in the preparation of the solution (A) except that nPr acetate and DP-1 were changed to the solvents and compounds shown in Table I below. All solvents used were dehydrated in advance. The materials of the compounds used are shown below.
  • a particle size distribution curve (horizontal axis particle size (nm), vertical axis: frequency distribution) was created using analysis software (particle size / hole size analysis software NANO-Solver manufactured by Rigaku Corporation).
  • the particle size corresponding to the maximum peak in the particle size distribution curve was calculated as R ′.
  • the particle diameter corresponding to the maximum peak showing the minimum particle diameter among these maximum peaks was calculated as R ′.
  • the value of n was determined by the following formula.
  • n R '/ r
  • a ⁇ b) represents 1/2 .
  • the maximum peak corresponding to the particle size R ′ in each coating solution was the maximum peak with the largest frequency distribution among the maximum peaks in the particle size distribution curve.
  • r of DP-1 was 0.86 nm (major axis length 2.28 nm, minor axis length 1.17 nm).
  • r was determined in the same manner, and the value of n was calculated. Further, the full width at half maximum of the maximum peak indicating the particle size having the smallest particle size value was calculated, and the results are shown in Table I. In addition, when the half width exceeds 10 nm or when the determination is difficult, it is indicated by x.
  • Example 2 Particle size distribution analysis of small-angle X-ray scattering measurement result of coating film
  • Each coating solution obtained in Example 1 was formed by spin coating at 1500 rpm for 30 seconds, and then held at 80 ° C. for 30 minutes.
  • a coating film having a thickness of 40 nm was formed on a silicon wafer to obtain a measurement sample.
  • SPring-8 synchrotron radiation was used to irradiate the coating film sample with a wavelength of 0.1 nm.
  • a multi-axis diffractometer manufactured by HUBER is used, the X-ray incident angle ⁇ is fixed at 0.2 °, and the coated film sample is irradiated.
  • the detector uses a scintillation counter to measure scattered radiation from 1 to 43 °.
  • a particle size distribution curve (horizontal axis particle size (nm), vertical axis: frequency distribution) was created from the obtained scattering diffraction data using the above-described analysis software. Moreover, the particle size corresponding to the maximum peak in the particle size distribution curve was calculated as R. In addition, when it had a plurality of maximum peaks, the particle size corresponding to the maximum peak indicating the minimum particle size among these maximum peaks was calculated as R. Further, the value of n was determined by the following formula.
  • n R / r
  • a ⁇ b) represents 1/2 .
  • the maximum peak corresponding to the particle size R in each coating film was the maximum peak having the largest frequency distribution among the maximum peaks of the particle size distribution curve.
  • the half-value width of the maximum peak showing the smallest particle size and the frequency distribution of the maximum peak were calculated, and the results are shown in Table I. In addition, when the half width exceeds 10 nm or when the determination is difficult, it is indicated by x.
  • Luminescence intensity measurement A quartz substrate having a size of 50 mm ⁇ 50 mm and a thickness of 0.7 mm was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. The quartz substrate was placed in a spin coater, and each (dopant) coating solution obtained in Example 1 was formed by spin coating at 1500 rpm for 30 seconds, and then held at 80 ° C. for 30 minutes to obtain a film thickness of 40 nm. A coating film was formed on a quartz substrate to obtain a measurement sample. Each of the produced measurement samples was irradiated with ultraviolet rays having an excitation wavelength of 365 nm at 23 ° C., and the photoluminescence intensity was measured.
  • the emission intensity of each coating film is shown in Table I with the emission intensity of the coating film obtained by solidifying the solutions (A) to (M) serving as the mother liquor being 100. Note that USB2000 (manufactured by Ocean Optics) was used for measuring the emission intensity.
  • Example 2 ⁇ Preparation of organic EL element 101> As shown below, the anode / hole injection layer / hole transport layer / light emitting layer / blocking layer / electron transport layer / electron injection layer / cathode are laminated and sealed on the base material to form a bottom emission type organic material. An EL element 101 was produced. (Preparation of base material) First, an atmospheric pressure plasma discharge treatment apparatus having a configuration described in Japanese Patent Application Laid-Open No. 2004-68143 is used on the entire surface of the polyethylene naphthalate film (manufactured by Teijin DuPont, hereinafter abbreviated as PEN) on the anode forming side.
  • PEN polyethylene naphthalate film
  • an inorganic gas barrier layer made of SiO x was formed to a thickness of 500 nm.
  • a flexible base material having a gas barrier property with an oxygen permeability of 0.001 mL / (m 2 ⁇ 24 h) or less and a water vapor permeability of 0.001 g / (m 2 ⁇ 24 h) or less was produced.
  • ITO indium tin oxide
  • the base material on which the hole injection layer is formed is transferred to a nitrogen atmosphere using nitrogen gas (grade G1), and is applied by an inkjet method using a coating liquid for forming a hole transport layer having the following composition. It dried at 130 degreeC for 30 minutes, and formed the 30-nm-thick hole transport layer.
  • the base material on which the hole transport layer was formed was applied by an inkjet method using a light emitting layer forming coating solution having the following composition, and dried at 120 ° C. for 30 minutes to form a light emitting layer having a layer thickness of 50 nm. .
  • the light emitting layer forming coating solution was prepared by forming the following host coating solution and then adding the following fluorescent light emitting dopant.
  • the sealing base material was adhere
  • An agent layer was provided, and a laminate of a polyethylene terephthalate (PET) film having a thickness of 12 ⁇ m was prepared.
  • a thermosetting adhesive as a sealing adhesive was uniformly applied at a thickness of 20 ⁇ m along the adhesive surface (shiny surface) of the aluminum foil of the sealing substrate using a dispenser.
  • thermosetting adhesive an epoxy adhesive mixed with the following (A) to (C) was used.
  • A Bisphenol A diglycidyl ether (DGEBA)
  • B Dicyandiamide (DICY)
  • C Epoxy adduct-based curing accelerator
  • DGEBA Bisphenol A diglycidyl ether
  • DIY Dicyandiamide
  • C Epoxy adduct-based curing accelerator
  • the sealing base material is closely attached to the laminate, and a pressure roll is used at a pressure roll temperature of 100 ° C., a pressure of 0.5 MPa, and an apparatus speed of 0.3 m / second. It was tightly sealed under a pressure bonding condition of min.
  • the organic EL element 101 was produced as described above.
  • organic EL elements 102 to 110 In the production of the organic EL element 101, the host material contained in the host coating solution is changed as shown in Table II, and the above-described S1 (ultrasonic treatment) or S3 (supercritical chromatographic treatment) treatment is performed on a part thereof. Then, organic EL elements 102 to 110 were produced in the same manner except that a fluorescent dopant (DP-1) was added to form a light emitting layer forming coating solution and a light emitting layer was formed.
  • DP-1 fluorescent dopant
  • Luminous efficiency measurement Luminous efficiency is measured at room temperature (25 ° C) at a constant current density of 2.5 mA / cm 2 and a spectral radiance meter CS-2000 (manufactured by Konica Minolta). Was used to measure the light emission luminance of each organic EL element, and the light emission efficiency (external extraction efficiency) at the current value was determined.
  • the light emission efficiency of the organic EL element 101 comparativative example was expressed as a relative value with 100.
  • Luminous lifetime is measured by driving each organic EL element continuously under the conditions of room temperature 25 ° C and humidity 55% RH, and measuring the luminance using a spectral radiance meter CS-2000. The time (half life) during which the brightness was reduced by half was determined as a measure of life.
  • the driving condition was set to a current value of 1000 cd / m 2 at the start of continuous driving. And it represented with the relative value which sets the light emission lifetime of the organic EL element 101 (comparative example) to 100.
  • Luminous efficiency measurement Luminous efficiency is measured at room temperature (25 ° C) at a constant current density of 2.5 mA / cm 2 and a spectral radiance meter CS-2000 (manufactured by Konica Minolta). was used to measure the light emission luminance of each organic EL element, and the light emission efficiency (external extraction efficiency) at the current value was determined. It represents with the relative value which sets the luminous efficiency of the organic EL element 201 (comparative example) to 100.
  • the luminescence lifetime is measured by continuously driving each organic EL element under the conditions of room temperature 25 ° C and humidity 40% RH, and measuring the luminance using a spectral radiance meter CS-2000. The time (half life) during which the brightness was reduced by half was determined as a measure of life.
  • the driving condition was set to a current value of 10,000 cd / m 2 at the start of continuous driving. And it represented with the relative value which sets the light emission lifetime of the organic EL element 201 (comparative example) to 100.
  • n the half-value width of the maximum peak showing the smallest particle size and the frequency distribution of the maximum peak were calculated, and the results are shown in Table III.
  • x the half width exceeds 10 nm or the determination is difficult, it is indicated by x.
  • the organic EL device of the present invention is superior in luminous efficiency and luminous lifetime as compared with the organic EL device of the comparative example.
  • a thin film was formed on this transparent support substrate by spin coating using a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS) with pure water at 3000 rpm for 30 seconds. After the formation, it was dried at 200 ° C. for 1 hour to provide a hole injection layer having a thickness of 20 nm.
  • PEDOT / PSS polystyrene sulfonate
  • the transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 250 mg of ⁇ -NPD is placed in a molybdenum resistance heating boat, and 200 mg of compound A is placed in another molybdenum resistance heating boat. Attached. Next, the pressure in the vacuum chamber was reduced to 4 ⁇ 10 ⁇ 4 Pa, and the heating boat containing ⁇ -NPD was energized and heated, and deposited on the hole injection layer at a deposition rate of 0.1 nm / second to 20 nm. The hole transport layer was provided.
  • the substrate fabricated up to the hole transport layer was moved into a glove box under a nitrogen atmosphere.
  • a light emitting layer forming coating solution having the following composition was mixed, and a thin film was formed by spin coating under conditions of 700 rpm and 25 seconds. Furthermore, drying under reduced pressure (5 hpa or less, 30 ° C., 30 minutes) was performed to form a light emitting layer having a layer thickness of 50 nm.
  • the substrate on which the light emitting layer was formed was returned to the vacuum deposition apparatus, heated by energizing a heating boat containing the compound (H-2), and deposited on the light emitting layer at a deposition rate of 0.1 nm / second.
  • a hole blocking layer was provided.
  • the heating boat containing the compound A was energized and heated, and deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 40 nm electron transport layer.
  • organic EL elements 302 to 315 were produced in the same manner except that the host material and the solvent contained in the light emitting layer forming coating solution were changed as shown in Table IV.
  • Luminous efficiency measurement Luminous efficiency is measured at room temperature (25 ° C) at a constant current density of 2.5 mA / cm 2 and a spectral radiance meter CS-2000 (manufactured by Konica Minolta). Was used to measure the light emission luminance of each organic EL element, and the light emission efficiency (external extraction efficiency) at the current value was determined. It represents with the relative value which sets the luminous efficiency of the organic EL element 301 (comparative example) to 100.
  • the luminescence lifetime is measured by continuously driving each organic EL element under the conditions of room temperature 25 ° C and humidity 40% RH, and measuring the luminance using a spectral radiance meter CS-2000. The time (half life) during which the brightness was reduced by half was determined as a measure of life.
  • the driving condition was set to a current value of 10,000 cd / m 2 at the start of continuous driving. And it represented with the relative value which sets the light emission lifetime of the organic EL element 301 (comparative example) to 100.
  • n was calculated
  • n is less than 6.0 ⁇ : n is less than 10.0, 6.0 or more ⁇ : n is less than 18.0, 10.0 or more ⁇ : n is 18.0 or more ⁇ Maximum peak frequency distribution> ⁇ : Frequency distribution of maximum peak is 0.5 or more ⁇ : Frequency distribution of maximum peak is 0.3 or more and less than 0.5 ⁇ : Frequency distribution of maximum peak is less than 0.3 ⁇ Half width> ⁇ : Half width is less than 3.0 nm ⁇ : Half width is 3.0 nm or more and less than 6.0 nm ⁇ : Half width is 6.0 nm or more and less than 10.0 nm X: Half width is 10.0 nm or more
  • the organic EL device of the present invention is superior in terms of light emission efficiency, light emission lifetime and driving voltage as compared with the organic EL device of the comparative example.
  • the present invention can be used for a coating film having a small particle size of organic compound particles in the film and a method for producing the same, and is also used for an organic electroluminescence device excellent in luminous efficiency and durability using the coating film. can do.

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  • Electroluminescent Light Sources (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)

Abstract

Cette invention concerne un film de revêtement comprenant au moins un type de composé organique, dans lequel il existe au moins un pic maximal dans une courbe de distribution de diamètre des particules (axe horizontal : diamètre des particules, axe vertical : distribution des fréquences), de molécules ou d'agrégats, obtenue à partir d'une mesure de diffusion de rayons X à petit angle du composé organique, et où R et r ci-dessous satisfont la relation représentée par l'équation (1). (1) R ≤ 15r (dans l'équation (1), R représente un diamètre de particule correspondant au pic maximal présentant le plus petit diamètre de particule parmi les pics maximaux de la courbe de distribution de diamètre des particules obtenue à partir d'une mesure de diffusion de rayons X de petit angle, et r représente le rayon moléculaire du composé organique, r = (a×b)1/2, lorsque la longueur de l'axe majeur moléculaire du composé organique telle que calculée par théorie de la fonctionnelle de la densité est de 2a (nm) et la longueur de l'axe mineur moléculaire du composé organique telle que calculée par théorie de la fonctionnelle de la densité est 2b (nm).
PCT/JP2018/005024 2017-03-23 2018-02-14 Film de revêtement, procédé de production de film de revêtement, et dispositif électroluminescent organique Ceased WO2018173553A1 (fr)

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Cited By (1)

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CN114127014A (zh) * 2019-07-12 2022-03-01 住友化学株式会社 粉体及固体组合物

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JP4389494B2 (ja) * 2003-06-13 2009-12-24 コニカミノルタホールディングス株式会社 有機エレクトロルミネッセンス材料の精製方法
US20110214487A1 (en) * 2008-09-11 2011-09-08 The Ohio State University Research Foundation Electro-spun fibers and applications therefore
JP2013122994A (ja) * 2011-12-12 2013-06-20 Konica Minolta Inc 有機エレクトロルミネッセンス素子、表示装置及び照明装置
WO2013141190A1 (fr) * 2012-03-23 2013-09-26 コニカミノルタ株式会社 Élément d'étanchéité pour élément à électroluminescence organique et procédé pour fabriquer l'élément à électroluminescence organique

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JP2003347624A (ja) * 2002-05-27 2003-12-05 Konica Minolta Holdings Inc 有機半導体材料の精製方法、該精製方法を用いて得られた有機半導体材料及びそれを用いた半導体素子
JP4389494B2 (ja) * 2003-06-13 2009-12-24 コニカミノルタホールディングス株式会社 有機エレクトロルミネッセンス材料の精製方法
US20110214487A1 (en) * 2008-09-11 2011-09-08 The Ohio State University Research Foundation Electro-spun fibers and applications therefore
JP2013122994A (ja) * 2011-12-12 2013-06-20 Konica Minolta Inc 有機エレクトロルミネッセンス素子、表示装置及び照明装置
WO2013141190A1 (fr) * 2012-03-23 2013-09-26 コニカミノルタ株式会社 Élément d'étanchéité pour élément à électroluminescence organique et procédé pour fabriquer l'élément à électroluminescence organique

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Publication number Priority date Publication date Assignee Title
CN114127014A (zh) * 2019-07-12 2022-03-01 住友化学株式会社 粉体及固体组合物
CN114127014B (zh) * 2019-07-12 2023-09-01 住友化学株式会社 粉体及固体组合物

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