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WO2018221173A1 - Élément électroluminescent organique, dispositif d'affichage et dispositif d'éclairage - Google Patents

Élément électroluminescent organique, dispositif d'affichage et dispositif d'éclairage Download PDF

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Publication number
WO2018221173A1
WO2018221173A1 PCT/JP2018/018451 JP2018018451W WO2018221173A1 WO 2018221173 A1 WO2018221173 A1 WO 2018221173A1 JP 2018018451 W JP2018018451 W JP 2018018451W WO 2018221173 A1 WO2018221173 A1 WO 2018221173A1
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group
ring
organic
light emitting
layer
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Japanese (ja)
Inventor
小林　史明
秀雄 ▲高▼
鈴木　隆嗣
一成 多田
卓史 波多野
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Konica Minolta Inc
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Konica Minolta Inc
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    • 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
    • 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

Definitions

  • the present invention relates to an organic electroluminescence element, a display device, and a lighting device, and in particular, an organic electroluminescence element that can improve the density of a light emitting layer, improve luminous efficiency and element lifetime, and is easy to manufacture, and the organic
  • the present invention relates to a display device and an illumination device including an electroluminescence element.
  • EL organic electroluminescence
  • An organic EL element has a structure in which a light-emitting layer containing a compound that emits light (hereinafter also referred to as “light-emitting material”) is sandwiched between a cathode and an anode, and recombines by injecting electrons and holes into the light-emitting layer.
  • This is an element that generates excitons (excitons) by light emission, and emits light by utilizing light emission (fluorescence / phosphorescence) when the excitons are deactivated.
  • Such an organic EL element can emit light at a low voltage of several V to several tens V, and further has a wide viewing angle and high visibility because it is a self-luminous type.
  • the organic EL element is a thin-film type complete solid-state element, it has attracted attention from the viewpoints of space saving and portability.
  • an organic EL element capable of emitting light with better luminous efficiency, luminance and chromaticity is desired.
  • an organic EL element for example, see Patent Document 1 using zinc sulfide (ZnS), which is an inorganic material, as a hole injection layer, an electron transport layer, and a protective layer
  • ZnS zinc sulfide
  • An organic EL element used in the above has been proposed (see, for example, Patent Documents 2 and 3).
  • Patent Document 1 zinc sulfide is used for the hole injection layer.
  • the element evaluation is performed as an organic EL element using NPD as the hole transport layer between the hole injection layer and the light emitting layer. Is going. Therefore, detailed investigations have been made on the evaluation of the element lifetime and the like in a layer configuration in which electrodes / zinc sulfide / light-emitting layers are stacked in this order (that is, a configuration in which a light-emitting layer is directly stacked on a layer containing zinc sulfide). Not.
  • Patent Documents 2 and 3 only describe that the use of zinc sulfide for the electron transport layer can improve the electron injection property and the response speed.
  • the present invention has been made in view of the above problems and situations, and a solution to that problem is to improve the density of the light emitting layer, improve the light emission efficiency and the device life, and can be easily manufactured. It is providing the luminescent element, the display apparatus and illuminating device which were equipped with the said organic electroluminescent element.
  • the present inventor in the process of examining the cause of the above problems, by directly laminating the light emitting layer on the layer containing zinc sulfide, the density of the light emitting layer is improved, The present inventors have found that an organic electroluminescence device and the like that can improve the light emission efficiency and the device life and can be easily manufactured can be provided.
  • An organic electroluminescence device in which at least a hole injection layer and a light emitting layer are laminated between a pair of electrodes, The hole injection layer contains zinc sulfide; The light emitting layer is directly laminated on the hole injection layer, The light emitting layer contains an organic compound that interacts with the zinc sulfide, and An organic electroluminescence device wherein the density of the light emitting layer is in the range of 1.0 to 1.8 g / cm 3 .
  • a display apparatus provided with the organic electroluminescent element as described in any one of Claim 1 to 3.
  • An illuminating device provided with the organic electroluminescent element as described in any one of 1st term
  • an organic electroluminescence device that can improve the density of the light emitting layer, achieve high luminous efficiency and increase the lifetime of the device, and is easy to manufacture.
  • a light emitting layer containing an organic compound that interacts with ZnS is directly laminated on a hole injection layer made of at least zinc sulfide (ZnS). Therefore, since the hole injection layer functions as a substrate of the light emitting layer, when forming the light emitting layer on the substrate, the organic compound is caused by the interaction (affinity) between ZnS (especially S) and organic compound molecules.
  • ZnS zinc sulfide
  • Molecular molecules are regularly arranged at the interface between the hole injection layer and the light emitting layer, and accordingly, organic compound molecules in the vicinity of the interface and further inside are also regularly arranged. It is assumed that the regular arrangement of the organic compound molecules improves the density of the light emitting layer and suppresses the generation of defects in the light emitting layer. As a result, it is presumed that an element having a light emitting layer with high luminous efficiency and long life could be formed.
  • ZnS has a hole transport function and exciton stabilization (block) function
  • recombination of carriers in the vicinity of the interface between the hole injection layer and the light emitting layer is increased, which contributes to the improvement of the light emission efficiency. Is also inferred.
  • such a phenomenon is considered to have an influence on the improvement of the density due to the temporal change of the morphology (morphology / fine structure) of the light emitting layer.
  • ZnS which is an inorganic material it is excellent in solvent tolerance, the choice of the solvent of a light emitting layer spreads, and it becomes easy to manufacture an organic EL element.
  • 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 Schematic diagram of lighting device Cross section of the lighting device
  • the organic electroluminescence device of the present invention is an organic electroluminescence device in which at least a hole injection layer and a light emitting layer are laminated between a pair of electrodes, wherein the hole injection layer contains zinc sulfide, and the light emission A layer is directly laminated on the hole injection layer, the light-emitting layer contains an organic compound having an interaction with the zinc sulfide, and the density of the light-emitting layer is 1.0 to 1.8 g / Within the range of cm 3 .
  • This feature is a technical feature common to or corresponding to the claimed invention.
  • the hole injection layer contains zinc sulfide doped with a metal oxide from the viewpoint of further improving luminous efficiency.
  • the thickness of the hole injection layer is preferably in the range of 5 to 10 nm from the viewpoint that the light emission efficiency and the device life can be further improved.
  • the organic electroluminescence element of the present invention is suitably used for display devices and lighting devices.
  • the organic electroluminescence device of the present invention (hereinafter also referred to as “organic EL device”) is an organic electroluminescence device in which at least a hole injection layer and a light emitting layer are laminated between a pair of electrodes, The injection layer contains zinc sulfide, the light emitting layer is laminated directly on the hole injection layer, the light emitting layer contains an organic compound that interacts with the zinc sulfide, and the light emitting layer Is in the range of 1.0 to 1.8 g / cm 3 .
  • the density of the light emitting layer according to the present invention is preferably in the range of 1.4 to 1.7 g / cm 3 from the viewpoint of further improving the density of the light emitting layer and further improving the light emission efficiency and the device lifetime.
  • the density of the light emitting layer can be determined by the X-ray reflectivity method. It is obtained by measuring the reflectance at a very low angle, for example, in the range of 0.2 to 2 degrees, and fitting the obtained reflectance curve to the reflectance formula of the multilayer film sample obtained from the Fresnel formula. . For the fitting method, see L.C. G. Parrat. Phis. Rev. 95 359 (1954).
  • the X-ray generation source uses copper as a target, operates at 50 kV-300 mA, and uses X-rays monochromatic with a multilayer mirror and a Ge (111) channel cut monochromator. The measurement was performed using the software-ATX-Crystal Guide Ver.
  • the pair of electrodes is an anode and a cathode.
  • the organic EL device of the present invention preferably, an anode and a cathode, and at least a hole injection layer and a light emitting layer are laminated between these electrodes on a substrate.
  • the light-emitting layer refers to a layer that emits light when an electric current is applied to an electrode composed of a cathode and an anode.
  • an electric current is applied to an electrode composed of a cathode and an anode
  • the organic EL device of the present invention may have an electron injection layer and an electron transport layer in addition to the hole injection layer and the light emitting layer as necessary, and these layers are sandwiched between the cathode and the anode. Take the structure.
  • 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 substrate that can be used in the organic EL device of the present invention (hereinafter also referred to as a base, a support substrate, a base material, a support, etc.) is not particularly limited, and a glass substrate, a plastic substrate, or 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. In order to prevent oxygen and water from entering from the substrate side, 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 inorganic polymer 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.
  • barrier film a 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). It is preferably a high gas barrier film having a water vapor permeability of 1 ⁇ 10 ⁇ 5 g / (m 2 ⁇ 24 h) or less.
  • the material constituting the barrier film is not particularly limited as long as it is a material having a function of suppressing intrusion of elements that cause deterioration of the element such as moisture and oxygen.
  • a metal oxide, a metal oxynitride, a metal nitride, or the like Inorganic materials, organic materials, hybrid materials of the both, or the like can be used.
  • Metal oxides, metal oxynitrides or metal nitrides include metal oxides such as silicon oxide, titanium oxide, indium oxide, tin oxide, indium tin oxide (ITO) and aluminum oxide, and metal nitrides 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 gas barrier film is preferable, and further, the oxygen permeability measured by a method according to JIS K 7126-1987 is 1 ⁇ 10 ⁇ 3 mL / (m 2 ⁇ 24 h ⁇ atm) or less, A high gas barrier film having a water vapor permeability of 1 ⁇ 10 ⁇ 5 g / (m 2 ⁇ 24 h) or less is preferable.
  • the method of providing the barrier film on the resin film is not particularly limited, and any method may be used.
  • vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam method, ion plating Method plasma polymerization method, atmospheric pressure plasma polymerization method, CVD method (chemical vapor deposition: for example, plasma CVD method, laser CVD method, thermal CVD method, etc.), coating method, sol-gel method, etc.
  • 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 include a metal plate such as aluminum and stainless steel, a film, an opaque resin substrate, a ceramic substrate, 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 a pattern accuracy is not required (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. Furthermore, although the layer thickness of the anode depends on the material constituting it, it is usually selected within the range of 10 nm to 1 ⁇ m, preferably 10 to 200 nm.
  • the material used for the hole injection layer (also referred to as “hole injection / transport layer”) according to the present invention contains zinc sulfide (ZnS) applicable as a hole injection material and a hole transport material. . Therefore, the hole injection layer in the present invention is a hole injection layer having a hole transport function.
  • the hole injection material has either hole injection or electron barrier properties.
  • the hole transport material has an electron barrier property and has a function of transporting holes to the light emitting layer.
  • the hole injection layer according to the present invention may be doped with a metal oxide or the like as long as it contains ZnS.
  • metal oxides that can be doped with ZnS include molybdenum oxide, vanadium oxide, and tungsten oxide.
  • the doping concentration of the metal oxide is preferably in the range of 25 to 75%.
  • the hole injection material used for the hole injection layer may be either organic or inorganic. Specifically, 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 ′.
  • No. 5,061,569 Having a ring in the molecule, for example, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (hereinafter abbreviated as ⁇ -NPD), 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) in which triphenylamine units described in No. 308688 are linked in three starburst types
  • inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material.
  • the hole injection layer may be formed by either a dry process or a wet process, and the hole injection material may be formed using, for example, 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.
  • the thin film can be formed by a known method such as a method.
  • the thickness of the hole injection layer is in the range of 5 to 10 nm, the density of the light emitting layer can be in the range of 1.0 to 1.7 g / cm 3 , and the light emission efficiency and the device life can be reduced. It is preferable in that it can be further improved.
  • the light emitting layer according to the present invention is directly laminated on the hole injection layer, the light emitting layer contains an organic compound having an interaction with zinc sulfide contained in the hole injection layer, and the density of the light emitting layer is It is within the range of 1.0 to 1.8 g / cm 3 .
  • the density of the light emitting layer is more preferably in the range of 1.4 to 1.7 g / cm 3 .
  • the thickness of the hole injection layer is adjusted within the range of 5 to 10 nm as described above, or the ZnS layer is doped with a metal oxide.
  • 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 injection 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.
  • Organic compounds used in the light emitting layer As an organic compound used for a light emitting layer, it is preferable that the host compound and the light emission dopant are contained.
  • the light emitting dopant contained in the light emitting layer may be contained at a uniform concentration or may have a concentration distribution in the thickness direction of the light emitting layer.
  • the thickness of each light emitting layer included in each light emitting unit is not particularly limited, but the homogeneity of a layer to be formed and a high voltage unnecessary for light emission are not required.
  • the phosphorescent host compound and phosphorescent dopant contained in the light emitting layer will be described.
  • Phosphorescent host compound used in the present invention is not particularly limited in terms of structure, but typically includes, for example, a carbazole derivative, a triarylamine derivative, an aromatic borane derivative, Those having basic skeletons such as nitrogen heterocyclic compounds, thiophene derivatives, furan derivatives, oligoarylene compounds, carboline derivatives and diazacarbazole derivatives (here, diazacarbazole derivatives are carbonizations constituting the carboline ring of carboline derivatives) And the like in which at least one carbon atom of the hydrogen ring is substituted with a nitrogen atom.
  • the phosphorescent host compound may be used alone or in combination of two or more.
  • the phosphorescent host compound used in the light emitting layer according to the present invention is preferably a compound represented by the following general formula (a).
  • X represents NR ′, O, S, CR′R ′′ or SiR′R ′′.
  • R ′ and R ′′ each independently represents a hydrogen atom or a substituent.
  • Ar represents an aromatic ring.
  • N represents an integer of 0 to 8.
  • examples of the substituent represented by R ′ and R ′′ include an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group).
  • an alkyl group for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group.
  • X preferably represents NR ′ or O
  • R ′ particularly preferably represents an aromatic hydrocarbon group or an aromatic heterocyclic group.
  • examples of the aromatic ring represented by Ar include an aromatic hydrocarbon ring and an aromatic heterocyclic ring.
  • the aromatic ring represented by Ar may be either a single ring or a condensed ring, and further has a substituent represented by the above R ′ and R ′′ even if it is unsubstituted. May be.
  • examples of the aromatic hydrocarbon ring represented by Ar include a benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, and triphenylene.
  • examples of the aromatic heterocycle represented by Ar include a furan ring, a dibenzofuran ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring.
  • the aromatic ring represented by Ar is preferably a carbazole ring, carboline ring, dibenzofuran ring or benzene ring, more preferably a carbazole ring, carboline ring or benzene ring, Preferred is a benzene ring having a substituent, and most preferred is a benzene ring having a carbazolyl group.
  • the aromatic ring represented by Ar is preferably a condensed ring having three or more rings, as shown below.
  • Specific examples of the aromatic hydrocarbon condensed ring in which three or more rings are condensed include, for example, naphthacene ring, anthracene ring, tetracene ring, pentacene ring, hexacene ring, phenanthrene ring, pyrene ring, benzopyrene ring, benzoazulene ring, Chrysene ring, benzochrysene ring, acenaphthene ring, acenaphthylene ring, triphenylene ring, coronene ring, benzocoronene ring, hexabenzocoronene ring, fluorene ring, benzofluorene ring, fluoranthene ring, perylene ring, naphthoperylene ring, penta
  • aromatic heterocyclic condensed ring in which three or more rings are condensed include, for example, an acridine ring, a benzoquinoline ring, a carbazole ring, a carboline ring, a phenazine ring, a phenanthridine ring, a phenanthroline ring, and a carboline ring.
  • n represents an integer of 0 to 8, preferably an integer of 0 to 2, particularly 1 or 2 when X is O or S. It is preferable.
  • the phosphorescent host compound used in the present invention may be a 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 ’s okay.
  • the phosphorescent host compound a compound having a hole transporting ability and an electron transporting ability, which prevents emission of light from being increased in wavelength and has a high Tg (glass transition temperature) is preferable.
  • a compound having a glass transition point of 90 ° C. or higher is preferable, and a compound having a glass transition temperature of 130 ° C. or higher is preferable because excellent characteristics can be obtained.
  • the glass transition point (Tg) is a value obtained by a method based on JIS K 7121 using DSC (Differential Scanning Calorimetry).
  • a conventionally known host compound can also be used.
  • conventionally known host compounds compounds described in the following documents can be suitably used.
  • the phosphorescent host compound may be different for each light emitting layer of each light emitting unit, but the same compound is preferable in terms of production efficiency and process management.
  • the phosphorescent host compound preferably has a lowest excited triplet energy (T1) larger than 2.7 eV because higher luminous efficiency can be obtained.
  • the lowest excited triplet energy as used in the present invention refers to the peak energy of an emission band corresponding to the transition between the lowest vibrational bands of a phosphorescence emission spectrum observed at a liquid nitrogen temperature after dissolving a host compound in a solvent.
  • the phosphorescence emission dopant which can be used for this invention can be selected from a well-known thing. For example, it can be selected from complex compounds containing metals of Group 8 to Group 10 in the periodic table of elements, preferably iridium compounds, osmium compounds or platinum compounds (platinum complex compounds), or rare earth complexes. Of these, iridium compounds are most preferred.
  • a phosphorescent light emitting material is preferable as a light emitter that emits light in at least the green, yellow, and red regions.
  • Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group.
  • Rb and Rc each independently represents a hydrogen atom or a substituent.
  • A1 represents a residue necessary for forming an aromatic ring or an aromatic heterocyclic ring.
  • M represents Ir or Pt.
  • Ra represents a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group.
  • Rb, Rc, Rb 1 and Rc 1 each independently represent a hydrogen atom or a substituent.
  • A1 represents a residue necessary for forming an aromatic ring or an aromatic heterocyclic ring.
  • M represents Ir or Pt.
  • Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group.
  • Rb and Rc each independently represents a hydrogen atom or a substituent.
  • A1 represents a residue necessary for forming an aromatic ring or an aromatic heterocyclic ring.
  • M represents Ir or Pt.
  • examples of the aliphatic group represented by Ra include an alkyl group (eg, methyl group, ethyl group, propyl group, butyl group, pentyl group, isopentyl group, 2-ethyl group). -Hexyl group, octyl group, undecyl group, dodecyl group, tetradecyl group) and cycloalkyl group (for example, cyclopentyl group, cyclohexyl group).
  • alkyl group eg, methyl group, ethyl group, propyl group, butyl group, pentyl group, isopentyl group, 2-ethyl group.
  • cycloalkyl group for example, cyclopentyl group, cyclohexyl group.
  • Examples of the aromatic group represented by Ra include a phenyl group, a tolyl group, an azulenyl group, an anthranyl group, a phenanthryl group, a pyrenyl group, a chrycenyl group, a naphthacenyl group, an o-terphenyl group, an m-terphenyl group, p -Terphenyl group, acenaphthenyl group, coronenyl group, fluorenyl group, perylenyl group and the like.
  • heterocyclic group represented by Ra examples include pyrrolyl, indolyl, furyl, thienyl, imidazolyl, pyrazolyl, indolizinyl, quinolinyl, carbazolyl, indolinyl, thiazolyl, pyridyl, pyridazinyl.
  • These groups may have a substituent represented by R ′ and R ′′ in the general formula (a).
  • examples of the substituent represented by Rb, Rc, Rb 1 and Rc 1 include an alkyl group (eg, methyl group, ethyl group, propyl group, isopropyl group, tert- Butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (eg, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (eg, vinyl group, allyl group) Etc.), alkynyl groups (eg ethynyl group, propargyl group etc.), aryl groups (eg phenyl group, naphthyl group etc.), aromatic heterocyclic groups (eg furyl group, thienyl group, pyridyl
  • examples of the aromatic ring represented by A1 include a benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, and naphthacene ring.
  • Triphenylene ring Triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring , Pyrene ring, pyranthrene ring, anthraanthrene ring and the like.
  • aromatic heterocycle represented by A1 for example, furan ring, thiophene ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, benzimidazole ring, oxadiazole ring, triazole ring, imidazole ring, Pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, carbazole ring, carboline ring, diazacarbazole ring (the hydrocarbon ring constituting the carboline ring) A ring in which one of the carbon atoms is substituted with a nitrogen atom.) And the like.
  • M represents Ir or Pt, with Ir being preferred.
  • the structures of the general formulas (A) to (C) are partial structures, and a ligand corresponding to the valence of the central metal is necessary for the structure itself to be a light-emitting dopant of a completed structure.
  • ligands include, for example, halogen (eg, fluorine atom, chlorine atom, bromine atom or iodine atom), aryl group (eg, phenyl group, p-chlorophenyl group, mesityl group, Tolyl group, xylyl group, biphenyl group, naphthyl group, anthryl group, phenanthryl group, etc.), alkyl group (for example, methyl group, ethyl group, isopropyl group, hydroxyethyl group, methoxymethyl group, trifluoromethyl group, t-butyl) Group), alkyloxy group, aryloxy group, alkylthio group, arylthio group,
  • a tris body having a completed structure with three partial structures of the general formulas (A) to (C) is preferable.
  • Fluorescent luminescent dopants include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes. Fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes, polythiophene dyes, rare earth complex phosphors, and the like.
  • 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.
  • materials for organic EL elements used in this electron injection layer include heterocyclic rings such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, naphthalene perylene, and the like.
  • Examples include tetracarboxylic anhydride, carbodiimide, 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 in which the 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.
  • a preferable material for an organic EL element used for the electron transport layer preferably has a fluorescence maximum wavelength at 415 nm or less. That is, the organic EL element material used for the electron transport layer is preferably a compound that has an electron transport ability, prevents the emission of light from becoming longer, 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 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 block layer). Examples thereof include, for example, WO00 / 70655, JP2001-313178, JP11-204258, and 11-204359. And the like described in page 237 of “Organic EL devices and their forefront of industrialization” (issued on November 30, 1998 by NTS).
  • a hole blocking layer hole blocking layer
  • a buffer layer may exist between the anode and 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.
  • cathode As the cathode of the organic EL element, a metal having a low work function (less than 4 eV) (hereinafter referred to as an electron injecting metal), an alloy, a metal electrically conductive compound, or a mixture thereof is used.
  • 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.
  • 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.
  • Specific examples of 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 functional layer by depositing 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 following is preferable, and the layer thickness is usually selected in the range of 10 nm to 1 ⁇ m, preferably 50 to 200 nm.
  • the layer thickness is usually selected in the range of 10 nm to 1 ⁇ m, preferably 50 to 200 nm.
  • it is preferable that either one of the anode and the cathode of the organic EL element is made transparent or semi-transparent because the light emission efficiency is improved.
  • a method for producing an organic EL device comprising anode / hole injection 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. Make it.
  • the organic compound thin film of the hole injection layer, the light emitting layer, the electron transport layer, the electron injection layer, and the hole blocking layer containing at least ZnS described above is sequentially formed thereon.
  • spin coating methods there are spin coating methods, casting methods, ink jet methods, vapor deposition methods, printing methods, and the like as methods for thinning these organic compound thin films.
  • a vacuum deposition method or a spin coating method is preferable from the viewpoint that it is difficult to form.
  • the spin coating method is particularly preferable because the composition of the present invention can be used as a coating solution.
  • 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 silicone 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. 1 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.
  • FIG. 2 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. 2 shows a case where the light emitted from the pixel 53 is extracted in the white arrow direction (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 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. 3 is a schematic diagram illustrating 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. 3, but shown in FIG. 1) 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 drive 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. 3). 2) Each organic EL element 60 emits light. Such 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.
  • a passive matrix light emission drive in which the organic EL element emits light according to the data signal only when the scanning signal is scanned.
  • FIG. 4 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 lighting device of the present invention includes home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources of optical storage media, exposure light sources of electrophotographic copying machines, light sources of optical communication processors, and optical sensors.
  • the present invention is not limited to these.
  • the non-light emitting surface of the organic EL device of the present invention is covered with a glass case, a 300 ⁇ m thick glass substrate is used as a sealing substrate, and an epoxy photocurable adhesive (LUX The track LC0629B) is applied, and this is overlaid on the cathode and brought into close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured, sealed, and illuminated as shown in FIGS.
  • a device can be formed.
  • FIG. 5 shows a schematic diagram of the lighting device.
  • the organic EL element 101 is covered with a glass cover 102.
  • the sealing operation with the glass cover 102 is preferably performed in a glove box (in an atmosphere of high purity nitrogen gas having a purity of 99.999% or more) in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere.
  • FIG. 6 shows a cross-sectional view of the lighting device.
  • the lighting device mainly includes a cathode 105, an organic EL layer 106, and a glass substrate 107 with a transparent electrode, and these members are covered with a glass cover 102.
  • the glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.
  • the organic EL element of the present invention is not only the display device and the display, but also various light emitting sources, lighting devices, home lighting, interior lighting, a kind of lamp such as an exposure light source, and a liquid crystal display. 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.
  • ITO Indium Tin Oxide
  • 1.0 nm of lithium fluoride was deposited as an electron injection layer and 110 nm of aluminum was deposited as a cathode, thereby fabricating an organic EL device 1-1.
  • the density of the light emitting layer of each organic EL element was computed by the X-ray reflectivity method.
  • the X-ray generation source was a copper target, operated at 50 kV-300 mA, and X-rays monochromatized with a multilayer mirror and a Ge (111) channel cut monochromator were used.
  • the organic EL device using ZnS according to the present invention as the material for the hole injection layer has an initial performance higher than that of the comparative organic EL device not using ZnS as the material for the hole injection layer. It is excellent in any of luminous efficiency, half life, and density of the light emitting layer.
  • Example 2 Example in which the density of the light emitting layer can be controlled by the thickness when ZnS is used for the hole injection layer ⁇ Preparation of Organic EL Element 2-1> Patterning was performed on a substrate (NAV 45 manufactured by AvanStrate Co., Ltd.) on which a 100 nm ITO film was formed as an anode on a 100 mm ⁇ 100 mm ⁇ 1.1 mm glass substrate. Thereafter, the transparent support 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 transparent support substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while ZnS is put into a molybdenum resistance heating boat, 1-6 is put into another molybdenum resistance heating boat, another molybdenum resistance heating boat D-28 was put in, LiF was put in another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.
  • the pressure in the vacuum chamber was reduced to 4 ⁇ 10 ⁇ 4 Pa, and the heating boat containing ZnS was heated by energization.
  • the vapor deposition rate was 0.1 nm / sec. A layer was provided.
  • the produced organic EL element it carried out similarly to the said Example 1, and measured the luminous efficiency (external extraction quantum efficiency (EQE)), luminous lifetime, and the density of the light emitting layer.
  • EQE extraction quantum efficiency
  • the organic EL device in which the thickness of the hole injection layer made of ZnS is in the range of 5 to 10 nm is higher in luminous efficiency (external extraction quantum efficiency) than other organic EL devices, Both the half life (light emission life) and the density of the light emitting layer are excellent.
  • Example 3 Example for showing the effect of ZnS contained in the hole injection layer regardless of the material of the light emitting layer ⁇ Production of Organic EL Element 3-1> Patterning was performed on a substrate (NAV 45 manufactured by AvanStrate Co., Ltd.) on which a 100 nm ITO film was formed as an anode on a 100 mm ⁇ 100 mm ⁇ 1.1 mm glass substrate. Thereafter, the transparent support 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 transparent support substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while ZnS is put into a molybdenum resistance heating boat, 1-6 is put into another molybdenum resistance heating boat, another molybdenum resistance heating boat D-28 was placed in the container, KF was placed in another molybdenum resistance heating boat, and attached to a vacuum deposition apparatus.
  • the vacuum chamber was depressurized to 4 ⁇ 10 ⁇ 4 Pa, heated by energizing the heating boat containing ZnS, and deposited on a transparent support substrate at a deposition rate of 0.1 nm / second to form a 10 nm hole injection layer.
  • ZnS is placed in a molybdenum resistance heating boat, and ⁇ -NPD (4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl), 1-6 in another molybdenum resistance heating boat, D-28 in another molybdenum resistance heating boat, another molybdenum resistance KF was put into a heating boat and attached to a vacuum deposition apparatus.
  • the vacuum chamber was depressurized to 4 ⁇ 10 ⁇ 4 Pa, heated by energizing the heating boat containing ZnS, and deposited on a transparent support substrate at a deposition rate of 0.1 nm / second to form a 10 nm hole injection layer.
  • Example 4 Solvent resistance of a layer containing ZnS A glass substrate of 100 mm x 100 mm x 1.1 mm was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus, while ZnS was placed in a molybdenum resistance heating boat and attached to the vacuum deposition apparatus. Next, the pressure in the vacuum chamber was reduced to 4 ⁇ 10 ⁇ 4 Pa, and the heating boat containing ZnS was energized and heated, and deposited on the substrate at a deposition rate of 0.1 nm / second to form a 50 nm hole injection layer.
  • a provided single membrane was prepared.
  • a layer containing ZnS by adding various solvents as shown in Table IV below to the prepared hole injection layer (single film) containing ZnS, spin-coating, drying, and measuring the thickness. The solvent resistance of was examined.
  • Table IV The abbreviations in Table IV are as follows: TFPO: 2,2,3,3-tetrafluoro-1-propanol THF: tetrahydrofuran 2mTHF: 2-methyltetrahydrofuran
  • Example 5 Production of illumination device ⁇ Production of white light-emitting organic EL element 4-1>
  • the transparent support substrate provided with the ITO transparent electrode used in the production of the organic EL element 1-1 was attached to a vacuum deposition apparatus, and the vacuum chamber was decompressed to 4 ⁇ 10 ⁇ 4 Pa.
  • 10 nm of ZnS was deposited as a hole injection layer to provide a hole injection layer.
  • spin coating was performed at 2000 rpm for 30 seconds. A thin film was formed.
  • the first light emitting layer was formed by vacuum drying at 60 ° C. for 1 hour. Further, on this first light-emitting layer, a solution in which HOST-94 (100 mg) as a host compound and D-84 (16 mg) as a dopant were dissolved in 6 mL of hexafluoroisopropanol (HFIP) was used, and the conditions were 2000 rpm for 30 seconds. A thin film was formed by spin coating and vacuum dried at 60 ° C. for 1 hour to form a second light emitting layer.
  • HOST-94 100 mg
  • D-84 16 mg
  • a thin film was formed by spin coating and vacuum dried at 60 ° C. for 1 hour to form a second light emitting layer.
  • This substrate is fixed to a substrate holder of a vacuum deposition apparatus, and the vacuum chamber is depressurized to 4 ⁇ 10 ⁇ 4 Pa, and then ET-35 is deposited on the second light emitting layer to form an electron transport layer having a thickness of 30 nm. Subsequently, lithium fluoride was vapor-deposited to form a cathode buffer layer having a thickness of 0.5 nm, and aluminum was further vapor-deposited to form a cathode having a thickness of 110 nm. Thus, an organic EL element 4-1 was produced. .
  • Example 6 Production of full-color display device ⁇ Production of blue light-emitting element>
  • the organic EL device 1-1 of Example 1 was used as a blue light emitting device.
  • a green light emitting device was produced in the same manner as the organic EL device 1-1 except that D-86 was used as a green light emitting dopant.
  • red light emitting element A red light emitting device was produced in the same manner as the organic EL device 1-1 except that Ir-9 was used as a red light emitting dopant.
  • each of the red, green and blue light emitting organic EL elements produced above was placed on the same substrate to produce an active matrix type full color display device having the form as shown in FIG. 1, and FIG. Only the schematic diagram of the display section A of the display device is shown. That is, a wiring portion including a plurality of scanning lines 55 and data lines 56 on the same substrate, and a plurality of juxtaposed pixels 53 (light emission color is a red region pixel, a green region pixel, a blue region pixel, etc.)
  • 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 grid pattern and are connected to the pixels 53 at orthogonal positions ( Details are not shown).
  • the plurality of pixels 53 are driven by an active matrix system in which an organic EL element corresponding to each emission color, a switching transistor as an active element, and a driving transistor are provided, and a scanning signal is applied from a scanning line 55. Then, an image data signal is received from the data line 56, and light is emitted according to the received image data.
  • a full color display device was produced by juxtaposing the red, green, and blue pixels appropriately. It was found that by driving the full-color display device, a clear full-color moving image display having high luminance, high durability, and clearness can be obtained.
  • Example 7 Example of doping metal oxide into ZnS of hole injection layer ⁇ Preparation of organic EL element 6-1> Patterning was performed on a substrate (AvanState Co., Ltd., NA45) in which ITO (Indium Tin Oxide) 100 nm was formed on a 100 mm ⁇ 100 mm ⁇ 1.1 mm glass substrate as an anode. Thereafter, the transparent support 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 transparent support substrate was attached to a vacuum deposition apparatus, and the vacuum chamber was depressurized to 4 ⁇ 10 ⁇ 4 Pa.
  • ITO Indium Tin Oxide
  • a hole transport layer ZnS was deposited to a thickness of 10 nm to provide a hole injection layer.
  • 1.0 nm of lithium fluoride was deposited as an electron injection layer and 110 nm of aluminum was deposited as a cathode, thereby fabricating an organic EL element 6-1.
  • Organic EL elements 6-2 to 6-4 were prepared in the same manner as in the production of the organic EL element 6-1, except that ZnS was doped with a metal oxide shown in Table V below as a hole injection layer.
  • the produced organic EL element it carried out similarly to the said Example 1, and measured the luminous efficiency (external extraction quantum efficiency (EQE)), luminous lifetime, and the density of the light emitting layer.
  • EQE extraction quantum efficiency
  • the organic EL device containing ZnS in which the hole injection layer is doped with a metal oxide has excellent luminous efficiency as compared with the case where the metal oxide is not doped.
  • the present invention can be used for an organic electroluminescence element that can improve the density of the light emitting layer, improve the light emission efficiency and the element lifetime, and is easy to manufacture, and a display device and an illumination device equipped with the organic electroluminescence element. be able to.

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Abstract

La présente invention concerne un élément électroluminescent organique EL qui comprend une couche d'injection de trous et/ou une couche émettrice de lumière stratifiée entre une paire d'électrodes, la couche d'injection de trous contenant du sulfure de zinc, la couche émettrice de lumière étant directement stratifiée sur la couche d'injection de trous, la couche émettrice de lumière contenant un composé organique interagissant avec ce sulfure de zinc, et la densité de la couche émettrice de lumière se situant dans la plage de la plage de 1,0 à 1,8 g/cm 3.
PCT/JP2018/018451 2017-06-02 2018-05-14 Élément électroluminescent organique, dispositif d'affichage et dispositif d'éclairage Ceased WO2018221173A1 (fr)

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Cited By (2)

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Publication number Priority date Publication date Assignee Title
WO2020175624A1 (fr) * 2019-02-27 2020-09-03 国立大学法人九州大学 Composé, matériau électroluminescent et élément laser à semi-conducteur organique
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WO2022064580A1 (fr) * 2020-09-24 2022-03-31 シャープ株式会社 Élément électroluminescent et dispositif d'affichage

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