WO2012002221A1

WO2012002221A1 - Material for light emitting element, and light emitting element

Info

Publication number: WO2012002221A1
Application number: PCT/JP2011/064275
Authority: WO
Inventors: 玲武田
Original assignee: 富士フイルム株式会社
Priority date: 2010-06-30
Filing date: 2011-06-22
Publication date: 2012-01-05
Also published as: JP2012033892A; JP5951939B2

Abstract

Disclosed is a material for a light emitting element, which is suitable for the purpose of lowering the driving voltage and improving luminous efficiency and durability of a light emitting element. Specifically disclosed is a material for a light emitting element, which contains an impurity in an amount of more than 0.5% by mass but 10% by mass or less. The material for a light emitting element is characterized in that the impurity satisfies two or more of the following conditions (I)-(III). (I) The ionization potential Ip (1) of the material for a light emitting element and the ionization potential Ip (2) of the impurity satisfy the following relation: Ip (1) ≤ Ip (2). (II) The electron affinity Ea (1) of the material for a light emitting element and the electron affinity Ea (2) of the impurity satisfy the following relation: Ea (1) ≥ Ea (2). (III) The triplet state excitation energy T₁ (1) of the material for a light emitting element and the triplet state excitation energy T₁ (2) of the impurity satisfy the following relation: T₁ (1) ≤ T₁ (2).

Description

Light emitting device material and light emitting device

The present invention relates to a light emitting element material and a light emitting element.

An organic electroluminescent element (hereinafter also referred to as “element” or “organic EL element”) that uses an organic thin film that emits light when excited by passing current as a light-emitting element can emit light with high brightness when driven at a low voltage. Therefore, active research and development has been carried out in recent years. In general, an organic electroluminescent element is composed of an organic layer including a light emitting layer and a pair of electrodes sandwiching the layer, and electrons injected from the cathode and holes injected from the anode are recombined in the light emitting layer, The generated exciton energy is used for light emission.

In recent years, the use of phosphorescent light-emitting materials has advanced the efficiency of devices. For example, an organic electroluminescent element using a phosphorescent material and a platinum complex and having excellent luminous efficiency and durability has been studied. In addition, a doped element using a light emitting layer in which a light emitting material is doped in a host material is widely used.

As a method for synthesizing organic compounds, there is a cross-coupling reaction in which different types of raw material compounds are combined in the presence of a catalyst to obtain the target organic compound. It is known that coupling bodies are by-produced. (See Patent Document 1). Many organic compounds used as organic electroluminescent element materials can also be obtained by cross-coupling reactions (see Patent Document 2).
When an organic compound (cross-coupled body) obtained by a cross-coupling reaction is used as a material for an organic electroluminescent device, the by-product homo-coupled body is an impurity, which is considered to be a cause of deteriorating device performance, and its content It has been desired to reduce this. For example, Patent Document 3 includes an organic compound layer in which the content of impurities including a homo-coupled body that can be generated by a cross-coupling reaction is 0.5% by mass or less for the purpose of improving the durability of the device. A light emitting element is described.

Japanese Laid-Open Patent Publication No. 2004-67595 Japanese Unexamined Patent Publication No. 2009-167175 Japanese Unexamined Patent Publication No. 2002-373786

In Patent Document 3, purification by chromatography and recrystallization is repeatedly performed so that the content of impurities including a homo-coupled body is 0.5% by mass or less. In general, repeating the purification step increases the manufacturing cost of the material.
On the other hand, the inventors of the present invention have achieved the device performance (driving voltage, luminous efficiency, We have found conditions that do not affect durability, etc.) Thereby, the light emitting element material which can maintain a high performance with a small manufacturing load can be provided.
That is, an object of the present invention is to provide a light-emitting element material that has a small influence on element performance even if impurities are contained.
Another object of the present invention is to provide a light emitting device using the light emitting device material. Furthermore, another object of the present invention is to provide an illumination device and a display device using the light emitting element.

The above problem is solved by the following means.
(1)
A material for a light-emitting element containing an impurity having a content of more than 0.5% by mass and not more than 10% by mass, wherein the impurity satisfies any two or more of the following conditions [I] to [III]: Material for light emitting elements.
[I] The ionization potential Ip (1) of the light emitting element material and the ionization potential Ip (2) of the impurity satisfy Ip (1) ≦ Ip (2).
[II] The electron affinity Ea (1) of the light emitting device material and the electron affinity Ea (2) of the impurity satisfy Ea (1) ≧ Ea (2).
[III] an excited triplet state of the material for a light-emitting element energy T ₁ (1), excitation energy T ₁ of the triplet state of the impurities and (2), but at _{_{T 1 (1) ≦ T 1}} (2) .
(2)
The light emitting device material according to (1), wherein the light emitting device material is represented by the following general formula (1-1), and the impurity is represented by the following general formula (1-2).
(1-1): (A1) _n1- (B1)
(1-2): (A1)-(A1)
(Wherein n1 represents an integer of 1 to 10. A1 represents an optionally substituted aryl group having 6 to 30 carbon atoms or heteroaryl group having 2 to 30 carbon atoms. B1 Represents an n1-valent aryl structure having 6 to 30 carbon atoms or a heteroaryl structure having 2 to 30 carbon atoms, which may have a substituent, provided that A1 and B1 are not the same. , A halogen atom, an alkyl group, an alkenyl group, an aryl group, a heteroaryl group, an amino group, an alkoxy group, a silyl group, a carboxyl group, or a cyano group, and each group may be further substituted with these substituents. When a plurality of substituents are present, the substituents may be the same or different.)
(3)
The light emitting device material represented by the general formula (1-1) is a cross-coupled body represented by the following general formula (2-1), and the impurity represented by the general formula (1-2) is The light emitting device material according to (2) above, which is a homocoupled body represented by the following general formula (2-2).
(2-1): (A2) _n2- (B2)
(2-2): (A2)-(A2)
(Wherein n2 represents an integer of 1 to 6. A2 represents an optionally substituted aryl group having 6 to 15 carbon atoms or a heteroaryl group having 4 to 15 carbon atoms. B2 represents Represents an n2-valent aryl structure having 6 to 15 carbon atoms or a heteroaryl structure having 3 to 15 carbon atoms which may have a substituent, provided that A2 and B2 are not the same. An atom, an alkyl group, an alkenyl group, an aryl group, a heteroaryl group, an amino group, a silyl group, or a cyano group, and each group may be further substituted with these substituents. And the substituents may be the same or different.)
(4)
The cross-coupling body is a cross-coupling body represented by the following general formula (3-1), and the homo-coupling body is a homo-coupling body represented by the following general formula (3-2) The material for a light emitting device according to (3).
(3-1): (A3) _n3- (B3)
(3-2): (A3)-(A3)
(Wherein n3 represents an integer of 1 to 6. A3 represents an aryl group having 6 to 15 carbon atoms which may have a substituent. B3 represents n3 which may have a substituent. Represents a valent aryl structure having 6 to 15 carbon atoms, provided that A3 and B3 are not the same, and the substituent includes an alkyl group, an alkenyl group, an aryl group, a carbazolyl group, an indolyl group, a diarylamino group, a silyl group, Or a cyano group, and each group may be further substituted with these substituents. When a plurality of substituents are present, the substituents may be the same or different.)
(5)
The cross-coupling body is a cross-coupling body represented by the following general formula (4-1), and the homo-coupling body is a homo-coupling body represented by the following general formula (4-2) (3) or the light emitting device material according to (4).

(Wherein n4 represents an integer of 1 to 5. R _4a and R _4b each independently represents an aryl group which may have a substituent, a carbazolyl group which may have a substituent, or a cyano group. The substituent represents an alkyl group, an alkenyl group, or an aryl group, provided that R _4a and R _4b are not the same, and na and nb each independently represents an integer of 1 to 5. R _4a or When a plurality of R _4b are present, the plurality of R _4a or R _4b may be the same or different.)
(6)
A light-emitting element having at least one organic layer, wherein the light-emitting element includes the light-emitting element material according to any one of (1) to (5) above in at least one layer of the organic layer.
(7)
The light emitting device according to (6), wherein the organic layer is an organic electroluminescent device that is sandwiched between a pair of electrodes and emits light when a voltage is applied between the electrodes.
(8)
The light emitting element according to (6) or (7), wherein the organic layer is a layer formed by a coating method.
(9)
An illumination device comprising the light emitting device according to any one of (6) to (8) above.
(10)
A display device comprising the light emitting device according to any one of (6) to (8).

According to the present invention, it is possible to provide a material for a light emitting element that contains a specific amount of impurities but does not affect the performance of the light emitting element. In particular, a material for a light-emitting element that does not affect the performance of the light-emitting element although a homo-coupled body is included in the cross-coupled body can be provided. The light emitting element material can provide a light emitting element with low driving voltage and excellent light emission efficiency and durability. The material used for the light-emitting element of the present invention is a material that can reduce the cost of the purification process.

It is the schematic which shows an example (1st Embodiment) of the layer structure of the organic EL element which concerns on this invention. It is the schematic which shows an example (2nd Embodiment) of the light-emitting device which concerns on this invention. It is the schematic which shows an example (3rd Embodiment) of the illuminating device which concerns on this invention.

In the description of the general formula according to the present invention, a hydrogen atom includes an isotope (deuterium atom and the like), and an atom constituting a substituent further includes the isotope.

Hereinafter, the present invention will be described in detail.
[Light emitting element materials]
The light-emitting element material of the present invention is a light-emitting element material containing an impurity having a content of more than 0.5% by mass and not more than 10% by mass, and the impurity is any of the following [I] to [III]: Satisfy two or more conditions.
[I] The ionization potential Ip (1) of the light emitting element material and the ionization potential Ip (2) of the impurity satisfy Ip (1) ≦ Ip (2).
[II] The electron affinity Ea (1) of the light emitting device material and the electron affinity Ea (2) of the impurity satisfy Ea (1) ≧ Ea (2).
[III] an excited triplet state of the material for a light-emitting element energy T ₁ (1), excitation energy T ₁ of the triplet state of the impurities and (2), but at _{_{T 1 (1) ≦ T 1}} (2) .

In light-emitting element materials, impurities are conventionally considered to have an adverse effect on element performance as described in Patent Document 2 described above, and it has been considered that the content thereof should be reduced as much as possible.
However, in the case of an impurity that satisfies any two of the above conditions [I] to [III], if the content of the light emitting device material is more than 0.5% by mass and 10% by mass or less, device performance ( The present inventors have found that good performance can be maintained without adversely affecting low drive voltage, luminous efficiency, and durability. Therefore, in the manufacturing process of the material for a light emitting device of the present invention, an excessive purification process is not required to reduce impurities, so that the cost of the purification process can be reduced.
With respect to the above conditions [I] to [III], all three light emitting device materials of the present invention are used from the viewpoint of maintaining good performance without adversely affecting device performance (low driving voltage, light emission efficiency, durability). It is more preferable that the above condition is satisfied. Further, when the light emitting device material of the present invention is used in a light emitting layer described later, it is preferable that at least [III] is satisfied among the above conditions [I] to [III], and [I] and [III Or [II] and [III] are more preferable, and when used in a layer other than the light emitting layer, at least [I] and [II] among the above conditions [I] to [III] are satisfied. It is preferable.

From the viewpoint of less influence of impurities on device performance (low driving voltage, light emission efficiency, durability), the light emitting device material is represented by the general formula (1-1), and the light emitting device material Impurities that are contained in an amount of more than 0.5% by mass and not more than 10% by mass and satisfy any two or more of the conditions [I] to [III] are represented by the following general formula (1-2) The case is preferred.
(1-1): (A1) _n1- (B1)
(1-2): (A1)-(A1)
(Wherein n1 represents an integer of 1 to 10. A1 represents an optionally substituted aryl group having 6 to 30 carbon atoms or heteroaryl group having 2 to 30 carbon atoms. B1 Represents an n1-valent aryl structure having 6 to 30 carbon atoms or a heteroaryl structure having 2 to 30 carbon atoms, which may have a substituent, provided that A1 and B1 are not the same. , A halogen atom, an alkyl group, an alkenyl group, an aryl group, a heteroaryl group, an amino group, an alkoxy group, a silyl group, a carboxyl group, or a cyano group, and each group may be further substituted with these substituents. When a plurality of substituents are present, the substituents may be the same or different.)

In particular, the light-emitting element material represented by the general formula (1-1) is a cross cup of a compound represented by the following general formula (1-4) and a compound represented by the following general formula (1-5). It is preferably a cross-coupled body obtainable by a ring reaction, and a homo-coupled body in which the impurity represented by the general formula (1-2) is by-produced by the cross-coupling reaction.
(1-4): (A1)-(X1)
(1-5): (B1)-(X2)
(In the formula, A1 and B1 each represent a group corresponding to A1 and B1 in the general formula (1-1). X1 and X2 represent a halogen atom or a group containing a halogen atom.)
In the cross-coupling reaction, the compound represented by the general formula (1-2) (homo-coupled body), etc., in addition to the target cross-coupled body represented by the general formula (1-1). To be born. These homo-coupled bodies are conventionally considered to have an adverse effect on device performance as described in Patent Document 2 described above, and it has been considered that the content thereof should be reduced as much as possible.
However, as described above, the homo-coupled body represented by the general formula (1-2) and the cross-coupled body represented by the general formula (1-1) are any of the above [I] to [III]. When the two or more conditions are satisfied, the content of the homocoupled body represented by the general formula (1-2) is 0 with respect to the cross-coupled body represented by the general formula (1-1). If it is more than 5% by mass and not more than 10% by mass, the device performance (low driving voltage, luminous efficiency, durability) is not adversely affected, and good performance can be maintained.
Such a light emitting device material of the present invention comprises a homo-coupling product represented by the general formula (1-2) in a cross-coupling reaction for obtaining a cross-coupling product represented by the general formula (1-1). By selectively by-producing, the light emitting device material of the present invention can be obtained. In the process of manufacturing the light emitting device material of the present invention, an excessive purification step is not required to reduce the homo-coupled body represented by the general formula (1-2), so that the cost of the purification step can be reduced. Can do.

The general formulas (1-1) and (1-2) will be described.
n1 represents an integer of 1 to 10. n1 is preferably 1 to 6, more preferably 1 to 5, further preferably 1 to 3, and particularly preferably 1.
A1 represents an aryl group having 6 to 30 carbon atoms or a heteroaryl group having 2 to 30 carbon atoms, which may have a substituent.
The aryl group preferably has 6 to 15 carbon atoms, and more preferably 6 to 12 carbon atoms. Examples of the aryl group include a phenyl group, a naphthyl group, a biphenyl group, an anthranyl group, a triphenyl group, a phenanthryl group, and a triphenylenyl group. A phenyl group, a naphthyl group, a phenanthryl group, and a triphenylenyl group are preferable, and a phenyl group is more preferable.
The carbon number of the heteroaryl group is more preferably 2-18, and particularly preferably 2-12. Examples of the hetero atom of the heteroaryl group include a nitrogen atom, an oxygen atom, and a sulfur atom. Heteroaryl groups include imidazolyl, pyridyl, quinolyl, furyl, thienyl, benzofuryl, benzothienyl, dibenzofuryl, dibenzothienyl, piperidyl, benzoxazolyl, benzimidazolyl, benzthiazolyl Group, indolyl group, carbazolyl group, azepinyl group and the like. Preferably, pyridyl group, furyl group, thienyl group, benzofuryl group, benzothienyl group, dibenzofuryl group, dibenzothienyl group, piperidyl group, indolyl group, carbazolyl group, azepinyl group, more preferably pyridyl group, furyl group, A thienyl group, a dibenzofuryl group, a dibenzothienyl group, a carbazolyl group, and an azepinyl group, and more preferably a pyridyl group.

B1 represents an n1-valent aryl structure having 6 to 30 carbon atoms or a heteroaryl structure having 2 to 30 carbon atoms, which may have a substituent.
The aryl structure preferably has 6 to 15 carbon atoms, more preferably 6 to 12 carbon atoms. Examples of the aryl structure include phenyl, naphthyl, biphenyl, anthranyl, triphenyl, phenanthryl and the like. Preferred are phenyl, naphthyl and biphenyl, and more preferred is a phenyl group.
The heteroaryl structure preferably has 2 to 18 carbon atoms, and more preferably 2 to 12 carbon atoms. Examples of the hetero atom of the heteroaryl structure include a nitrogen atom, an oxygen atom, and a sulfur atom. Examples of heteroaryl include imidazole, pyridine, quinoline, furan, thiophene, benzofuran, benzothiophene, dibenzofuran, dibenzothiophene, piperidine, benzoxazole, benzimidazole, benzthiazole, indole, carbazole, and azepine. Preferred are pyridine, furan, thiophene, benzofuran, benzothiophene, dibenzofuran, dibenzothiophene, piperidine, indole, carbazole, and azepine, more preferably pyridine, thiophene, dibenzothiophene, and dibenzofuran, and more preferably pyridine. .
A1 and B1 are not the same.

The substituents that A1 and B1 may have are a halogen atom, an alkyl group, an alkenyl group, an aryl group, a heteroaryl group, an amino group, an alkoxy group, a silyl group, a carboxyl group, or a cyano group.
Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, and a bromine atom. Preferably, it is a fluorine atom.
The alkyl group as a substituent preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 10 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, and the like, preferably methyl, ethyl, tert-butyl, and more preferably tert-butyl. Butyl.
The number of carbon atoms of the alkenyl group as a substituent is preferably 2 to 30, more preferably 2 to 20, and particularly preferably 2 to 10. Examples of the alkenyl group include a vinyl group, an allyl group, a 2-butenyl group, and a 3-pentenyl group. A vinyl group and an allyl group are preferable, and a vinyl group is more preferable.
The number of carbon atoms of the aryl group as a substituent is preferably 6 to 30, more preferably 6 to 20, and particularly preferably 6 to 12. Examples of the aryl group include a phenyl group, a naphthyl group, a biphenyl group, an anthranyl group, a triphenyl group, and a phenanthryl group. A phenyl group, a biphenyl group, and a phenanthryl group are preferable, and a phenyl group is more preferable.
The number of carbon atoms of the heteroaryl group as a substituent is preferably 1-30, and more preferably 1-12. Examples of the hetero atom include a nitrogen atom, an oxygen atom, and a sulfur atom. Heteroaryl groups include imidazolyl, pyridyl, quinolyl, furyl, thienyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl, indolyl, azepinyl, etc. Can be mentioned. A carbazolyl group, an indolyl group, and an azepinyl group are preferable, and a carbazolyl group is more preferable.
The number of carbon atoms of the alkoxy group as a substituent is preferably 1 to 30, more preferably 1 to 20, and particularly preferably 1 to 10. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a tert-butoxy group. A methoxy group and a tert-butoxy group are preferable, and a methoxy group is more preferable.

The substituent may further have a substituent. Examples of the further substituent include the halogen atom, alkyl group, aryl group, heteroaryl group, amino group, alkoxy group, silyl group, carboxyl group, A cyano group is mentioned. As the further substituent, an alkyl group and an aryl group are preferable, and a tert-butyl group and a phenyl group are more preferable.

As the substituent that A1 and B1 may have, an aryl group, a heteroaryl group, an amino group, a silyl group, and a cyano group are preferable, and an aryl group, a carbazolyl group, an indolyl group, a diarylamino group, a silyl group, and a cyano group Are more preferable, and a phenyl group, a carbazolyl group, and a cyano group are particularly preferable.
You may have multiple A1 and B1 each independently. A1 preferably has 1 to 3 substituents, more preferably 1 substituent. B1 preferably has 1 to 3 substituents, and more preferably has 1 to 2 substituents. When A1 and B1 each have a plurality of substituents, the plurality of substituents may be the same or different.

A1 is preferably an aryl group which may have a substituent, more preferably a phenyl group having a phenanthryl group or a carbazolyl group, and particularly preferably a phenyl group having a carbazolyl group.
B1 is preferably an aryl structure which may have a substituent, more preferably phenyl having a phenyl group, a carbazolyl group and / or a cyano group, and particularly preferably phenyl having a carbazolyl group.

The light-emitting element material represented by the general formula (1-1) and the impurity represented by the general formula (1-2) are, respectively, a cross coupling represented by the following general formula (2-1) and The homo-coupled body is preferably a homo-coupled body represented by the following general formula (2-2).
(2-1): (A2) _n2- (B2)
(2-2): (A2)-(A2)
(Wherein n2 represents an integer of 1 to 6. A2 represents an optionally substituted aryl group having 6 to 15 carbon atoms or a heteroaryl group having 4 to 15 carbon atoms. B2 represents Represents an n2-valent aryl structure having 6 to 15 carbon atoms or a heteroaryl structure having 3 to 15 carbon atoms which may have a substituent, provided that A2 and B2 are not the same. An atom, an alkyl group, an alkenyl group, an aryl group, a heteroaryl group, an amino group, a silyl group, or a cyano group, and each group may be further substituted with these substituents. And the substituents may be the same or different.)

The general formulas (2-1) and (2-2) will be described.
n2 represents an integer of 1 to 6. n2 is more preferably 1 to 5, further preferably 1 to 3, and particularly preferably 1.
A2 represents an aryl group having 6 to 15 carbon atoms or a heteroaryl group having 4 to 15 carbon atoms, which may have a substituent.
B2 represents an n2-valent aryl structure having 6 to 15 carbon atoms or a heteroaryl structure having 3 to 15 carbon atoms, which may have a substituent.
Specific examples and preferred examples of the aryl group and heteroaryl group represented by A2 and the aryl structure and heteroaryl structure represented by B2 are the aryl group represented by A1 in the general formulas (1-1) and (1-2), and This is the same as the heteroaryl group and the aryl structure and heteroaryl structure represented by B1.
The substituents that A2 and B2 may have are a halogen atom, an alkyl group, an alkenyl group, an aryl group, a heteroaryl group, an amino group, a silyl group, or a cyano group. Specific examples and preferred ranges of the respective groups are the same as those listed as the substituents that A1 and B1 in the general formulas (1-1) and (1-2) may have. Preferred examples of the substituent that A2 and B2 may have are the same as A1 and B1 in the general formulas (1-1) and (1-2).
A2 and B2 are not the same.

The cross-coupled body represented by the general formula (1-1) or (1-2) and the homo-coupled body represented by the general formula (1-2) or (2-2) are respectively The cross coupling represented by the general formula (3-1) and the homo-coupled body are preferably a homo-coupled body represented by the following general formula (3-2).
(3-1): (A3) _n3- (B3)
(3-2): (A3)-(A3)
(Wherein n3 represents an integer of 1 to 6. A3 represents an aryl group having 6 to 15 carbon atoms which may have a substituent. B3 represents n3 which may have a substituent. Represents a valent aryl structure having 6 to 15 carbon atoms, provided that A3 and B3 are not the same, and the substituent includes an alkyl group, an alkenyl group, an aryl group, a carbazolyl group, an indolyl group, a diarylamino group, a silyl group, Or a cyano group, and each group may be further substituted with these substituents. When a plurality of substituents are present, the substituents may be the same or different.)

General formulas (3-1) and (3-2) will be described.
n3 represents an integer of 1 to 6. n3 is more preferably 1 to 5, further preferably 1 to 3, and particularly preferably 1.
A3 represents an aryl group having 6 to 15 carbon atoms or a heteroaryl group having 4 to 15 carbon atoms, which may have a substituent.
B3 represents an n3-valent aryl structure having 6 to 15 carbon atoms or a heteroaryl structure having 3 to 15 carbon atoms, which may have a substituent.
Specific examples and preferred examples of the aryl group and heteroaryl group represented by A3, and the aryl structure and heteroaryl structure represented by B3 are the aryl group represented by A1 in the general formulas (1-1) and (1-2), and This is the same as the heteroaryl group and the aryl structure and heteroaryl structure represented by B1.
The substituents that A3 and B3 may have are an alkyl group, an alkenyl group, an aryl group, a carbazolyl group, an indolyl group, a diarylamino group, a silyl group, or a cyano group. Specific examples and preferred ranges of the alkyl group and aryl group are the same as the alkyl group and aryl group mentioned as the substituents that A1 and B1 of the general formulas (1-1) and (1-2) may have. . As the substituent that A3 and B3 may have, a phenyl group, a carbazolyl group, and a cyano group are more preferable.
A3 and B3 are not the same.

The cross-coupled bodies represented by the general formulas (1-1) to (3-1) and the homo-coupled bodies represented by the general formulas (1-2) to (3-2) are respectively The cross coupling represented by the general formula (4-1) and the homo-coupled body are preferably a homo-coupled body represented by the following general formula (4-2).

(Wherein n4 represents an integer of 1 to 5. R _4a and R _4b each independently represents an aryl group which may have a substituent, a carbazolyl group which may have a substituent, or a cyano group. The substituent is an alkyl group, an alkenyl group, or an aryl group, provided that R _4a and R _4b are not the same, and na and nb each independently represents an integer of 1 to 5. R _4a or R When a plurality of _4b are present, the plurality of R _4a or R _4b may be the same or different.)

The general formulas (4-1) and (4-2) will be described.
n4 represents an integer of 1 to 5. n4 is more preferably 1 to 3, and particularly preferably 1.
R _4a and R _4b each independently represent an aryl group that may have a substituent, a carbazolyl group that may have a substituent, or a cyano group. The substituent is an alkyl group, an alkenyl group, or an aryl group.
R _4a is preferably an unsubstituted carbazolyl group.
R _4b is preferably a phenyl group having a substituent, an optionally substituted carbazolyl group, or a cyano group, and more preferably an optionally substituted carbazolyl group or cyano group.
The substituent is preferably a tert-butyl group or a phenyl group.
na and nb each independently represents an integer of 1 to 5. na is preferably 1 to 2, and more preferably 1. nb is preferably 1 to 3, and more preferably 1 to 2.
When n4 = 1, R _4a and R _4b are not the same. If R _4a or _{R 4b} there are a plurality, _{R 4a} or _{R 4b} the plurality of it may be the same or different.

The cross-coupled body represented by the general formula (4-1) and the homo-coupled body represented by the general formula (4-2) are respectively cross cloths represented by the following general formula (5-1). The coupling and the homocoupled body are preferably a homocoupled body represented by the following general formula (5-2).

(In the formula, R ₅₁ represents a phenyl group which may have a substituent or a carbazolyl group which may have a substituent. R ₅₂ and R ₅₃ each independently have a hydrogen atom or a substituent. A phenyl group which may be substituted, a carbazolyl group which may have a substituent, or a cyano group, wherein the substituent represents an alkyl group or an aryl group, provided that R ₅₂ and R ₅₃ are simultaneously hydrogen atoms. (If either R ₅₂ or R ₅₃ is a hydrogen atom, the other is not the same as R _51. )

General formulas (5-1) and (5-2) will be described.
R ₅₁ represents a phenyl group which may have a substituent or a carbazolyl group which may have a substituent. An unsubstituted carbazolyl group is preferable.
R ₅₂ and R ₅₃ each independently represent a hydrogen atom, a phenyl group which may have a substituent, a carbazolyl group which may have a substituent, or a cyano group. A hydrogen atom, a phenyl group having a substituent, an optionally substituted carbazolyl group or a cyano group is preferable, and a hydrogen atom, an optionally substituted carbazolyl group or a cyano group is more preferable.
The substituent represents an alkyl group or an aryl group, and is preferably a tert-butyl group or a phenyl group.
R ₅₂ and R ₅₃ are not simultaneously a hydrogen atom, and when one of R ₅₂ and R ₅₃ is a hydrogen atom, the other is not the same as R ₅₁ .

Next, the conditions [I] to [III] will be described.
[I] In one embodiment of the light emitting device material of the present invention, the ionization potential of the cross-coupled body represented by the general formulas (1-1) to (5-1) contained in the light emitting device material Ip (1) and the ionization potential Ip (2) of the homocoupled body represented by the general formulas (1-2) to (5-2) satisfy Ip (1) ≦ Ip (2).
If a material with a certain ionization potential (Ip) contains a small amount of a material with a relatively small Ip, the movement of holes passing through the material is prevented, which is expected when only a material with a certain Ip is used. Although it is difficult to reproduce the emitted light emission characteristics, in this embodiment, the expected light emission characteristics can be obtained by satisfying Ip (1) ≦ Ip (2). Furthermore, Ip (2) −Ip (1) may be 0 eV or more and 1.0 eV or less because the smaller the difference between Ip (1) and Ip (2), the smaller the effect on hole movement. It is preferably 0 eV or more and 0.5 eV or less, more preferably 0 eV or more and 0.2 eV or less, and particularly preferably 0 eV or more and 0.1 eV or less.
The ionization potential is measured by using an atmospheric photoelectron spectroscopy (PES) apparatus AC-2 / AC-3 manufactured by Riken Keiki Co., Ltd. It can be carried out with a solid state material such as a crystal or a crystal. It can also be measured using ultraviolet photoelectron spectroscopy (UPS), photoelectron yield analysis (PYS), etc., and the cyclic voltammetry (CV) oxidation potential and the HOMO (highest occupied molecular orbital) level by quantum chemical calculations. You can also compare.

[II] In one embodiment of the light emitting device material of the present invention, the electron affinity of the cross-coupled body represented by the general formulas (1-1) to (5-1) contained in the light emitting device material Ea (1) and the electron affinity Ea (2) of the homocoupled body represented by the general formulas (1-2) to (5-2) satisfy Ea (1) ≧ Ea (2).
When a material having a certain electron affinity (Ea) contains a small amount of a material having a relatively large Ea, the movement of electrons passing through the material is prevented, and the emission characteristics expected when only a material having a certain Ea is used. However, in this embodiment, the expected light emission characteristics can be obtained by satisfying Ea (1) ≧ Ea (2). Furthermore, it is preferable that Ea (1) -Ea (2) is 0 eV or more and 1.0 eV or less because the smaller the difference between Ea (1) and Ea (2), the smaller the influence on electron movement. It is more preferably 0 eV or more and 0.5 eV or less, further preferably 0 eV or more and 0.2 eV or less, and particularly preferably 0 eV or more and 0.1 eV or less.
The electron affinity is obtained from the energy level Eg corresponding to the short wavelength end of the absorption spectrum of the material and the above-mentioned Ip by the calculation formula of Ea = Ip−Eg. It can also be measured by using inverse photoelectron spectroscopy (IPES), and can be compared by the reduction potential of cyclic voltammetry (CV) or the LUMO (lowest empty orbit) level by quantum chemical calculation.

[III] In one embodiment of the light emitting device material of the present invention, the excitation energy of the cross coupling body represented by the general formulas (1-1) to (5-1) contained in the light emitting device material T ₁ (1) and the excitation energy T ₁ (2) of the homocoupled body represented by the general formulas (1-2) to (5-2) are T ₁ (1) ≦ T ₁ (2) Meet.
When a material having a small triplet state excitation energy T ₁ contains a small amount of a material having a relatively small T ₁ , excitons generated in the light-emitting element are deactivated by charge recombination, and the material having a certain T ₁ Although it is difficult to reproduce the expected light emission characteristics when using only this, in this embodiment, the expected light emission characteristics are obtained by satisfying T ₁ (1) ≦ T ₁ (2). be able to. In addition, T _{1 (1)} and T ₁ (2) should the difference is large, and from the impact is less than the reason given to the inactivation of the _{_{exciton, T 1 (2) -T 1}} (1) is more 0eV 0.1eV Or less, more preferably 0 eV or more and 1.0 eV or less.
The excitation energy of the triplet state can be obtained from the short wavelength end of the phosphorescence emission spectrum of the thin film of the material. For example, a material is deposited on a cleaned quartz glass substrate to a thickness of about 50 nm by vacuum deposition, and the phosphorescence emission spectrum of the thin film is measured at F-7000 Hitachi Spectrofluorimeter (Hitachi High Technologies) under liquid nitrogen temperature. Use to measure. The T ₁ energy can be obtained by converting the rising wavelength on the short wavelength side of the obtained emission spectrum into energy units.

In order to satisfy the above conditions [I] to [III], a material used for the cross-coupling reaction is selected so that Ip, Ea, and T _{1 of the} by-product homo-coupled body satisfy the above conditions. . In particular, in the case of Suzuki coupling in which an organoboron compound and an aryl halide are cross-coupled using a palladium catalyst or the like, a homo-coupled product by-produced from a material containing boron satisfies the above conditions. Select the material.

In the light emitting device material of the present invention, the cross coupling bodies represented by the general formulas (1-1) to (5-1) are represented by the general formulas (1-2) to (5-2). The content of the homocoupled body satisfying at least one of the above [I] to [III] is more than 0.5% by mass and not more than 10% by mass. From the viewpoint of suppressing fluctuations in device performance, the content is preferably 5% by mass or less, and more preferably 1% by mass or less. On the other hand, if the material purification is carried out excessively, the production cost increases, so the content of the homocoupled body is preferably 0.5% by mass or more, and more preferably 0.7% by mass or more.

From the viewpoint of cost reduction of material purification, the cross-coupled bodies represented by the general formulas (1-1) to (5-1) are represented by the general formulas (1-2) to (5-2). The content of the homocoupled body that is not satisfied with any of the above [I] to [III] is preferably 0.5% by mass or more, and preferably 1% by mass or more. More preferably, the content is 2% by mass or more and 5% by mass or less.

Examples of cross-coupling reactions that give a cross-coupled body represented by the general formula (1-1) and a corresponding homo-coupled body represented by the general formula (1-2) are shown below. However, the present invention is not limited to these. In the formula, Ax and Ay represent a place where a bond is generated by a coupling reaction, and represent a halogen atom, a substituted sulfonate, or a group containing a metal atom before the reaction.

[Cross coupling reaction]
The cross-coupled body represented by the general formulas (1-1) to (5-1) according to the present invention can be obtained by a cross-coupling reaction.
For example, in the case of a cross-coupled body represented by the general formula (1-1), a cross-linking between a compound represented by the following general formula (1-4) and a compound represented by the following general formula (1-5) It can be obtained by a coupling reaction.
(1-4): (A1)-(X1)
(1-5): (B1)-(X2)
(In the formula, A1 and B1 each represent a group corresponding to A1 and B1 in the general formula (1-1). X1 and X2 each represent a halogen atom, a substituted sulfonate, or a group containing a metal atom. .)
As the halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom can be used. As the substituted sulfonate, methanesulfonate (mesylate), trifluoromethanesulfonate (triflate), nonafluorobutanesulfonate (nonaflate), Phenyl sulfonate, p-toluene sulfonate (tosylate) and the like can be used.
As the compound having a group containing a metal atom, a Grignard reagent containing Mg, an organoboron compound containing B, an organosilicon compound containing Si, an organotin compound containing Sn, an organozinc compound containing Zn, or the like can be used. .

The reaction conditions for the coupling reaction are described in Chem. Rev. 1995, 95, 2457-2483. Or “Metal-Catalyzed Cross-Coupling Reactions, 2nd, Completely Revised AND Enhanced Edition” (A. Meijere (Editor), F. Diedrich (Criteria), V. Can be used. Preferred conditions for the reaction are described below.
As the catalyst, transition metals can be used, and in particular, metals such as palladium, nickel, iron, ruthenium, rhodium, iridium, platinum, gold, and copper can be used. These metals alone or inorganic salts, or The reaction is conducted in the form of an organometallic complex having an appropriate ligand.
As the palladium catalyst, a divalent palladium salt or a zero-valent palladium salt is used. Examples of the divalent palladium include palladium acetate and dichlorobistoluphenylphosphine palladium, and examples of the zero-valent palladium include tetrakistriphenylphosphine palladium and bis (dibenzylideneacetone) palladium. Palladium acetate and tetrakis (triphenylphosphine) palladium are preferable.
The solvent for the reaction is not particularly limited, but water; aromatic hydrocarbons such as benzene, toluene and xylene; halogenated hydrocarbons such as dichloroethane and chloroform; tetrahydrofuran, 1,2-dimethoxyethane, 1,4 -Ethers such as dioxane and diethyl ether; alcohols such as methanol, ethanol and isopropyl alcohol; esters such as ethyl acetate and butyl acetate. Of these, water, aromatic hydrocarbons, and ethers are preferable. These solvents may be used as a mixture of two or more.
The reaction temperature is not particularly limited. Usually, the reaction is performed between 0 ° C. and the boiling point of the solvent. However, when the product does not decompose, the boiling point of the solvent is increased in order to improve the reaction rate. It is preferable to make it react at the temperature of vicinity.
The above reaction may be performed by further adding a ligand as necessary. Examples of the ligand include a phosphine ligand and a carbene ligand. Of these, phosphine ligands are preferred.
The ligand is usually used in an amount of 0.5 to 20 mol times, preferably 1 to 10 mol times, more preferably 1 to 5 mol times based on the palladium catalyst used. It is.
Although it does not specifically limit as a base used for the said reaction, Specifically, alkaline-earth metal, such as alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, calcium hydroxide, barium hydroxide Alkali metal bicarbonates such as hydroxide, sodium bicarbonate and potassium bicarbonate, alkaline earth metal bicarbonates such as calcium bicarbonate and barium bicarbonate, alkali metal carbonates such as sodium carbonate and calcium carbonate, calcium carbonate And alkaline earth metal carbonates such as barium carbonate, and phosphates such as sodium phosphate and potassium phosphate. Among these, alkali metal bicarbonate, alkali metal carbonate, and phosphate are preferable.
The amount of the base to be used is generally 0.1 to 50 mol times, preferably 1 to 20 mol times, more preferably 2 to 10 mol times based on the compound (1-4). Amount.

In addition, WO2007 / 021107 and Tetrahedron Letters, Vol. 33, Issue 20, May 12, 1992, pages 2773-2776, and the like.

In the cross-coupling reaction, in order to selectively produce a homo-coupled product represented by the general formulas (1-2) to (5-2) as a by-product, the general formulas (1-2) to (5-2) The material that gives a homo-coupled body represented by the formula (1) is equal to or more than the equivalent of the material to be paired in the cross-coupling reaction, preferably 1.1 to 10 times equivalent, more preferably 1.1 to 2 times equivalent, More preferably, 1.1 to 1.2 times equivalent is used. Alternatively, it is preferable to select a material having a group containing a metal atom, such as an organic boron compound, as the material that provides the homocoupled body represented by the general formulas (1-2) to (5-2).

After the cross-coupling reaction, purification by column chromatography, recrystallization or the like may be performed. The impurity content that changes the performance of the light-emitting element can be reduced to an allowable amount or less by purification.

[Light emitting element]
The light emitting device of the present invention is a light emitting device having at least one organic layer, and the light emitting device material of the present invention is included in at least one layer of the organic layer.
The content of the light emitting device material of the present invention in the organic layer is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and 99% by mass or more and 100% by mass. More preferably, it is at most mass%. In addition, when used as a light emitting layer, it can be used together with a light emitting material, but the content of a light emitting element material other than the light emitting material is preferably 90% by mass or more and 100% by mass or less, and 95% by mass or more. More preferably, it is 100 mass% or less, More preferably, it is 99 mass% or more and 100 mass% or less.

Although the aspect of the light emitting element of this invention is not limited, An organic electroluminescent element, a luminescent organic field effect transistor, etc. are mentioned.
Preferably, the organic electroluminescent element emits light when an organic layer is sandwiched between a pair of electrodes and a voltage is applied between the electrodes.

[Organic electroluminescence device]
In the organic electroluminescent element, at least one of the organic layers is a light emitting layer, and can further have a plurality of organic layers.
FIG. 1 shows an example of the configuration of an organic electroluminescent device according to the present invention. An organic electroluminescent element 10 according to the present invention shown in FIG. 1 has a pair of electrodes (anode 3 and cathode 9) on a substrate 2, and a light emitting layer 6 between the pair of electrodes. Specifically, a hole injection layer 4, a hole transport layer 5, a light emitting layer 6, a hole block layer 7, and an electron transport layer 8 are provided in this order between the anode 3 and the cathode 9.
In view of the properties of the element, at least one of the anode and the cathode is preferably transparent or translucent.

<Structure of organic layer>
There is no restriction | limiting in particular as a layer structure of the said organic layer, According to the use and objective of an organic electroluminescent element, it can select suitably. It is preferably formed on the anode or the cathode. In this case, the organic layer is formed on the front surface or one surface on the anode or the cathode.
There is no restriction | limiting in particular about the shape of a organic layer, a magnitude | size, thickness, etc., According to the objective, it can select suitably.

Specific examples of the layer configuration include the following, but the present invention is not limited to these configurations.
Anode / hole transport layer / light emitting layer / electron transport layer / cathode,
Anode / hole transport layer / light emitting layer / block layer / electron transport layer / cathode,
Anode / hole transport layer / light emitting layer / block layer / electron transport layer / electron injection layer / cathode,
Anode / hole injection layer / hole transport layer / light emitting layer / block layer / electron transport layer / cathode,
Anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode,
Anode / hole injection layer / hole transport layer / light emitting layer / block layer / electron transport layer / electron injection layer / cathode.
The element configuration, the substrate, the cathode, and the anode of the organic electroluminescence element are described in detail in, for example, Japanese Patent Application Laid-Open No. 2008-270736, and the matters described in the publication can be applied to the present invention.

In the organic electroluminescence device, the light emitting device material of the present invention may be contained in any layer of the organic layer. Preferably, it is used for any of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer, and more preferably for a hole transport layer, a light emitting layer, and an electron transport layer. More preferably, it is used for the light emitting layer.
When the light-emitting element material of the present invention is contained in the light-emitting layer, the light-emitting element material of the present invention is preferably included in an amount of 10 to 99% by mass, and preferably 40 to 95% by mass with respect to the total mass of the light-emitting layer. Is more preferable, and 70 to 90% by mass is even more preferable.
When the light emitting device material of the present invention is contained in a layer other than the light emitting layer, it is preferably contained in an amount of 60 to 100% by mass, more preferably 70 to 100% by mass, and more preferably 85 to 100% by mass. More preferably.

<Board>
The substrate is preferably a substrate that does not scatter or attenuate light emitted from the organic layer. In the case of an organic material, it is preferable that it is excellent in heat resistance, dimensional stability, solvent resistance, electrical insulation, and workability.
<Anode>
The anode usually only needs to have a function as an electrode for supplying holes to the organic layer, and there is no particular limitation on the shape, structure, size, etc., depending on the use and purpose of the light-emitting element, It can select suitably from well-known electrode materials. As described above, the anode is usually provided as a transparent anode.
<Cathode>
The cathode usually has a function as an electrode for injecting electrons into the organic layer, and there is no particular limitation on the shape, structure, size, etc., and it is known depending on the use and purpose of the light-emitting element. The electrode material can be selected as appropriate.
Regarding the substrate, anode, and cathode, the matters described in paragraph numbers [0070] to [0089] of JP-A-2008-270736 can be applied to the present invention.

<Organic layer>-Formation of organic layer-
In the organic electroluminescent element, each organic layer can be suitably formed by any of dry film forming methods such as vapor deposition and sputtering, wet film forming methods such as solution coating, transfer methods, and printing methods.

(Light emitting layer)
<Light emitting material>
The light emitting material in the light emitting layer of the organic electroluminescent element of the present invention is preferably a phosphorescent light emitting material, and preferably an iridium complex and a platinum complex.

The light emitting material in the light emitting layer is preferably contained in an amount of 0.1% by mass to 50% by mass with respect to the mass of all compounds generally forming the light emitting layer in the light emitting layer. In view of the above, the content is more preferably 1% by mass to 50% by mass, and further preferably 2% by mass to 40% by mass.
The phosphorescent light emitting material in the light emitting layer is preferably contained in the light emitting layer in an amount of 1% by mass to 30% by mass, and more preferably 2% by mass to 20% by mass from the viewpoint of durability and emission hue.

The thickness of the light emitting layer is not particularly limited, but is usually preferably 2 nm to 500 nm, and more preferably 3 nm to 200 nm, and more preferably 5 nm to 100 nm from the viewpoint of external quantum efficiency. More preferably.

The light emitting layer may be composed of only a light emitting material, or may be a mixed layer of a host material and a light emitting material. The light emitting material may be a fluorescent light emitting material or a phosphorescent light emitting material, and the dopant may be one kind or two or more kinds.
The host material is preferably a charge transport material. The host material may be one kind or two or more kinds, and examples thereof include a configuration in which an electron transporting host material and a hole transporting host material are mixed. Furthermore, the light emitting layer may include a material that does not have charge transporting properties and does not emit light.
Further, the light emitting layer may be composed of a plurality of layers, and when the light emitting layer is composed of a plurality of layers, the respective emission colors may be the same or different.

<Host material>
The host material used in the present invention may contain the following compounds. For example, pyrrole, indole, carbazole (eg, CBP (4,4′-di (9-carbazoyl) biphenyl)), azaindole, azacarbazole, triazole, oxazole, oxadiazole, pyrazole, imidazole, thiophene, polyarylalkane, Pyrazoline, pyrazolone, phenylenediamine, arylamine, amino-substituted chalcone, styrylanthracene, fluorenone, hydrazone, stilbene, silazane, aromatic tertiary amine compound, styrylamine compound, porphyrin compound, polysilane compound, poly (N-vinyl) Carbazole), aniline copolymers, thiophene oligomers, conductive polymer oligomers such as polythiophene, organic silane, carbon film, pyridine, pyrimidine, triazine, imidazo , Pyrazole, triazole, oxazole, oxadiazol, fluorenone, anthraquinodimethane, anthrone, diphenylquinone, thiopyran dioxide, carbodiimide, fluorenylidenemethane, distyrylpyrazine, fluorine-substituted aromatic compounds , Metal complexes of heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene, phthalocyanines, 8-quinolinol derivatives and metal complexes represented by metal phthalocyanines, benzoxazoles and benzothiazoles as metal ligands And derivatives thereof (which may have a substituent or a condensed ring).

In the light emitting layer, the triplet minimum excitation energy (T ₁ energy) of the host material is preferably higher than the T ₁ energy of the phosphorescent light emitting material in terms of color purity, light emission efficiency, and driving durability.

The content of the host compound is not particularly limited, but is preferably 15% by mass or more and 95% by mass or less with respect to the total compound mass forming the light emitting layer, from the viewpoint of luminous efficiency and driving voltage.

(Fluorescent material)
Examples of fluorescent materials that can be used in the present invention include, for example, benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives. , Condensed aromatic compounds, perinone derivatives, oxadiazole derivatives, oxazine derivatives, aldazine derivatives, pyralidine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, cyclopentadiene derivatives, styryl Complexes of amine derivatives, diketopyrrolopyrrole derivatives, aromatic dimethylidin compounds, 8-quinolinol derivatives and pyromethene derivatives Various complexes represented, polythiophene, polyphenylene, polyphenylene vinylene polymer compounds include compounds such as organic silane derivatives.

(Phosphorescent material)
Examples of phosphorescent light-emitting materials that can be used in the present invention include US Pat. / 19373A2, JP-A No. 2001-247859, JP-A No. 2002-302671, JP-A No. 2002-117978, JP-A No. 2003-133074, JP-A No. 2002-1235076, JP-A No. 2003-123684, JP-A No. 2002-170684, EP No. 121157, JP-A No. 2002 -226495, JP 2002-234894, JP 2001-247859, JP 2001-298470, JP 2002-17367 , JP 2002-203678, JP 2002-203679, JP 2004-357799, JP 2006-256999, JP 2007-19462, JP 2007-84635, JP 2007-96259, and the like. Examples of such a luminescent dopant include Ir complex, Pt complex, Cu complex, Re complex, W complex, Rh complex, Ru complex, Pd complex, Os complex, Eu complex, Tb complex, among others. Gd complex, Dy complex, and Ce complex are mentioned. Particularly preferred is an Ir complex, a Pt complex, or a Re complex, among which an Ir complex or a Pt 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. Or Re complexes are preferred. Furthermore, from the viewpoints of luminous efficiency, driving durability, chromaticity, etc., an Ir complex, a Pt complex, or a Re complex containing a tridentate or higher polydentate ligand is particularly preferable.

-Hole injection layer, hole transport layer-
The hole injection layer and the hole transport layer are layers having a function of receiving holes from the anode or the anode side and transporting them to the cathode side.
In the present invention, the organic layer preferably includes a hole injection layer or a hole transport layer containing an electron-accepting dopant.

-Electron injection layer, electron transport layer-
The electron injection layer and the electron transport layer are layers having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side.

Regarding the hole injection layer, the hole transport layer, the electron injection layer, and the electron transport layer, the matters described in paragraph numbers [0165] to [0167] of JP-A-2008-270736 can be applied to the present invention. .

-Hole blocking layer-
The hole blocking layer is a layer having a function of preventing holes transported from the anode side to the light emitting layer from passing through to the cathode side. In the present invention, a hole blocking layer can be provided as an organic layer adjacent to the light emitting layer on the cathode side.
Examples of organic compounds constituting the hole blocking layer include aluminum (III) bis (2-methyl-8-quinolinato) 4-phenylphenolate (Aluminum (III) bis (2-methyl-8-quinolinato) 4- aluminum complexes such as phenylphenolate (abbreviated as BAlq), triazole derivatives, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (2,9-Dimethyl-4,7-diphenyl-1,10-) phenanthroline derivatives such as phenanthroline (abbreviated as BCP)) and the like.
The thickness of the hole blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and even more preferably 10 nm to 100 nm.
The hole blocking layer may have a single layer structure made of one or more of the materials described above, or may have a multilayer structure made of a plurality of layers having the same composition or different compositions.

-Electronic block layer-
The electron blocking layer is a layer having a function of preventing electrons transported from the cathode side to the light emitting layer from passing through to the anode side. In the present invention, an electron blocking layer can be provided as an organic layer adjacent to the light emitting layer on the anode side.
As an example of the organic compound constituting the electron blocking layer, for example, those mentioned as the hole transport material described above can be applied.
The thickness of the electron blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and even more preferably 10 nm to 100 nm.
The electron blocking layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

<Protective layer>
The entire organic light emitting device may be protected by a protective layer.
As for the protective layer, the matters described in JP-A-2008-270736, paragraphs [0169] to [0170] can be applied to the present invention.

<Sealing container>
The element of this invention may seal the whole element using a sealing container.
Regarding the sealing container, the matters described in paragraph [0171] of JP-A-2008-270736 can be applied to the present invention.

(Drive)
The organic electroluminescence device of the present invention emits light by applying a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode. Obtainable.
The driving method of the organic electroluminescence device of the present invention is described in JP-A-2-148687, JP-A-6-301355, JP-A-5-290080, JP-A-7-134558, JP-A-8-234585, and JP-A-8-2441047. The driving methods described in each publication, Japanese Patent No. 2784615, US Pat. Nos. 5,828,429 and 6,023,308 can be applied.

The organic electroluminescence device of the present invention can improve the light extraction efficiency by various known devices. For example, by processing the substrate surface shape (for example, forming a fine concavo-convex pattern), controlling the refractive index of the substrate / ITO layer / organic layer, controlling the film thickness of the substrate / ITO layer / organic layer, etc. It is possible to improve light extraction efficiency and external quantum efficiency.

The organic electroluminescent element of the present invention may be a so-called top emission method in which light emission is extracted from the anode side.

The organic electroluminescent element in the present invention may have a resonator structure. For example, a multilayer mirror made of a plurality of laminated films having different refractive indexes, a transparent or translucent electrode, a light emitting layer, and a metal electrode are superimposed on a transparent substrate. The light generated in the light emitting layer resonates repeatedly with the multilayer mirror and the metal electrode as a reflection plate.
In another preferred embodiment, a transparent or translucent electrode and a metal electrode each function as a reflecting plate on a transparent substrate, and light generated in the light emitting layer repeats reflection and resonates between them.
In order to form a resonant structure, the optical path length determined from the effective refractive index of the two reflectors and the refractive index and thickness of each layer between the reflectors is adjusted to an optimum value to obtain the desired resonant wavelength. Is done. The calculation formula in the case of the first embodiment is described in JP-A-9-180883. The calculation formula in the case of the second embodiment is described in Japanese Patent Application Laid-Open No. 2004-127795.

The external quantum efficiency of the organic electroluminescent element of the present invention is preferably 5% or more, more preferably 10% or more, and particularly preferably 17% or more. The value of the external quantum efficiency should be the maximum value of the external quantum efficiency when the device is driven at 20 ° C., or the value of the external quantum efficiency near 100 to 300 cd / m ² when the device is driven at 20 ° C. Can do.

The internal quantum efficiency of the organic electroluminescence device of the present invention is preferably 30% or more, more preferably 50% or more, and further preferably 70% or more. The internal quantum efficiency of the device is calculated by dividing the external quantum efficiency by the light extraction efficiency. In a normal organic EL element, the light extraction efficiency is about 20%. However, the shape of the substrate, the shape of the electrode, the thickness of the organic layer, the thickness of the inorganic layer, the refractive index of the organic layer, the refractive index of the inorganic layer, etc. By devising it, it is possible to increase the light extraction efficiency to 20% or more.

The organic electroluminescent element of the present invention preferably has an emission maximum wavelength (maximum intensity wavelength of emission spectrum) at 350 nm or more and 700 nm or less, more preferably 400 nm or more and 650 nm or less, and more preferably 400 nm or more and 520 nm or less as a blue light emitting element. In particular, it is 400 nm to 470 nm, preferably 470 nm to 520 nm, particularly preferably 490 nm to 510 nm as a green light emitting element, and preferably 550 nm to 650 nm, particularly preferably 590 nm to 630 nm as a red light emitting element. It is.

(Use of the organic electroluminescence device of the present invention)
The organic electroluminescent element of the present invention is suitable for light emitting devices, pixels, display elements, displays, backlights, electrophotography, illumination light sources, recording light sources, exposure light sources, reading light sources, signs, signboards, interiors, optical communications, etc. Available. In particular, it is preferably used for a device that is driven in a region where light emission luminance is high, such as a light emitting device, a lighting device, and a display device.

Next, the light emitting device of the present invention will be described with reference to FIG.
The light emitting device of the present invention uses the organic electroluminescent element.
FIG. 2 is a cross-sectional view schematically showing an example of the light emitting device of the present invention.
The light emitting device 20 in FIG. 2 includes a transparent substrate (support substrate) 2, an organic electroluminescent element 10, a sealing container 16, and the like.

The organic electroluminescent device 10 is configured by sequentially laminating an anode (first electrode) 3, an organic layer 11, and a cathode (second electrode) 9 on a substrate 2. A protective layer 12 is laminated on the cathode 9, and a sealing container 16 is provided on the protective layer 12 with an adhesive layer 14 interposed therebetween. In addition, a part of each

electrode

3 and 9, a partition, an insulating layer, etc. are abbreviate | omitted.
Here, as the adhesive layer 14, a photocurable adhesive such as an epoxy resin or a thermosetting adhesive can be used, and for example, a thermosetting adhesive sheet can also be used.

The use of the light-emitting device of the present invention is not particularly limited, and for example, it can be a display device such as a television, a personal computer, a mobile phone, and electronic paper in addition to a lighting device.

(Lighting device)
Next, an illumination device according to an embodiment of the present invention will be described with reference to FIG.
FIG. 3 is a cross-sectional view schematically showing an example of a lighting device according to an embodiment of the present invention.
As shown in FIG. 3, the illumination device 40 according to the embodiment of the present invention includes the organic EL element 10 and the light scattering member 30 described above. More specifically, the lighting device 40 is configured such that the substrate 2 of the organic EL element 10 and the light scattering member 30 are in contact with each other.
The light scattering member 30 is not particularly limited as long as it can scatter light. In FIG. 3, the light scattering member 30 is a member in which fine particles 32 are dispersed on a transparent substrate 31. As the transparent substrate 31, for example, a glass substrate can be preferably cited. As the fine particles 32, transparent resin fine particles can be preferably exemplified. As the glass substrate and the transparent resin fine particles, known ones can be used. In such an illuminating device 40, when light emitted from the organic electroluminescent element 10 is incident on the light incident surface 30A of the scattering member 30, the incident light is scattered by the light scattering member 30, and the scattered light is emitted from the light emitting surface 30B. It is emitted as illumination light.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention is not limited to the following examples.

<Example 1>
[Synthesis example]
[Synthesis of Cross Coupling Body 4]
Intermediate 1, Intermediate 2, Intermediate 3, and Cross Coupling 4 were synthesized by the following synthesis routes 1 to 3. Here, Intermediate 1 was synthesized by the method described on page 100 of WO2006 / 062062, and Intermediate 2 was synthesized by the method described on page 102 of WO2006 / 062062. Intermediate 3 was synthesized from tert-butylcarbazole described on page 28 of WO2006 / 070185 in the same manner as intermediate 1-1.
Intermediate 2 (28.7 g, 0.1 mol), Intermediate 3 (37.8 g, 0.1 mol), palladium acetate (0.22 g, 1 mmol), triphenylphosphine (1.05 g, 4 mmol) , Sodium carbonate (31.8 g, 0.3 mol), THF (tetrahydrofuran) (200 mL) and water (200 mL) were heated to reflux for 4 hours under a nitrogen atmosphere, cooled to room temperature, the aqueous layer was removed, After washing the organic layer with saturated saline, THF is distilled off and concentrated, and then hexane and acetonitrile are added. The precipitate is filtered, washed with acetonitrile, dried under reduced pressure, and cross-coupled. Body 4 was obtained. Yield 49.4 g, 91% yield. HPLC area 97.8% (content of homo-coupled 4-a was 1.4% by mass relative to cross-coupled 4).

NMR data of the obtained cross coupling body 4 are shown below. δ (ppm, in heavy DMSO) 8.30 (s, 1H), 8.24 (d, 3H), 8.06 (d, 2H), 7.96 (t, 2H), 7.79 (dt, 2H), 7.66 (d, 2H), 7.52-5.39 (m, 8H), 7.29 (t, 2H), 7.27 (t, 1H), 1.41 (s, 18H) )

[Synthesis of homo-coupled body 4-a]
Homocoupled 4-a was synthesized by the following reaction. By using Intermediate 1 and Intermediate 2, homo-coupled 4-a was synthesized in the same manner as the synthesis of cross-coupling 4 described above.

The NMR data of the obtained homocoupled body 4-a are shown below. δ (ppm, in heavy DMSO) 8.26 (d, 4H), 8.07 (s, 2H), 7.97 (d, 2H), 7.80 (t, 2H), 7.67 (d, 2H), 7.49 (d, 4H), 7.44 (t, 4H), 7.30 (t, 4H)

[Synthesis of homo-coupled body 4-b]
Homocoupled 4-b was synthesized by the following reaction. Intermediate 4 was synthesized from intermediate 3 in the same manner as intermediate 2.
By using Intermediate 3 and Intermediate 4, homo-coupled 4-b was synthesized by the same method as the synthesis of cross-coupling 4 described above.

The NMR data of the obtained homocoupled body 4-b is shown below. δ (ppm, in heavy DMSO) 8.28 (d, 2H), 8.24 (s, 2H), 8.05 (s, 2H), 7.95 (d, 2H), 7.79 (t, 2H), 7.66 (d, 2H), 7.51 (dd, 2H), 7.48 (d, 2H), 7.42 (d, 2H), 7.41 (t, 2H), 7. 27 (t, 2H), 1.41 (s, 18H)

[Synthesis of Cross Coupling Body 6]
A cross coupling body 6 was synthesized by the following synthesis route 4. Here, the intermediate 5 is prepared according to J.I. Am. Chem. Soc. , 1986, 108 (19), pp. Synthesized from carbazole and bromofluorobenzonitrile according to the method described in 5991-5997.
By using the intermediate body 2 and the intermediate body 5, the cross coupling body 6 was synthesized by the same method as the synthesis of the cross coupling body 4 described above. The content of the homo-coupled body 6-a with respect to the cross-coupled body 6 was 1.5% by mass.

NMR data of the obtained cross coupling body 6 are shown below. δ (ppm in deuterated chloroform) 8.16 (d, 4H), 8.12 (s, 1H), 8.00 (s, 1H), 7.91 (s, 1H), 7.85 (s, 1H), 7.76 (t, 1H), 7.72 (d, 1H), 7.69 (d, 1H), 7.48-7.41 (m, 8H), 7.38-7.29 (M, 4H)

[Synthesis of homo-coupled bodies 6-a and 6-b]
Homocouple 6-a was synthesized in the same manner as homocouple 4-a.
Homocoupled body 6-b was synthesized by the following method. Intermediate 6 was synthesized from intermediate 5 by the method described on page 100 of WO 2006/062062.
By using the intermediate body 5 and the intermediate body 6, the homocoupled body 6-b can be synthesized by the same method as the synthesis of the cross coupling body 4 described above.

The NMR data of the obtained homocoupled body 6-b are shown below. δ (ppm, in heavy DMSO) 8.62 (s, 2H), 8.61 (s, 2H), 8.26 (s, 2H), 8.26 (d, 4H), 7.54 (d, 4H), 7.46 (d, 4H), 7.33 (d, 4H)

[Synthesis of Cross Coupling Body 10]
The cross coupling body 10 was synthesized by the following synthesis route 5 by the method described in paragraph [0080] of JP-A No. 2007-266598.

The content of the homo-coupled body 10-a with respect to the cross-coupled body 10 after synthesis was 2% by mass. Moreover, the NMR data of the obtained cross coupling body 10 are shown below.
δ (ppm, in deuterated chloroform) 7.33 (m, 2H), 7.43-7.50 (m, 4H), 7.54-7.62 (m, 6H), 7.64-7.74 (M, 7H), 7.82-7.85 (m, 2H)

[Synthesis of homo-coupled body 10-a]
Homocouple 10-a is described in Chemical & Pharmaceutical Bulletin, 1982, vol. 30, # 7, p. It was synthesized by the method described in 2369-2379.

[Synthesis of Cross Coupling Body 12]
The cross-coupled body 12 was synthesized by the following synthesis routes 6-8.

In Synthesis Route 8, the content of homo-coupled body 12-a with respect to cross-coupled body 12 after synthesis was 1% by mass. The NMR data of the obtained cross coupling body 12 are shown below.
δ (ppm, in heavy DMSO) 9.17 (s, 1H), 9.08 (d, 1H), 8.92 (s, 1H), 8.90-8.81 (m, 3H), 8. 31 (s, 1H), 8.17 (s, 1H), 8.13 (s, 1H), 8.00 (d, 1H), 7.93 (d, 2H), 7.97 (t, 2H) ), 7.81 (d, 2H), 7.79-7.75 (m, 7H), 7.70 (t, 1H), 7.66 (t, 1H), 7.50 (t, 2H) 7.40 (t, 1H)

[Synthesis of homo-coupled body 12-a]
Homocouple 12-a was synthesized by Suzuki coupling of intermediate 7 and its precursor bromide. The NMR data of homo-coupled body 12-a is shown below.
δ (ppm, deuterated chloroform) 8.94 (s, 2H), 8.80-8.74 (m, 4H), 8.73-8.68 (m, 6H), 8.12 (s, 2H ), 8.00 (d, 2H), 7.87 (d, 2H), 7.79 (d, 2H), 7.72-7.67 (m, 10H)

[Purification of cross-coupled body]
The cross coupling body 4 was synthesized by the following synthesis route 9.

Intermediate 1 (12.0 g, 0.037 mol), Intermediate 4 (12.8 g, 0.037 mol), palladium acetate (0.21 g, 0.9 mmol), triphenylphosphine (0.98 g, 4 Mmol), sodium carbonate (19.8 g, 0.19 mol), DME (dimethyl ether) (370 mL) and water (370 mL) were heated to reflux for 4 hours under a nitrogen atmosphere, cooled to room temperature, the aqueous layer was removed, 200 mL of isopropanol was added, and the precipitated gray powder was separated by filtration. A solution obtained by dissolving the obtained powder in toluene and filtering through a silica gel column was concentrated to about 50 mL, crystallized by adding isopropanol, and the precipitated gray powder was separated by filtration. It dried under reduced pressure and the cross coupling body 4 was obtained. Yield 16.8 g, 84% yield. HPLC area 97.4% (the content of homo-coupled body 4-a is 0.9% by mass and the content of homo-coupled body 4-b is 1.3% by mass relative to cross-coupled body 4) All other impurities were 0.5% by mass or less).
The operation of dissolving this synthetic crude product in toluene and crystallizing with isopropanol was further repeated twice. Finally, sublimation purification was performed at 270 ° C. under a reduced pressure of 0.54 Pa. The purity of the obtained material after each crystallization and after sublimation purification is shown in Table 1 below.

As described above, in order to reduce impurities contained in the cross-coupled body to less than 0.5% by mass, the crystallization process must be repeated, and the addition of an excessive purification process increases the manufacturing cost of the material. Let

Ionization potentials of the

cross-coupled bodies

4, 6, 10 and 12 synthesized as described above and the homo-coupled bodies 4-a, 4-b, 6-a, 6-b, 10-a and 12-a The electron affinity and the excitation energy of the triplet state were examined as follows.
For cross-coupled bodies (Exemplified compounds 4, 6, 10 and 12), in order to eliminate the influence of homo-coupled bodies, crystallization, recrystallization, column chromatography, and sublimation purification were repeated, A compound having a content of 99.9% by mass or more was obtained.
The resulting cross-coupling member, the homo-coupled compounds, each, by vacuum evaporation on a quartz substrate, and a thin film having a thickness of 50 nm, ionization potential Ip, excitation energy T ₁ of the electron affinity Ea and triplet states Was measured.
The ionization potential Ip was measured using an atmospheric photoelectron spectroscopy (PES) apparatus AC-2 manufactured by Riken Keiki Co., Ltd.
The electron affinity Ea is calculated from the energy level Eg corresponding to the short wavelength end of the absorption spectrum of the thin film on the quartz substrate using the spectrophotometer U-3310 (Hitachi High-Technologies) and Ea = Ip− It calculated | required with the calculation formula of Eg.
The excitation energy T _{1 in the} triplet state was measured using the F-7000 Hitachi spectrofluorometer (Hitachi High-Technologies) at a liquid nitrogen temperature, and the phosphorescence emission spectrum of the thin film was measured on the short wavelength side of the obtained emission spectrum. The T ₁ energy was determined by converting the rising wavelength into energy units.
The measurement results are shown in Table 2 below.

In Table 2, (O) in the column of Ip indicates that the ionization potential Ip (2) of the homo-coupling body satisfies Ip (1) ≦ Ip (2) with respect to the ionization potential Ip (1) of the cross-coupling body. (X) indicates that Ip (1) ≦ Ip (2) is not satisfied.
(O) in the column of Ea indicates that the electron affinity Ea (2) of the homo-coupled body satisfies Ea (1) ≧ Ea (2) with respect to the electron affinity Ea (1) of the cross-coupled body. (X) represents that Ea (1) ≧ Ea (2) is not satisfied.
T ₁ of the column (○), the excitation energy T ₁ of the triplet state of the homo-coupled compounds with respect to the excitation energy T ₁ of the triplet state of the cross-coupling member (1) (2) T ₁ (1 ) ≦ T ₁ (2) is satisfied, and (×) indicates that T ₁ (1) ≦ T ₁ (2) is not satisfied.

<Example 2>
[Production of element]
A glass substrate having a ITO film with a thickness of 0.7 mm and a 2.5 cm square (manufactured by Geomat Co., Ltd., surface resistance 10Ω / □) is placed in a cleaning container, ultrasonically cleaned in 2-propanol, and then treated with UV-ozone for 30 minutes. Went. The following organic compound layers were sequentially deposited on the transparent anode (ITO film) by vacuum deposition.
First layer: NPD: film thickness 40 nm
Second layer: material X and luminescent material (mass ratio 90:10): film thickness 30 nm
Third layer: CBP: film thickness 5 nm
Fourth layer: BAlq: film thickness 45 nm
On this, 1 nm of lithium fluoride and 70 nm of metal aluminum were vapor-deposited in this order, and it was set as the cathode.
This is put in a glove box substituted with nitrogen gas without being exposed to the atmosphere, and sealed with a glass sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba Co., Ltd.). Thus, each organic electroluminescent element shown in Table 3 was obtained.
As a result of light emission of these elements, light emission derived from the light emitting material was obtained for each element.
In addition, in order to investigate the influence of a homo-coupled body, the content of the homo-coupled body in the material X was prepared by adding a single homo-coupled body. In Table 3, content (mass%) of the homo coupling body with respect to an exemplary compound is shown.

(Performance evaluation of organic electroluminescence device)
For each of the obtained devices, the driving voltage, external quantum efficiency and driving durability were measured to evaluate the performance of the device. Various measurements were performed as follows. The results are shown in Table 3.
(A) Driving voltage Each element was set in an emission spectrum measurement system (ELS1500) manufactured by Shimadzu Corporation, and an applied voltage at a luminance of 1000 cd / m ² was measured. The drive voltage of Comparative Example 1 was used as a reference value and evaluated according to the following criteria.
A: The driving voltage does not change with respect to the reference value.
○: The drive voltage was changed higher than 0% and 5% or less higher than the reference value.
Δ: The driving voltage was changed more than 5% and 15% or less higher than the reference value.
X: The drive voltage changed by more than 15% with respect to the reference value.
(B) External quantum efficiency Using a source measure unit 2400 manufactured by Toyo Technica, a direct current voltage was applied to each element to emit light, and the luminance was measured using a luminance meter BM-8 manufactured by Topcon Corporation. The emission spectrum and emission wavelength were measured using a spectrum analyzer PMA-11 manufactured by Hamamatsu Photonics. Based on these, the external quantum efficiency at a luminance of around 1000 cd / m ² was calculated by the luminance conversion method. The external quantum efficiency of Comparative Example 1 was evaluated using the following criteria as a reference value.
A: The external quantum efficiency does not change with respect to the reference value.
○: External quantum efficiency decreased by more than 0% and 5% or less with respect to the reference value.
(Triangle | delta): External quantum efficiency fell 15% or less over 5% with respect to a reference value.
X: External quantum efficiency fell more than 15% with respect to a reference value.
(C) Initial luminance decay time (drive durability)
Each element brightness applying a DC voltage to be 5000 cd / ^{m 2,} the time was measured until the brightness is 4000 cd / ^{m 2.} This luminance half time was used as an index for evaluating driving durability. Evaluation was made according to the following criteria using the decay time of Comparative Example 1 as a reference value.
A: The decay time does not change with respect to the reference value.
○: Decay time was shorter than 0% and 5% or shorter than the reference value.
(Triangle | delta): Decay time became short 15% or less over 5% with respect to the reference value.
X: Decay time was shortened by more than 15% with respect to the reference value.

From Table 3, more than 0.5% by mass of the homo-coupled body in which the ionization potential, the electron affinity, and / or the excitation energy of the triplet state are in a specific relationship with respect to the specific cross-coupled body (exemplary compound) It can be seen that an element using a material containing 10% by mass or less has a small variation in driving voltage, external quantum efficiency, and driving durability. Since this material does not need to excessively purify the homo-coupled body, the purification cost and load can be suppressed.

<Example 3>
[Production of element]
In the fabrication of the device of Example 2, the device was fabricated in the same manner except that the material X was changed to that of Table 4, and the driving voltage, the external quantum efficiency and the comparative examples 2 and 3 and Reference Example 1 were used as a reference. The initial luminance decay time was evaluated. The evaluation results are shown in Table 4.

From Table 4, more than 0.5% by mass of the homo-coupled body in which the ionization potential, the electron affinity, and / or the excitation energy of the triplet state are in a specific relationship with respect to the specific cross-coupled body (exemplary compound) It can be seen that an element using a material containing 10% by mass or less has a small variation in driving voltage, external quantum efficiency, and driving durability. Since this material does not need to excessively purify the homo-coupled body, the purification cost and load can be suppressed.

<Example 4>
[Production of element]
A glass substrate having a ITO film with a thickness of 0.7 mm and a 2.5 cm square (manufactured by Geomat Co., Ltd., surface resistance 10Ω / □) is placed in a cleaning container, subjected to ultrasonic cleaning in 2-propanol, and then subjected to UV-ozone treatment for 30 minutes. Went. The following organic compound layers were sequentially deposited on the transparent anode (ITO film) by vacuum deposition.
First layer: NPD: film thickness 40 nm
Second layer: CBP and luminescent material (mass ratio 90:10): film thickness 30 nm
Third layer: Material X: film thickness 5 nm
Fourth layer: BAlq: film thickness 45 nm
On this, 1 nm of lithium fluoride and 70 nm of metal aluminum were vapor-deposited in this order, and it was set as the cathode.
This is put in a glove box substituted with nitrogen gas without being exposed to the atmosphere, and sealed with a glass sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba Co., Ltd.). Thus, each organic electroluminescent element shown in Table 5 was obtained.
As a result of light emission of these elements, light emission derived from the light emitting material was obtained for each element.
In addition, in order to investigate the influence of a homo-coupled body, the content of the homo-coupled body in the material X was prepared by adding a single homo-coupled body. In Table 5, content (mass%) of the homo coupling body with respect to an exemplary compound is shown.
With respect to each of the obtained devices, the driving voltage, the external quantum efficiency, and the initial luminance decay time were evaluated based on Comparative Example 4 and Reference Example 2. The evaluation results are shown in Table 5.

From Table 5, more than 0.5% by mass of the homo-coupled body in which the ionization potential, the electron affinity, and / or the excitation energy of the triplet state are in a specific relationship with respect to the specific cross-coupled body (exemplary compound) It can be seen that an element using a material containing 10% by mass or less has a small variation in driving voltage, external quantum efficiency, and driving durability. Since this material does not need to excessively purify the homo-coupled body, the purification cost and load can be suppressed.

<Example 5>
[Production of element]
A glass substrate having a ITO film with a thickness of 0.7 mm and a 2.5 cm square (manufactured by Geomat Co., Ltd., surface resistance 10Ω / □) is placed in a cleaning container, subjected to ultrasonic cleaning in 2-propanol, and then subjected to UV-ozone treatment for 30 minutes. Went. The following organic compound layers were sequentially deposited on the transparent anode (ITO film) by vacuum deposition.
First layer: Material X: film thickness 40 nm
Second layer: CBP and luminescent material (mass ratio 90:10): film thickness 30 nm
Third layer: CBP: film thickness 5 nm
Fourth layer: BAlq: film thickness 45 nm
On this, 1 nm of lithium fluoride and 70 nm of metal aluminum were vapor-deposited in this order, and it was set as the cathode.
This is put in a glove box substituted with nitrogen gas without being exposed to the atmosphere, and sealed with a glass sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba Co., Ltd.). Thus, each organic electroluminescent element described in Table 6 was obtained.
As a result of light emission of these elements, light emission derived from the light emitting material was obtained for each element.
In addition, in order to investigate the influence of a homo-coupled body, the content of the homo-coupled body in the material X was prepared by adding a single homo-coupled body. In Table 6, content (mass%) of the homo coupling body with respect to an exemplary compound is shown.
About each obtained element, the drive voltage, the external quantum efficiency, and the initial luminance decay time were evaluated using Comparative Example 5 as a reference. The evaluation results are shown in Table 6.

From Table 6, more than 0.5% by mass of the homocoupled body in which the ionization potential, the electron affinity, and / or the excitation energy of the triplet state are in a specific relationship with respect to the specific cross-coupled body (exemplary compound) It can be seen that an element using a material containing 10% by mass or less has a small variation in driving voltage, external quantum efficiency, and driving durability. Since this material does not need to excessively purify the homo-coupled body, the purification cost and load can be suppressed.

<Example 6>
[Production of element]
A glass substrate having a 0.7 mm thickness and a 2.5 cm square ITO film (manufactured by Geomatech Co., Ltd., surface resistance 10 Ω / □) is placed in a cleaning container, subjected to ultrasonic cleaning in 2-propanol, and then subjected to UV-ozone treatment for 30 minutes. Went. A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS) to 70% with pure water was applied to this with a spin coater to provide a 50 nm hole transport layer. A methylene chloride solution in which the material X and the light emitting material (mass ratio 95: 5) were dissolved was applied with a spin coater to obtain a light emitting layer having a thickness of 30 nm. On this, BAlq was vapor-deposited 40 nm. On the organic compound layer, 1 nm of lithium fluoride as a cathode buffer layer and 70 nm of aluminum as a cathode were deposited in a deposition apparatus. Without exposing it to the atmosphere, put it in a glove box substituted with argon gas and seal it with a stainless steel sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba Co., Ltd.) Each organic electroluminescent element shown in Table 7 was produced. As a result of applying a constant DC voltage to the organic EL element to emit light using a source measure unit 2400 type manufactured by Toyo Technica, light emission derived from the light emitting material was obtained.
In addition, in order to investigate the influence of a homo-coupled body, the content of the homo-coupled body in the material X was prepared by adding a single homo-coupled body. In Table 7, content (mass%) of the homo coupling body with respect to an exemplary compound is shown.
About each obtained element, the drive voltage, the external quantum efficiency, and the initial luminance decay time were evaluated using Comparative Example 6 as a reference. Table 7 shows the evaluation results.

From Table 7, more than 0.5% by mass of the homocoupled body in which the ionization potential, the electron affinity, and / or the excitation energy of the triplet state are in a specific relationship with respect to the specific cross-coupled body (exemplary compound) It can be seen that an element using a material containing 10% by mass or less has a small variation in driving voltage, external quantum efficiency, and driving durability. Since this material does not need to excessively purify the homo-coupled body, the purification cost and load can be suppressed.

The compounds used in the examples are shown below.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on June 30, 2010 (Japanese Patent Application No. 2010-150589), the contents of which are incorporated herein by reference.

DESCRIPTION OF SYMBOLS 2 ... Substrate 3 ... Anode 4 ... Hole injection layer 5 ... Hole transport layer 6 ... Light emitting layer 7 ... Hole block layer 8 ... Electron transport layer 9 ...・ Cathode 10: Organic electroluminescent device (organic EL device)
DESCRIPTION OF SYMBOLS 11 ... Organic layer 12 ... Protective layer 14 ... Adhesive layer 16 ... Sealing container 20 ... Light emitting device 30 ... Light scattering member 30A ... Light incident surface 30B ... Light Outgoing surface 32 ... fine particle 40 ... illumination device

Claims

A material for a light-emitting element containing an impurity having a content of more than 0.5% by mass and not more than 10% by mass, wherein the impurity satisfies any two or more of the following conditions [I] to [III]: Material for light emitting element.
[I] The ionization potential Ip (1) of the light emitting element material and the ionization potential Ip (2) of the impurity satisfy Ip (1) ≦ Ip (2).
[II] The electron affinity Ea (1) of the light emitting device material and the electron affinity Ea (2) of the impurity satisfy Ea (1) ≧ Ea (2).
[III] an excited triplet state of the material for a light-emitting element energy T 1 (1), excitation energy T 1 of the triplet state of the impurities and (2), but at T 1 (1) ≦ T 1 (2) .
The light emitting device material according to claim 1, wherein the light emitting device material is represented by the following general formula (1-1), and the impurities are represented by the following general formula (1-2).
(1-1): (A1) n1- (B1)
(1-2): (A1)-(A1)
(Wherein n1 represents an integer of 1 to 10. A1 represents an optionally substituted aryl group having 6 to 30 carbon atoms or heteroaryl group having 2 to 30 carbon atoms. B1 Represents an n1-valent aryl structure having 6 to 30 carbon atoms or a heteroaryl structure having 2 to 30 carbon atoms, which may have a substituent, provided that A1 and B1 are not the same. , A halogen atom, an alkyl group, an alkenyl group, an aryl group, a heteroaryl group, an amino group, an alkoxy group, a silyl group, a carboxyl group, or a cyano group, and each group may be further substituted with these substituents. When a plurality of substituents are present, the substituents may be the same or different.)
The light emitting device material represented by the general formula (1-1) is a cross-coupled body represented by the following general formula (2-1), and the impurity represented by the general formula (1-2) is The light emitting device material according to claim 2, which is a homo-coupled body represented by the following general formula (2-2).
(2-1): (A2) n2- (B2)
(2-2): (A2)-(A2)
(Wherein n2 represents an integer of 1 to 6. A2 represents an optionally substituted aryl group having 6 to 15 carbon atoms or a heteroaryl group having 4 to 15 carbon atoms. B2 represents Represents an n2-valent aryl structure having 6 to 15 carbon atoms or a heteroaryl structure having 3 to 15 carbon atoms which may have a substituent, provided that A2 and B2 are not the same. An atom, an alkyl group, an alkenyl group, an aryl group, a heteroaryl group, an amino group, a silyl group, or a cyano group, and each group may be further substituted with these substituents. And the substituents may be the same or different.)
The cross-coupling body is a cross-coupling body represented by the following general formula (3-1), and the homo-coupling body is a homo-coupling body represented by the following general formula (3-2). Item 4. The light emitting device material according to Item 3.
(3-1): (A3) n3- (B3)
(3-2): (A3)-(A3)
(Wherein n3 represents an integer of 1 to 6. A3 represents an aryl group having 6 to 15 carbon atoms which may have a substituent. B3 represents n3 which may have a substituent. Represents a valent aryl structure having 6 to 15 carbon atoms, provided that A3 and B3 are not the same, and the substituent includes an alkyl group, an alkenyl group, an aryl group, a carbazolyl group, an indolyl group, a diarylamino group, a silyl group, Or a cyano group, and each group may be further substituted with these substituents. When a plurality of substituents are present, the substituents may be the same or different.)
The cross-coupling body is a cross-coupling body represented by the following general formula (4-1), and the homo-coupling body is a homo-coupling body represented by the following general formula (4-2). Item 5. The light emitting device material according to Item 3 or 4.

(Wherein n4 represents an integer of 1 to 5. R 4a and R 4b each independently represents an aryl group which may have a substituent, a carbazolyl group which may have a substituent, or a cyano group. The substituent represents an alkyl group, an alkenyl group, or an aryl group, provided that R 4a and R 4b are not the same, and na and nb each independently represents an integer of 1 to 5. R 4a or When a plurality of R 4b are present, the plurality of R 4a or R 4b may be the same or different.)
A light-emitting element having at least one organic layer, the light-emitting element including the light-emitting element material according to claim 1 in at least one of the organic layers.
The light emitting device according to claim 6, wherein the organic layer is an organic electroluminescent device that emits light by being sandwiched between a pair of electrodes and applying a voltage between the electrodes.
The light emitting device according to claim 6 or 7, wherein the organic layer is a layer formed by a coating method.
An illumination device comprising the light emitting element according to any one of claims 6 to 8.
A display device comprising the light emitting element according to any one of claims 6 to 8.