JP2017175074A - Luminescent organic thin film, organic electroluminescent element, display device, and lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a long-life organic EL element which exhibits less deterioration in luminous efficiency due to oxygen and water and achieves high luminous efficiency.SOLUTION: A luminescent organic thin film contains a steroid skeleton compound represented by general formula (1) and a phosphorescent material. (In the general formula (1), Rrepresents a substituted or unsubstituted tertiary amino group, a substituted or unsubstituted aromatic hydrocarbon group (excluding an aromatic hydrocarbon group substituted with a tertiary amino group), or a substituted or unsubstituted aromatic heterocyclic group; and Rto Reach independently represent a hydrogen atom or a substituent.)SELECTED DRAWING: None

Description

  The present invention relates to a light-emitting organic thin film, an organic electroluminescence element, a display device, and a lighting device.

  An organic EL element using organic electroluminescence (hereinafter abbreviated as “organic EL”) has a configuration in which an organic functional layer containing a light emitting material is sandwiched between a cathode and an anode. When an electric field is applied to the organic EL element, holes injected from the anode and electrons injected from the cathode are recombined in the light emitting layer to generate excitons. In the organic EL element, the excitons are deactivated. It is a light emitting element utilizing the emission of light. Since the organic EL element can emit light on a flat surface, it has recently been applied to lighting equipment as well as an electronic display, and its development is expected.

There are two types of emission methods for organic EL elements: phosphorescence emission, which emits light when returning from the triplet excited state to the ground state, and fluorescence emission, which emits light when returning from the singlet excited state to the ground state. There is a street.
When an electric field is applied to the organic EL element, holes and electrons are injected from the anode and the cathode, respectively, and recombine in the light emitting layer to generate excitons. At this time, since singlet excitons and triplet excitons are generated at a ratio of 25%: 75%, phosphorescence using triplet excitons is theoretically higher in internal quantum than fluorescence. It is known that efficiency can be obtained.

  As development for practical application of organic EL elements, development of technology that efficiently emits light with high luminance with low power consumption is desired. Since Princeton University reported on organic EL devices using phosphorescent materials from excited triplets by Non-Patent Document 1, research on materials that exhibit phosphorescence at room temperature by Non-Patent Document 2, Patent Document 1, etc. Has become active.

  However, the organic EL element has a problem that it is vulnerable to moisture and oxygen in the atmosphere and is likely to be deteriorated or deteriorated. For this reason, practical application to displays and lighting devices that require a long life and a wide light emitting area is delayed. In particular, in an organic EL element using a phosphorescent material as a light-emitting material, triplet excitons generated by electric field excitation are easily quenched by oxygen, and as a result, the emission quantum efficiency is significantly reduced. Therefore, under the present circumstances, it is necessary to strictly seal the organic EL element so that the organic EL element is not exposed to moisture or oxygen in the atmosphere.

  FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a conventional organic EL element. Here, the substrate 23 is made of glass, resin, film, or the like. And the organic EL element 10 is pinched | interposed with the sealing case 22 which opposes. Here, the sealing case 22 is made of, for example, metal or glass. The organic EL element 10 is an element capable of self-emission with a low voltage of about several volts to several tens of volts. The adhesive 21 is an adhesive for bonding the substrate 23 and the sealing case 22. The substrate 23 and the sealing case 22 are fixed by bonding the substrate 23 and the sealing case 22 with the adhesive 21. Thus, in the prior art, moisture that enters the organic EL element 10 from between the substrate 23 and the sealing case 22 is prevented. However, in such a technique, there is permeation of oxygen and moisture in the atmosphere from the joint or base of the adhesive 21 that bonds the substrate c and the sealing case 22, and the organic EL element 10 is altered and darkened. In many cases, a non-light emitting region called a spot is generated or the light emission efficiency is lowered. Therefore, means for preventing the influence of oxygen and moisture in the atmosphere by a method other than sealing is required.

For example, Non-Patent Document 3 discloses an organic thin film using β-estradiol represented by the following formula as a host of a luminescent material as a means for preventing a decrease in luminescence quantum yield due to oxygen. Has been. According to Non-Patent Document 3, an organic thin film using β-estradiol as a host can prevent the penetration of oxygen into the film, so that exciton quenching is difficult to occur.

Non-Patent Document 4 uses 3- (N-carbazolyl) -androst-2-ene (CzSte), which is a compound having a steroid skeleton represented by the following formula, as a host material, and N, N-bis. An organic EL device having a light-emitting layer doped with (2-methylphenyl) -N, N′-bis (phenyl) -9,9′-dimethylethyl-fluorene (DMFLTPD) is described.

Furthermore, Patent Document 2 discloses an organic phosphorescent material containing a matrix containing a reversible agent and a dye having a phosphorescence lifetime of 0.1 seconds or longer in a 77K rigid medium. It is also disclosed that one type of cholesterol represented by the following formula or the above estradiol is used as a reversible agent. Patent Document 2 describes that by using a compound having a steroid skeleton as a reversible agent, the matrix becomes rigid and local molecular motion is reduced, and as a result, excitation energy loss of the dye is prevented. Has been.

  Patent Document 3 discloses a compound having a steroid skeleton as a phosphorescent material.

US Pat. No. 6,097,147 International Publication No. 09/069790 Japanese Patent Laying-Open No. 2015-164989

M.M. A. Baldo et al. , Nature, 395, 151-154 (1998) M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000) Adv. Funct. Mater. 2013, 23, 3386 Adv. Mater. 2016, 28, 655

  Non-Patent Document 3 and Patent Document 2 describe phosphorescence emission using a compound having a steroid skeleton as a host, but do not describe that it is useful as a host of an organic EL device. Although Non-Patent Document 4 discloses an organic EL element using a compound having a steroid skeleton as a host, the light emitting material used is a material having a long phosphorescence lifetime and a short phosphorescence lifetime. There is no description about the organic EL element using a luminescent material.

  Even when the present inventors create an organic EL device using a compound having a steroid skeleton as described in Non-Patent Documents 2 and 3 and Patent Documents 2 and 3 as a host material, sufficient luminous efficiency and long Life could not be achieved. Accordingly, the present inventors have developed a light-emitting organic thin film that suppresses a decrease in light emission efficiency due to oxygen or water, and has made it an object to provide an organic EL element having high light emission efficiency and a long lifetime.

  As a result of diligent studies to solve the above problems, the present inventors have reduced the luminous efficiency due to oxygen and water by combining a material having a specific steroid skeleton and a phosphorescent material. It has been found that an organic EL device with high light emission efficiency and long life can be provided, and the present invention has been achieved.

（一般式（１）において、
Ｒ^１は、置換または無置換の３級アミノ基、置換または無置換の芳香族炭化水素基（但し、３級アミノ基で置換された芳香族炭化水素基を除く）、あるいは置換または無置換の芳香族複素環基を表し、
Ｒ^２〜Ｒ^２２は、各々独立に、水素原子または置換基を表す。）
［２］ 前記リン光発光性材料は、金属錯体であることを特徴とする、［１］に記載の発光性有機薄膜。
［３］ 前記金属錯体は、イリジウム錯体であることを特徴とする、［２］に記載の発光性有機薄膜。
［４］ 前記ステロイド骨格化合物が、下記一般式（２）〜（４）のいずれかで表されることを特徴とする、［１］〜［３］のいずれかに記載の発光性有機薄膜。

（一般式（２）〜（４）において、
Ｒ^１は、置換または無置換の３級アミノ基、置換または無置換の芳香族炭化水素基、あるいは置換または無置換の芳香族複素環基を表す。）
［５］ 前記Ｒ^１は、置換または無置換の３級アミノ基、電子吸引性基で置換された芳香族炭化水素基、あるいは電子吸引性基で置換された芳香族複素環基であることを特徴とする、［１］〜［４］のいずれかに記載の発光性有機薄膜。
［６］ 前記Ｒ^１は、置換または無置換の３級アミノ基であることを特徴とする、［１］〜［５］のいずれかに記載の発光性有機薄膜。
［７］ 前記Ｒ^１は、電子吸引性基で置換された３級アミノ基であることを特徴とする、［６］に記載の発光性有機薄膜。
［８］ 前記Ｒ^１は、電子吸引性基で置換されたカルバゾリル基であることを特徴とする、［７］に記載の発光性有機薄膜。
［９］ ［１］〜［８］のいずれかに記載の発光性有機薄膜を含む、有機エレクトロルミネッセンス素子。
［１０］ ［９］に記載の有機エレクトロルミネッセンス素子を含む、表示装置。
［１１］ ［９］に記載の有機エレクトロルミネッセンス素子を含む、照明装置。 That is, the said subject which concerns on this invention is solved by the following means.
[1] A luminescent organic thin film comprising a steroid skeleton compound represented by the general formula (1) and a phosphorescent material.

(In general formula (1),
R ¹ represents a substituted or unsubstituted tertiary amino group, a substituted or unsubstituted aromatic hydrocarbon group (excluding an aromatic hydrocarbon group substituted with a tertiary amino group), or a substituted or unsubstituted aromatic hydrocarbon group Represents an aromatic heterocyclic group,
R ^{2 to} R ²² each independently represents a hydrogen atom or a substituent. )
[2] The luminescent organic thin film according to [1], wherein the phosphorescent material is a metal complex.
[3] The luminescent organic thin film according to [2], wherein the metal complex is an iridium complex.
[4] The luminescent organic thin film according to any one of [1] to [3], wherein the steroid skeleton compound is represented by any one of the following general formulas (2) to (4).

(In the general formulas (2) to (4),
R ¹ represents a substituted or unsubstituted tertiary amino group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group. )
[5] R ¹ is a substituted or unsubstituted tertiary amino group, an aromatic hydrocarbon group substituted with an electron-withdrawing group, or an aromatic heterocyclic group substituted with an electron-withdrawing group. The luminescent organic thin film according to any one of [1] to [4].
[6] The luminescent organic thin film according to any one of [1] to [5], wherein R ¹ is a substituted or unsubstituted tertiary amino group.
[7] The luminescent organic thin film according to [6], wherein R ¹ is a tertiary amino group substituted with an electron-withdrawing group.
[8] The luminescent organic thin film according to [7], wherein R ¹ is a carbazolyl group substituted with an electron-withdrawing group.
[9] An organic electroluminescence device comprising the light-emitting organic thin film according to any one of [1] to [8].
[10] A display device comprising the organic electroluminescence element according to [9].
[11] A lighting device including the organic electroluminescence element according to [9].

  By the above means of the present invention, it is possible to provide a long-life organic EL element that achieves high luminous efficiency with little decrease in luminous efficiency due to oxygen or water. In addition, an organic electroluminescent element using the light-emitting thin film, and a display device and a lighting device including the organic electroluminescent element can be provided.

Schematic sectional view showing an example of the configuration of a conventional organic EL element Schematic diagram showing an example of a display device composed of organic EL elements Schematic diagram of an active matrix display device Schematic showing the pixel circuit Schematic diagram of a passive matrix display device Schematic of lighting device Cross section of the lighting device

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

  In the following, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. Before entering into this discussion, the organic EL light emission method and light emission related to the technical idea of the present invention. Describe materials.

<< Light emission method of organic EL >>
There are two types of organic EL emission methods: “phosphorescence emission” that emits light when returning from the triplet excited state to the ground state and “fluorescence emission” that emits light when returning from the singlet excited state to the ground state. There is.
When excited by an electric field such as an organic EL, triplet excitons are generated with a probability of 75% and singlet excitons are generated with a probability of 25%. Therefore, phosphorescence emission can increase luminous efficiency compared with fluorescence emission, and is an excellent method for realizing low power consumption.

<Phosphorescent compound>
As described above, phosphorescence emission is theoretically three times more advantageous than fluorescence emission in terms of luminous efficiency. However, the energy deactivation (= phosphorescence emission) from the triplet excited state to the singlet ground state is a forbidden transition, and similarly, the intersystem crossing from the singlet excited state to the triplet excited state is also a forbidden transition. In general, the rate constant is small. That is, since the transition is difficult to occur, the phosphorescence lifetime is increased from millisecond to second order, and it is difficult to obtain desired light emission. However, when a complex using a heavy metal such as iridium or platinum emits light, the rate constant of the forbidden transition increases by three orders of magnitude or more due to the heavy atom effect of the central metal. Furthermore, depending on the choice of ligand, it is possible to obtain a phosphorescence quantum yield of 100%.

<Fluorescent compound>
A general fluorescent material is not particularly required to be a heavy metal complex like a phosphorescent material, and is a so-called organic compound composed of a combination of common elements such as carbon, oxygen, nitrogen and hydrogen. Can be applied. Furthermore, it is possible to use other non-metallic elements such as phosphorus, sulfur, silicon, and the like, and since the complexes of typical metals such as aluminum and zinc can also be used, the diversity is almost infinite. However, in the conventional fluorescent compound, since only 25% of the excitons can be applied to light emission as described above, high efficiency light emission such as phosphorescence emission cannot be expected.
Recently, even in fluorescence emission, triplet excitons, which are usually generated with a probability of 75% and become heat only by non-radiation deactivation, are present at a high density. A system using a TTA (triplet-triplet annealing, also abbreviated as “TTF”) mechanism that generates singlet excitons to improve luminous efficiency has been found.

<Problems of conventional luminescent materials>
However, the conventional organic EL device using the phosphorescent compound or the fluorescent compound described above has the following problems.
An organic EL element emits light using singlet excitons or triplet excitons generated by electric field excitation, but these excitons are quenched by oxygen or water, resulting in a decrease in light emission quantum efficiency and deterioration of the element. Triplet excitons are particularly susceptible to quenching due to their long exciton lifetime. Therefore, the conventional organic EL element using the phosphorescent material is sealed to prevent the influence of oxygen and water in the atmosphere. In particular, when a plastic film is used for the base, oxygen and water easily pass through the base, and thus a high-level sealing technique is required. However, in order to perform advanced sealing, there are problems such as high cost and low productivity.
Therefore, development of a technique for preventing the influence of oxygen and water in the atmosphere by a simpler technique is desired.

  On the other hand, the present inventors can easily produce a light-emitting organic thin film by combining a steroid skeleton compound represented by the general formula (1) and a phosphorescent material, particularly a phosphorescent material. In addition, it has been found that quenching by atmospheric oxygen and water can be prevented. In addition, it has also been found that an organic EL element having high luminous efficiency and a long lifetime can be obtained by using this luminescent organic thin film.

<< Mechanism to prevent quenching of steroid skeleton compound of the present invention >>
The steroid skeleton compound represented by the general formula (1) used in the present invention has a steroid skeleton composed of a plurality of cyclo rings. Since the steroid skeleton is a rigid skeleton and has a C—H bond outside the surface, the steroid skeleton easily interacts between molecules and aggregates to form a strong film. This strong film suppresses the penetration of oxygen and water, thereby preventing the deactivation of triplet excitons generated in the phosphorescent material and suppressing the deterioration of the organic EL element.
Furthermore, the steroid skeleton compound can function as a host compound when combined with an appropriate phosphorescent material. By using a steroid skeleton compound, it is possible to achieve high luminous efficiency even with a small amount of luminescent material.

1. Luminescent Organic Thin Film The luminescent organic thin film of the present invention contains a steroid skeleton compound represented by the general formula (1) and a phosphorescent material.

1-1. Steroid skeleton compound The steroid skeleton compound used in the present invention is not particularly limited as long as it is a compound represented by the general formula (1).

R ^{1 in the} general formula (1) represents a substituted or unsubstituted tertiary amino group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group.

When the tertiary amino group of the “substituted or unsubstituted tertiary amino group” used as R ¹ has two substituents, they may be the same as or different from each other.

  As the substituent that the tertiary amino group has, an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group) , Pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group, etc.), aromatic hydrocarbon group (aromatic hydrocarbon ring group, aromatic carbocyclic group, aryl group, etc., for example, phenyl group, Mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc.), aromatic heterocyclic group (for example, pyridine ring, pyrimidine) Ring, furan ring, pyrone ring, imidazole ring, benzimidazole ring, Zole ring, pyrazine ring, triazole ring, triazine ring, dibenzothiophene oxide ring, dibenzothiophene dioxide ring, pyridazine ring, quinoline ring, isoquinoline ring, quinazoline ring, cinnoline ring, quinoxaline ring, phthalazine ring, pteridine ring, phenanthridine A group derived from a ring, a phenanthroline ring, a dibenzofuran ring, a dibenzosilole ring, a dibenzoborol ring, an azadibenzofuran ring, a diazadibenzofuran ring, and a dibenzophosphole oxide ring).

In addition, these substituents include substituents represented by the following R ^{2 to} R ²² , such as halogen atoms (eg, fluorine atom, chlorine atom, bromine atom), fluorinated hydrocarbon groups (eg, fluoromethyl group). An alkyl group substituted with a fluorine atom such as a trifluoromethyl group or a pentafluoroethyl group, or an aryl group substituted with a fluorine atom such as a fluorophenyl group), a cyano group, a nitro group, or an optionally substituted carbonyl Further substituted with an electron-withdrawing group such as a group, an optionally substituted sulfonyl group, an optionally substituted phosphine oxide group, an optionally substituted boryl group, and an aromatic heterocyclic group .

  In addition, substituents substituted with a tertiary amino group may be bonded to each other to form a cyclic structure. Examples of tertiary amino groups in which two substituents substituted with a nitrogen atom are bonded to each other to form a cyclic structure include carbazolyl group, azacarbazolyl group, diazacarbazolyl group, benzocarbazole group, phenoxazyl group, phenothiazyl group , An acridyl group, a 9,10-dihydroacridyl group, and an indoloindolyl group.

The “aromatic hydrocarbon group” in the “substituted or unsubstituted aromatic hydrocarbon group” used as R ¹ includes a phenyl group, a mesityl group, a tolyl group, a xylyl group, a naphthyl group, an anthryl group, an azulenyl group, an acenaphthenyl group. Fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group and the like. The aromatic hydrocarbon group may be a group in which two or more aromatic hydrocarbon groups are bonded via a single bond.

  The substituent that the “aromatic hydrocarbon group” has is a group other than the tertiary amino group, and examples thereof include an alkyl group, a cycloalkyl group, an alkoxy group (for example, a methoxy group, an ethoxy group, a propyloxy group, Pentyloxy, hexyloxy, octyloxy, dodecyloxy, etc.) and silyl groups (eg, trimethylsilyl, triisopropylsilyl, triphenylsilyl, phenyldiethylsilyl, etc.), halogen atoms (eg, fluorine) Atoms, chlorine atoms, bromine atoms, etc.), fluorinated hydrocarbon groups (eg alkyl groups substituted with fluorine atoms such as fluoromethyl groups, trifluoromethyl groups, pentafluoroethyl groups), cyano groups, nitro groups, substituted Optionally substituted carbonyl group, optionally substituted sulfonyl group, optionally substituted photo Fins oxide group, substituted optionally may be boryl group, and an aromatic heterocyclic group and the like. The alkyl group and the cycloalkyl group are the same as the alkyl group and the cycloalkyl group as substituents of the tertiary amino group, respectively. Moreover, these substituents may be further substituted with the following substituents. Further, these substituents may be bonded together to form a ring.

The “aromatic heterocyclic group” in the “substituted or unsubstituted aromatic heterocyclic group” used as R ¹ includes a pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group , Triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazol-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 group, quinoxalinyl group, pyridazinyl group, triazinyl group, quinazolinyl group, phthalazinyl group, and the like. The aromatic heterocyclic group may be a group in which two or more aromatic heterocyclic groups are bonded via a single bond.

  Examples of the substituent that the “aromatic heterocyclic group” has include an alkyl group, a cycloalkyl group, an alkoxy group, a silyl group, an aromatic hydrocarbon group, a halogen atom, a fluorinated hydrocarbon group, a cyano group, a nitro group, and a substituted group. Examples thereof include an optionally substituted carbonyl group, an optionally substituted sulfonyl group, an optionally substituted phosphine oxide group, and an optionally substituted boryl group.

  The alkyl group, cycloalkyl group and aromatic hydrocarbon group are the same as the alkyl group, cycloalkyl group and aromatic hydrocarbon group as substituents of the tertiary amino group, respectively. The alkoxy group, silyl group, halogen atom and fluorinated hydrocarbon group are the same as the alkoxy group, silyl group, halogen atom and fluorinated hydrocarbon group as substituents of the aromatic hydrocarbon group. Moreover, these substituents may be further substituted with the following substituents. Further, these substituents may be bonded together to form a ring.

In the steroid skeleton compound used in the present invention, R ¹ is substituted with a tertiary amino group substituted with an electron withdrawing group, an aromatic hydrocarbon group substituted with an electron withdrawing group, or an electron withdrawing group. It is preferably an aromatic heterocyclic group. R ¹ is preferably a substituent substituted with an electron-withdrawing group because it easily carries electrons. R ¹ is more preferably a tertiary amino group substituted with an electron withdrawing group, and further preferably a carbazolyl group substituted with an electron withdrawing group. A tertiary amino group substituted with an electron-withdrawing group is preferable because it easily carries holes and electrons, and a tertiary amino group is preferably a carbazolyl group because of high chemical stability.

  “The electron-withdrawing group” in the aromatic hydrocarbon group substituted with an electron-withdrawing group is a fluorine atom, a cyano group, an alkyl group which may be substituted with a fluorine atom, an optionally substituted carbonyl group, It is preferably a sulfonyl group that may be substituted, a phosphine oxide group that may be substituted, a boryl group that may be substituted, or an electron-withdrawing aromatic heterocyclic group that may be substituted. The “electron withdrawing group” in the “aromatic heterocyclic group substituted with an electron withdrawing group” and the “carbazolyl group substituted with an electron withdrawing group” is substituted with a fluorine atom, a cyano group or a fluorine atom. Alkyl group, optionally substituted carbonyl group, optionally substituted sulfonyl group, optionally substituted phosphine oxide group, optionally substituted boryl group, optionally substituted aromatic It is preferably a hydrocarbon group. The “electron-withdrawing group” in the “tertiary amino group substituted with an electron-withdrawing group” is an alkyl group that may be substituted with a fluorine atom, an aromatic hydrocarbon group that is substituted with a fluorine atom, or An aromatic heterocyclic group which may be substituted with a fluorine atom is preferable.

R ^{2 to} R ^{22 in} the general formula (1) each independently represent a hydrogen atom or a substituent.

The number and kind of other substituents are not particularly limited as long as the steroid skeleton compound has the substituent described above as R ¹ . Therefore, all of R ^{2 to} R ²² may be unsubstituted (that is, a hydrogen atom). When two or more of R ^{2 to} R ²² are substituents, the plurality of substituents may be the same as or different from each other.

Examples of the substituent represented by R ^{2 to} R ²² include an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group). , Tetradecyl group, pentadecyl group etc.), cycloalkyl group (eg cyclopentyl group, cyclohexyl group etc.), alkenyl group (eg vinyl group, allyl group etc.), alkynyl group (eg ethynyl group, propargyl group etc.), aromatic Aromatic hydrocarbon group (also referred to as aromatic hydrocarbon ring group, aromatic carbocyclic group, aryl group, etc., for example, phenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, Fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc.), aromatic A cyclic group (for example, pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazol-1-yl group, 1, 2,3-triazol-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 group, carbazolyl group, carbolinyl group, diazacarbazolyl group (indicating that one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom), quinoxalinyl group, pyridazinyl group , Triazinyl group, quinazolinyl group, Tarazinyl group, etc.), heterocyclic group (eg, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (eg, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group) Group, dodecyloxy group, etc.), cycloalkoxy 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 (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alcohol Xyloxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, 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.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group) Pentylcarbonyl group, cyclohexylcarbonyl 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, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (eg, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group) Group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, Carbonylamino 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, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido) Group, octylureido group, dodecylureido group, phenylureido group naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, Methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl Group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroarylsulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group) Etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, diphenylamino group, butylamino group, cyclopentylamino group, -Ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom etc.), fluorinated hydrocarbon group (eg, fluoromethyl group) , Trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.), phosphono Group, phosphine oxide group, boryl group and the like. Alkyl groups, aromatic hydrocarbon groups, aromatic heterocyclic groups, and alkoxy groups are preferable because they have good charge transport properties and strongly interact with each other to form a strong film. Moreover, these substituents may be further substituted with the above substituents. Further, these substituents may be bonded together to form a ring.

Furthermore, the steroid skeleton compound used in the present invention is preferably represented by any one of the following general formulas (2) to (4).

^{R 1} in the general formula (2) to (4) has the same meaning as ^{R 1} in the general formula (1).

The compound represented by the general formula (2) is a compound in which R ¹⁰ in the general formula (1) is a methyl group, and the compound represented by the general formula (3) is R ^{7 in the} general formula (1). A compound having R ¹⁰ as a methyl group, and the compound represented by the general formula (4) is a compound having R ¹⁰ and R ¹⁹ in the general formula (1) as a methyl group. The steroid skeleton compounds represented by the general formulas (2) to (4) are preferable because they strongly interact with each other and form a strong film.

  Examples of organic compounds A-1 to A-61 that are preferably used in the present invention will be given below, but the present invention is not limited thereto.

The steroid skeleton compound represented by the general formula (1) can be synthesized by combining known reactions. For example, a compound in which R ¹ in the general formula (1) is a substituted or unsubstituted tertiary amino group can be synthesized by reacting the following two compounds.

^R 2 ^{to R 22} in the above reaction formula, the general formula (1) have the same meanings as the substituents ^R 2 ^{to R 22 of, R 23} and ^{R 24,} the substituents of a substituted or unsubstituted tertiary amino group It is synonymous.
The above reaction is an application of a known coupling reaction, and known reaction conditions can be appropriately selected and used. The details of the above reaction can be referred to the synthesis examples described below. The compound represented by the general formula (1) can also be synthesized by combining other known synthesis reactions.

  In the luminescent organic thin film of the present invention, the steroid skeleton compound represented by the general formula (1) functions as a host compound. The host compound is a compound mainly responsible for charge injection and transport in the light-emitting organic thin film, and its own light emission is not substantially observed.

  Since the steroid skeleton compound functions as a host compound, from the viewpoint of reverse energy transfer, a compound having an excitation energy larger than the excitation triplet energy of the phosphorescent material to be used in combination is preferable. Those having an excited singlet energy larger than the excited triplet energy of the photoluminescent material are more preferable. By combining a steroid skeleton compound that satisfies the above-described excitation energy relationship and a phosphorescent material, it is possible to achieve high luminous efficiency even with a small amount of phosphorescent material.

  The content of the steroid skeleton compound in the light-emitting organic thin film of the present invention is preferably 50 to 95% by mass, and more preferably 70 to 95% by mass. If the content of the steroid skeleton compound is 50% by mass or more, by suppressing the penetration of water and oxygen in the atmosphere, the deactivation of triplet excitons generated in the phosphorescent material is prevented, and the organic EL element is deteriorated. Can be suppressed. In addition, since the steroid skeleton compound can function as a host compound, sufficiently high luminous efficiency is achieved when the content of the steroid skeleton compound is 95% by mass or less and the content of the luminescent material is 5% or more. be able to.

1-2. Phosphorescent Material The luminescent material used in the present invention is a compound in which light emission from an excited triplet is observed, specifically, a compound that emits phosphorescence at room temperature (25 ° C.). The phosphorescent compound is defined as a compound having a phosphorescence quantum yield of 0.01 or more at 25 ° C. The phosphorescence quantum yield of the phosphorescent material used in the present invention is preferably 0.1. That's it.

  The phosphorescence quantum yield can be measured by the method described in Fourth Edition Experimental Chemistry Course 7, Spectroscopic II, page 398 (1992 edition, Maruzen). Various solvents can be used for the measurement of the phosphorescence quantum yield in a solution. The phosphorescent material used in the present invention is not limited to the phosphorescence quantum yield (0. (01 or more) can be achieved.

The phosphorescent material used for this invention can be suitably selected from the well-known things used for the light emitting layer of an organic EL element. Specific examples of phosphorescent materials that can be used in the present invention include compounds described in the following documents.
Nature 395, 151 (1998), Appl. Phys. Lett. 78, 1622 (2001), Adv. Mater. 19, 739 (2007), Chem. Mater. 17, 3532 (2005), Adv. Mater. 17, 1059 (2005), International Publication No. 2009/100991, International Publication No. 2008/101842, International Publication No. 2003/040257, US Patent Application Publication No. 2006/835469, US Patent Application Publication No. 2006 /. No. 0202194, U.S. Patent Application Publication No. 2007/0087321, U.S. Patent Application Publication No. 2005/0244673, Inorg. Chem. 40, 1704 (2001), Chem. Mater. 16, 2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. lnt. Ed. 2006, 45, 7800, Appl. Phys. Lett. 86, 153505 (2005), Chem. Lett. 34, 592 (2005), Chem. Commun. 2906 (2005), Inorg. Chem. 42, 1248 (2003), International Publication No. 2009/050290, International Publication No. 2002/015645, International Publication No. 2009/000673, US Patent Application Publication No. 2002/0034656, US Pat. No. 7,332,232, US Patent Application Publication No. 2009/0108737, United States Patent Application Publication No. 2009/0039776, United States Patent No. 6921915, United States Patent No. 6,687,266, United States Patent Application Publication No. 2007/0190359, United States Patent Application Publication No. 2006/0008670, United States Patent Application Publication No. 2009/0165846, United States Patent Application Publication No. 2008/0015355, United States Patent No. 7250226, United States Patent No. 7396598, United States Patent Application Publication No. 2006 0263635 Pat, U.S. Patent Application Publication No. 2003/0138657, U.S. Patent Application Publication No. 2003/0152802, U.S. Patent No. 7090928, Angew. Chem. lnt. Ed. 47, 1 (2008), Chem. Mater. 18, 5119 (2006), Inorg. Chem. 46, 4308 (2007), Organometallics 23, 3745 (2004), Appl. Phys. Lett. 74, 1361 (1999), International Publication No. 2002/002714, International Publication No. 2006/009024, International Publication No. 2006/056418, International Publication No. 2005/019373, International Publication No. 2005/123873, International Publication No. 2007/004380, International Publication No. 2006/082742, U.S. Patent Application Publication No. 2006/0251923, U.S. Patent Application Publication No. 2005/0260441, U.S. Patent No. 7393599, U.S. Pat. No. 7,534,505, U.S. Pat. Patent No. 7445855, U.S. Patent Application Publication No. 2007/0190359, U.S. Patent Application Publication No. 2008/0297033, U.S. Pat. No. 7,338,722, U.S. Patent Application Publication No. 2002/0134984, U.S. Pat. 72 9704, US Patent Application Publication No. 2006/098120, US Patent Application Publication No. 2006/103874, International Publication No. 2005/076380, International Publication No. 2010/032663, International Publication No. 2008140115, International Public Publication No. 2007/052431, International Publication No. 2011/134013, International Publication No. 2011/157339, International Publication No. 2010/086089, International Publication No. 2009/113646, International Publication No. 2012/020327, International Publication No. 2011/051404, International Publication No. 2011/004639, International Publication No. 2011/073149, US Patent Application Publication No. 2012/228585, US Patent Application Publication No. 2012/212126, Japanese Patent Application Laid-Open No. 2012-0697 7, JP 2012-195554, JP 2009-114086, JP 2003-81988, JP 2002-302671 discloses a JP 2002-363552 and the like.

  A preferable phosphorescent material is a metal complex, and an organometallic complex having a heavy metal such as iridium, ruthenium or platinum (platinum) as a central metal is more preferable. When a complex using a heavy metal such as iridium or platinum emits light, the rate constant of the forbidden transition is increased by three orders of magnitude or more due to the heavy atom effect of the central metal, and a high phosphorescence quantum yield is achieved. Iridium complexes are preferred because of their high phosphorescence quantum yield. Further, the organometallic complex is preferably a complex containing at least one coordination mode of a metal-carbon bond, a metal-nitrogen bond, a metal-oxygen bond, and a metal-sulfur bond. By selecting such a ligand, it becomes possible to obtain a higher phosphorescence quantum yield.

  The phosphorescent material content in the luminescent organic thin film of the present invention is preferably 1 to 40% by mass, and more preferably 5 to 20% by mass. If the content of the phosphorescent material is 1% by mass or more, sufficient light emission can be obtained, and if it is 40% by mass or less, triplet-triplet exciton annihilation can be suppressed.

1-3. Other Components The luminescent organic thin film of the present invention may contain other components in addition to the steroid skeleton compound and the phosphorescent material. Examples of such other components include known host compounds that can be used in combination with a steroid skeleton compound as a host material.

  A host compound that can be used in combination with a steroid skeleton compound and a phosphorescent material will be described.

In the present invention, other host compounds that can be used in combination with the steroid skeleton compound are not particularly limited, but those having an excitation energy larger than the excitation triplet energy of the phosphorescent material are preferable from the viewpoint of reverse energy transfer. Those having an excited singlet energy larger than the excited triplet energy of the photoluminescent material are more preferable.
Other host compounds are responsible for carrier transport and exciton generation in the emissive layer. Therefore, it can stably exist in all active species states such as a cation radical state, an anion radical state, and an excited state, and does not cause chemical changes such as decomposition and addition reaction. It is preferred that the host molecule does not move at the angstrom level.

The other host compound used in the present invention may be a low molecular compound having a molecular weight capable of sublimation purification or a polymer having a repeating unit.
In the case of a low molecular weight compound, sublimation purification is possible, so that there is an advantage that purification is easy and a high-purity material is easily obtained. The molecular weight is not particularly limited as long as sublimation purification is possible, but the preferred molecular weight is 3000 or less, more preferably 2000 or less.

In the case of a polymer or oligomer having a repeating unit, there is an advantage that it is easy to form a film by a wet process, and since a polymer generally has a high Tg, it is preferable from the viewpoint of heat resistance.
In addition, other host compounds have a hole transporting ability or an electron transporting ability, prevent emission of longer wavelengths, and are stable against heat generation when the organic EL element is driven at a high temperature or while the element is being driven. From the viewpoint of operating, it is preferable to have a high glass transition temperature (Tg). Tg is preferably 90 ° C. or higher, more preferably 120 ° C. or higher.
Here, the glass transition point (Tg) is a value obtained by a method based on JIS K 7121-2012 using DSC (Differential Scanning Colorimetry).

Specific examples of known host compounds that can be used for the light-emitting organic thin film of the present invention include, but are not limited to, 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. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, US Patent Application Publication No. 2003/0175553, US Patent Application Publication No. 2006/0280965, US Patent Application Publication No. 2005/0112407, US Patent Application Publication No. 2009/0017330, US Patent Application Publication No. 2009/0030202, US Patent Application Publication No. 2005/0238919, International Publication First 001/039234, International Publication No. 2009/021126, International Publication No. 2008/056746, International Publication No. 2004/093207, International Publication No. 2005/089025, International Publication No. 2007/063796, International Publication No. 2007/2007 / No. 063754, International Publication No. 2004/107822, International Publication No. 2005/030900, International Publication No. 2006/114966, International Publication No. 2009/086028, International Publication No. 2009/003898, International Publication No. 2012/023947 JP 2008-0749939, JP 2007-254297, EP 2034538, International Publication No. 2011/055933, International Publication No. 2012/035853, and the like.

  Other host compounds may be used alone or in combination of two or more. By using a plurality of other host compounds, charge transfer can be adjusted.

  It is preferable that content of the other host compound in the luminescent organic thin film of this invention is 1 mass% or more and 30 mass% or less with respect to the total mass of the component contained in a luminescent organic thin film. If the content of the other host material is 1% by mass or more, the effect of the combined use with the steroid skeleton compound is exhibited, and if it is 30% by mass or less, the interaction between the steroid skeleton compounds is not hindered, and the water in the atmosphere And a film capable of suppressing the influence of oxygen is formed.

1-4. Method for Forming Light-Emitting Organic Thin Film The light-emitting organic thin film according to the present invention contains the steroid skeleton compound described above, a phosphorescent light-emitting material, and any other component.

There is no restriction | limiting in particular in the formation method of the luminescent organic thin film which concerns on this invention, A conventionally well-known method, for example, a vacuum evaporation method, a wet method (it is also called a wet process), etc. can be used.
Examples of the wet method include a spin coating method, a casting method, an ink jet method, a printing method, a die coating method, a blade coating method, a roll coating method, a spray coating method, a curtain coating method, and an LB method (Langmuir-Blodgett method). From the viewpoint of obtaining a homogeneous thin film easily and high productivity, a method with high roll-to-roll method suitability such as a die coating method, a roll coating method, an ink jet method and a spray coating method is preferable.

Examples of the liquid medium in which the phosphorescent material used in the present invention, the steroid skeleton compound represented by the general formula (1), and any other component are dissolved or dispersed include ketones such as methyl ethyl ketone and cyclohexanone, Fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, aromatic hydrocarbons such as toluene, xylene, mesitylene, and cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, DMF, DMSO An organic solvent such as
Examples of the dispersion method include dispersion methods such as ultrasonic waves, high shear force dispersion, and media dispersion.

Further, different film formation methods may be applied for each layer. When a vapor deposition method is employed for film formation, the vapor deposition conditions vary depending on the type of compound used, but generally the boat heating temperature is in the range of 50 to 450 ° C., and the degree of vacuum is in the range of 10 ⁻⁶ to 10 ⁻² Pa. Of these, the deposition rate is appropriately selected within the range of 0.01 to 50 nm / second, the substrate temperature within the range of −50 to 300 ° C., the layer thickness within the range of 0.1 nm to 5 μm, and preferably within the range of 5 to 200 nm. desirable.
When a spin coat method is employed for film formation, it is preferable to perform the spin coater within a range of 100 to 1000 rpm and within a range of 10 to 120 seconds in a dry inert gas atmosphere.

2. Organic EL device The light-emitting organic thin film of the present invention can be suitably used as a light-emitting layer of an organic EL device. By using the light-emitting organic thin film of the present invention, an organic EL device having high light emission efficiency and long life can be realized.

2-1. Constituent Layer of Organic EL Element Typical element structures in the organic EL element of the present invention include the following structures, but are not limited thereto.
(1) Anode / light emitting layer // cathode (2) Anode / light emitting layer / electron transport layer / cathode (3) Anode / hole transport layer / light emitting layer / cathode (4) Anode / hole transport layer / light emitting layer / Electron transport layer / cathode (5) Anode / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (6) Anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / cathode (7) Anode / hole injection layer / hole transport layer / (electron blocking layer /) light emitting layer / (hole blocking layer /) electron transport layer / electron injection layer / cathode Among the above, the configuration of (7) is Although used preferably, it is not limited to this.
The light emitting layer used in the present invention is composed of a single layer or a plurality of layers. When there are a plurality of light emitting layers, a non-light emitting intermediate layer may be provided between the light emitting layers.

If necessary, a hole blocking layer (also referred to as a hole blocking layer) or an electron injection layer (also referred to as a cathode buffer layer) may be provided between the light emitting layer and the cathode. An electron blocking layer (also referred to as an electron barrier layer) or a hole injection layer (also referred to as an anode buffer layer) may be provided therebetween.
The electron transport layer used in the present invention is a layer 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. Moreover, you may be comprised by multiple layers.
The hole transport layer used in the present invention is a layer 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. Moreover, you may be comprised by multiple layers.
In the above-described typical element configuration, the layer excluding the anode and the cathode is also referred to as “organic layer”.

(Tandem structure)
The organic EL element of the present invention may be a so-called tandem element in which a plurality of light emitting units including at least one light emitting layer are stacked.
As typical element configurations of the tandem structure, for example, the following configurations can be given.
Anode / first light emitting unit / intermediate layer / second light emitting unit / intermediate layer / third light emitting unit / cathode Here, the first light emitting unit, the second light emitting unit and the third light emitting unit are all the same, May be different. Two light emitting units may be the same, and the remaining one may be different.
A plurality of light emitting units may be laminated directly or via an intermediate layer, and the intermediate layer is generally an intermediate electrode, an intermediate conductive layer, a charge generation layer, an electron extraction layer, a connection layer, an intermediate layer. A known material structure can be used as long as it is also called an insulating layer and has a function of supplying electrons to the anode-side adjacent layer and holes to the cathode-side adjacent layer.

Examples of materials used for the intermediate layer include ITO (indium tin oxide), IZO (indium zinc oxide), ZnO ₂ , TiN, ZrN, HfN, TiO _x , VO _x , CuI, InN, GaN, Conductive inorganic compound layers such as CuAlO ₂ , CuGaO ₂ , SrCu ₂ O ₂ , LaB ₆ , RuO ₂ and Al, two-layer films such as Au / Bi ₂ O ₃ , SnO ₂ / Ag / SnO ₂ , ZnO / Multi-layer film such as Ag / ZnO, Bi ₂ O ₃ / Au / Bi ₂ O ₃ , TiO ₂ / TiN / TiO ₂ , TiO ₂ / ZrN / TiO ₂ , fullerenes such as C ₆₀ , conductivity such as oligothiophene Examples include organic material layers, conductive organic compound layers such as metal phthalocyanines, metal-free phthalocyanines, metal porphyrins, and metal-free porphyrins. The present invention is not limited thereto.
As a preferable configuration in the light emitting unit, for example, a configuration in which the anode and the cathode are excluded from the configurations (1) to (7) described in the above-described typical element configurations, and the like is described. It is not limited.

  Specific examples of the tandem organic EL element include, for example, US Pat. No. 6,337,492, US Pat. No. 7,420,203, US Pat. No. 7,473,923, US Pat. No. 6,872,472, US Pat. No. 6,107,734, US Pat. No. 6,337,492, International JP 2005/009087, JP 2006-228712, JP 2006-24791, JP 2006-49393, JP 2006-49394, JP 2006-49396, JP 2011. JP-A-96679, JP-A-2005-340187, JP-A-4711424, JP-A-34096681, JP-A-3848564, JP-A-4213169, JP-A-2010-192719, JP-A-2009-076929. No. 1 and JP 2 Examples include the element configurations and constituent materials described in JP-A-08-078414, JP-A-2007-059848, JP-A-2003-272860, JP-A-2003-045676, and International Publication No. 2005/094130. However, the present invention is not limited to these.

  Hereinafter, each layer which comprises the organic EL element of this invention is demonstrated.

2-2. Light-emitting layer The light-emitting layer used in the present invention is a layer that provides a field in which electrons and holes injected from an electrode or an adjacent layer are recombined to emit light via excitons. It may be within the layer or the interface between the light emitting layer and the adjacent layer. The structure of the light emitting layer used in the present invention is not particularly limited as long as it is the light emitting organic thin film of the present invention.
The total thickness of the light emitting layer is not particularly limited, but it prevents the uniformity of the film to be formed, the application of unnecessary high voltage during light emission, and the improvement of the stability of the emission color against the drive current. From the viewpoint, it is preferable to adjust in the range of 2 nm to 5 μm, more preferably in the range of 2 to 500 nm, and still more preferably in the range of 5 to 200 nm.
Further, the thickness of each light emitting layer used in the present invention is preferably adjusted within the range of 2 nm to 1 μm, more preferably adjusted within the range of 2 to 200 nm, and further preferably 3 to 150 nm. Adjusted within range.

2-3. Electron Transport Layer In the present invention, the electron transport layer is made of a material having a function of transporting electrons and may have a function of transmitting electrons injected from the cathode to the light emitting layer.
Although there is no restriction | limiting in particular about the total layer thickness of the electron carrying layer which concerns on this invention, Usually, it is the range of 2 nm-5 micrometers, More preferably, it is 2-500 nm, More preferably, it is 5-200 nm.
Further, in the organic EL element, when the light generated in the light emitting layer is extracted from the electrode, the light extracted directly from the light emitting layer interferes with the light extracted after being reflected by the electrode from which the light is extracted and the electrode located at the counter electrode. It is known to wake up. When light is reflected by the cathode, this interference effect can be efficiently utilized by appropriately adjusting the total thickness of the electron transport layer between several nanometers and several micrometers.
On the other hand, when the layer thickness of the electron transport layer is increased, the voltage is likely to increase. Therefore, particularly when the layer thickness is thick, the electron mobility of the electron transport layer is preferably 10 ⁻⁵ cm ² / Vs or more. .
The material used for the electron transport layer (hereinafter referred to as an electron transport material) may be any of electron injecting or transporting properties and hole blocking properties, and can be selected from conventionally known compounds. Can be selected and used.

  For example, nitrogen-containing aromatic heterocyclic derivatives (carbazole derivatives, azacarbazole derivatives (one or more carbon atoms constituting the carbazole ring are substituted with nitrogen atoms), pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, pyridazine derivatives, Triazine derivatives, quinoline derivatives, quinoxaline derivatives, phenanthroline derivatives, azatriphenylene derivatives, oxazole derivatives, thiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, triazole derivatives, benzimidazole derivatives, benzoxazole derivatives, benzthiazole derivatives, etc.), dibenzofuran derivatives, Dibenzothiophene derivatives, silole derivatives, aromatic hydrocarbon ring derivatives (naphthalene derivatives, anthracene derivatives, triphenylene derivatives, etc.) That.

In addition, a metal complex having a quinolinol skeleton or a dibenzoquinolinol skeleton as a ligand, for example, 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 their metal complexes A metal complex in which the central metal is replaced with In, Mg, Cu, Ca, Sn, Ga, or Pb can also be used as the electron transport material.
In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transport material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and the hole transport layer. Can also be used as an electron transporting material.
Further, 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 the electron transport layer according to the present invention, the electron transport layer may be doped with a doping material as a guest material to form an electron transport layer having a high n property (electron rich). Examples of the doping material include n-type dopants such as metal complexes and metal compounds such as metal halides. Specific examples of the electron transport layer having such a structure include, for example, JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J. Pat. Appl. Phys. , 95, 5773 (2004) and the like.

Specific examples of known preferable electron transport materials used in the organic EL device of the present invention include compounds described in the following documents, but the present invention is not limited thereto.
US Pat. No. 6,528,187, US Pat. No. 7,230,107, US Patent Application Publication No. 2005/0025993, US Patent Application Publication No. 2004/0036077, US Patent Application Publication No. 2009/0115316, US Patent Application Publication No. 2009/0101870, United States Patent Application Publication No. 2009/0179554, International Publication No. 2003/060956, International Publication No. 2008/132805, Appl. Phys. Lett. 75, 4 (1999), Appl. Phys. Lett. 79, 449 (2001), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 79, 156 (2001), U.S. Patent No. 7964293, U.S. Patent Application Publication No. 2009/030202, International Publication No. 2004/080975, International Publication No. 2004/063159, International Publication No. 2005/085387, International Publication No. Public Publication No. 2006/067931, International Publication No. 2007/086552, International Publication No. 2008/114690, International Publication No. 2009/066942, International Publication No. 2009/066779, International Publication No. 2009/054253, International Publication No. 2011/086935, International Publication No. 2010/150593, International Publication No. 2010/047707, EP23111826, JP2010-251675A, JP2009-209133A, JP2009-124114A, JP JP-A-2008-277810, JP-A-2006-156445, JP-A-2005-340122, JP-A-2003-45662, JP-A-2003-31367, JP-A-2003-282270, International Publication No. 2012. / 115034.

More preferable electron transport materials in the present invention include aromatic heterocyclic compounds containing at least one nitrogen atom. For example, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, azadibenzofuran derivatives. , Azadibenzothiophene derivatives, carbazole derivatives, azacarbazole derivatives, benzimidazole derivatives, and the like.
The electron transport material may be used alone or in combination of two or more.

2-4. Hole blocking layer In a broad sense, the hole blocking layer is a layer having the function of an electron transport layer, preferably made of a material that has a function of transporting electrons but has a small ability to transport holes, and transports electrons. However, the probability of recombination of electrons and holes can be improved by blocking holes.
Moreover, the structure of the electron carrying layer mentioned above can be used as a hole-blocking layer concerning this invention as needed.
The hole blocking layer provided in the organic EL device of the present invention is preferably provided adjacent to the cathode side of the light emitting layer.
The layer thickness of the hole blocking layer according to the present invention is preferably in the range of 3 to 100 nm, more preferably in the range of 5 to 30 nm.
As the material used for the hole blocking layer, the material used for the above-described electron transport layer is preferably used, and the material used as the above-described host compound is also preferably used for the hole blocking layer.

2-5. Electron Injection Layer The electron injection layer (also referred to as “cathode buffer layer”) according to the present invention is a layer provided between the cathode and the light emitting layer for the purpose of lowering the driving voltage and improving the light emission luminance. It is described in detail in Chapter 2 “Electrode Materials” (pages 123 to 166) of the second edition of “Devices and the Forefront of Industrialization (issued by NTT Corporation on November 30, 1998)”.
In the present invention, the electron injection layer may be provided as necessary, and may be present between the cathode and the light emitting layer or between the cathode and the electron transport layer as described above.
The electron injection layer is preferably a very thin film, and the layer thickness is preferably in the range of 0.1 to 5 nm, although it depends on the material. Moreover, the nonuniform layer (film | membrane) in which a constituent material exists intermittently may be sufficient.

The details of the electron injection layer are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specific examples of materials preferably used for the electron injection layer are as follows. , Metals typified by strontium and aluminum, alkali metal compounds typified by lithium fluoride, sodium fluoride, potassium fluoride, etc., alkaline earth metal compounds typified by magnesium fluoride, calcium fluoride, etc., oxidation Examples thereof include metal oxides typified by aluminum, metal complexes typified by 8-hydroxyquinolinate lithium (Liq), and the like. Further, the above-described electron transport material can also be used.
Moreover, the material used for said electron injection layer may be used independently, and may be used in combination of multiple types.

2-6. Hole transporting layer In the present invention, the hole transporting layer is made of a material having a function of transporting holes, and may have a function of transmitting holes injected from the anode to the light emitting layer.
Although there is no restriction | limiting in particular about the total layer thickness of the positive hole transport layer which concerns on this invention, Usually, it is the range of 0.5 nm-5 micrometers, More preferably, it is 2-500 nm, More preferably, it is 5-200 nm.
As a material used for the hole transport layer (hereinafter referred to as a hole transport material), any material that has either a hole injection property or a transport property or an electron barrier property may be used. Any one can be selected and used.
For example, porphyrin derivatives, phthalocyanine derivatives, oxazole derivatives, oxadiazole derivatives, triazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, hydrazone derivatives, stilbene derivatives, polyarylalkane derivatives, triarylamine derivatives, carbazole derivatives , Indolocarbazole derivatives, isoindole derivatives, acene derivatives such as anthracene and naphthalene, fluorene derivatives, fluorenone derivatives, and polyvinyl carbazole, polymeric materials or oligomers with aromatic amines introduced into the main chain or side chain, polysilane, conductive And polymer (for example, PEDOT / PSS, aniline copolymer, polyaniline, polythiophene, etc.).

Examples of triarylamine derivatives include benzidine type typified by α-NPD (4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl), starburst type typified by MTDATA, Examples include compounds having fluorene or anthracene in the triarylamine-linked core.
In addition, hexaazatriphenylene derivatives such as those described in JP-A-2003-519432 and JP-A-2006-135145 can also be used as a hole transport material.
Furthermore, a hole transport layer having a high p property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like.

JP-A-11-251067, J. Org. Huang et. al. It is also possible to use so-called p-type hole transport materials and inorganic compounds such as p-type-Si and p-type-SiC, as described in the literature (Applied Physics Letters 80 (2002), p. 139). Further, ortho-metalated organometallic complexes having Ir or Pt as the central metal as typified by Ir (ppy) ₃ are also preferably used.
Although the above-mentioned materials can be used as the hole transport material, a triarylamine derivative, a carbazole derivative, an indolocarbazole derivative, an azatriphenylene derivative, an organometallic complex, or an aromatic amine is introduced into the main chain or side chain. The polymer materials or oligomers used are preferably used.

Specific examples of known preferred hole transport materials used in the organic EL device of the present invention include the compounds described in the following documents in addition to the documents listed above, but the present invention is not limited thereto. Not.
For example, Appl. Phys. Lett. 69, 2160 (1996), J. MoI. Lumin. 72-74, 985 (1997), Appl. Phys. Lett. 78, 673 (2001), Appl. Phys. Lett. 90, 183503 (2007), Appl. Phys. Lett. 51, 913 (1987), Synth. Met. 87, 171 (1997), Synth. Met. 91, 209 (1997), Synth. Met. 111, 421 (2000), SID Symposium Digest, 37, 923 (2006), J. Am. Mater. Chem. 3, 319 (1993), Adv. Mater. 6, 677 (1994), Chem. Mater. 15, 3148 (2003), US Patent Application Publication No. 2003/0162053, US Patent Application Publication No. 2002/0158242, US Patent Application Publication No. 2006/0240279, US Patent Application Publication No. 2008 / No. 0220265, U.S. Patent No. 5061569, International Publication No. 2007/002683, International Publication No. 2009/018009, EP650955, U.S. Patent Application Publication No. 2008/0124572, U.S. Patent Publication No. 2007/0278938. Specification, US Patent Application Publication No. 2008/0106190, US Patent Application Publication No. 2008/0018221, International Publication No. 2012/115034, Japanese Translation of PCT International Publication No. 2003-519432, Japanese Patent Application Laid-Open No. 2006-135145 , US Patent Application No. 13/585981 and the like.
The hole transport material may be used alone or in combination of two or more.

2-7. Electron blocking layer The electron blocking layer is a layer having a function of a hole transport layer in a broad sense, and is preferably made of a material having a function of transporting holes and a small ability to transport electrons. By blocking electrons while transporting, the recombination probability of electrons and holes can be improved.
Moreover, the structure of the positive hole transport layer mentioned above can be used as an electron blocking layer according to the present invention, if necessary.
The electron blocking layer provided in the organic EL device of the present invention is preferably provided adjacent to the anode side of the light emitting layer.
The layer thickness of the electron blocking layer according to the present invention is preferably in the range of 3 to 100 nm, more preferably in the range of 5 to 30 nm.
As the material used for the electron blocking layer, the material used for the above-described hole transport layer is preferably used, and the above-mentioned host compound is also preferably used for the electron blocking layer.

2-8. Hole Injection Layer The hole injection layer according to the present invention (also referred to as “anode buffer layer”) is a layer provided between the anode and the light emitting layer in order to reduce drive voltage or improve light emission luminance. It is described in detail in Chapter 2 “Electrode Materials” (pages 123 to 166) of the second edition of “Organic EL devices and the forefront of industrialization” (issued by NTT Corporation on November 30, 1998).
In the present invention, the hole injection layer may be provided as necessary, and may be present between the anode and the light emitting layer or between the anode and the hole transport layer as described above.
The details of the hole injection layer are also described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, etc. Examples of the material used for the hole injection layer include: Examples thereof include materials used for the above-described hole transport layer.
Among them, phthalocyanine derivatives typified by copper phthalocyanine, hexaazatriphenylene derivatives as described in JP-T-2003-519432 and JP-A-2006-135145, metal oxides typified by vanadium oxide, amorphous carbon Preferred are conductive polymers such as polyaniline (emeraldine) and polythiophene, orthometalated complexes represented by tris (2-phenylpyridine) iridium complex, and triarylamine derivatives.
The materials used for the hole injection layer described above may be used alone or in combination of two or more.

2-9. Additives The organic layer in the present invention described above may further contain other additives.
Examples of the additive include halogen elements such as bromine, iodine and chlorine, halogenated compounds, alkali metals and alkaline earth metals such as Pd, Ca, and Na, transition metal compounds, complexes, and salts.
The content of the additive can be arbitrarily determined, but is preferably 1000 ppm or less, more preferably 500 ppm or less, and further preferably 50 ppm or less with respect to the total mass% of the contained layer. .
However, it is not within this range depending on the purpose of improving the transportability of electrons and holes or the purpose of favoring the exciton energy transfer.

2-10. Method for Forming Organic Layer A method for forming an organic layer (hole injection layer, hole transport layer, light emitting layer, hole blocking layer, electron transport layer, electron injection layer, etc.) according to the present invention will be described.
The method for forming the organic layer according to the present invention is not particularly limited, and a conventionally known method such as a vacuum deposition method or a wet method (also referred to as a wet process) can be used.
Examples of the wet method include a spin coating method, a casting method, an ink jet method, a printing method, a die coating method, a blade coating method, a roll coating method, a spray coating method, a curtain coating method, and an LB method (Langmuir-Blodgett method). From the viewpoint of obtaining a homogeneous thin film easily and high productivity, a method with high roll-to-roll method suitability such as a die coating method, a roll coating method, an ink jet method and a spray coating method is preferable.

Examples of the liquid medium for dissolving or dispersing the organic EL material 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, xylene, Aromatic hydrocarbons such as 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.

Further, different film formation methods may be applied for each layer. When a vapor deposition method is employed for film formation, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 to 450 ° C., a vacuum degree of 10 ⁻⁶ to 10 ⁻² Pa, and a vapor deposition rate of 0.01 to It is desirable to select appropriately within a range of 50 nm / second, a substrate temperature of −50 to 300 ° C., and a layer (film) thickness of 0.1 nm to 5 μm, preferably 5 to 200 nm.
The organic layer according to the present invention is preferably formed 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 formation methods. In that case, it is preferable to perform the work in a dry inert gas atmosphere.

2-11. Anode As the anode in the organic EL element, a material having a work function (4 eV or more, preferably 4.5 eV or more) of a metal, an alloy, an electrically conductive compound or a mixture thereof is preferably used. Specific examples of such electrode substances 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, a thin film may be formed by vapor deposition or sputtering of these electrode materials, and a pattern of a desired shape may be formed by photolithography, or when pattern accuracy is not required (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.
The film thickness of the anode depends on the material, but is usually selected within the range of 10 nm to 1 μm, preferably 10 to 200 nm.

2-12. Cathode 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 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, aluminum, rare earth metals and the like. Among these, in terms of durability against electron injection and oxidation, etc., 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 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 emission luminance is advantageously improved.
Moreover, after producing the above metal with a film thickness of 1 to 20 nm on the cathode, a transparent or translucent cathode can be produced by producing a conductive transparent material mentioned in the description of the anode on the cathode. By applying the above, it is possible to manufacture a device in which both the anode and the cathode are transparent.

2-13. 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 transparent Or 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.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, cellulose acetate propionate ( CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones, Cycloolefin resins such as polyether imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned. In addition, when the emitted light is transmitted from the sealing member, a material other than the transparent resin can be selected. For example, a metal such as copper, copper alloy, aluminum, aluminum alloy, gold, nickel, titanium, stainless steel, and tin. Is mentioned. One of these may be used alone, or two or more of these may be mixed or multilayered.

  Although the thickness of the element substrate is not particularly limited, it is preferably 50 μm to 500 μm in consideration of molding processability, handleability, and the like. The thickness of the element substrate can be measured using a micrometer.

An inorganic film, an organic film, or a hybrid film of both may be formed on the surface of the resin film, and the water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. , Relative humidity (90 ± 2)% RH) is preferably 0.01 g / m ² · 24 h or less barrier film, and moreover, oxygen permeability measured by a method according to JIS K 7126-1987 However, it is preferable that it is a high-barrier film whose 1 * 10 < ^-3 > mol / m < ² > * s * Pa or less and water vapor permeability are 1 * 10 < ^-5 > g / m < ² > * 24h or less.

As a material for forming the barrier film, any material may be used as long as it has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Furthermore, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and layers made of organic materials. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.
The method for forming the barrier film is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, atmospheric pressure plasma polymerization A plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

Examples of the opaque support substrate include metal plates such as aluminum and stainless steel, films, opaque resin substrates, and ceramic substrates.
The external extraction quantum efficiency at room temperature (25 ° C.) of light emission of the organic EL device of the present invention is preferably 1% or more, and more preferably 5% or more.
Here, external extraction quantum efficiency (%) = number of photons emitted to the outside of the organic EL element / number of electrons flowed to the organic EL element × 100.
In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor may be used in combination.

2-14. Sealing The organic EL device of the present invention includes the luminescent organic thin film of the present invention as a light emitting layer. As described above, the steroid skeleton compound represented by the general formula (1) contained in the light-emitting organic thin film of the present invention has a rigid steroid skeleton and further has a CH bond outside the plane. It is easy to interact between molecules and aggregates to form a strong film. It is considered that this strong film suppresses the penetration of oxygen and water, thereby preventing the deactivation of triplet excitons generated in the light emitting material and suppressing the deterioration of the organic EL element. Therefore, in the organic EL element including the light-emitting organic thin film of the present invention, quenching due to oxygen or water in the atmosphere can be prevented without positively providing a sealing means.
However, the organic EL element can be sealed for further extending the life of the organic EL element of the present invention.

Examples of the sealing means used for sealing the organic EL element of the present invention include a method of bonding a sealing member, an electrode, and a support substrate with an adhesive. 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 it may be concave plate shape or flat plate shape. Moreover, transparency and electrical insulation are not particularly limited.
Specific examples include a glass plate, a polymer plate / film, and a metal plate / film. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

In the present invention, a polymer film and a metal film can be preferably used because the organic EL element can be thinned. Furthermore, the polymer film has an oxygen permeability measured by a method according to JIS K 7126-1987, which is measured by a method according to JIS K 7129-1992, which is 1 × 10 ⁻³ mol / m ² · s · Pa or less. The water vapor permeability (25 ± 0.5 ° C., relative humidity 90 ± 2%) is preferably 1 × 10 ⁻³ g / m ² · 24 h or less.
For processing the sealing member into a concave shape, sandblasting, chemical etching, or the like is used.

Specific examples of adhesives include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.
In addition, since an organic EL element may deteriorate by heat processing, what can be adhesive-hardened from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print like screen printing.

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. . In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can.
Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. There are no particular limitations on the method of forming these films. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, atmospheric pressure plasma A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil can be injected in the gas phase and liquid phase. preferable. A vacuum can also be used. Moreover, a hygroscopic compound can also be enclosed inside.
Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate). Etc.), metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide etc.), perchloric acids (eg perchloric acid) Barium, magnesium perchlorate and the like), and anhydrous salts are preferably used in sulfates, metal halides and perchloric acids.

2-15. Protective film, protective plate A protective film or a protective plate may be provided outside the sealing film or the sealing film on the side facing the support substrate with the organic layer interposed therebetween, in order to increase the mechanical strength of the element. . In particular, when 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, etc. used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

2-16. Technology for improving light extraction Organic EL elements emit light inside a layer having a higher refractive index than air (within a refractive index of about 1.6 to 2.1), and 15% to 20% of the light generated in the light emitting layer. It is generally said that only about% light can be extracted. 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 light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the side surface of the device.

  As a technique 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 transparent substrate and the air interface (for example, US Pat. No. 4,774,435), A method for improving efficiency by providing light condensing property (for example, JP-A-63-314795), a method for forming a reflective surface on a side surface of an element (for example, JP-A-1-220394), a substrate, etc. A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the substrate and the light emitter (for example, Japanese Patent Application Laid-Open No. 62-172691), lower refraction than the substrate between the substrate and the light emitter A method of introducing a flat layer having a refractive index (for example, Japanese Patent Application Laid-Open No. 2001-202827), and a method of forming a diffraction grating between any one of the substrate, the transparent electrode layer and the light emitting layer (including between the substrate and the outside world) ( JP-A-11 No. 283,751 Publication), and the like.

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, an element excellent in high luminance or durability can be obtained by combining these means.

When a low refractive index medium is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower. Become.
Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally in the range of about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Furthermore, it is preferable that it is 1.35 or less.
The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave exuded by evanescent enters the substrate.

  The method of introducing a diffraction grating into an interface that causes total reflection or in any medium has a feature that the effect of improving the light extraction efficiency is high. This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction, such as first-order diffraction or second-order diffraction. The light that cannot be emitted due to total internal reflection between layers is diffracted by introducing a diffraction grating into any layer or medium (in the transparent substrate or transparent electrode). , Trying to extract light out.

The introduced diffraction grating desirably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. The light extraction efficiency does not increase so much.
However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.
The position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated. At this time, the period of the diffraction grating is preferably within a range of about 1/2 to 3 times the wavelength of light in the medium. The arrangement of the diffraction gratings is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

2-17. Light Condensing Sheet The organic EL device of the present invention is processed in a specific direction by, for example, providing a structure on a microlens array on the light extraction side of a support substrate (substrate) or combining with a so-called light collecting sheet. For example, the brightness | luminance in a specific direction can be raised by condensing in a front direction with respect to an element light emission surface.
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 within a range of 10 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.

As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used. As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.
Moreover, in order to control the light emission angle from an organic EL element, you may use a light-diffusion plate and a film together with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

2-18. Applications The organic EL element of the present invention can be used as an electronic device, for example, a display device or various light emitting devices.
Examples of light-emitting devices include lighting devices (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 Although the light source of a sensor etc. are mentioned, It is not limited to this, Especially, it can use effectively for the use as a backlight of a liquid crystal display device, and a light source for illumination.
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.

3. TECHNICAL FIELD The present invention relates to a display device including the organic electroluminescence element of the present invention.

The display device including the organic EL element of the present invention may be single color or multicolor, but here, the multicolor display device will be described.
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, there is no limitation on the method, but a vapor deposition method, an inkjet method, a spin coating method, and a 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 multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The alternating current waveform to be applied may be arbitrary.

  The multicolor display device can be used as a display device, a display, or various light emission sources. In a display device or display, full-color display is possible by using three types of organic EL elements of blue, red, and green light emission.

Examples of the display device or 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-emitting devices include household lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, optical storage media light sources, electrophotographic copying machine light sources, optical communication processor light sources, optical sensor light sources, etc. However, the present invention is not limited to these.

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, a wiring unit C that electrically connects the display unit A and the control unit B, and the like.
The control unit B is electrically connected to the display unit A via the wiring unit C, and sends a scanning signal and an image data signal to each of a plurality of pixels based on image information from the outside. Sequentially emit light according to the image data signal, scan the image, and display the image information on the display unit A.

FIG. 3 is a schematic diagram of a display device using an active matrix method.
The display unit A includes a wiring unit C 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.
FIG. 3 shows a case where the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

The scanning line 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 the orthogonal positions (details are illustrated). 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 showing a pixel circuit.
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.

  In FIG. 4, an image data signal is applied from the control unit B to the drain of the switching transistor 11 through 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 of 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, since the capacitor 13 holds the charged potential of the image data signal even if the driving of the switching transistor 11 is turned off, 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 organic EL element 10 emits light by the switching transistor 11 and the drive transistor 12 that are active elements for the organic EL element 10 of each of the plurality of pixels, and the light emission of the organic EL element 10 of each of the plurality of pixels 3. 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 diagram of a passive matrix display device. 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.
By using the organic EL element of the present invention, a display device with improved luminous efficiency was obtained.

4). TECHNICAL FIELD The present invention relates to a lighting device including the organic electroluminescence 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. Examples of the purpose of use of the organic EL element having such a resonator structure include a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processing machine, and a light source of an optical sensor. It is not limited. Moreover, you may use for the said use by making a laser oscillation.
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 apparatus for projecting an image, or a type for directly viewing a still image or a moving image. It may be used as a display device (display).
The driving method when used as a display device for reproducing a moving image may be either a passive matrix method or an active matrix method. Alternatively, it is possible to produce a full-color display device by using two or more organic EL elements of the present invention having different emission colors.

  Further, the fluorescent compound used in the present invention can be applied to an organic EL element that emits substantially white light as a lighting device. For example, when a plurality of light emitting materials are used, white light emission can be obtained by simultaneously emitting a plurality of light emission colors and mixing the colors. The combination of a plurality of emission colors may include three emission maximum wavelengths of three primary colors of red, green, and blue, or two of the 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 method for forming the organic EL device of the present invention may be simply arranged by providing a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, or the like, and separately coating with the mask. Since the other layers are common, patterning of a mask or the like is unnecessary, and for example, an electrode film can be formed on one surface 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 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 emit white light.

[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 300 μm thick glass substrate is used as a sealing substrate, and an epoxy photocurable adhesive (LUX The track LC0629B) is applied, and this is overlaid on the cathode and brought into close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured, sealed, and illuminated as shown in FIGS. A device can be formed.
FIG. 6 shows a schematic diagram of the lighting device, and the organic EL element of the present invention (organic EL element 101 in the lighting device) is covered with a glass cover 102 (note that the sealing operation with the glass cover is performed by lighting. This was performed in a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more) without bringing the organic EL element 101 in the apparatus into contact with the air.
FIG. 7 is a cross-sectional view of the lighting device, 105 is a cathode, 106 is an organic layer, and 107 is a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.
By using the organic EL element of the present invention, an illumination device with improved luminous efficiency was obtained.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "mass part" or "mass%" is represented.
Moreover, the volume% of the compound in each Example is calculated | required from specific gravity by measuring the layer thickness to produce by the quartz crystal microbalance method, and calculating mass.
The compound used for preparation of an organic EL element is shown below.

1. Phosphorescent material (A)

2. Host material (B)
(1) Steroid skeleton compounds

(2) Other host compounds

(Synthesis Example 1)
Compound A-1 was synthesized according to the following scheme.
The starting material 3-deoxy-3-iodoestrone was obtained from Angew. Chem. Int. Ed. It was synthesized by the method described in 2014, 53, 11046.

[Scheme 1] Synthesis of 3-carbazolyl estrone 3-deoxy-3-iodoestrone (1.52 g, 4.00 mmol), carbazole (669 mg, 4.00 mmol), copper (I) iodide (381 mg, 2. 00 mmol), phenanthroline (721 mg, 4.00 mmol) and potassium carbonate (1.11 g, 8.00 mmol) were dissolved in dimethyl sulfoxide (40 mL), followed by reaction at 180 ° C. for 10 hours. After completion of the reaction, water was added and the mixture was extracted with ethyl acetate. The organic layer was dried over magnesium sulfate and concentrated with an evaporator. The obtained concentrate was purified by column chromatography on silica gel (eluent: heptane / ethyl acetate = 80/20) to give 3-carbazolyl estrone (yield 1.34 g, yield 80%).

[Scheme 2] Synthesis of Compound A-1 After 3-carbazolylestrone (1.34 g, 3.20 mmol) was dissolved in diethylene glycol (30 mL), hydrazine hydrate (176 mg, 3.52 mmol) was added, The reaction was carried out at 120 ° C. for 2 hours. After completion of the reaction, potassium hydroxide (539 mg, 9.60 mmol) was added and reacted at 210 ° C. for 4 hours. After completion of the reaction, water was added and the mixture was extracted with ethyl acetate. The organic layer was dried over magnesium sulfate and concentrated with an evaporator. The obtained concentrate was purified by silica gel column chromatography (eluent: heptane / ethyl acetate = 80/20) to obtain compound A-1 (yield 779 mg, yield 60%).

(Synthesis Example 2)
Compound A-40 was synthesized according to the following scheme.
The starting material 3- (trifluoromethanesulfonyl) estrone was obtained from Angew. Chem. Int. Ed. It was synthesized by the method described in 2014, 53, 11046.

[Scheme 1] Synthesis of 3-dibenzofurylestrone 3- (trifluoromethanesulfonyl) estrone (1.61 g, 4.00 mmol), dibenzofuran-2-boronic acid (848 mg, 4.00 mmol), tetrakis (triphenylphosphine) palladium (0) (231 mg, 0.20 mmol) and potassium carbonate (1.11 g, 8.00 mmol) were dissolved in tetrahydrofuran (50 mL), then refluxed and reacted for 8 hours. After completion of the reaction, the solvent was distilled off and the resulting concentrate was purified by silica gel column chromatography (eluent: heptane / ethyl acetate = 80/20) to give 3-dibenzofuryl estrone (yield 1. 43 g, yield 85%).

[Scheme 2] Synthesis of Compound A-40 3-Dibenzofurylestrone (1.35 g, 3.20 mmol) was dissolved in diethylene glycol (30 mL), hydrazine hydrate (176 mg, 3.52 mmol) was added, and 120 was added. The reaction was carried out at 2 ° C. for 2 hours. After completion of the reaction, potassium hydroxide (539 mg, 9.60 mmol) was added and reacted at 210 ° C. for 4 hours. After completion of the reaction, water was added and the mixture was extracted with ethyl acetate. The organic layer was dried over magnesium sulfate and concentrated with an evaporator. The obtained concentrate was purified by silica gel column chromatography (eluent: heptane / ethyl acetate = 80/20) to obtain A-40 (yield 846 mg, yield 65%).

  Compounds A-16, A-23, A-29, A-30, A-35, A-41, A-43, A-57, and A-58 were synthesized in the same manner as in Synthesis Example 1 or Synthesis Example 2. did.

[Example 1]
(Preparation of organic EL element 1-1)
A transparent substrate with an ITO (Indium Tin Oxide) film having a thickness of 150 nm formed on a glass substrate of 50 mm × 50 mm and a thickness of 0.7 mm, patterned, and this ITO transparent electrode was attached After ultrasonic cleaning with isopropyl alcohol, drying with dry nitrogen gas and UV ozone cleaning for 5 minutes, this transparent substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus.
Each of the vapor deposition crucibles in the vacuum vapor deposition apparatus was filled with the constituent material of each layer in an amount optimal for device fabrication. The evaporation crucible used was made of a resistance heating material made of molybdenum or tungsten.

After reducing the vacuum to 1 × 10 ⁻⁴ Pa, the deposition crucible containing the following compound HI-1 was energized and heated, deposited on the ITO transparent electrode at a deposition rate of 0.1 nm / second, and a layer thickness of 10 nm. A hole injection transport layer was formed.

Subsequently, α-NPD (4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl) was deposited on the hole injection layer at a deposition rate of 0.1 nm / second, and the layer thickness was 40 nm. The hole transport layer was formed. The host material (B) is H-1, which is another host compound, and the phosphorescent material (A) is compound D-1, with a deposition rate of 0.1 nm / min so as to be 90% and 10% by volume, respectively. Co-evaporation was performed in seconds to form a light emitting layer having a layer thickness of 30 nm.
Thereafter, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) was deposited at a deposition rate of 0.1 nm / second to form an electron transport layer having a layer thickness of 30 nm.
Furthermore, after forming lithium fluoride with a film thickness of 0.5 nm, 100 nm of aluminum was vapor-deposited to form a cathode.

(Preparation of organic EL elements 1-2 to 1-21)
Except that the types of phosphorescent materials (A) and host materials (B) used in the light emitting layer and the ratios thereof were changed as shown in Table 1, organic EL element 1-1 was used in the same manner. EL elements 1-2 to 1-21 were produced respectively.

  (Evaluation of Organic EL Element) The non-light emitting surface side of each organic EL element after production was covered with a can-shaped glass case in the atmosphere, and an electrode lead-out wiring was installed, and used for evaluation of the following organic EL element. .

(Evaluation of external quantum yield (emission brightness))
Each organic EL element is allowed to emit light at room temperature (about 25 ° C.) under a constant current condition of ^2.5 mA / cm ² , and the emission luminance immediately after the start of emission is measured by a spectral radiance meter CS-2000 (manufactured by Konica Minolta). It measured using.
Next, relative light emission luminance was obtained by setting the light emission luminance of the organic EL element 1-1 as a comparative example to 100, and this was used as a measure of the light emission efficiency (external quantum yield). In addition, it represents that it is excellent in luminous efficiency, so that a numerical value is large.

(Evaluation of half-life)
Each organic EL element was driven at a constant current with a current giving an initial luminance of 1000 cd / m ² , and a time required to be ½ (500 cd / m ² ) of the initial luminance was obtained.
The half life was expressed as a relative value with the organic EL element 1-1 as 100.

(result)
From the results shown in Table 1, the organic EL elements 1-5 to 1-21 using a steroid skeleton compound as a host material all emitted twice or more (that is, 200% or more) of the organic EL element 1-1. It was an excellent organic EL device showing efficiency and half life. In particular, the organic EL elements 1-15 and 1-16 in which the steroid skeleton compound is A-30 or A-57, which is a compound having a carbazolyl group substituted with an electron-withdrawing group as R ^{1 in the} general formula (1), , A luminous efficiency exceeding 400% and a half-life exceeding 300% were simultaneously achieved. This is because the light-emitting organic thin film according to the present invention containing a steroid skeleton compound and a light-emitting material can prevent a decrease in luminous efficiency due to the influence of oxygen and water in the atmosphere and a decrease in device lifetime. Conceivable.

  Moreover, according to the organic EL elements 1-15, 1-18 and 1-19 using the same light emitting material and steroid skeleton compound in different ratios, the ratio of phosphorescent materials is small and the ratio of steroid skeleton compounds is large. The higher the luminous efficiency and the half life.

  Furthermore, organic EL devices 1-20 and 1-21 using a steroid skeleton compound in combination with another host compound are organic EL devices 1-20 using the same kind and the same amount of phosphorescent material and the same steroid skeleton compound. Compared with 6, luminous efficiency was improved.

  On the other hand, the organic EL devices 1-2 to 1-4 using a host compound other than the steroid skeleton compound defined in the present invention had a luminous efficiency of 280% or more, but a half-life of less than 200. It was low.

  According to the present invention, it is possible to provide a long-life organic EL element that achieves high luminous efficiency with little decrease in luminous efficiency due to oxygen or water. In addition, an organic electroluminescent element using the light-emitting thin film, and a display device and a lighting device including the organic electroluminescent element can be provided.

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 21 Adhesive 22 Sealing case 23 Substrate 101 Organic EL element 102 in a lighting device 102 Glass cover 105 Cathode 106 Organic layer 107 Glass substrate with transparent electrode 108 Nitrogen gas 109 Water trapping agent A Display unit B Control unit C Wiring unit

Claims (11)

A luminescent organic thin film comprising a steroid skeleton compound represented by the general formula (1) and a phosphorescent material.

(In general formula (1),
R ¹ represents a substituted or unsubstituted tertiary amino group, a substituted or unsubstituted aromatic hydrocarbon group (excluding an aromatic hydrocarbon group substituted with a tertiary amino group), or a substituted or unsubstituted aromatic hydrocarbon group Represents an aromatic heterocyclic group,
R ^{2 to} R ²² each independently represents a hydrogen atom or a substituent. )   The luminescent organic thin film according to claim 1, wherein the phosphorescent material is a metal complex.   The luminescent organic thin film according to claim 2, wherein the metal complex is an iridium complex. The luminescent organic thin film according to any one of claims 1 to 3, wherein the steroid skeleton compound is represented by any one of the following general formulas (2) to (4).

(In the general formulas (2) to (4),
R ¹ represents a substituted or unsubstituted tertiary amino group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group. ) R ¹ is a substituted or unsubstituted tertiary amino group, an aromatic hydrocarbon group substituted with an electron-withdrawing group, or an aromatic heterocyclic group substituted with an electron-withdrawing group. The luminescent organic thin film as described in any one of Claims 1-4. The luminescent organic thin film according to claim 1, wherein R ¹ is a substituted or unsubstituted tertiary amino group. The luminescent organic thin film according to claim 6, wherein R ¹ is a tertiary amino group substituted with an electron-withdrawing group. The luminescent organic thin film according to claim 7, wherein R ¹ is a carbazolyl group substituted with an electron-withdrawing group.   The organic electroluminescent element containing the luminescent organic thin film as described in any one of Claims 1-8.   A display device comprising the organic electroluminescence element according to claim 9.   The illuminating device containing the organic electroluminescent element of Claim 9.

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