WO2014069637A1

WO2014069637A1 - Organic electroluminescent element, lighting device and display device

Info

Publication number: WO2014069637A1
Application number: PCT/JP2013/079761
Authority: WO
Inventors: みゆき岡庭; 川邉　里美; 大津　信也
Original assignee: コニカミノルタ株式会社
Priority date: 2012-11-02
Filing date: 2013-11-01
Publication date: 2014-05-08
Also published as: JP6295959B2; JPWO2014069637A1

Abstract

An organic electroluminescent element which contains at least one light emitting layer that is sandwiched between a positive electrode and a negative electrode. This organic electroluminescent element is characterized in that: at least one of the light emitting layer(s) contains at least one light emitting dopant and at least one host; at least one of the light emitting dopant(s) is a phosphorescent dopant that has an emission peak wavelength of 470 nm or less and a HOMO value of from -4.50 eV to -5.50 eV; and at least one of the host(s) is a compound represented by general formula (1) or a specific compound, which has a HOMO value of from -4.60 eV to -5.10 eV.

Description

Organic electroluminescence element, lighting device and display device

The present invention relates to an organic electroluminescence element, an illumination device provided with the organic electroluminescence device, and a display device.

An organic electroluminescence element (hereinafter also referred to as an organic EL element) has a configuration in which a light-emitting layer containing a light-emitting compound is sandwiched between a cathode and an anode, and a positive electrode injected from the anode by applying an electric field. This is a light emitting device that uses the emission of light (fluorescence / phosphorescence) when excitons are generated by recombining electrons injected from holes and cathodes in the light emitting layer to generate excitons. is there. An organic EL element is an all-solid-state element composed of an organic material film with a thickness of only a submicron between electrodes, and can emit light at a voltage of several volts to several tens of volts. It is expected to be used for next-generation flat display and lighting.

As for the development of organic EL elements for practical use, Princeton University has reported organic EL elements that use phosphorescence emission from excited triplets (see, for example, Non-Patent Document 1). Research on materials that exhibit phosphorescence has become active (see, for example, Patent Document 1 and Non-Patent Document 2).
In addition, organic EL elements that utilize phosphorescence emission can in principle achieve light emission efficiency that is approximately four times that of organic EL elements that utilize fluorescence emission. Research and development of device layer configurations and electrodes are performed all over the world. For example, many compounds have been studied focusing on heavy metal complexes such as iridium complexes (see Non-Patent Document 3, for example).

As described above, the phosphorescence emission method is a method having a very high potential. However, an organic EL device using phosphorescence emission is greatly different from an organic EL device using fluorescence emission, and controls the position of the emission center. The method, particularly how to recombine within the light emitting layer to stabilize the light emission, is an important technical issue in grasping the efficiency and lifetime of the device.
Therefore, in recent years, a multi-layered element having a hole transport layer located on the anode side of the light emitting layer and an electron transport layer located on the cathode side of the light emitting layer in a form adjacent to the light emitting layer is well known. (For example, refer to Patent Document 2). In addition, a mixed layer using a host compound and a phosphorescent compound as a dopant is often used for the light emitting layer.
In addition, from the viewpoint of use in displays and lighting, organic EL elements are required to have high light emission efficiency and long light emission lifetime. Therefore, materials having high carrier transportability and thermally and electrically stable materials are required. Is required.

Furthermore, in recent years, an illumination light source with a high color temperature and a display with a wide color gamut have been demanded. To achieve these, a short-wavelength blue light-emitting dopant that exhibits an emission maximum wavelength of 470 nm, more preferably 460 nm or less, is required. Indispensable.
As short-wavelength blue light-emitting dopants, fluorescent light-emitting dopants having anthracene, chrysene or the like in the skeleton are well known, but as described above, they are disadvantageous compared to phosphorescent light-emitting dopants in terms of light emission efficiency.
On the other hand, FIrpic is a material well known as a short wavelength phosphorescent blue light emitting dopant. FIrpic is realized by using two fluorine atoms in the main ligand, phenylpyridine, and using picolinic acid as a sub-ligand, but with two fluorine atoms with high electronegativity. Due to the substitution, iridium as a central metal is easily oxidized, and the HOMO is very deep at about −5.90 eV in a calculated value. Therefore, it becomes difficult to inject holes from the anode side into the light emitting layer, the balance of hole and electron injection is deteriorated, and problems such as a decrease in recombination probability and an increase in driving voltage occur in the light emitting layer.

Further, since the carrier injection balance is lost, the recombination region is easily limited to a narrow region near the transport layer interface, and exciton leakage occurs from the light emitting layer to the adjacent transport layer. For this reason, the subject of the light emission efficiency fall and the light emission lifetime fall resulting from deterioration of a material generate | occur | produces.
On the other hand, when a light emitting dopant having a shallow HOMO, for example, less than −4.50 eV, is used, the LUMO becomes relatively shallow and the compound becomes unstable. In addition, it is easily affected by external factors such as oxygen, and there is a problem in terms of stability of device performance.

In response to the above problem, for example, in Patent Document 3, a high-efficiency element and a long lifetime are achieved by using a biscarbazole derivative with improved hole transportability and electron transportability as a host. However, the light emission maximum wavelength of the light-emitting dopant used in Examples in Patent Document 3 shows a light emission maximum wavelength exceeding 470 nm as studied by the present inventor, and is used for high color temperature illumination applications and displays with a wide color gamut. It was found that the wavelength is not long and satisfactory. In addition, the above document does not describe the relationship between the luminescent dopant and the HOMO of the material used for the host.

Furthermore, it is known that such a light emitting dopant with a short wavelength often has a feature that the light emission efficiency is lowered at a high temperature. This is thought to be due to the large non-radiative process knr other than the radiative process kr that emits light in the process of deactivation of the dopant from the excited state to the ground state. This is thought to be due to the large deactivation process. A large knr leads to a problem of reduced efficiency, but it is largely due to the structure of the luminescent dopant, and there is a problem of coexistence with required performance such as emission of light having a long wavelength by reducing thermal vibration.

US Pat. No. 6,097,147 JP 2005-112765 A International Publication No. 2011/132683

Thus, conventionally, various compounds relating to organic EL element materials have been disclosed, and attempts have been made to develop organic EL elements having low driving voltage, high luminous efficiency and long life. However, it is desired to develop an organic EL device that further improves these performances compared to the conventional one. In addition, it is desired to develop an organic EL element suitable for illumination use at a high color temperature and display application having a wide color gamut (that is, having good chromaticity).

The present invention has been made in view of the above problems, and has high luminous efficiency, low driving voltage, long life, and good chromaticity, an organic electroluminescence element having good chromaticity, and an illumination device and a display device using the element It is an issue to provide.

The above-mentioned problem according to the present invention is solved by the following means.
1. In an organic electroluminescent device including at least one light emitting layer sandwiched between an anode and a cathode, at least one layer of the light emitting layer contains at least one kind of light emitting dopant and at least one kind of host. At least one is a phosphorescent light emitting dopant having an emission maximum wavelength on the shortest wavelength side of 470 nm or less and a HOMO value of −4.50 to −5.50 eV in an emission spectrum in a solution, At least one of the compounds represented by any one of the following general formulas (1) to (4) is a compound having a HOMO value of −4.60 to −5.10 eV. Electroluminescence element.

(In General Formula (1), R ₁₁₁ and R ₁₁₂ represent a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocycloalkyl group, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group, (The compound represented may further have a substituent.)

(In the general formula (2), R ₂₁₁ and R ₂₁₂ represent an alkyl group, an aromatic hydrocarbon ring group or an aromatic heterocyclic group. Rings Z ₁ to Z ₃ represent an aromatic hydrocarbon ring or an aromatic heterocyclic ring. Represents a residue to be formed and may have a substituent.)

(In the general formula (3), R ₂₁₁ and R ₂₁₂ represent an alkyl group, an aromatic hydrocarbon ring group or an aromatic heterocyclic group. Rings Z ₁ to Z ₃ represent an aromatic hydrocarbon ring or an aromatic heterocyclic ring. Represents a residue to be formed and may have a substituent.)

(In General Formula (4), R ₃₁₁ and R _{312 each} represent a hydrogen atom, an arylsilyl group, an arylphosphoryl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a diarylamino group, or an alkyl group. ₁ to A ₈ each independently represents C—Rx or N, and a plurality of Rxs may be the same or different, and Rx each independently represents a hydrogen atom or a substituent.

2. 2. The organic electroluminescent device according to 1 above, wherein the phosphorescent luminescent dopant is a compound represented by the following general formula (5).

(In the general formula (5), M represents Ir, Pt, Rh, Ru, Ag or Cu, X ₁ and X ₂ represent a carbon atom or a nitrogen atom, and ring Z ₁ represents a 6-membered aromatic with C═C. Represents a 5-membered aromatic ring, or a 5- or 6-membered aromatic heterocyclic ring, wherein ring Z ₂ represents a 5-membered heterocyclic ring together with X ₁ -X _2. L ′ represents a monoanionic divalent ring coordinated to M A bidentate ligand, m ′ represents an integer of 0 to 2, n ′ is an integer of at least 1, and m ′ + n ′ is 2 or 3.)

3. 2. The organic electroluminescent device according to 1 above, wherein the phosphorescent luminescent dopant is a compound represented by the following general formula (6).

(In General Formula (6), M represents Ir, Pt, Rh, Ru, Ag, or Cu, X ₁ and X ₂ represent a carbon atom or a nitrogen atom, and ring Z ₂ is a 5-membered member together with X ₁ -X _2. R ₁ represents an electron-withdrawing group, R ₂ represents an electron-donating group or F. L ′ is a monoanionic bidentate ligand coordinated to M, and m ′ is 0. Represents an integer of ˜2, n ′ is an integer of at least 1 and m ′ + n ′ is 2 or 3.)

4). 2. The organic electroluminescence device according to 1 above, wherein the phosphorescent light-emitting dopant is a compound represented by the following general formula (7).

(In the general formula (7), M represents Ir, Pt, Rh, Ru, Ag or Cu, and ring Z ₁ is a 6-membered aromatic hydrocarbon ring together with C = C, or a 5-membered or 6-membered aromatic ring. R ₃ , R ₄ , and R ₅ each represent a hydrogen atom or a substituent, and R ₄ and R ₅ may form a ring, and L ′ is a monoanionic divalent group coordinated to M. A bidentate ligand, m ′ represents an integer of 0 to 2, n ′ is an integer of at least 1, and m ′ + n ′ is 2 or 3.)

5. 2. The organic electroluminescent device according to 1 above, wherein the phosphorescent luminescent dopant is a compound represented by the following general formula (8).

(In the general formula (8), M represents Ir, Pt, Rh, Ru, Ag or Cu, X ₁ to X ₄ represent —CR ₆ or a nitrogen atom, and X ₃ and X ₄ are —CR ₆ . The ring Z ₃ represents a 6-membered aromatic hydrocarbon ring, or a 5-membered or 6-membered aromatic heterocycle, and the ring Z ₄ is a 5-membered with X ₁ -X ₂ R ₆ represents a carbon atom or a nitrogen atom, L ′ represents a monoanionic bidentate ligand coordinated to M, m ′ represents an integer of 0 to 2, and n ′ Is an integer of at least 1 and m ′ + n ′ is 2 or 3.)

6). In the compound represented by the general formula (6), the ring Z ₂ is an organic electroluminescent device according to the 3, characterized in that a substituted or unsubstituted triazole ring.

7). 7. The organic electroluminescence device according to any one of 1 to 6, wherein the phosphorescent luminescent dopant has an emission maximum wavelength on the shortest wavelength side in an emission spectrum in a solution of 460 nm or less.

8). 8. The organic electroluminescence device as described in any one of 1 to 7 above, wherein the emission color is white.

9. 9. An illumination device comprising the organic electroluminescence element according to any one of 1 to 8 above.

10. 9. A display device comprising the organic electroluminescence element according to any one of 1 to 8 above.

The present invention can provide an organic electroluminescence element that realizes high luminous efficiency and long life, low driving voltage, and good chromaticity, an illumination device using the element, and a display device.

(A)-(d) is a schematic diagram which shows the width of the recombination area | region in a light emitting layer. It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. It is a schematic diagram of the display part A in FIG. It is a schematic diagram of a pixel. FIG. 4 is a schematic diagram of a passive matrix type full-color display device according to display unit A of FIG. 3. It is the schematic of an illuminating device. It is a schematic diagram of an illuminating device. (A)-(e) is a schematic block diagram of an organic electroluminescent full color display apparatus.

Hereinafter, although the form for implementing this invention is demonstrated in detail, this invention is not limited to these.

<< Organic EL element >>
The organic EL device of the present invention includes at least one light emitting layer sandwiched between an anode and a cathode. At least one light emitting dopant and at least one host are contained in at least one layer of the light emitting layer, and at least one of the light emitting dopants has a light emission maximum at the shortest wavelength side in the light emission spectrum in the solution. A phosphorescent light-emitting dopant having a wavelength of 470 nm or less and a HOMO value of −4.50 to −5.50 eV, wherein at least one of the hosts is represented by any one of the general formulas (1) to (4): Which has a HOMO value of −4.60 to −5.10 eV.

In the present invention, at least one of the luminescent dopants may be a phosphorescent luminescent dopant having an emission maximum wavelength of 470 nm or less and a HOMO value of −4.50 to −5.50 eV. The phosphorescent light emitting dopant may be used.
Further, at least one of the hosts may be a compound represented by any one of the general formulas (1) to (4) and a compound having a HOMO value of −4.60 to −5.10 eV, All of the hosts may be the compound.

In the present invention, in view of the above-mentioned problems, hole injection from the adjacent layer to the light emitting layer is improved by making the relationship between the HOMO of the light emitting dopant and the HOMO of the host as in the present invention. By using the compound having the structure represented by (4) as a host, the carrier injection balance into the light emitting layer was improved, and the recombination region was separated from the vicinity of the interface between the light emitting layer and the adjacent layer. As a result, an organic electroluminescence device having both high luminous efficiency and a long lifetime could be obtained.
Here, since the compounds represented by the general formulas (1) to (4) have a condensed ring structure, the molecules are more molecules than the triarylamine derivatives typically represented by α-NPD having hole transport properties. As a result, the carrier mobility in the layer is improved and a low driving voltage can be achieved.
Furthermore, it was confirmed that knr could be reduced by using the compounds represented by the general formulas (1) to (4). This is because the arrangement of molecules of such a compound has a role like a housing, and by dispersing a light emitting dopant there, thermal vibration is suppressed, knr is reduced, while kr is increased. it is conceivable that.

<< Constituent layers of organic EL elements >>
The constituent layers of the organic EL element will be described. In this invention, although the preferable specific example of the layer structure of an organic EL element is shown below, this invention is not limited to these.
(I) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode (iii) Anode / hole transport layer / Light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode (iv) anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (V) anode / Hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode In addition to the hole blocking layer, an electron blocking layer can also be used as the blocking layer.

When a plurality of light emitting layers are included, a non-light emitting intermediate layer may be provided between the light emitting layers. In addition, among the above layer structures, an organic layer including a light emitting layer excluding an anode and a cathode can be used as one light emitting unit, and a plurality of light emitting units can be stacked. The plurality of stacked light emitting units may have a non-light emitting intermediate layer between the light emitting units, and the intermediate layer may further include a charge generation layer.
The organic EL element of the present invention is preferably a white light emitting layer, and is preferably an illumination device or a display device using these. That is, the organic EL element preferably emits white light.
Each layer which comprises the organic EL element of this invention is demonstrated.

<Light emitting layer>
The light-emitting layer 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. It may be an interface with an adjacent layer.
The total film thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the uniformity of the film, preventing unnecessary application of high voltage during light emission, and improving the stability of the emission color with respect to the drive current. It is preferable to adjust in the range of 2 nm to 5 μm, more preferably in the range of 2 nm to 200 nm, and particularly preferably in the range of 5 nm to 100 nm.

For the production of the light emitting layer, a light emitting dopant or host compound described later is used, for example, a vacuum deposition method, a wet method (also referred to as a wet process, for example, a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, The film can be formed by an inkjet method, a printing method, a spray coating method, a curtain coating method, an LB method (such as Langmuir-Blodgett method) and the like.
The light emitting layer of the organic EL device of the present invention contains a light emitting dopant and a host.

<Light-emitting host (also referred to as light-emitting host compound or host compound)>
The present invention is characterized in that the host material of the light emitting layer contains a compound represented by any one of the general formulas (1) to (4).

<Compounds represented by general formulas (1) to (4)>
Next, the compounds represented by the general formulas (1) to (4) will be described.
The compounds represented by the general formulas (1) to (4) are non-metallic complex compounds and have a HOMO value of −4.60 to −5.10 eV.

The HOMO value referred to in the present invention is Gaussian 03 (Gaussian 03, Revision D02, MJ Frisch, et al, Gaussian, Inc., Wallingford CT, 2004.), which is a molecular orbital calculation software manufactured by Gaussian, USA. This is the calculated value.

The compound represented by the general formulas (1) to (4), the host compound, the hole transport material, and the electron transport material of the present invention use B3LYP / 6-31G * as a keyword, and the phosphorescent dopant compound is B3LYP / The HOMO value is calculated by performing structural optimization of the target molecular structure using LanL2DZ (eV unit conversion value). It is known that the correlation between the calculated value obtained by this method and the experimental value is high as a background to the effectiveness of this calculated value.

The HOMO values of the compounds represented by the general formulas (1) to (4) of the present invention are −4.60 to −5.10 eV.
The reason why the HOMO value is in the above range is that when the HOMO value is deeper than −5.10 eV, hole injection into the light emitting layer is remarkably reduced, resulting in deterioration of efficiency and lifetime. On the other hand, if it is shallower than −4.60 eV, the hole trapping property of the dopant in the light emitting layer is strong, so that holes are likely to accumulate at the light emitting layer / hole transporting layer interface, and the efficiency and life are also reduced. . The HOMO value is preferably −4.70 to −5.10 eV.

In the general formula (1), R ₁₁₁ and R ₁₁₂ represent a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocycloalkyl group, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group, and represented by the general formula (1) The compound to be obtained may further have a substituent.

Examples of the aromatic hydrocarbon ring group represented by R ₁₁₁ and R ₁₁₂ in the general formula (1) include, for example, a benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, Naphthacene ring, triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, And monovalent groups derived from a pyranthrene ring, anthraanthrene ring, and the like.

Examples of the aromatic heterocyclic group represented by R ₁₁₁ and R ₁₁₂ in the general formula (1) include a silole ring, a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, and a pyrazine. Ring, triazine ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzthiazole ring, benzoxazole ring, quinoline ring, quinoxaline ring, quinazoline ring, phthalazine ring, thieno Thiophene ring, carbazole ring, azacarbazole ring (representing any one or more of the carbon atoms constituting the carbazole ring replaced by a nitrogen atom), dibenzosilole ring, dibenzofuran ring, dibenzothiophene ring, benzothiophene ring, dibenzofuran Ring Rings in which any one or more of the carbon atoms formed are replaced by nitrogen atoms, benzodifuran ring, benzodithiophene ring, acridine ring, benzoquinoline ring, phenazine ring, phenanthridine ring, phenanthroline ring, cyclazine ring, kindrin ring, Tepenidine ring, quinindrin ring, triphenodithiazine ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, naphthofuran ring, naphthothiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran And monovalent groups derived from a ring, anthrathiophene ring, anthradithiophene ring, thianthrene ring, phenoxathiin ring, dibenzocarbazole ring, indolocarbazole ring, dithienobenzene ring and the like.
Aromatic hydrocarbon ring represented by R _111, _{R 112,} aromatic heterocycle may be substituted with the later-described _R _111, the compound has optionally may substituent represented by _{R 112.}
In addition, as the aromatic hydrocarbon ring group or aromatic heterocyclic group represented by R ₁₁₁ or R ₁₁₂ in the general formula (1), a compound represented by R ₁₁₁ or R ₁₁₂ described later may be included. What was demonstrated by the good substituent can be used.

Examples of the substituent that the compound represented by R ₁₁₁ and R ₁₁₂ in the general formula (1) may have include, for example, a hydrogen atom, an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, (T) 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 group (eg, propargyl group, etc.), aromatic hydrocarbon ring group (also referred to as aryl group, eg, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, Anthryl, azulenyl, acenaphthenyl, fluorenyl, phenanthryl, indenyl, Renyl group, biphenylyl group, etc.), heterocyclic group (for example, epoxy ring, aziridine ring, thiirane ring, oxetane ring, azetidine ring, thietane ring, tetrahydrofuran ring, dioxolane ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring , Tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran ring, 1,3-dioxane ring 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine ring, thiomorpholine-1,1-dioxide ring, pyranose ring, diazabicyclo [2,2,2] -octane ring), aromatic heterocycle Ring group (pi Zyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazole- 1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl A group, an indoloindolyl group, a carbazolyl group, a carbolinyl group, a diazacarbazolyl group (in which one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom), a quinoxalinyl group, a pyridazinyl group, Triazinyl group, quinazolinyl group Phthalazinyl group, etc.), halogen atom (eg, chlorine atom, bromine atom, iodine atom, fluorine atom, etc.), alkoxyl group (eg, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group) , Dodecyloxy group etc.), cycloalkoxyl group (eg cyclopentyloxy group, cyclohexyloxy group etc.), aryloxy group (eg phenoxy group, naphthyloxy group etc.), alkylthio group (eg methylthio group, ethylthio group, propylthio) Group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (for example, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (for example, phenylthio group, naphthylthio group, etc.), alkoxycarbo Nyl group (for example, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (for example, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.) Sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, Naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclyl) Hexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group) Group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octyl) Carbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethyl carbonate) Bonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group ( For example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylamino Carbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), sulfinyl group (for example, methyls Rufinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group or arylsulfonyl group (for example, Methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group) Ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group), anilino group, diary Ruamino group (eg, diphenylamino group, dinaphthylamino group, phenylnaphthylamino group, etc.), naphthylamino group, 2-pyridylamino group, etc.), nitro group, cyano group, hydroxyl group, mercapto group, alkylsilyl group or arylsilyl group Groups (for example, trimethylsilyl group, triethylsilyl group, (t) butyldimethylsilyl group, triisopropylsilyl group, (t) butyldiphenylsilyl group, triphenylsilyl group, trinaphthylsilyl group, 2-pyridylsilyl group, etc.), Alkylphosphino group or arylphosphino group (dimethylphosphino group, diethylphosphino group, dicyclohexylphosphino group, methylphenylphosphino group, diphenylphosphino group, dinaphthylphosphino group, di (2-pyridyl) phosphosphino group ) Alkylphosphoryl group or arylphosphoryl group (dimethylphosphoryl group, diethylphosphoryl group, dicyclohexylphosphoryl group, methylphenylphosphoryl group, diphenylphosphoryl group, dinaphthylphosphoryl group, di (2-pyridyl) phosphoryl group), alkylthiophosphoryl group or arylthio group Any one selected from a phosphoryl group (dimethylthiophosphoryl group, diethylthiophosphoryl group, dicyclohexylthiophosphoryl group, methylphenylthiophosphoryl group, diphenylthiophosphoryl group, dinaphthylthiophosphoryl group, di (2-pyridyl) thiophosphoryl group) Represents a group of These substituents may be further substituted with the above-mentioned substituents, or they may be condensed with each other to further form a ring.
Furthermore, an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a heterocyclic group, and a cycloalkyl group are preferable.

In the general formula (1), R ₁₁₁ and R ₁₁₂ are more preferably a phenyl group, dibenzofuran, dibenzothiophene or carbazole.

As the compound represented by the general formula (1), compounds represented by the following general formulas (11) to (13) are preferable.

_R _{111, R 112} in formula (11) to (13) has the same meaning as _R _{111, R 112} in formula (1).
In the general formulas (11) to (13), R ₁₁₁ and R ₁₁₂ are more preferably a phenyl group, dibenzofuran, dibenzothiophene, or carbazole.

Specific examples of the compounds represented by the general formulas (1) and (11) to (13) are given below, but the present invention is not limited thereto.

In General Formula (2) and General Formula (3), R ₂₁₁ and R ₂₁₂ represent an alkyl group, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group. Rings Z ₁ to Z ₃ represent a residue that forms an aromatic hydrocarbon ring or an aromatic heterocyclic ring, and may have a substituent.

The alkyl group, aromatic hydrocarbon ring group or aromatic heterocyclic group in general formulas (2) and (3) has the same _meaning as described for R ₁₁₁ and R ₁₁₂ in general formula (1).
The substituents for the rings Z ₁ to Z ₃ are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 11 carbon atoms, an aromatic hydrocarbon ring group having 6 to 12 carbon atoms, or Represents an aromatic heterocyclic group having 3 to 11 carbon atoms. The substituent of the ring Z ₂ may form a condensed ring together with the ring to which the substituent is bonded. Preferably, rings Z ₁ to Z ₃ are aromatic hydrocarbon rings, more preferably benzene rings. More preferably, the rings Z ₁ to Z ₃ are all benzene rings.
R ₂₁₁ and R ₂₁₂ are preferably an aromatic hydrocarbon ring group or an aromatic heterocyclic group, and more preferably a benzene ring, a pyridine ring, a pyrimidine ring, a triazine ring, or a quinoline ring.

Preferred examples of the compound represented by the general formula (2) or the general formula (3) are shown below, but are not limited thereto.

In the general formula (4), R ₃₁₁ and R _{312 each} represent a hydrogen atom, an arylsilyl group, an arylphosphoryl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a diarylamino group, or an alkyl group.
R ₃₁₁ and R ₃₁₂ are preferably any of an arylsilyl group, an arylphosphoryl group, an aromatic hydrocarbon ring group, and an aromatic heterocyclic group, and any of an aromatic hydrocarbon ring group or an aromatic heterocyclic group More preferably. Among these, a substituent containing an oxygen atom or a sulfur atom is preferable.
The aromatic hydrocarbon ring group or aromatic heterocyclic group in R ₃₁₁ and R ₃₁₂ has the same meaning as described for R ₁₁₁ and R ₁₁₂ in the general formula (1). In particular, a dibenzofuryl group, a dibenzothienyl group, etc. are mentioned as the most preferable substituents.
As the arylsilyl group, arylphosphoryl group, diarylamino group, and alkyl group, those described for R ₁₁₁ and R ₁₁₂ in the general formula (1) can be used.

A ₁ to A ₈ each independently represent C—Rx or N, and the plurality of Rx may be the same or different. Rx each independently represents a hydrogen atom or a substituent.
As a substituent, it is synonymous with the substituent quoted by General formula (1).

Of the plurality of independent Rx's, one or more are preferably substituents, and more preferably one or two are substituents.
When one or more Rxs out of a plurality of Rx each independently represent a substituent, any one or more of A ₁ , A ₂ , A ₄ is preferably C—Rx, and more preferably A ₁ or A preferably any one or more of ₂ is C-Rx, in particular a ₁ may be mentioned as more preferred form to be a C-Rx.

In the case where one or more Rx's in the plurality of independent Rx's each independently represent a substituent, Rx is an arylsilyl group, an arylphosphoryl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, or a diarylamino group. It is preferably any one, and further preferably any one of an arylsilyl group, an arylphosphoryl group, an aromatic hydrocarbon ring group, and an aromatic heterocyclic group, and among them, an aromatic hydrocarbon ring group or an aromatic heterocyclic group. It is more preferably any of a cyclic group, and particularly preferably an aromatic heterocyclic group. Among them, a substituent containing an oxygen atom or a sulfur atom is preferable because it has a high charge transporting ability and high durability against charges, and an aromatic heterocyclic group is preferable because of high thermal stability. . In particular, a dibenzofuryl group, a dibenzothienyl group, etc. are mentioned as the most preferable substituents.

The substituent represented by Rx is preferably further substituted, and the substituent is any of an arylsilyl group, an arylphosphoryl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, and a diarylamino group. And more preferably an arylsilyl group, an arylphosphoryl group, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group, and among them, an aromatic hydrocarbon ring group or an aromatic heterocyclic ring Particularly preferred is any of the groups.

In the present invention, any one or more of Rx, R ₃₁₁ and R ₃₁₂ in the general formula (4) is a pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group. Group, triazolyl group, oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, It is preferably any group selected from an indoloindolyl group, a quinoxalinyl group, a pyridazinyl group, a triazinyl group, a quinazolinyl group, a phthalazinyl group, an arylsilyl group, and an arylphosphoryl group.

Although the preferable specific example of a compound represented by General formula (4) below is shown, it is not limited to these. R ₃₁₁ and R ₃₁₂ may be functional groups other than those described above, and specific examples thereof are also shown.

In addition to the compounds represented by the general formulas (1) to (4) of the present invention, a plurality of known luminescent hosts may be used in combination as long as the effects of the present invention are not impaired.
Specific examples of the known light-emitting host include compounds described in the following documents.
JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-260861, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, and the like.
Specific examples of the light emitting layer used in the organic EL device of the present invention as a known light emitting host include, for example, the compounds OC-1 to OC32 described in JP2012-164731A. It is not limited.

<Light emitting dopant (also referred to as light emitting dopant, light emitting dopant compound, light emitting dopant compound)>
The luminescent dopant will be described.
As the light emitting dopant, a fluorescent dopant (also referred to as a fluorescent compound), a phosphorescent light emitting dopant (phosphorescent dopant, phosphorescent light emitting dopant, phosphorescent light emitting dopant group, phosphorescent light emitting dopant compound, phosphorescent light emitting dopant) Compounds, phosphorescent emitters, phosphorescent compounds, phosphorescent compounds, and the like) can be used.

(Phosphorescent dopant)
The phosphorescent light emitting dopant will be described.
A phosphorescent light-emitting dopant compound 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 is defined as a compound having a phosphorescence quantum yield of 0.01 or more at 25 ° C. 1 or more.
The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence emission dopant should just achieve the said phosphorescence quantum yield (0.01 or more) in any solvent. .

There are two types of light emission of the phosphorescent light emitting dopant in principle. One is that the recombination of carriers occurs on the host compound to which carriers are transported, and an excited state of the light emitting host compound is generated. The energy transfer type, in which light emission from the phosphorescent light-emitting dopant is obtained by transferring to the light dopant, and the other is that the phosphorescent dopant becomes a carrier trap, and carrier recombination occurs on the phosphorescent light-emitting dopant, and phosphorescence In any case, the excited state energy of the phosphorescent light emitting dopant is lower than the excited state energy of the host compound. .

Here, as a result of intensive studies to achieve the object of the present invention, the present inventors have found that at least one of the light emitting layers of the organic EL element is on the shortest wavelength side in the emission spectrum in the solution. Inclusion of at least one phosphorescent light-emitting dopant having an emission maximum wavelength of 470 nm or less and a HOMO value of −4.50 to −5.50 eV improves the light emission efficiency, lifetime, and driving voltage of the organic EL device, It was clarified that the color gamut of the element can be improved.
Therefore, at least one of the phosphorescent dopants used in the present invention has an emission maximum wavelength on the shortest wavelength side of 470 nm or less and a HOMO value of −4 in the emission spectrum of the solution in the region of 400 to 700 nm. A compound of .50 to −5.50 eV.

When there are a plurality of emission peaks in the emission spectrum in the solution, the phosphorescent emission dopant used in the present invention has an emission maximum wavelength (peak wavelength) of emission at the shortest wavelength side of 470 nm or less.
When the emission maximum wavelength exceeds 470 nm, it is unsuitable for use in high color temperature illumination applications or displays with a wide color gamut. Therefore, the emission maximum wavelength of the phosphorescent light emitting dopant is 470 nm or less. In order to further improve the effect, the thickness is preferably 460 nm or less.
The emission spectrum in the solution can be obtained from, for example, a fluorescence spectrum obtained by irradiating a solution obtained by dissolving a dopant in a nonpolar solvent with excitation light. In the present invention, a dopant was dissolved in 2-methyltetrahydrofuran, and a fluorescence spectrum in the region of 400 to 700 nm was measured using Hitachi F-4500.

The HOMO value of the phosphorescent light-emitting dopant used in the present invention is −4.50 to −5.50 eV. The value of HOMO in the phosphorescent light emitting dopant can be obtained by the calculation method described for the light emitting host compound.
The reason why the HOMO value is in the above range is that when the HOMO value is deeper than −5.50 eV, the hole injection property from the hole transport layer to the light emitting layer is remarkably reduced, resulting in deterioration of efficiency and lifetime. It is because it becomes. On the other hand, if the HOMO value is shallower than −4.50 eV, the LUMO of the dopant becomes shallow or the compound becomes unstable in order to make a blue phosphorescent light-emitting dopant whose emission maximum wavelength is 470 nm or less. .

In the present invention, a preferred phosphorescent light emitting dopant is a compound represented by the following general formula (5).

In the general formula (5), M represents Ir, Pt, Rh, Ru, Ag or Cu, X ₁ and X ₂ represent a carbon atom or a nitrogen atom, and the ring Z ₁ is a 6-membered aromatic together with C═C. hydrocarbon ring or an aromatic 5- or 6-membered heterocyclic ring, the ring Z ₂ represents a heterocyclic 5-membered together with X ₁ -X _2.

Examples of the 6-membered aromatic hydrocarbon ring of the ring Z ₁ include a benzene ring. Examples of the 5-membered or 6-membered aromatic heterocycle include furan ring, thiophene ring, oxazole ring, pyrrole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, oxadiazole ring, triazole ring, An imidazole ring, a pyrazole ring, a thiazole ring, etc. are mentioned. Ring Z ₁ and ring Z ₂ may have a substituent, and those exemplified in formula (1) can be used.
L ′ is a monoanionic bidentate ligand coordinated to M, m ′ represents an integer of 0 to 2, n ′ is an integer of at least 1, and m ′ + n ′ is 2 or 3. is there.

Here, ring Z ₁ is a substituted or unsubstituted benzene ring or pyridine ring, ring Z ₂ is a substituted or unsubstituted imidazole ring, substituted or unsubstituted pyrazole ring, or substituted or unsubstituted triazole ring. It is preferable that it represents.

Preferred as the compound represented by the general formula (5) are compounds represented by the following general formulas (6), (7) and (8).

In general formula (6), M, L ′, m ′, and n ′ have the same meaning as in general formula (5). R ₁ represents an electron withdrawing group, and R ₂ represents an electron donating group or F. X ₁ and _{X 2} represents a carbon atom or a nitrogen atom, the ring _{Z 2} represents a heterocyclic 5-membered together with _X 1 -X _2. Examples of the electron withdrawing group include a keto group such as a halogen atom, a cyano group, a nitro group, a phenyl group, and an acyl group, and examples of the electron donating group include an alkyl group, a hydroxyl group, an alkoxy group, and an amino group.

Here, in the compound represented by the general formula (6), it is preferable that the ring Z ₂ represents a substituted or unsubstituted triazole ring.

In the general formula (7), M, L ′, m ′, and n ′ have the same meaning as in the general formula (5). R ₃ , R ₄ and R ₅ each represent a hydrogen atom or a substituent, and R ₄ and R ₅ may form a ring. Ring Z ₁ represents a 6-membered aromatic hydrocarbon ring together with C═C, or a 5-membered or 6-membered aromatic heterocycle.
The substituent for R3, R4, and R5 represents a group having the same meaning as the substituent represented by Formula (1).

In the general formula (8), M, L ′, m ′, and n ′ have the same meaning as in the general formula (5). X ₁ to X _{4 each} represent —CR ₆ or a nitrogen atom. When X ₃ and X ₄ are —CR ₆ , they may form a ring. Ring Z ₃ represents a 6-membered aromatic hydrocarbon ring or a 5-membered or 6-membered aromatic heterocycle, and ring Z ₄ represents a 5-membered heterocycle together with X ₁ -X ₂ . R ₆ represents a carbon atom or a nitrogen atom.

Specific examples of the general formulas (5) to (8) are given below, but the present invention is not limited to these.

In addition to the phosphorescent light-emitting dopant related to the present invention, compounds described in the following patent publications may be used in combination.
For example, International Publication No. 00/70655, JP 2002-280178, JP 2001-181616, JP 2002-280179, JP 2001-181617, JP 2002-280180, JP 2001-247859, JP 2002-299060, JP 2001-313178, JP 2002-302671, JP 2001-345183, JP 2002-324679, International publication No. 02/15645, JP 2002-332291 A, JP 2002-50484 A, JP 2002-332292 A, JP 2002-83684 A, JP 2002-540572 A, JP 2002-2002 A. No. 117978, Japanese Patent Laid-Open No. 2002-33858 Publication No. 2002-170684 Publication No. 2002-352960 Publication No. WO 01/93642 Publication No. 2002-50483 Publication No. 2002-1000047 Publication No. 2002-173684 Publication JP-A-2002-359082, JP-A-2002-17584, JP-A-2002-363552, JP-A-2002-184582, JP-A-2003-7469, JP-A-2002-525808, JP 2003-7471, JP-A 2002-525833, JP-A 2003-31366, JP-A 2002-226495, JP-A 2002-234894, JP-A 2002-23576, JP-A 2002 -241751 and JP-A-2001-319779 Japanese Patent Laid-Open No. 2001-319780, Japanese Patent Laid-Open No. 2002-62824, Japanese Patent Laid-Open No. 2002-1000047, Japanese Patent Laid-Open No. 2002-203679, Japanese Patent Laid-Open No. 2002-343572, Japanese Patent Laid-Open No. 2002-203678, etc. It is.

(Fluorescent dopant (also called fluorescent compound))
Fluorescent 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, and compounds having a high fluorescence quantum yield such as laser dyes.
The light emitting dopant may be used in combination of a plurality of types of compounds, or may be a combination of phosphorescent light emitting dopants having different structures, or a combination of a phosphorescent light emitting dopant and a fluorescent dopant.

(Recombination area)
Of the entire region of the light emitting layer, the region contributing to light emission (recombination region) can be calculated from the value of ΔPL / ΔEL and the width of the region can be estimated from the calculation result.
ΔEL and ΔPL respectively represent the intensity decay rates of electroluminescence (EL) and photoluminescence (PL) before and after driving, and can be represented by the following equations.

ΔEL = 1− [EL (after driving) / EL (before driving)]
ΔPL = 1− [PL (after driving) / PL (before driving)]

In the EL drive, light emission occurs only in the recombination region, whereas in the PL drive, light irradiation is performed on the entire element, so that the light emission is considered to occur in the entire film thickness direction (layer thickness direction) of the light emitting layer. As a measurement condition, the PL value after the PL driving is measured in a state after driving the organic EL element until the light emission luminance is about half from the initial luminance (ΔEL is about 0.5). Here, ΔPL represents a recombination region with respect to the entire light emitting layer. Therefore, when ΔPL / ΔEL is small, it is estimated that the recombination region contributing to light emission is narrow, and when ΔPL / ΔEL is large, it contributes to light emission. It is presumed that the recombination region to be wide is wide.

These are schematically described as follows.
FIG. 1 is a schematic view showing each region in the layer thickness direction of the light emitting layer 100, and the left-right direction in the drawing corresponds to the layer thickness direction.
As shown in FIG. 1A, the light emitting layer 100 is partitioned into a region contributing to light emission (recombination region T1) and a region T2 not contributing to light emission.
Accordingly, the “EL before driving” is the measurement target in the recombination region T1.
On the other hand, as described above, in the PL driving, light irradiation is performed on the entire element, and therefore, “PL before driving” is a measurement target in the region T3 representing the entire light emitting layer.
Thereafter, when EL driving is performed until the light emission luminance is about half that of the initial luminance (ΔEL is about 0.5), as shown in FIG. 1B, light is not emitted in about half of the recombination region T1. When this is schematically expressed, it is considered that the non-light emitting region T4 is formed in the recombination region T1.
Therefore, “EL after driving” is a measurement target in a region T5 obtained by subtracting the non-light emitting region T4 from the recombination region T1.
On the other hand, “PL after driving” is the measurement target of the remaining region T6 obtained by subtracting the non-light emitting region T4 from the region T3 representing the entire light emitting layer in accordance with the formation of the non-light emitting region T4 in the recombination region T1. It becomes.

When ΔPL / ΔEL is small, since ΔEL is fixed at about 0.5, “ΔPL” is small. When ΔPL is small, “1− [PL (after driving) / PL (before driving)]” is small. When {1- [PL (after driving) / PL (before driving)]} is small, the PL before driving is fixed with the region T3 of the entire light emitting layer as a measurement target, and thus “PL (after driving)” is large. It will be. When the PL (after driving) is large, the region after the driving is the region T6 to be measured, which leads to the wide region T6.
Therefore, when ΔPL / ΔEL is small, the region T6 is widened. As shown in FIG. 1C, it can be concluded that the original recombination region T1 is “narrow”. Conversely, when ΔPL / ΔEL is large, the region T6 is narrowed, and it can be concluded that the original recombination region T1 is “wide” as shown in FIG.

<Injection layer: hole injection layer (anode buffer layer), electron injection layer (cathode buffer layer)>
The injection layer is a layer provided between the electrode and the organic layer for reducing the driving voltage and improving the light emission luminance as required. “The organic EL element and its industrialization front line (November 30, 1998 Chapter 2 “Electrode Materials” (pages 123 to 166) of Volume 2 of “TS Co., Ltd.”) is described in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer). )

The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Representative phthalocyanine buffer layer, oxide buffer layer typified by vanadium oxide, amorphous carbon buffer layer, polymer buffer layer using conductive polymer such as polyaniline (emeraldine) or polythiophene, tris (2-phenylpyridine) ) Orthometalated complex layers represented by iridium complexes and the like.

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, alkali metal compound buffer layer typified by lithium fluoride, sodium fluoride and potassium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, and aluminum oxide And an oxide buffer layer. 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 μm, although it depends on the material.
In addition, the materials used for the anode buffer layer and the cathode buffer layer can be used in combination with other materials. For example, they can be mixed in the hole transport layer or the electron transport layer.

<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 (issued 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 in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking.
Moreover, the structure of the above-mentioned electron carrying layer can be used as a hole-blocking layer concerning this invention as needed.
The hole blocking layer of the organic EL device of the present invention is preferably provided adjacent to the light emitting layer.

The hole blocking layer contains carbazole derivatives, azacarbazole derivatives (where azacarbazole derivatives are those in which one or more carbon atoms constituting the carbazole ring are replaced by nitrogen atoms), pyridine derivatives, and the like. It is preferable to contain a nitrogen compound.
Further, in the present invention, when a plurality of light emitting layers having different emission colors are provided, the light emitting layer having the shortest wavelength of the light emission maximum wavelength (shortest wave layer) is closest to the anode among all the light emitting layers. preferable. In such a case, it is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the shortest wave layer.
The thickness of the hole blocking layer and electron blocking layer that can be used in the present invention is preferably 3 nm to 100 nm, and more preferably 3 nm to 30 nm.

<Hole transport layer>
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 any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, 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.

Representative examples of 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-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N -Di (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadri N; N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenyl Amino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and further described in US Pat. No. 5,061,569 Having four condensed aromatic rings in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8688 are linked in a starburst type ( MTDATA) and the like.

Furthermore, 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. In addition, 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 as described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, these materials are preferably used 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 μm, preferably 5 nm to 200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.
Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like.
In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

<Electron transport layer>
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 with a single layer or a plurality of layers. An electron transport material (including a hole blocking material and an electron injection material) used for the electron transport layer only needs to have a function of transmitting electrons injected from the cathode to the light emitting layer. Can be selected from any conventionally known compounds and used alone or in combination.

Examples of conventionally known materials used for the electron transport layer (hereinafter referred to as electron transport materials) include heterocyclic tetracarboxylic acid anhydrides such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, naphthalene perylene, And azacarbazole derivatives including carbodiimide, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, carboline derivatives, and the like.
Here, the azacarbazole derivative refers to one in which one or more carbon atoms constituting the carbazole ring are replaced with a nitrogen atom.
Furthermore, in the above oxadiazole derivative, 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 transport material.
It is also possible to use a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain.

In addition, metal complexes of 8-quinolinol derivatives, such as tris (8-quinolinol) aluminum (Alq), 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), and the like, and the central metals of these metal complexes are In, Mg, A metal complex replaced with Cu, Ca, Sn, Ga, or Pb can also be used as an electron transport material.
In addition, metal-free or metal phthalocyanine, or those having the terminal substituted with an alkyl group or a sulfonic acid group can also be used as the electron transport material.
Further, similarly to the hole injection layer and the hole transport layer, inorganic semiconductors such as n-type-Si and n-type-SiC can also be used as the electron transport material.

The electron transport layer is made of an electron transport material such as a vacuum deposition method, a wet method (also referred to as a wet process, such as a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, an ink jet method, a printing method, or a spraying method. The film is preferably formed by thinning by a coating method, curtain coating method, LB method (Langmuir Brodgett method, etc.).

The thickness of the electron transport layer is not particularly limited, but is usually about 5 nm to 5000 nm, preferably 5 nm to 200 nm. This electron transport layer may have a single layer structure composed of one or more of the above materials.
Moreover, you may dope and use n-type dopants, such as metal compounds, such as a metal complex and a metal halide.

Examples of conventionally known compounds (electron transport materials) that are preferably used for forming an electron transport layer include, for example, compounds of ET-1-ET-43 described in JP2012-164731A, but are not limited thereto. Not.

<Anode>
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound and a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO.
Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the 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 pattern accuracy is not so high (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.
Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

<Cathode>
On the other hand, as the cathode, a material having a low 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.
Specific examples of such 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.
Among these, from the point of durability against electron injection and oxidation, a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function value 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 Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm.
In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.
In addition, a transparent or semi-transparent cathode can be produced by producing the conductive transparent material mentioned in the description of the anode on the cathode after producing the metal with a film thickness of 1 nm to 20 nm. By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

《Support substrate》
As a support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention, there is no particular limitation on the type of glass, plastic, etc., and it is transparent. May be opaque. When extracting light from the support substrate side, the support substrate is preferably transparent.
Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of giving flexibility to the organic EL element.

<< Method for Manufacturing Organic EL Element >>
As an example of the manufacturing method of the organic EL element, from anode / hole injection layer (anode buffer layer) / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer (cathode buffer layer) / cathode A method for manufacturing the device will be described.

First, a desired electrode material, for example, a thin film made of an anode material is formed on a suitable substrate so as to have a thickness of 1 μm or less, preferably 10 nm to 200 nm, and an anode is manufactured.
Next, a thin film containing an organic compound such as a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer, which is a device material, is formed thereon.
As a method for forming the thin film, for example, the thin film can be formed by a vacuum deposition method, a wet method (also referred to as a wet process), or the like.

Wet methods include spin coating, casting, die coating, blade coating, roll coating, ink jet, printing, spray coating, curtain coating, and LB, but precise thin films can be formed. From the viewpoint of high productivity, a method having high suitability for a roll-to-roll method such as a die coating method, a roll coating method, an ink jet method, or a spray coating method is preferable. Different film formation methods may be applied for each layer.

Examples of the liquid medium for dissolving or dispersing the organic EL material that can be used in the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, Aromatic hydrocarbons such as xylene, mesitylene and cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin and dodecane, and organic solvents such as DMF and DMSO can be used.
Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

After these layers are formed, a thin film made of a cathode material is formed thereon so as to have a thickness of 1 μm or less, preferably in the range of 50 to 200 nm, and a desired organic EL device can be obtained by providing a cathode. .
Alternatively, the cathode, electron injection layer, electron transport layer, hole blocking layer, light emitting layer, hole transport layer, hole injection layer, and anode can be formed in this order in the reverse order.
The organic EL device of the present invention is preferably produced 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 preferable to perform the work in a dry inert gas atmosphere.

<Sealing>
As a sealing means used for this invention, the method of adhere | attaching a sealing member, an electrode, and a support substrate with an adhesive agent can be mentioned, for example.
As a sealing member, it should just be arrange | positioned so that the display area | region of an organic EL element may be covered, and concave plate shape or flat plate shape may be sufficient. Further, transparency and electrical insulation are not particularly limited. Specific examples include a glass plate, a polymer plate / film, and a metal plate / film. For processing the sealing member into a concave shape, sandblasting, chemical etching, or the like is used.
In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. .

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween or on the sealing film. In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate.
As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

《Light extraction》
The organic EL 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 can extract only about 15% to 20% of the light generated in the light emitting layer. It is generally said. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ 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 the 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 element side surface.

As a method for improving the light extraction efficiency, for example, 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 (US Pat. No. 4,774,435), A method for improving efficiency by giving light condensing property to a substrate (Japanese Patent Laid-Open No. 63-314795), a method of forming a reflective surface on the side surface of an element (Japanese Patent Laid-Open No. 1-220394), and light emission from the substrate A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the bodies (Japanese Patent Laid-Open No. 62-172691), a flat having a lower refractive index between the substrate and the light emitter than the substrate A method of introducing a layer (Japanese Patent Laid-Open No. 2001-202827), a method of forming a diffraction grating between any one of a substrate, a transparent electrode layer and a light emitting layer (including between the substrate and the outside) (Japanese Patent Laid-Open No. 11-283951) Gazette).

In the present invention, these methods can be used in combination with the organic EL device of the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate, transparent A method of forming a diffraction grating between any layers of the electrode layer and the light emitting layer (including between the substrate and the outside) can be suitably used.
In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

《Condensing sheet》
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 device light emitting surface. By condensing in the front direction, the luminance in a specific direction can be increased.
As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are arranged two-dimensionally on the light extraction side of the substrate. One side is preferably 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

In addition, the “supporting substrate”, “sealing”, “protective film, protective plate”, “light extraction”, “light condensing” other than the characteristic portions of the present invention regarding the “each layer constituting the organic EL element” described above. Other details of the “sheet” and the like can be the same as those described in publicly known documents such as Japanese Patent Application Laid-Open No. 2012-164731 and Japanese Patent Application Laid-Open No. 2012-156299.

Further, the synthesis of the compound examples 1-1 to 1-40, 21-1 to 26-21, 4-1 to 4-155, etc. described above is described in, for example, International Publication No. 2008/056746, US Patent Application Publication No. 2011. / 0260138, Japanese Patent Application No. 2011-195331, and the like. DP-1 to DP-31 and the like can be synthesized with reference to International Publication No. 2008/140069 and the like.

<Application>
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources. For example, lighting devices (home lighting, interior lighting), clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources of optical storage media, light sources of electrophotographic copying machines, light sources of optical communication processors, light Although the light source of a sensor etc. are mentioned, It is not limited to this, It can use effectively for the use as a backlight of a liquid crystal display device, and an illumination light source especially.

In the organic EL element of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like as needed during film formation. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire layer of the element may be patterned. In the fabrication of the element, a conventionally known method is used. Can do.
The light emission color of the organic EL device of the present invention and the compound according to the present invention is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with a total of CS-1000 (manufactured by Konica Minolta Sensing Co., Ltd.) is applied to the CIE chromaticity coordinates.

When the organic EL element of the present invention is a white element, white means that the chromaticity in the CIE1931 color system at 1000 cd / m ² is X when the 2 ° viewing angle front luminance is measured by the above method. = 0.33 ± 0.07 and Y = 0.33 ± 0.1.

<Display device>
The display device of the present invention will be described. The display device of the present invention includes the organic EL element of the present invention.
Although the display device of the present invention may be single color or multicolor, the multicolor display device will be described here.

In the case of a multicolor display device, a shadow mask is provided only at the time of forming a light emitting layer, and a film can be formed on one surface by vapor deposition, casting, spin coating, ink jet, printing, or the like.
In the case of patterning only the light emitting layer, the method is not limited. However, the vapor deposition method, the ink jet method, the spin coating method, and the printing method are preferable.
The configuration of the organic EL element provided in the display device is selected from the above-described configuration examples of the organic EL element as necessary.
Moreover, the manufacturing method of an organic EL element is as having shown to the one aspect | mode of manufacture of the organic EL element of said invention.

When a DC voltage is applied to the obtained multicolor display device, light emission can be observed by applying a voltage of about 2V to 40V with the anode as + and the cathode as-polarity. 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. In display devices and displays, full-color display is possible by using three types of organic EL elements of blue, red, and green light emission.

Examples of the display device and display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in an automobile. In particular, it may be used as a display device for reproducing still images and moving images, and 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 present invention is not limited to these examples.

Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.
FIG. 2 is a schematic view showing an example of a display device composed of 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 1 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 a plurality of pixels based on image information from the outside, and the pixels for each scanning line respond to the image data signal by the scanning signal. The image information is sequentially emitted to scan the image and display the image information on the display unit A.

FIG. 3 is a schematic diagram of the display unit A.
The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below.
In the figure, the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

The scanning lines 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at orthogonal positions (details are shown in the figure). Not)
When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 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 on the same substrate.

Next, the light emission process of the pixel will be described.
FIG. 4 is a schematic diagram of a pixel.
The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, 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 10 in a plurality of pixels, and juxtaposing them on the same substrate.

4, an image data signal is applied from the control unit B to the drain of the switching transistor 11 via the data line 6. When a scanning signal is applied from the control unit B to the gate of the switching transistor 11 via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is supplied to the capacitor 13 and the driving transistor 12. Is transmitted to the gate.

By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the drive transistor 12 is turned on. The drive transistor 12 has a drain connected to the power supply line 7 and a source connected to the electrode of the organic EL element 10, and the power supply line 7 connects to the organic EL element 10 according to the potential of the image data signal applied to the gate. Current is supplied.

When the scanning signal is moved to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off.
However, even if the driving of the switching transistor 11 is turned off, the capacitor 13 maintains the potential of the charged image data signal, so that the driving of the driving transistor 12 is kept on and the next scanning signal is applied. Until then, the light emission of the organic EL element 10 continues.
When the scanning signal is next applied by sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.
That is, the light emission of the organic EL element 10 is performed by providing the switching transistor 11 and the drive transistor 12 which are active elements with respect to the organic EL element 10 of each of the plurality of pixels. It is carried out. Such a light emitting method is called an active matrix method.

Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or by turning on / off a predetermined light emission amount by a binary image data signal. Good. The potential of the capacitor 13 may be held continuously until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.
In the present invention, not only the active matrix method described above, but also 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. 5 is a schematic view of a passive matrix display device according to the display unit A of FIG. In FIG. 5, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.
When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal.
In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.

《Lighting device》
The lighting device of the present invention will be described. The lighting device of the present invention includes the organic EL element of the present invention.
The organic EL element of the present invention may be used as an organic EL element having a resonator structure. The purpose of use of the organic EL element having such a resonator structure is as follows. The light source of a machine, the light source of an optical communication processing machine, the light source of a photosensor, etc. are mentioned, However It is not limited to these. Moreover, you may use for the said use by making a laser oscillation.
Further, the organic EL element of the present invention may be used as a kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a display for directly viewing a still image or a moving image. It may be used as a device (display).
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, a full-color display device can be manufactured by using two or more organic EL elements of the present invention having different emission colors.

The organic EL material of the present invention can 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 the three primary colors of blue, green, and blue, or two using the relationship of complementary colors such as blue and yellow, blue green and orange, etc. The thing containing the light emission maximum wavelength may be used.
In addition, the combination of luminescent materials for obtaining multiple luminescent colors is a combination of multiple phosphorescent or fluorescent materials that emit light, fluorescent materials or phosphorescent materials, and light from the luminescent materials. Any combination with a dye material that emits light as light may be used, but in the white organic EL device according to the present invention, it is only necessary to mix and mix a plurality of light emitting dopants.

It is only necessary to provide a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, etc., and simply arrange them separately by coating with the mask. Since other layers are common, patterning of the mask or the like is not necessary. In addition, for example, an electrode film can be formed by a vapor deposition method, a cast method, a spin coating method, an ink jet method, a printing method, or the like, and productivity is also improved.
According to this method, unlike a white organic EL device in which light emitting elements of a plurality of colors are arranged in parallel in an array, the elements themselves are luminescent white.
There is no restriction | limiting in particular as a luminescent material used for a light emitting layer, For example, if it is a backlight in a liquid crystal display element, the metal complex which concerns on this invention so that it may suit the wavelength range corresponding to CF (color filter) characteristic, Any one of known luminescent materials may be selected and combined to whiten.

<< One Embodiment of Lighting Device of the Present Invention >>
One aspect of the lighting device of the present invention that includes the organic EL element of the present invention will be described.
The non-light emitting surface of the organic EL device of the present invention is covered with a glass case, a glass substrate having a thickness of 300 μm is used as a sealing substrate, and an epoxy-based photocurable adhesive (LUX TRACK manufactured by Toagosei Co., Ltd.) is used as a sealing material. LC0629B) is applied, and this is overlaid on the cathode to be in close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured and sealed, and as shown in FIG. 6 and FIG. Can be formed.
FIG. 6 shows a schematic diagram of the lighting device, and the organic EL element 101 of the present invention is covered with a glass cover 102 (in the sealing operation with the glass cover, the organic EL element 101 is brought into contact with the atmosphere. And a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more).
7 shows a cross-sectional view of the lighting device. In FIG. 7, reference numeral 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode (anode).
The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
Moreover, the structure of the compound used for an Example is shown below. In addition, about another compound, it is a thing as described in this specification.

<< Production of Organic EL Element 1-1 >>
A transparent substrate provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) as an anode on a glass substrate of 100 mm × 100 mm × 1.1 mm. The supporting substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by HC Starck, CLVIO P VP AI 4083) to 70% with pure water on the transparent support substrate. After forming a thin film by spin coating at 3000 rpm for 30 seconds, the film was dried at 200 ° C. for 1 hour to provide a hole injection layer having a thickness of 20 nm.

This transparent support substrate is fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus, and on the other hand, it is the same as 1-12 (compound (1) described in WO2011 / 122132) as a host compound in a resistance heating boat made of molybdenum. 200 mg), 200 mg of ET-8 as an electron transport material is put into another molybdenum resistance heating boat, and 100 mg of the compound (DP-BL1) as a dopant compound is put into another resistance heating boat made of molybdenum. 100 mg of TPD as a hole transport material was placed in a molybdenum resistance heating boat, and 100 mg of lithium fluoride was placed in another molybdenum resistance heating boat as a cathode buffer material, and attached to a vacuum deposition apparatus.

Next, the pressure in the vacuum chamber was reduced to 4 × 10 ⁻⁴ Pa, and the heating boat containing TPD was heated by energization. A hole having a thickness of 20 nm was formed on the hole injection layer at a deposition rate of 0.1 nm / second. A transport layer was provided.
Further, the heating boat containing 1-12 as a host compound and the compound (DP-BL1) as a dopant compound is heated by energization, and the hole transport is performed at a deposition rate of 0.1 nm / second and 0.025 nm / second, respectively. A light-emitting layer having a thickness of 30 nm was provided by co-evaporation on the layer.
Further, the heating boat containing ET-8 was energized and heated, and was deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide an electron transport layer having a thickness of 30 nm.
In addition, the substrate temperature at the time of vapor deposition was room temperature.
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, a comparative organic EL element 1-1 was produced.

<< Production of Organic EL Elements 1-2 to 1-15 >>
Organic EL elements 1-2 to 1-15 were prepared by the same method except that the dopant compound and the host compound in the light emitting layer were changed to the compounds shown in Table 1 in the production of the organic EL element 1-1. .

<< Evaluation of Organic EL Elements 1-1 to 1-15 >>
When evaluating the obtained organic EL elements 1-1 to 1-15, the non-light-emitting surface of each organic EL element after production was covered with a glass case, and a glass substrate having a thickness of 300 μm was used as a sealing substrate. An epoxy photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealant around the periphery, and this is placed on the cathode so as to be in close contact with the transparent support substrate and irradiated with UV light from the glass substrate side. Then, it was cured and sealed, and a lighting device as shown in FIGS. 6 and 7 was produced and evaluated.
The following evaluation was performed for each sample thus prepared. The evaluation results are shown in Table 1.

(1) External extraction quantum efficiency (also simply referred to as EQE)
By lighting the organic EL element under a constant current condition of room temperature (about 23 to 25 ° C.) and 2.5 mA / cm ² , and measuring the emission luminance (L) [cd / m ² ] immediately after the start of lighting, The external extraction quantum efficiency (η) was calculated.
Here, the measurement of emission luminance was performed using CS-1000 (manufactured by Konica Minolta Sensing), and the external extraction quantum efficiency was expressed as a relative value where the organic EL element 1-1 was 100.
Larger values are preferred because of higher efficiency.

(2) Half-life The half-life was evaluated according to the measurement method shown below.
Each organic EL device driven with a constant current at a current giving an initial luminance 1000 cd / ^{m 2,} obtains the time to be 1/2 (500cd / ^{m 2)} of the initial luminance, which was used as a measure of the half-life.
The half life was expressed as a relative value with the organic EL element 1-1 as 100.
Larger values are preferred for longer life.

(3) Drive voltage The voltage when the organic EL element is driven at room temperature (about 23 ° C. to 25 ° C.) and a constant current of ^2.5 mA / cm ² is measured, and the organic EL element 1-1 is set to 100. Expressed as a relative value.
The smaller the value, the lower the drive voltage and the better.

(4) EQE reduction rate at the time of heating The organic EL element is lighted under a constant current condition of 20 ° C. and ^2.5 mA / cm ² , and the light emission luminance (L) [cd / m ² ] immediately after the start of lighting is measured. Thus, the external extraction quantum efficiency (η @ 20 ° C.) was calculated. Furthermore, the temperature was set to 50 ° C., and the external extraction quantum efficiency (η @ 50 ° C.) was similarly calculated.
A value calculated as follows from these values was used as a measure of the EQE reduction rate during heating.

EQE reduction rate upon heating = [(η @ 20 ° C-η @ 50 ° C) / η @ 20 ° C] x 100
Here, the measurement of light emission luminance is performed using CS-1000 (manufactured by Konica Minolta Sensing Co., Ltd.), and becomes 0 when the external extraction efficiency does not change between 20 ° C. and 50 ° C.
The smaller the numerical value of the EQE reduction rate during heating, the more stable and preferable EQE is.

The element chromaticity is the chromaticity in the CIE 1931 color system at 1000 cd / m ² when the 2-degree viewing angle front luminance is measured using CS-1000 (manufactured by Konica Minolta Sensing Co., Ltd.).
The measurement of the light emitting region (recombination region) is as follows.

Each sample is electrically driven until the front light emission luminance is about half of the initial luminance (this state is set to ΔEL = 0.5), and the photoluminescence spectrum is measured before and after the driving to emit light. The maximum intensity was calculated to calculate the attenuation rate (ΔPL).
“ΔEL” indicates the intensity decay rate of the electroluminescence (EL) before and after driving, and “ΔPL” indicates the intensity decay rate of the photoluminescence (PL) before and after driving.
Specifically, each value of ΔEL and ΔPL is expressed by the following formula.

USB spectrum (manufactured by Ocean Optics) was used for PL spectrum measurement, and the spectrum measurement was performed under conditions of room temperature (23 ° C.) and excitation wavelength of 365 nm. The spectrum measurement after the drive was performed within 2 hours from that time after the EL was driven until the initial luminance became about half.
Thereafter, the ratio of each value between ΔPL and ΔEL (ΔPL / ΔEL) was calculated.
The calculation results are shown in Table 1.
The light emitting area is expressed as a relative value in which the light emitting area of the organic EL element 1-1 is set to 100.

From Table 1, the organic EL devices 1-5, 1-7 to 1-10, and 1-13 to 1-15 of the present invention each exhibit high luminous efficiency and long life, and have a low driving voltage. It can be seen that the characteristics are improved. Moreover, it turns out that the thing using the host compound which concerns on this invention has a low EQE fall rate at the time of a heating. In addition, it can be seen that the device characteristics are improved by making the HOMO level of the light emitting dopant and the host material the relationship of the present invention.

<< Preparation of organic EL elements 2-1 to 2-15 >>
In the organic EL element 1-1 of Example 1, was fixed to a substrate holder of a vacuum deposition apparatus without providing the hole injection layer, and change the hole transporting material to the alpha-NPD, change the electron transporting material Alq ₃ Organic EL devices 2-1 to 2-15 were produced in the same manner except that the dopant compound and host compound in the light emitting layer were changed to the compounds shown in Table 2.

The obtained organic EL devices 2-1 to 2-15 were subjected to the same method as in Example 1, (1) external extraction quantum efficiency (also simply referred to as EQE), (2) half-life, and (3) driving voltage. And (4) The EQE reduction rate during heating was evaluated, and the values other than the EQE reduction rate during heating were expressed as relative values with the organic EL element 2-1 being 100. Further, the element chromaticity and the light emitting region were measured in the same manner as in Example 1. The light emitting area is expressed as a relative value in which the light emitting area of the organic EL element 2-1 is set to 100.

From Table 2, it can be seen that each of the organic EL devices 2-7 to 2-12 of the present invention exhibits high luminous efficiency and long life, low driving voltage, and improved device characteristics. Moreover, it turns out that the thing using the host compound which concerns on this invention has a low EQE fall rate at the time of a heating. In addition, it can be seen that the device characteristics are improved by making the HOMO level of the light emitting dopant and the host material the relationship of the present invention.

The α-NPD vapor deposition film of the organic EL device 2-1 was changed to a co-deposition film of HTM1: F4-TCNQ = 97: 3, and the vapor deposition film of Alq ₃ was changed to a co-deposition film of BPhen: Cs = 1: 1. Then, organic EL elements 3-1 to 3-12 were produced in exactly the same manner except that LiF was not deposited.

The obtained organic EL devices 3-1 to 3-12 were subjected to the same method as in Example 1, (1) external extraction quantum efficiency (also simply referred to as EQE), (2) half-life, and (3) driving voltage. (4) The EQE reduction rate during heating was evaluated, and the values other than the EQE reduction rate during heating were expressed as relative values with the organic EL element 3-1 being 100. Further, the element chromaticity and the light emitting region were measured in the same manner as in Example 1. The light emitting area is expressed as a relative value in which the light emitting area of the organic EL element 3-1 is set to 100.

From Table 3, it can be seen that the organic EL devices 3-7 to 3-11 of the present invention each exhibit high luminous efficiency and long life, low driving voltage, and improved device characteristics. Moreover, it turns out that the thing using the host compound which concerns on this invention has a low EQE fall rate at the time of a heating. In addition, it can be seen that the device characteristics are improved by making the HOMO level of the light emitting dopant and the host material the relationship of the present invention.

In the organic EL element 1-1 of Example 1, the hole injection layer was not provided and fixed to the substrate holder of the vacuum evaporation apparatus, the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and then the HT-30 was added. A heating boat was energized and heated, and a hole injection layer having a thickness of 10 nm was provided on the transparent support substrate at a deposition rate of 0.1 nm / second. Organic EL elements 4-1 to 4-11 were produced in exactly the same manner except that the hole transport material was changed to α-NPD.

The obtained organic EL devices 4-1 to 4-11 were subjected to the same method as in Example 1, (1) external extraction quantum efficiency (also simply referred to as EQE), (2) half-life, and (3) driving voltage. And (4) The EQE reduction rate during heating was evaluated. Except for the EQE reduction rate during heating, each was expressed as a relative value where the organic EL element 4-1 was 100. Further, the element chromaticity and the light emitting region were measured in the same manner as in Example 1. The light emitting area is expressed as a relative value in which the light emitting area of the organic EL element 4-1 is set to 100.

Table 4 shows that each of the organic EL elements 4-7 to 4-10 of the present invention exhibits high luminous efficiency and long life, has a low driving voltage, and has improved characteristics as an element. Moreover, it turns out that the thing using the host compound which concerns on this invention has a low EQE fall rate at the time of a heating. In addition, it can be seen that the device characteristics are improved by making the HOMO level of the light emitting dopant and the host material the relationship of the present invention.

<< Preparation of white light-emitting organic EL element 5-1 >>
A transparent substrate provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) as an anode on a glass substrate of 100 mm × 100 mm × 1.1 mm. The supporting substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

This transparent support substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus. Meanwhile, 200 mg of α-NPD as a hole transport material is placed in a molybdenum resistance heating boat and a comparative compound as a host compound in another molybdenum resistance heating boat. Put 200 mg of H-1, 200 mg of ET-8 as an electron transport material in another molybdenum resistance heating boat, 100 mg of DP-BL1 as a dopant compound in another molybdenum resistance heating boat, another resistance heating made of molybdenum 100 mg of D-1 as a dopant compound was placed in a boat and attached to a vacuum deposition apparatus.

Next, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, energizing the heating boat containing α-NPD and depositing it on the transparent support substrate at a deposition rate of 0.1 nm / second, transporting holes with a thickness of 20 nm. A layer was provided.
Further, the heating boat containing DP-BL1 and D-1 as comparative compounds H-1 as the host compounds and DP-BL1 and D-1 as the dopant compounds is heated and heated so that the respective deposition rates become 100: 5: 0.6. And a light emitting layer having a thickness of 40 nm was provided.
Further, the heating boat containing ET-8 was energized and heated, and deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide an electron transport layer having a thickness of 30 nm.
In addition, the substrate temperature at the time of vapor deposition was room temperature.

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 5-1 was produced.
When the produced organic EL element 5-1 was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

<< Production of organic EL elements 5-2 to 5-6 >>
In the production of the organic EL device 5-1, the organic EL device 5-2 was prepared in the same manner except that the host comparison compound H-1 and dopant compound DP-BL1 used in the light emitting layer were changed to the compounds shown in Table 5. ~ 5-6 were prepared respectively. The dopant compound includes D-1. When the produced organic EL elements 5-2 to 5-6 were energized, almost white light was obtained, and it was found that they could be used as a lighting device.

In addition, the obtained organic EL elements 5-1 to 5-6 were subjected to the same method as in Example 1. (1) External extraction quantum efficiency (also simply referred to as EQE), (2) Half life, (3) The drive voltage and (4) the EQE reduction rate during heating were evaluated, and the values other than the EQE reduction rate during heating were expressed as relative values with the organic EL element 5-1 being 100. Further, the light emitting region was measured by the same method as in Example 1. The light emitting area is expressed as a relative value in which the light emitting area of the organic EL element 5-1 is set to 100.

From Table 5, it can be seen that each of the organic EL devices 5-2 to 5-6 of the present invention has high luminous efficiency and long life, low driving voltage, and improved device characteristics. Moreover, it turns out that the thing using the host compound which concerns on this invention has a low EQE fall rate at the time of a heating. In addition, it can be seen that the device characteristics are improved by making the HOMO level of the light emitting dopant and the host material the relationship of the present invention.

<< Production of organic EL full-color display device >>
FIG. 8 shows a schematic configuration diagram of an organic EL full-color display device.
After patterning at a pitch of 100 μm on a substrate (NA45 manufactured by NH Techno Glass Co., Ltd.) having a 100 nm ITO transparent electrode 202 formed as an anode on a glass substrate 201 (see FIG. 8A), on this glass substrate 201 Then, a non-photosensitive polyimide partition wall 203 (width 20 μm, thickness 2.0 μm) was formed between the ITO transparent electrodes 202 by photolithography (see FIG. 8B).

A hole injection layer composition having the following composition is ejected and injected on the ITO transparent electrode 202 between the partition walls 203 using an inkjet head (manufactured by Epson Corporation; MJ800C), irradiated with ultraviolet light for 200 seconds, 60 A hole injection layer 204 having a thickness of 40 nm was provided by a drying process at 10 ° C. for 10 minutes (see FIG. 8C).

A blue light-emitting layer composition, a green light-emitting layer composition, and a red light-emitting layer composition having the following compositions are similarly ejected and injected onto the hole injection layer 204 using an inkjet head, and dried at 60 ° C. for 10 minutes. Then, the

light emitting layers

205B, 205G, and 205R for each color were provided (see FIG. 8D).
Next, an electron transport material is deposited so as to cover each of the

light emitting layers

205B, 205G, and 205R to provide an electron transport layer (not shown) with a thickness of 20 nm, and further lithium fluoride is deposited to have a thickness of 0.6 nm. A cathode buffer layer (not shown) was provided, Al was vapor-deposited, and a cathode 206 having a film thickness of 130 nm was provided to produce an organic EL device (see FIG. 8E).
It was found that the produced organic EL elements each emitted blue, green, and red light when a voltage was applied to the electrodes, and could be used as a full-color display device.

(Hole injection layer composition)
1-12 20 parts by mass Cyclohexylbenzene 50 parts by mass Isopropylbiphenyl 50 parts by mass

(Blue light emitting layer composition)
Host compound (1-12) 0.7 parts by mass Host DP-1 0.04 parts by mass Dopant cyclohexylbenzene 50 parts by mass Isopropylbiphenyl 50 parts by mass

(Green light emitting layer composition)
Host compound (H-1) 0.7 parts by mass D-2 0.04 parts by mass
Cyclohexylbenzene 50 parts by mass Isopropyl biphenyl 50 parts by mass

(Red light emitting layer composition)
Host compound (H-1) 0.7 parts by mass D-1 0.04 parts by mass cyclohexylbenzene 50 parts by mass Isopropylbiphenyl 50 parts by mass

As described above, the organic EL device of the present invention exhibits performance such as EQE, life, and driving voltage while the emission maximum wavelength of the dopant and the device chromaticity satisfy the required characteristics. It is known that the shorter the emission maximum wavelength (emission spectrum) of the dopant is, the more easily the dopant material becomes unstable, and the performance such as EQE, life, and driving voltage does not come out. However, it can be said that there is a gain in the case of a short wave as in the present invention.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 7 Power supply line 10 Organic EL element 11 Switching transistor 12 Drive transistor 13 Capacitor 100 Light emitting layer 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate 108 with a transparent electrode 108 Nitrogen gas 109 Water capturing agent 201 Glass substrate 202 ITO transparent electrode 203 Partition 204

Hole injection layer

205B, 205G, 205R Light emitting layer 206 Cathode A Display part B Control part T1 Recombination area T2 Area not contributing to light emission T4 Non-light emitting area T3, T5 , T6 area

Claims

In an organic electroluminescence device including at least one light emitting layer sandwiched between an anode and a cathode,
At least one of the light emitting layers contains at least one light emitting dopant and at least one host,
At least one of the light-emitting dopants is a phosphorescent light-emitting dopant having an emission maximum wavelength on the shortest wavelength side of 470 nm or less and a HOMO value of −4.50 to −5.50 eV in an emission spectrum in a solution. ,
At least one of the hosts is a compound represented by any one of the following general formulas (1) to (4), and has a HOMO value of −4.60 to −5.10 eV. An organic electroluminescence element.

(In General Formula (1), R 111 and R 112 represent a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocycloalkyl group, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group, (The compound represented may further have a substituent.)

(In the general formula (2), R 211 and R 212 represent an alkyl group, an aromatic hydrocarbon ring group or an aromatic heterocyclic group. Rings Z 1 to Z 3 represent an aromatic hydrocarbon ring or an aromatic heterocyclic ring. Represents a residue to be formed and may have a substituent.)

(In the general formula (3), R 211 and R 212 represent an alkyl group, an aromatic hydrocarbon ring group or an aromatic heterocyclic group. Rings Z 1 to Z 3 represent an aromatic hydrocarbon ring or an aromatic heterocyclic ring. Represents a residue to be formed and may have a substituent.)

(In General Formula (4), R 311 and R 312 each represent a hydrogen atom, an arylsilyl group, an arylphosphoryl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a diarylamino group, or an alkyl group. 1 to A 8 each independently represents C—Rx or N, and a plurality of Rxs may be the same or different, and Rx each independently represents a hydrogen atom or a substituent.
The organic electroluminescence device according to claim 1, wherein the phosphorescent light-emitting dopant is a compound represented by the following general formula (5).

(In the general formula (5), M represents Ir, Pt, Rh, Ru, Ag or Cu, X 1 and X 2 represent a carbon atom or a nitrogen atom, and ring Z 1 represents a 6-membered aromatic with C═C. Represents a 5-membered aromatic ring, or a 5- or 6-membered aromatic heterocyclic ring, wherein ring Z 2 represents a 5-membered heterocyclic ring together with X 1 -X 2. L ′ represents a monoanionic divalent ring coordinated to M A bidentate ligand, m ′ represents an integer of 0 to 2, n ′ is an integer of at least 1, and m ′ + n ′ is 2 or 3.)
The organic electroluminescence device according to claim 1, wherein the phosphorescent light-emitting dopant is a compound represented by the following general formula (6).

(In General Formula (6), M represents Ir, Pt, Rh, Ru, Ag, or Cu, X 1 and X 2 represent a carbon atom or a nitrogen atom, and ring Z 2 is a 5-membered member together with X 1 -X 2. R 1 represents an electron-withdrawing group, R 2 represents an electron-donating group or F. L ′ is a monoanionic bidentate ligand coordinated to M, and m ′ is 0. Represents an integer of ˜2, n ′ is an integer of at least 1 and m ′ + n ′ is 2 or 3.)
The organic electroluminescence device according to claim 1, wherein the phosphorescent light-emitting dopant is a compound represented by the following general formula (7).

(In the general formula (7), M represents Ir, Pt, Rh, Ru, Ag or Cu, and ring Z 1 is a 6-membered aromatic hydrocarbon ring together with C = C, or a 5-membered or 6-membered aromatic ring. R 3 , R 4 , and R 5 each represent a hydrogen atom or a substituent, and R 4 and R 5 may form a ring, and L ′ is a monoanionic divalent group coordinated to M. A bidentate ligand, m ′ represents an integer of 0 to 2, n ′ is an integer of at least 1, and m ′ + n ′ is 2 or 3.)
2. The organic electroluminescence device according to claim 1, wherein the phosphorescent light-emitting dopant is a compound represented by the following general formula (8).

(In the general formula (8), M represents Ir, Pt, Rh, Ru, Ag or Cu, X 1 to X 4 represent —CR 6 or a nitrogen atom, and X 3 and X 4 are —CR 6 . The ring Z 3 represents a 6-membered aromatic hydrocarbon ring, or a 5-membered or 6-membered aromatic heterocycle, and the ring Z 4 is a 5-membered with X 1 -X 2 R 6 represents a carbon atom or a nitrogen atom, L ′ represents a monoanionic bidentate ligand coordinated to M, m ′ represents an integer of 0 to 2, and n ′ Is an integer of at least 1 and m ′ + n ′ is 2 or 3.)
In the compound represented by the general formula (6),
Ring Z 2 is an organic electroluminescent device according to claim 3, characterized in that a substituted or unsubstituted triazole ring.
The organic electroluminescence device according to any one of claims 1 to 6, wherein the phosphorescent luminescent dopant has an emission maximum wavelength on the shortest wavelength side in an emission spectrum in a solution of 460 nm or less. .
The organic electroluminescence device according to any one of claims 1 to 7, wherein the emission color is white.
A lighting device comprising the organic electroluminescence element according to any one of claims 1 to 8.
A display device comprising the organic electroluminescence element according to any one of claims 1 to 8.