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WO2010134419A1 - Elément électroluminescent organique et dispositif d'éclairage utilisant celui-ci - Google Patents

Elément électroluminescent organique et dispositif d'éclairage utilisant celui-ci Download PDF

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Publication number
WO2010134419A1
WO2010134419A1 PCT/JP2010/057347 JP2010057347W WO2010134419A1 WO 2010134419 A1 WO2010134419 A1 WO 2010134419A1 JP 2010057347 W JP2010057347 W JP 2010057347W WO 2010134419 A1 WO2010134419 A1 WO 2010134419A1
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Prior art keywords
layer
organic
light
transparent conductive
composite material
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PCT/JP2010/057347
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English (en)
Japanese (ja)
Inventor
恭雄 當間
邦雅 檜山
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Konica Minolta Inc
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Konica Minolta Inc
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Priority to JP2011514371A priority Critical patent/JPWO2010134419A1/ja
Publication of WO2010134419A1 publication Critical patent/WO2010134419A1/fr
Anticipated expiration legal-status Critical
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Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/80—Constructional details
    • H10K50/805—Electrodes
    • H10K50/81—Anodes
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/80—Constructional details
    • H10K50/85—Arrangements for extracting light from the devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2102/00—Constructional details relating to the organic devices covered by this subclass
    • H10K2102/301—Details of OLEDs
    • H10K2102/351—Thickness

Definitions

  • the present invention relates to an organic electroluminescence element and a lighting device using the element.
  • ELD electroluminescence display
  • an inorganic electroluminescent element and an organic electroluminescent element are mentioned.
  • Inorganic electroluminescent elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.
  • the organic electroluminescence device has a configuration in which a light emitting layer containing a compound that emits light (an organic compound thin film containing a fluorescent organic compound) is sandwiched between a cathode and an anode, and injects electrons and holes into the light emitting layer, It is an element that emits light by utilizing light emission (fluorescence / phosphorescence) when excitons (excitons) are generated by recombination and the excitons are deactivated.
  • a transparent conductive layer such as ITO is used for at least one of the electrodes sandwiching the organic compound thin film, and the transparent conductive layer is further supported by a transparent substrate such as glass.
  • Organic EL devices can emit light at a low voltage of several volts to several tens of volts, are self-luminous, have a wide viewing angle, high visibility, and are thin-film, completely solid-state devices that save space. It is attracting attention from the viewpoint of portability.
  • the organic electroluminescence device has a problem that the light extraction efficiency (the ratio of the energy coming out of the substrate to the emitted energy) is low. That is, the light emission of the light emitting layer is not directional and dissipates in all directions, so there is a large loss when guiding light forward from the light emitting layer, and there is a problem that the display screen becomes dark due to insufficient light intensity. .
  • the light emitted from the light emitting layer uses only the light emitted in the forward direction, but the light extraction efficiency (light emission efficiency) in the forward direction derived from multiple reflection based on classical optics is 1 / 2n 2 . It can be approximated, and is almost determined by the refractive index n of the light emitting layer. If the refractive index of the light emitting layer is about 1.7, the light emission efficiency from the organic EL part is simply about 20%. The remaining light propagates in the area direction of the light emitting layer (spray in the lateral direction) or disappears at the metal electrode facing the transparent electrode with the light emitting layer interposed therebetween (absorption in the backward direction).
  • the organic electroluminescence element emits light inside a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1), and about 15% to 20% of the light generated in the light emitting layer. Can only take out the light. This is because light incident on the interface (interface between the transparent substrate and air) at an angle ⁇ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the side surface of the device.
  • refractive index higher than that of air
  • a variety of methods have been studied as methods for improving the light extraction efficiency.
  • a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and the air see, for example, Patent Document 1
  • a flat layer having a lower refractive index than the substrate glass between the substrate glass and the light emitter is considered.
  • a method of providing a layer having a light scattering function on the light extraction surface side of each of the high refractive index layer and the translucent body has been studied.
  • a light scattering layer is provided through an intermediate layer having a refractive index equivalent to that of the transparent electrode.
  • This intermediate layer is a layer provided mainly for smoothness and formed in contact with the transparent electrode. The effect of improving the light extraction efficiency by the layer is not obtained.
  • the present invention has been made in view of the above problems, and an object of the present invention is to provide an electroluminescent element with significantly improved light extraction efficiency and improved durability and a lighting device using the element. It is in.
  • the present inventors form an organic-inorganic composite material layer having a thickness of 5 to 50 times the sum of the thickness of the organic EL layer and the transparent conductive layer in contact with the transparent conductive layer.
  • the light extraction efficiency can be specifically improved as compared with the conventional case.
  • the organic-inorganic composite material layer of the present invention extracts guided light traveling in the plane direction inside the transparent conductive layer and the organic electroluminescence layer, and also the organic-inorganic composite It is presumed that the microscopic refractive index distribution of the material changed the optical path of light taken into the organic-inorganic composite material layer, and the effect of being easily taken into the transparent substrate was presumed. .
  • an organic electroluminescence device in which a transparent conductive layer, an organic electroluminescence layer, and a counter electrode are sequentially laminated on a transparent base material, the transparent conductive layer is formed between the transparent base material and the transparent conductive layer in contact with the transparent conductive layer.
  • An organic electroluminescence device having an organic-inorganic composite material layer, wherein the thickness of each layer satisfies the following formula.
  • t1 Film thickness ( ⁇ m) of the organic electroluminescence layer
  • t2 film thickness of transparent conductive layer ( ⁇ m)
  • t3 The film thickness ( ⁇ m) of the organic-inorganic composite material layer.
  • organic-inorganic composite material layer is made of an organic-inorganic composite material containing inorganic fine particles having a particle diameter of 1 to 20 nm in a resin.
  • the light extraction efficiency is greatly improved as compared with the prior art. Furthermore, the film physical property of the organic electroluminescence element having a fine film structure is greatly improved, and an organic electroluminescence element having excellent durability can be obtained.
  • Embodiments of an organic electroluminescence element also referred to as an organic EL element
  • a lighting device of the present invention will be described in detail below, but the contents described below are representative examples of the embodiment of the present invention. As long as the gist is not exceeded, it is not limited to these contents.
  • an organic EL element with high light extraction efficiency can be obtained by controlling the refractive index and film thickness of the organic electroluminescence layer, transparent conductive layer, and organic-inorganic composite material layer.
  • the organic electroluminescence layer as used herein refers to an anode buffer layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, a cathode buffer layer, or a portion between a transparent conductive layer and a counter electrode. Refers to the layer formed.
  • the film thickness t1 of the organic electroluminescence layer is usually 0.05 ⁇ m or more and 0.5 ⁇ m or less, and preferably 0.1 ⁇ m or more and 0.2 ⁇ m or less in terms of light emission efficiency and stability.
  • the transparent conductive layer of the present invention refers to a layer made of a transparent and conductive compound and acting as an electrode.
  • a metal oxide material such as ITO formed by vapor deposition or sputtering has a refractive index of 1.8 to 2.1 and a film thickness of 0.05 ⁇ m or more and 0.15 ⁇ m or less, or a metal nanowire A film having a refractive index of 1.6 to 1.8 and a film thickness of 0.1 ⁇ m or more and 1 ⁇ m or less can be used.
  • the refractive index of the transparent conductive layer is close to 1.7 and the film thickness t2 is larger than t1.
  • the transparent conductive layer of the present invention is preferably formed by applying metal nanowires such as silver nanowires together with a conductive polymer material, and preferably has a refractive index of 1.6 to 1.8.
  • the thickness t2 is preferably 0.1 ⁇ m or more and 0.5 ⁇ m or less.
  • the organic-inorganic composite material layer of the present invention is thicker than the organic electroluminescence layer and the transparent conductive layer, and thinner than the transparent base material, to provide sufficient durability, impact resistance, optical properties, and film physical properties.
  • the film thickness t3 of the organic-inorganic composite material layer is 1 ⁇ m to 20 ⁇ m, and more preferably 2 ⁇ m to 10 ⁇ m.
  • the refractive index is preferably such that the difference in refractive index from the transparent conductive layer is 0.1 or less because the guided light extraction effect is high. Therefore, for example, for a transparent conductive layer using silver nanowires, it is preferable to form an organic-inorganic composite material layer having a refractive index of 1.6 to 1.8 and a film thickness of 2 ⁇ m to 10 ⁇ m.
  • the present invention is characterized in that the following expressions 1 and 2 are satisfied.
  • T3 / (t1 + t2) represented by Equation 1 is larger than 5 and smaller than 50, but is preferably larger than 5 and smaller than 15.
  • the light taken into the organic-inorganic composite material layer is extracted outside through a transparent substrate due to a change in the optical path due to the microscopic refractive index distribution of the organic-inorganic composite material.
  • a method for improving light extraction efficiency by utilizing light scattering by a silver nanowire used for the transparent conductive layer or a light-scattering filler added to the organic-inorganic composite material layer is also one preferred embodiment.
  • the organic EL device of the present invention improves the bending-extraction resistance and durability during high-temperature storage in addition to the above-described improvement in light extraction efficiency. This is presumed to be due to the surprising effect that the stress applied to the transparent conductive layer by bending or heating is reduced by forming the organic-inorganic composite material layer in contact with the transparent conductive layer in the present invention. Is done.
  • the use of metal nanowires in the transparent conductive layer improves the strength of the transparent conductive layer due to the network structure of the metal nanowires and reduces the cracking and peeling of the transparent conductive layer due to the synergistic effect of the organic-inorganic composite material layer. It is preferable because a more durable organic EL element can be formed.
  • a commonly used method can be used as a method for measuring the refractive index.
  • it can be obtained from the measurement result of the spectral reflectance of a spectrophotometer (such as U-4000 type manufactured by Hitachi, Ltd.) for a sample in which each layer is coated alone. After roughening the back surface, light absorption treatment is performed with a black spray to prevent light reflection on the back surface, and the reflectance in the visible light region (400 to 700 nm) is measured under the condition of regular reflection at 5 degrees. Can be obtained.
  • a commonly used method can be used as a method of measuring the film thickness of each layer constituting the organic EL element.
  • the cross section of the organic EL element produced by laminating each layer can be obtained by photographing with a scanning electron microscope and measuring the film thickness.
  • the organic electroluminescent element of the present invention is characterized by having an organic-inorganic composite material layer formed in contact with the transparent conductive layer.
  • the organic-inorganic composite material layer of the present invention refers to a thin film layer formed of an organic-inorganic composite material in which a resin material that is an organic material and an inorganic material such as inorganic fine particles are combined.
  • a so-called polymer nanocomposite material or polymer hybrid material in which inorganic nanoparticles are dispersed is preferably used.
  • the organic-inorganic composite material layer of the present invention preferably has a small refractive index difference from the transparent conductive layer.
  • the difference in refractive index is preferably 0.2 or less, and more preferably 0.1 or less. Since a general resin material has a smaller refractive index than a material such as an inorganic oxide forming a transparent conductive layer, the organic-inorganic composite material layer of the present invention has a higher refractive index in the resin than the resin material.
  • the refractive index is preferably adjusted by dispersing inorganic fine particles.
  • resin Although there is no restriction
  • the curable resin used in the present invention it can be cured by any of ultraviolet and electron beam irradiation or heat treatment, and after being mixed in an uncured state with inorganic particles, it is transparent by curing.
  • Any resin composition can be used without particular limitation, and examples thereof include silicone resins, epoxy resins, vinyl ester resins, acrylic resins, and allyl ester resins.
  • the curable resin may be an actinic ray curable resin that is cured by being irradiated with ultraviolet rays or electron beams, or may be a thermosetting resin that is cured by heat treatment.
  • Such types of resins can be preferably used, and acrylic resins can be particularly preferably used.
  • Silicone Resin As a silicone resin that is a polymer having a main chain of siloxane bonds —Si—O— in which silicon (Si) and oxygen (O) are alternately bonded, a silicone-based resin composed of a predetermined amount of polyorganosiloxane resin is used. It can be used (for example, see JP-A-6-9937).
  • thermosetting polyorganosiloxane resin is not particularly limited as long as it becomes a three-dimensional network structure with a siloxane bond skeleton by a continuous hydrolysis-dehydration condensation reaction by heating, and is generally cured by heating at a high temperature for a long time. It has the property of being hard to re-soften by heating once cured.
  • a polyorganosiloxane resin includes the following general formula (A) as a structural unit, and the shape thereof may be any of a chain, a ring, and a network.
  • R 1 and R 2 represent the same or different substituted or unsubstituted monovalent hydrocarbon groups.
  • R 1 and R 2 an alkyl group such as a methyl group, an ethyl group, a propyl group, and a butyl group, an alkenyl group such as a vinyl group and an allyl group, an allyl group such as a phenyl group and a tolyl group, and a cyclohexyl group
  • a cycloalkyl group such as a cyclooctyl group, or a group in which a hydrogen atom bonded to a carbon atom of these groups is substituted with a halogen atom, a cyano group, an amino group, or the like, such as a chloromethyl group, 3,3,3-trimethyl
  • Examples include fluoropropyl group, cyanomethyl group,
  • the polyorganosiloxane resin is usually used after being dissolved in a hydrocarbon solvent such as toluene, xylene or petroleum solvent, or a mixture of these with a polar solvent. Moreover, you may mix
  • a hydrocarbon solvent such as toluene, xylene or petroleum solvent
  • the method for producing the polyorganosiloxane resin is not particularly limited, and any known method can be used. For example, it can be obtained by hydrolysis or alcoholysis of one or a mixture of two or more organohalogenosilanes.
  • Polyorganosiloxane resins generally contain hydrolyzable groups such as silanol groups or alkoxy groups. The group is contained in an amount of 1 to 10% by mass in terms of a silanol group.
  • These reactions are generally carried out in the presence of a solvent capable of melting the organohalogenosilane. It can also be obtained by a method of synthesizing a block copolymer by cohydrolyzing a linear polyorganosiloxane having a hydroxyl group, an alkoxy group or a halogen atom at the molecular chain terminal with an organotrichlorosilane.
  • the polyorganosiloxane resin thus obtained generally contains the remaining HCl, but in the composition of the present embodiment, the storage stability is good, so that the one having 10 ppm or less, preferably 1 ppm or less is used. Is good.
  • Epoxy resin As the epoxy resin, an alicyclic epoxy resin such as 3,4-epoxycyclohexylmethyl-3 ', 4'-cyclohexylcarboxylate (see International Publication No. 2004/031257) can be used. An epoxy resin containing a spiro ring or a chain aliphatic epoxy resin can also be used. In that case, you may use an oxetane resin together or independently.
  • an alicyclic epoxy resin such as 3,4-epoxycyclohexylmethyl-3 ', 4'-cyclohexylcarboxylate (see International Publication No. 2004/031257) can be used.
  • An epoxy resin containing a spiro ring or a chain aliphatic epoxy resin can also be used. In that case, you may use an oxetane resin together or independently.
  • Acrylic Resin As a raw material component of acrylic resin, for example, monofunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone and the like.
  • Examples include polyfunctional monomers such as acrylate.
  • Resin containing allyl ester compound Bromine-containing (meth) allyl ester containing no aromatic ring (see JP-A-2003-66201), allyl (meth) acrylate (see JP-A-5-286896), allyl ester resin ( JP-A-5-286896 and JP-A-2003-66201), a copolymer compound of an acrylate ester and an epoxy group-containing unsaturated compound (see JP-A-2003-128725), an acrylate compound (JP-A 2003-2003) No. 147072), acrylic ester compounds (see JP 2005-2064 A) and the like can be preferably used.
  • the inorganic particles used in the organic-inorganic composite material layer of the present invention are not particularly limited as long as the refractive index of the organic-inorganic composite material layer can be adjusted to a target value.
  • oxide fine particles, Inorganic fine particles such as metal salt fine particles and semiconductor fine particles are preferably used.
  • those which do not generate absorption, light emission, fluorescence and the like in the wavelength region to be used are preferably selected and used.
  • the inorganic particles used in the present invention are 1 nm or more and 20 nm or less. Preferably there is.
  • the average particle diameter is preferably 20 nm or less.
  • the average particle diameter refers to the volume average value of the diameter (sphere converted particle diameter) when each particle is converted into a sphere having the same volume.
  • the refractive index of the inorganic particles used in the present invention is preferably higher than that of the resin material, and the refractive index is preferably 1.6 or more and 2.5 or less.
  • the metal constituting the metal oxide is Li, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb. 1 selected from the group consisting of Sr, Y, Nb, Zr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, La, Ta, Hf, W, Ir, Tl, Pb, Bi and rare earth metals
  • a metal oxide that is a seed or two or more kinds of metals can be used.
  • rare earth oxides can also be used as oxide fine particles. Specifically, scandium oxide, yttrium oxide, lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide. Dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, and the like.
  • metal salt fine particles those having a refractive index of 1.6 or more among carbonates, phosphates, sulfates and composite particles thereof are applicable.
  • Ti and Zr oxo clusters are also applicable.
  • inorganic particles As a method for preparing inorganic particles, it is possible to obtain fine particles by spraying and firing inorganic raw materials in a gas phase. Furthermore, a method of preparing particles using plasma, a method of ablating raw material solids with a laser or the like to make fine particles, a method of oxidizing evaporated metal gas to prepare fine particles, and the like can be suitably used.
  • a method for preparing in the liquid phase it is possible to prepare an inorganic fine particle dispersion in which almost primary particles are dispersed by using a sol-gel method using an alkoxide or chloride solution as a raw material. Alternatively, it is possible to obtain a dispersion having a uniform particle size by using a reaction crystallization method utilizing a decrease in solubility.
  • drying means such as freeze drying, spray drying, and supercritical drying can be applied, and the firing is performed not only by raising the temperature while controlling the atmosphere but also by using an organic or inorganic sintering inhibitor. It is preferable.
  • inorganic particles can be selected in consideration of safety and safety, and the following inorganic particles are preferably used considering the ease of reducing the particle size. That, TiO 2, Al 2 O 3 , LiNbO 3, Nb 2 O 5, ZrO 2, Y 2 O 3, MgO, ZnO, SnO 2, Bi 2 O 3, ITO, CeO 2, AlN, diamond, etc. KTaO 3 It is particularly preferable to use
  • the filling rate into the resin there are no particular restrictions on the filling rate into the resin, but when filling inorganic particles of 20 nm or less into the resin, it is preferable that the filling rate be 30% by volume or less in view of securing moldability (fluidity and no cracks). On the other hand, in order to change the optical physical properties (refractive index) by filling with inorganic particles, a certain degree of filling rate is required, so 5 volume% or more, further 10 volume% or more is preferable.
  • the volume fraction of inorganic fine particles here is expressed by the formula (x / a) / Y ⁇ where the specific gravity of the inorganic fine particles is a, the content is x grams, and the total volume of the produced organic-inorganic composite material is Y milliliters. 100 is required.
  • the content of the inorganic fine particles can be determined by observing a semiconductor crystal image with a transmission electron microscope (TEM) (information on the semiconductor crystal composition can also be obtained by local elemental analysis such as EDX), or given resin composition It can be calculated from the contained mass of a predetermined composition obtained by elemental analysis of contained ash and the specific gravity of crystals of the composition.
  • TEM transmission electron microscope
  • a surface treatment for the bonding between the necessary surface treating agent and the particle surface, the following introduction methods are conceivable, but not limited to them.
  • Silane coupling agent A condensation reaction or a hydrogen bond between a silanol group and a hydroxyl group on the particle surface is used.
  • Examples include vinylsilazane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, trimethylalkoxysilane, dimethyldialkoxysilane, methyltrialkoxysilane, hexamethyldisilazane, and the like.
  • Trimethylmethoxysilane, dimethyldimethoxysilane, methyltrimethoxy Silane, hexamethyldisilazane and the like are preferably used.
  • Titanate, aluminate, and zirconate coupling agents are also applicable. Further, zircoaluminate, chromate, borate, stannate, isocyanate and the like can be used. A diketone coupling agent can also be used.
  • Resin-based surface treatment After introducing active species to the particle surface by the methods (1) to (3) above, a method of providing a polymer layer on the surface by graft polymerization, or adsorbing a pre-synthesized polymer dispersant to the particle surface , There is a method of combining. In order to provide a polymer layer more firmly on the particle surface, graft polymerization is preferred, and grafting at a high density is particularly preferred.
  • a composite material precursor (a molten state when a thermoplastic resin is used, an uncured state when a curable resin is used) is prepared, and then applied onto a substrate. It is formed by doing.
  • the composite material precursor may be prepared by mixing the curable resin dissolved in an organic solvent and the fine particles according to the present invention, and then removing the organic solvent, or curing. It may be prepared by adding and mixing the fine particles according to the present invention into a monomer solution which is one of the raw materials of the functional resin, followed by polymerization. Alternatively, it may be prepared by melting an oligomer in which a monomer is partially polymerized or a low molecular weight polymer, and adding and mixing the fine particles according to the present invention thereto.
  • organic solvent used herein examples include lower alcohols having about 1 to 4 carbon atoms, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, esters such as methyl acetate and ethyl acetate, hydrocarbons such as toluene and xylene, and the like. However, it is not particularly limited as long as it has a boiling point lower than that of the monomer and is compatible with these monomers.
  • a method of polymerizing after adding the fine particles according to the present invention to a monomer solution is preferable, and in particular, a highly viscous solution in which the monomer and the fine particles according to the present invention are mixed is given a share while cooling.
  • a highly viscous solution in which the monomer and the fine particles according to the present invention are mixed is given a share while cooling.
  • the method for adjusting the viscosity include adjustment of the particle diameter, surface state, and addition amount of the fine particles according to the present invention, addition of a solvent and a viscosity adjusting agent, etc. Since it is easy, an optimal kneading state can be obtained.
  • the fine particles according to the present invention can be added in a powder or agglomerated state. Or it is also possible to add in the state disperse
  • the fine particles according to the present invention are preferably added in a surface-treated state.
  • a method such as an integral blend in which a surface treatment agent and fine particles are added at the same time to form a composite with a curable resin. Is possible.
  • the organic-inorganic composite material layer of the present invention can contain a light scattering filler in addition to the above-described inorganic particles.
  • the light scattering filler is a filler having a function of multiply scattering light entering the organic-inorganic composite material layer, and preferably has a particle size of 0.5 ⁇ m or more and 5 ⁇ m or less. If it is less than 0.5 ⁇ m, the effect is small because the intensity of scattered light is low, and if it exceeds 5 ⁇ m, the transparency of the organic-inorganic composite material layer may be significantly deteriorated.
  • the refractive index of the light scattering filler is preferably 0.01 or less in refractive index difference with the organic-inorganic composite material layer to be added, and is 0.1 or less. It is preferable for maintaining transparency.
  • the light-scattering filler used in the present invention a known filler made of inorganic or polymer can be used.
  • inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, and calcium phosphate.
  • polymer include silicone resin, fluororesin, and acrylic resin. The amount of these fillers added is preferably 0.1 to 30% by mass, but may be adjusted according to the degree of light scattering.
  • the light scattering filler can have any shape such as a spherical shape, a needle shape, or a flat plate shape, and further, by performing the same surface treatment as that of the above-described inorganic particles, it is possible to improve the dispersibility in the resin. is there.
  • the transparent conductive layer provided on the light emitting layer side of the organic-inorganic composite material layer contains a light-scattering filler, and the light-scattering property is improved by devising the composition and shape of the conductive compound forming the transparent conductive layer. Giving it is also preferable because the same effect can be obtained.
  • the transparent substrate used in the organic EL device of the present invention is not particularly limited as long as it has high light transmittance.
  • a glass substrate, a resin substrate, a resin film, and the like are preferable in terms of excellent hardness as a base material and ease of film formation on the surface, but from the viewpoint of lightness and flexibility. It is preferable to use a transparent resin film.
  • the transparent resin film that can be preferably used as the transparent substrate in the present invention is not particularly limited, and the material, shape, structure, thickness and the like can be appropriately selected from known ones.
  • polyester resin films such as polyethylene terephthalate (PET), polyethylene naphthalate, modified polyester, polyethylene (PE) resin films, polypropylene (PP) resin films, polystyrene resin films, polyolefin resin films such as cyclic olefin resins, Vinyl resin films such as polyvinyl chloride and polyvinylidene chloride, polyether ether ketone (PEEK) resin film, polysulfone (PSF) resin film, polyether sulfone (PES) resin film, polycarbonate (PC) resin film, polyamide resin Examples include films, polyimide resin films, acrylic resin films, triacetyl cellulose (TAC) resin films, and the like, but wavelengths in the visible range (380 to 78).
  • TAC triacetyl cellulose
  • the resin film transmittance of 80% or more in nm can be preferably applied to a transparent resin film according to the present invention.
  • a transparent resin film according to the present invention is preferably a biaxially stretched polyethylene terephthalate film, a biaxially stretched polyethylene naphthalate film, a polyethersulfone film, or a polycarbonate film, and biaxially stretched. More preferred are polyethylene terephthalate films and biaxially stretched polyethylene naphthalate films.
  • the refractive index of the transparent resin film is preferably 1.50 or more, more preferably 1.60 or more and 1.80 or less.
  • the thickness of the transparent resin film is preferably from 50 ⁇ m to 250 ⁇ m, and more preferably from 75 ⁇ m to 200 ⁇ m.
  • the transparent substrate used in the present invention can be subjected to a surface treatment or an easy adhesion layer in order to ensure the wettability and adhesion of the coating solution.
  • a surface treatment or an easy adhesion layer in order to ensure the wettability and adhesion of the coating solution.
  • a conventionally well-known technique can be used about a surface treatment or an easily bonding layer.
  • the surface treatment includes surface activation treatment such as corona discharge treatment, flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment, active plasma treatment, and laser treatment.
  • examples of the easy adhesion layer include polyester, polyamide, polyurethane, vinyl copolymer, butadiene copolymer, acrylic copolymer, vinylidene copolymer, epoxy copolymer and the like.
  • the easy adhesion layer may be a single layer, but may be composed of two or more layers in order to improve adhesion.
  • the resin film may contain a filler for the purpose of imparting a light scattering function, and the particle size of the filler is preferably about 0.5 to 10 ⁇ m.
  • a barrier coat layer or a hard coat layer may be formed in advance on both surfaces or one surface of the transparent substrate.
  • the rate is preferably the same or slightly lower than the rate.
  • a resin containing fine particles having an average particle diameter of 1 nm or more and 400 nm or less may be used as the hard coat layer. Fine particles having a refractive index higher than that of the resin in the transparent resin have an average particle diameter of 1 to 400 nm. By dispersing, a transparent hard coat layer having a desired refractive index can be obtained.
  • Transparent conductive layer As the transparent conductive layer in the organic EL device of the present invention, a material having a work function (4 eV or more) of a metal, an alloy, an electrically conductive compound and a mixture thereof as an electrode material for forming the transparent conductive layer is preferably used.
  • electrode substances include metals such as Au, and conductive light-transmitting materials such as CuI, indium tin oxide (ITO), SnO 2 , and ZnO.
  • a material such as IDIXO (In 2 O 3 —ZnO) that can form an amorphous light-transmitting conductive film may be used.
  • the transparent conductive layer is preferably used as an anode.
  • these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when the pattern accuracy is not required (about 100 ⁇ m or more) ), A pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. Or when using the substance which can be apply
  • the sheet resistance as the anode is preferably several hundred ⁇ / ⁇ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 50 to 200 nm.
  • the transparent conductive layer can be used in combination with other resins having a relatively low refractive index while having high conductivity, and contains metal nanowires that can be expected to improve light extraction efficiency due to the light scattering effect. It is preferable. Furthermore, since the strength of the transparent conductive layer is increased by the network structure of the metal nanowire and the durability of the organic EL element is improved, it is preferable to use the metal nanowire for the transparent conductive layer.
  • the average length is preferably 3 ⁇ m or more. It is preferably 3 to 500 ⁇ m, particularly preferably 3 to 300 ⁇ m. In addition, the relative standard deviation of the length is preferably 40% or less. Moreover, it is preferable that an average diameter is small from a transparency viewpoint, On the other hand, the larger one is preferable from an electroconductive viewpoint.
  • the average diameter of the metal nanowire is preferably 10 to 300 nm, and more preferably 30 to 200 nm. In addition, the relative standard deviation of the diameter is preferably 20% or less.
  • a metal composition of the metal nanowire which concerns on this invention, although it can comprise from the 1 type or several metal of a noble metal element and a base metal element, noble metals (for example, gold, platinum, silver, palladium, rhodium, (Iridium, ruthenium, osmium, etc.) and at least one metal belonging to the group consisting of iron, cobalt, copper, and tin is preferable, and at least silver is more preferable from the viewpoint of conductivity.
  • noble metals for example, gold, platinum, silver, palladium, rhodium, (Iridium, ruthenium, osmium, etc.
  • at least one metal belonging to the group consisting of iron, cobalt, copper, and tin is preferable, and at least silver is more preferable from the viewpoint of conductivity.
  • the metal nanowire according to the present invention includes two or more kinds of metal elements, for example, the metal composition may be different between the inside and the surface of the metal nanowire, or the entire metal nanowire has the same metal composition. May be.
  • the metal nanowires come into contact with each other to form a three-dimensional conductive network, exhibiting high conductivity, and allowing light to pass through the window of the conductive network where no metal nanowire exists.
  • the light from the organic light emitting layer can be efficiently extracted by the scattering effect of the metal nanowires. If the metal nanowire is installed in the electrode part on the side close to the organic light emitting layer part, this scattering effect can be used more effectively, and this is a more preferable embodiment.
  • highly conductive electrodes can be completed by coating. Therefore, even if unevenness due to particles is present on the surface of the organic-inorganic composite material layer, the unevenness can be relaxed, and the possibility of damaging the light emitting layer can be eliminated.
  • the refractive index of the transparent conductive layer is preferably 1.5 or more and 2.0 or less, more preferably 1.6 or more and 1.9 or less.
  • the present invention by optimizing the balance of the refractive index and thickness of the transparent conductive layer, organic electroluminescence layer, and transparent resin film, not only the conventionally known light extraction efficiency is improved.
  • the film physical properties of the organic electroluminescence device having a fine film structure can be greatly improved.
  • Organic EL device Preferred specific examples of the layer structure of the organic EL element are shown below.
  • the light emitting layer preferably contains at least two kinds of light emitting materials having different emission colors, and a single layer or a light emitting layer comprising a plurality of light emitting layers A unit may be formed.
  • the hole transport layer also includes a hole injection layer and an electron blocking layer.
  • 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 structure of the light emitting layer according to the present invention is not particularly limited as long as the light emitting material included satisfies the above requirements.
  • the total thickness of the light emitting layers is preferably in the range of 1 to 100 nm, and more preferably 30 nm or less because a lower driving voltage can be obtained.
  • the sum total of the film thickness of the light emitting layer as used in the field of this invention is a film thickness also including the said intermediate
  • each light emitting layer is preferably adjusted in the range of 1 to 50 nm, more preferably in the range of 1 to 20 nm. There is no particular limitation on the relationship between the film thicknesses of the blue, green and red light emitting layers.
  • a light emitting material or a host compound which will be described later, is formed by forming a film by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, an ink jet method, or the like. it can.
  • a plurality of light emitting materials may be mixed in each light emitting layer, or a phosphorescent light emitting material and a fluorescent light emitting material may be mixed and used in the same light emitting layer.
  • the light emitting layer preferably contains a host compound and a light emitting material (also referred to as a light emitting dopant compound) and emits light from the light emitting material.
  • a light emitting material also referred to as a light emitting dopant compound
  • a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of less than 0.1 is preferable. More preferably, the phosphorescence quantum yield is less than 0.01. Moreover, it is preferable that the volume ratio in the layer is 50% or more among the compounds contained in a light emitting layer.
  • known host compounds may be used alone or in combination of two or more.
  • the organic EL element can be made highly efficient.
  • the host compound used in the present invention may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host). )But it is good.
  • the known host compound a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable.
  • the glass transition point (Tg) is a value determined by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry).
  • a fluorescent compound or a phosphorescent material (also referred to as a phosphorescent compound or a phosphorescent compound) is used.
  • a phosphorescent material is a compound in which light emission from an excited triplet is observed. Specifically, it is a compound that emits phosphorescence at room temperature (25 ° C.), and the phosphorescence quantum yield is 0 at 25 ° C. A preferred phosphorescence quantum yield is 0.1 or more, although it is defined as 0.01 or more compounds.
  • the phosphorescent quantum yield can be measured by the method described in Spectra II, page 398 (1992 version, Maruzen) of Experimental Chemistry Lecture 4 of the 4th edition.
  • the phosphorescence quantum yield in a solution can be measured using various solvents.
  • the phosphorescence quantum yield (0.01 or more) is achieved in any solvent. Just do it.
  • the carrier recombination occurs on the host compound to which the carrier is transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent material.
  • Energy transfer type to obtain light emission from the phosphorescent light emitting material, and another one is that the phosphorescent light emitting material becomes a carrier trap, and recombination of carriers occurs on the phosphorescent light emitting material, and light emission from the phosphorescent light emitting material is obtained.
  • the excited state energy of the phosphorescent material is required to be lower than the excited state energy of the host compound.
  • the phosphorescent light-emitting material can be appropriately selected from known materials used for the light-emitting layer of the organic EL element, and is preferably a complex compound containing a group 8-10 metal in the periodic table of elements. More preferably, an iridium compound, an osmium compound, or a platinum compound (platinum complex compound), or a rare earth complex, and most preferably an iridium compound.
  • Fluorescent light emitters can also be used for the organic electroluminescence device according to the present invention.
  • fluorescent emitters include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, and pyrylium dyes. Examples thereof include dyes, perylene dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors.
  • dopants can also be used in the present invention.
  • International Publication No. 00/70655 pamphlet JP-A Nos. 2002-280178, 2001-181616, 2002-280179, 2001 -181617, 2002-280180, 2001-247859, 2002-299060, 2001-313178, 2002-302671, 2001-345183, 2002 No. 324679, International Publication No. 02/15645, JP 2002-332291, 2002-50484, 2002-332292, 2002-83684, JP 2002-540572, JP 002-117978, 2002-338588, 2002-170684, 2002-352960, WO01 / 93642, JP2002-50483, 2002-1000047 No. 2002-173684, No.
  • At least one light emitting layer may contain two or more kinds of light emitting materials, and the concentration ratio of the light emitting materials in the light emitting layer may vary in the thickness direction of the light emitting layer.
  • ⁇ Middle layer ⁇ In the present invention, a case where a non-light emitting intermediate layer (also referred to as an undoped region) is provided between the light emitting layers will be described.
  • the non-light emitting intermediate layer is a layer provided between the light emitting layers.
  • the film thickness of the non-light emitting intermediate layer is preferably in the range of 1 to 20 nm, and more preferably in the range of 3 to 10 nm to suppress interaction such as energy transfer between adjacent light emitting layers, and This is preferable because a large load is not applied to the voltage characteristics.
  • the material used for the non-light emitting intermediate layer may be the same as or different from the host compound of the light emitting layer, but may be the same as the host material of at least one of the adjacent light emitting layers. preferable.
  • the non-light-emitting intermediate layer may contain a non-light-emitting layer, a compound common to each light-emitting layer (for example, a host compound), and each common host material (where a common host material is used) Including the case where the physicochemical characteristics such as phosphorescence emission energy and glass transition point are the same, and the case where the molecular structure of the host compound is the same, etc.)
  • a compound common to each light-emitting layer for example, a host compound
  • each common host material where a common host material is used
  • the host material is responsible for carrier transportation, and therefore a material having carrier transportation ability is preferable.
  • Carrier mobility is used as a physical property representing carrier transport ability, but the carrier mobility of an organic material generally depends on the electric field strength. Since a material having a high electric field strength dependency easily breaks the balance between injection and transport of holes and electrons, it is preferable to use a material having a low electric field strength dependency of mobility for the intermediate layer material and the host material.
  • the non-light emitting intermediate layer functions as a blocking layer described later, that is, a hole blocking layer and an electron blocking layer. It is done.
  • Injection layer electron injection layer, hole injection layer >> The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer. May be.
  • An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance.
  • Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).
  • anode buffer layer hole injection layer
  • copper phthalocyanine is used.
  • examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.
  • cathode buffer layer (electron injection layer) The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc.
  • Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc.
  • the buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 ⁇ m, although it depends on the material.
  • ⁇ Blocking layer hole blocking layer, electron blocking layer>
  • the blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film as described above. For example, it is described in JP-A Nos. 11-204258 and 11-204359, and “Organic EL elements and the forefront of industrialization (published by NTT Corporation on November 30, 1998)” on page 237. There is a hole blocking (hole blocking) layer.
  • the hole blocking layer has a function of an electron transport layer and is composed of a hole blocking material having a function of transporting electrons and having a remarkably small ability to transport holes, while transporting electrons. By blocking holes, the recombination probability of electrons and holes can be improved. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed.
  • the hole blocking layer is preferably provided adjacent to the light emitting layer.
  • the electron blocking layer in a broad sense, has a function of a hole transport layer, and is made of a material having a function of transporting holes while having a remarkably small ability to transport electrons, while transporting holes. By blocking electrons, the probability of recombination of electrons and holes can be improved. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed.
  • the film thickness of the hole blocking layer and the electron transporting layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.
  • the hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer.
  • the hole transport layer can be provided as a single layer or a plurality of layers.
  • the hole transport material has either hole injection or transport or electron barrier properties, and may be either organic or inorganic.
  • triazole derivatives oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives
  • Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.
  • the above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.
  • aromatic tertiary amine compounds and styrylamine compounds include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl; N, N′-diphenyl-N, N′— Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminoph
  • No. 5,061,569 Having a condensed aromatic ring of, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308 4,4 ′, 4 ′′ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 88 are linked in a starburst type ( MTDATA) and the like.
  • NPD 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl
  • JP-A-4-308 4,4 ′, 4 ′′ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 88 are linked in a starburst type ( MTDATA) and the
  • a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.
  • inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.
  • JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, it is preferable to use these materials because a light-emitting element with higher efficiency can be obtained.
  • the hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. it can.
  • the thickness of the hole transport layer is not particularly limited, but is usually about 5 nm to 5 ⁇ m, preferably 5 to 200 nm.
  • the hole transport layer may have a single layer structure composed of one or more of the above materials.
  • a hole transport layer having a high p property doped with impurities examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.
  • a hole transport layer having such a high p property because a device with lower power consumption can be produced.
  • the electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer.
  • the electron transport layer can be provided as a single layer or a plurality of layers.
  • an electron transport material also serving as a hole blocking material used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode.
  • any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like.
  • a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material.
  • a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.
  • metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (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.
  • Mg Metal complexes replaced with Cu, Ca, Sn, Ga, or Pb can also be used as electron transport materials.
  • metal-free or metal phthalocyanine or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material.
  • the distyrylpyrazine derivatives exemplified as the material of the light emitting layer can also be used as the electron transport material, and inorganic semiconductors such as n-type-Si and n-type-SiC can be used as well as the hole injection layer and the hole transport layer. It can be used as an electron transport material.
  • the electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method.
  • the thickness of the electron transport layer is not particularly limited, but is usually about 5 nm to 5 ⁇ m, preferably 5 to 200 nm.
  • the electron transport layer may have a single layer structure composed of one or more of the above materials.
  • an electron transport layer having a high n property doped with impurities examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.
  • an electron transport layer having such a high n property because an element with lower power consumption can be produced.
  • the counter electrode of the present invention refers to an electrode facing the transparent conductive layer.
  • the transparent conductive layer is mainly used as an anode, the following cathode can be used as the counter electrode.
  • the cathode a material having a work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound and a mixture thereof as an electrode material is used.
  • Electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al 2 O 3 ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like.
  • a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al 2 O 3 ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.
  • the cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering.
  • the sheet resistance as the cathode is preferably several hundred ⁇ / ⁇ or less, and the film thickness is usually selected in the range of 10 nm to 5 ⁇ m, preferably 50 nm to 200 nm.
  • the emission luminance is advantageously improved.
  • a transparent or semi-transparent cathode can be produced by producing a conductive transparent material on the cathode after the metal is produced with a thickness of 1 nm to 20 nm on the cathode.
  • An element in which both the anode and the cathode are transmissive can be manufactured.
  • the organic EL device of the present invention is processed on the light extraction side of the substrate so as to provide, for example, a microlens array structure, or combined with a so-called condensing sheet, for example, with respect to a specific direction, for example, the light emitting surface By condensing in the front direction, the luminance in a specific direction can be increased.
  • quadrangular pyramids having a side of 30 ⁇ m and an apex angle of 90 degrees are arranged two-dimensionally on the light extraction side of the substrate.
  • One side is preferably 10 ⁇ m to 100 ⁇ m. If it becomes smaller than this, the effect of diffraction will generate
  • the condensing sheet it is possible to use, for example, a sheet that has been put to practical use in an LED backlight of a liquid crystal display device.
  • a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used.
  • BEF brightness enhancement film
  • the shape of the prism sheet for example, the base material may be formed by forming a ⁇ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 ⁇ m, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.
  • a light diffusion plate / film may be used in combination with the light collecting sheet.
  • a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.
  • the organic EL device of the present invention can be produced by sequentially forming an organic-inorganic composite material layer, a transparent conductive layer, an organic electroluminescence layer, and a counter electrode on a transparent substrate.
  • the organic-inorganic composite material layer used in the organic EL element of the present invention is formed by a means such as coating a previously prepared organic-inorganic composite material on a transparent substrate.
  • These organic-inorganic composite material layers can be coated by a known method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, or an ink jet method.
  • the organic-inorganic composite material layer can be produced by methods such as curing by ultraviolet rays and heat, film formation by drying, and curing by chemical reaction.
  • a light source for curing by a photocuring reaction to form a cured film layer can be used without limitation as long as it is a light source that generates ultraviolet rays.
  • a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.
  • the irradiation conditions vary depending on individual lamps, irradiation of active rays, usually 5 ⁇ 500mJ / cm 2, but preferably 5 ⁇ 150mJ / cm 2, particularly preferably 20 ⁇ 100mJ / cm 2.
  • a transparent conductive layer can be formed using a desired electrode substance on a transparent substrate on which an organic-inorganic composite material layer is formed.
  • the transparent conductive layer can be formed by a method such as vapor deposition or sputtering.
  • a transparent conductive layer can be formed from a material containing metal nanowires, a conductive polymer, or a transparent conductive metal oxide by a liquid phase film forming method such as a coating method or a printing method.
  • a liquid conductive film forming method such as a coating method or a printing method is applied to a transparent conductive layer containing metal nanowires. It is preferable to form by.
  • coating methods roll coating method, bar coating method, dip coating method, spin coating method, casting method, die coating method, blade coating method, bar coating method, gravure coating method, curtain coating method, spray coating method, doctor coating method Etc. can be used.
  • a letterpress (letter) printing method a stencil (screen) printing method, a lithographic (offset) printing method, an intaglio (gravure) printing method, a spray printing method, an ink jet printing method, and the like can be used.
  • physical surface treatment such as corona discharge treatment or plasma discharge treatment can be applied to the surface of the releasable substrate as a preliminary treatment for improving the adhesion and coating properties.
  • an organic electroluminescence layer As an example of a method for producing this organic electroluminescence layer, a method for producing an organic electroluminescence layer comprising a hole injection layer / a hole transport layer / a light emitting layer / a hole blocking layer / an electron transport layer will be described.
  • the organic compound thin film of the hole injection layer, the hole transport layer, the light emitting layer, the hole blocking layer, and the electron transport layer, which are organic EL element materials, is formed. Let it form.
  • a method for thinning the organic compound thin film there are a vapor deposition method and a wet process (spin coating method, casting method, ink jet method, printing method) as described above, but it is easy to obtain a uniform film and a pinhole. From the point of being difficult to form, a vacuum deposition method, a spin coating method, an ink jet method, and a printing method are particularly preferable. Further, different film forming 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 degree of vacuum of 10 ⁇ 6 to 10 ⁇ 2 Pa, and a vapor deposition rate of 0.01 to It is desirable to select appropriately within a range of 50 nm / second, a substrate temperature of ⁇ 50 to 300 ° C., and a film thickness of 0.1 nm to 5 ⁇ m, preferably 5 to 200 nm.
  • 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 film thickness of 1 ⁇ m or less, preferably in the range of 50 to 200 nm. Is provided.
  • a desired organic EL element is obtained by the above steps.
  • the organic EL element is preferably produced from the hole injection layer to the cathode consistently by a single evacuation, but 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.
  • a DC voltage is applied to the organic EL 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.
  • An alternating voltage may be applied.
  • the alternating current waveform to be applied may be arbitrary.
  • the surface light emitter and the light emitting panel according to the present invention can be used as a display device, a display, and various light emitting sources.
  • 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, and light sources for optical sensors.
  • it is not limited to this, it can be effectively used for a backlight of a liquid crystal display device combined with a color filter and a light source for illumination.
  • the organic EL material according to the present invention can also be applied to an organic EL element that emits substantially white light as a lighting device.
  • a plurality of light emitting colors are simultaneously emitted by a plurality of light emitting materials to obtain white light emission by color mixing.
  • the combination of a plurality of emission colors may include three emission maximum wavelengths of three primary colors of blue, green, and red, or two using the complementary colors such as blue and yellow, blue green and orange, etc. The thing containing the light emission maximum wavelength may be used.
  • a combination of light emitting materials for obtaining a plurality of emission colors includes a combination of a plurality of phosphorescent or fluorescent materials (light emitting dopants), a light emitting material that emits fluorescent or phosphorescent light, and the light emission. Any combination of a dye material that emits light from the material as excitation light may be used, but in the white organic EL device according to the present invention, a method of combining a plurality of light-emitting dopants is preferable.
  • a method of having a plurality of emission dopants in one emission layer, a plurality of emission layers, and an emission wavelength of each emission layer examples thereof include a method in which different dopants are present, and a method in which minute pixels that emit light at different wavelengths are formed in a matrix.
  • patterning may be performed by a metal mask, an ink jet printing method, or the like at the time of film formation, if necessary.
  • patterning only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned.
  • the light emitting material used for the light emitting layer is not particularly limited.
  • the platinum complex according to the present invention is known so as to be suitable for the wavelength range corresponding to the CF (color filter) characteristics. Any one of the light emitting materials may be selected and combined to be whitened.
  • the white light-emitting organic EL element is used as a liquid crystal display as a kind of lamp such as various light-emitting light sources and lighting devices, home lighting, interior lighting, and exposure light source. It is also useful for display devices such as device backlights.
  • backlights such as clocks, signboard advertisements, traffic lights, light sources such as optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processing machines, light sources for optical sensors, etc.
  • Example 1 Preparation of organic-inorganic composite material 1 >> (Preparation of zirconia particles) To a zirconium salt solution in which 2600 g of zirconium oxychloride octahydrate was dissolved in 40 L (liter) of pure water, 340 g of 28% ammonia water and 20 L of diluted ammonia water were added with stirring, to obtain a zirconia precursor. A slurry was prepared.
  • this mixture was dried in the atmosphere at 120 ° C. for 24 hours using a dryer to obtain a solid.
  • the solid was pulverized with an automatic mortar or the like and then baked at 500 ° C. for 1 hour in the air using an electric furnace.
  • This fired product is put into pure water, stirred to form a slurry, washed using a centrifuge, sufficiently removed the added sodium sulfate, dried in a drier, and zirconia particles 1 was prepared.
  • the average particle size was 5 nm.
  • XRD confirmed that the particles were ZrO 2 crystals.
  • a curable resin monomer (fluorene acrylate) and the surface-treated zirconia dispersion (amount that gives a desired refractive index) were mixed at 30 vol%, and a polymerization initiator was added and dissolved.
  • the thin film layer of the organic-inorganic composite material 1 was observed with a scanning electron microscope, and the spherical equivalent particle diameter of each particle was determined from the projected area of 200 zirconia nanoparticles, and the average value was obtained. As a result, the average particle diameter of the zirconia nanoparticles dispersed in the organic-inorganic composite material 1 was 6 nm.
  • Organic-inorganic composite materials 2 and 3 having different refractive indices were prepared by changing the amount of the dispersion liquid of zirconia particles 1 to 20 vol% and 10 vol%, respectively, in the same manner as in the production of organic-inorganic composite material 1. .
  • the refractive index of each material and the average particle diameter of zirconia nanoparticles were measured by the same method, and the obtained results are shown in Table 1.
  • a zirconia particle 2 having an average particle diameter of 20 nm was prepared by adjusting the concentration of the aqueous sodium sulfate solution at the time of particle formation in the same manner as the preparation of the zirconia particle 1 described above. Thereafter, an organic-inorganic composite material 4 was prepared by mixing 30 vol% of the dispersion of zirconia particles 2 in the same manner as the preparation of the organic-inorganic composite material 1. The refractive index and the average particle diameter of the zirconia nanoparticles were measured by the same method, and the obtained results are shown in Table 1.
  • organic-inorganic composite material 5 a hard coat material Z7410E manufactured by JSR Corporation was used. Table 1 shows the results of applying Z7410E onto a smooth glass substrate so as to have a dry film thickness of 1 ⁇ m, irradiating it with ultraviolet rays and curing it, and evaluating it in the same manner.
  • ITO indium tin oxide; refractive index: 1.85
  • the transparent substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.
  • This substrate was transferred to a glove box in accordance with JIS B 9920 under a nitrogen atmosphere, with a measured cleanliness of class 100, a dew point temperature of ⁇ 80 ° C. or lower, and an oxygen concentration of 0.8 ppm.
  • a coating solution for a hole transport layer was prepared as follows in a glove box, and applied with a spin coater under conditions of 1500 rpm and 30 seconds. This substrate was dried by heating at a substrate surface temperature of 150 ° C. for 30 minutes to provide a hole transport layer. The film thickness was 20 nm when it apply
  • the coating liquid for electron carrying layers was prepared as follows, and it apply
  • a resistance heating boat containing potassium fluoride was energized and heated to provide a 3 nm electron injection layer made of potassium fluoride on the substrate.
  • a resistance heating boat containing aluminum was energized and heated, and a cathode having a thickness of 100 nm made of aluminum was provided at a deposition rate of 1 to 2 nm / second.
  • An organic EL device 1 was obtained by sticking to a light diffusing film (MTN-W1) manufactured by Kimoto Co., Ltd. via an adhesive layer on the light emitting surface of the obtained organic EL device.
  • MTN-W1 light diffusing film manufactured by Kimoto Co., Ltd.
  • the thickness of the organic electroluminescence layer was 0.12 ⁇ m, and the thickness of the transparent conductive layer was 0.1 ⁇ m.
  • Organic EL Element 2 ⁇ Production of Organic EL Element 2 >> The above-mentioned organic-inorganic composite material 1 is applied onto a 125 ⁇ m thick biaxially stretched PEN (manufactured by Teijin DuPont; refractive index: 1.75) so as to have a dry film thickness of 2 ⁇ m and cured by irradiation with ultraviolet rays. I let you. Thereafter, an ITO transparent conductive layer, an organic electroluminescence layer, a cathode, and a light extraction member were formed by the same method as the production of the organic EL element 1 to obtain an organic EL element 2.
  • PEN manufactured by Teijin DuPont; refractive index: 1.75
  • the film thickness of the organic electroluminescence layer was 0.12 ⁇ m
  • the film thickness of the transparent conductive layer was 0.1 ⁇ m
  • the film thickness of the organic-inorganic composite material was 2 ⁇ m.
  • Organic EL elements 3-7 were prepared in the same manner as the organic EL element 2 except that the organic-inorganic composite material and the film thickness used were changed as shown in Table 2.
  • silver nanowire dispersion liquid (silver nanowire content: 5% by mass) was prepared by redispersing in the solution.
  • an organic electroluminescence layer, a cathode, and a light extraction member were formed by the same method as the production of the organic EL element 2 to obtain an organic EL element 9.
  • the film thickness of each layer was measured by the same method, the film thickness of the organic electroluminescence layer was 0.12 ⁇ m, the film thickness of the transparent conductive layer was 0.2 ⁇ m, and the film thickness of the organic-inorganic composite material layer was 2 ⁇ m.
  • Organic EL elements 10 to 16 were prepared in the same manner as the organic EL element 9 except that the organic-inorganic composite material and film thickness to be used and the film thickness of the transparent conductive layer were changed as shown in Table 2.
  • a transparent conductive layer, an organic electroluminescence layer, a cathode, and a light extraction member containing silver nanowires were formed in the same manner as in the method for manufacturing the organic EL element 9, and the organic EL element 18 was obtained.
  • A There are no bright spots or black spots, and uniform light emission. O: Bright spots or black spots are observed, but stable light emission is observed. ⁇ : Bright spots or black spots are observed, and the emission luminance is unstable. Does not emit light.
  • the organic electroluminescence device having the configuration of the present invention has high external extraction quantum efficiency and excellent durability against stress due to bending and heating and heating.
  • Example 2 The organic EL element 10 of the present invention produced in Example 1 was covered with a glass case to obtain a lighting device.
  • the glass cover was filled with nitrogen gas, and a water capturing agent was provided in the glass cover on the side opposite to the light emitting surface.
  • the lighting device according to the present invention has high luminous efficiency and can be used as a thin lighting device that emits white light with a long light emission lifetime.
  • Example 3 The organic EL element 10 of the present invention produced in Example 1 was covered with a transparent barrier film (transparent resin film coated with a silicon dioxide film) to obtain a flexible lighting device.
  • the illuminating device according to the present invention can be used as a thin illuminating device that emits white light having a long emission life while maintaining high luminous efficiency even with some bending motion.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electroluminescent Light Sources (AREA)

Abstract

L'invention concerne un élément électroluminescent organique dans lequel une couche conductrice transparente, une couche électroluminescente organique et une contre-électrode sont agencées séquentiellement sur une base transparente. L'élément électroluminescent organique est caractérisé en ce qu'une couche de matériau composite organique-inorganique est formée entre la base transparente et la couche conductrice transparente de telle manière que la couche de matériau composite organique-inorganique est en contact avec la couche conductrice transparente, et que les épaisseurs de film des couches satisfont aux formules suivantes. L'invention concerne également un dispositif d'éclairage. Formule (1): 5 < t3/(t1 + t2) < 50 Formule (2): 1 < t3 < 20 Dans les formules, t1 représente l'épaisseur de film de la couche électroluminescente organique (µm), t2 représente l'épaisseur de film de la couche conductrice transparente et t3 représente l'épaisseur de film de la couche de matériau composite organique-inorganique (µm).
PCT/JP2010/057347 2009-05-20 2010-04-26 Elément électroluminescent organique et dispositif d'éclairage utilisant celui-ci Ceased WO2010134419A1 (fr)

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000260572A (ja) * 1999-03-04 2000-09-22 Sumitomo Electric Ind Ltd 有機エレクトロルミネッセンスパネル
JP2004296429A (ja) * 2003-03-07 2004-10-21 Nitto Denko Corp 有機エレクトロルミネッセンス素子とこの素子を用いた面光源および表示装置
JP2005190931A (ja) * 2003-12-26 2005-07-14 Nitto Denko Corp エレクトロルミネッセンス素子とこれを用いた面光源および表示装置
JP2006171228A (ja) * 2004-12-14 2006-06-29 Dainippon Printing Co Ltd 自発光型表示装置用カラーフィルタ
JP2006241183A (ja) * 2005-02-28 2006-09-14 Fuji Photo Film Co Ltd エレクトロルミネッセンス蛍光体及びそれを用いたｅｌ素子
JP2006294491A (ja) * 2005-04-13 2006-10-26 Seiko Epson Corp エレクトロルミネッセンス装置、エレクトロルミネッセンス装置の製造方法、電子機器
JP2007265987A (ja) * 2006-03-03 2007-10-11 Semiconductor Energy Lab Co Ltd 発光素子、発光装置、発光装置の作製方法及びシート状のシール材
JP2007280699A (ja) * 2006-04-05 2007-10-25 Matsushita Electric Ind Co Ltd 発光デバイス

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000260572A (ja) * 1999-03-04 2000-09-22 Sumitomo Electric Ind Ltd 有機エレクトロルミネッセンスパネル
JP2004296429A (ja) * 2003-03-07 2004-10-21 Nitto Denko Corp 有機エレクトロルミネッセンス素子とこの素子を用いた面光源および表示装置
JP2005190931A (ja) * 2003-12-26 2005-07-14 Nitto Denko Corp エレクトロルミネッセンス素子とこれを用いた面光源および表示装置
JP2006171228A (ja) * 2004-12-14 2006-06-29 Dainippon Printing Co Ltd 自発光型表示装置用カラーフィルタ
JP2006241183A (ja) * 2005-02-28 2006-09-14 Fuji Photo Film Co Ltd エレクトロルミネッセンス蛍光体及びそれを用いたｅｌ素子
JP2006294491A (ja) * 2005-04-13 2006-10-26 Seiko Epson Corp エレクトロルミネッセンス装置、エレクトロルミネッセンス装置の製造方法、電子機器
JP2007265987A (ja) * 2006-03-03 2007-10-11 Semiconductor Energy Lab Co Ltd 発光素子、発光装置、発光装置の作製方法及びシート状のシール材
JP2007280699A (ja) * 2006-04-05 2007-10-25 Matsushita Electric Ind Co Ltd 発光デバイス

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