JP5560592B2 - Nitrogen-containing heterocyclic compound, organic electroluminescent element material, composition for organic electroluminescent element, organic electroluminescent element, organic EL display and organic EL lighting - Google Patents

Description

  The present invention is a nitrogen-containing heterocyclic compound that is soluble in various solvents, has a high charge transporting ability, has a high amorphous property, and has an excellent film forming property, a material for an organic electroluminescent device comprising the compound, The present invention relates to a composition for an organic electroluminescent device containing the compound, an organic electroluminescent device having a layer containing the compound, an organic EL display using the organic electroluminescent device, and organic EL illumination.

  In recent years, an electroluminescent element (organic electroluminescent element) using an organic thin film has been developed. Examples of the method for forming the organic thin film in the organic electroluminescence device include a vacuum deposition method and a wet film formation method. Among these, the wet film-forming method does not require a vacuum process, is easy to increase in area, and a plurality of materials having various functions in a coating liquid (composition for an organic electroluminescent element) for forming one layer. There are advantages such as easy mixing and mixing.

Polymer materials such as poly (p-phenylene vinylene) derivatives and polyfluorene derivatives are mainly used as the material for the light emitting layer formed by the wet film formation method. There are points to be improved.
・ It is difficult to control the degree of polymerization and molecular weight distribution of polymer materials.
・ Deterioration due to terminal residues occurs during continuous driving.
・ High purity of the material itself is difficult and contains impurities.
Because of the above points to be improved, devices using a wet film formation method are inferior in driving stability to devices using a vacuum vapor deposition method and have not reached a practical level with some exceptions.

  As an attempt to solve the above problems, for example, Patent Document 1 discloses an organic thin film formed by a wet film forming method by mixing a plurality of low molecular materials (charge transport materials, light emitting materials) instead of a polymer compound. An organic electroluminescent device using is described. However, since the organic electroluminescent element described in Patent Document 1 uses fluorescent light emission, the light emission efficiency and the maximum light emission luminance of the element are low, and the practical characteristics are not satisfied.

  In an organic electroluminescent device using an organic thin film made of a plurality of low-molecular materials formed by a wet film formation method, Non-Patent Document 1 describes a device using phosphorescence emission in order to increase the luminous efficiency of the device. ing. The charge transport material of the organic electroluminescence device described in Non-Patent Document 1 uses the following biphenyl derivative.

However, the biphenyl derivative is very easy to crystallize, and it has been difficult to obtain a uniform film by the wet film forming method. Further, the biphenyl derivative has low solubility in a solvent. For this reason, it is necessary to use a halogen-based solvent such as chloroform or 1,2-dichloroethane as a coating solvent, but the halogen-based solvent has a large environmental load and has a practical problem. or,
Since there is a high possibility that the material is deteriorated by impurities contained in the halogen-based solvent, it is conceivable that the driving stability of the element formed by the wet film forming method using the halogen-based solvent is not sufficient.

Japanese Patent Laid-Open No. 11-238359

J a p a n e s J o u r n a l o f A p p l i e d P h y s i c s V o l. 4 4, N o. 1 B, 2 0 0 5, p p. 6 2 6-6 2 9

  The present invention has been made in view of the above-described conventional situation, and provides an organic electroluminescent element material that is soluble in various solvents, has a high charge transport ability, and does not easily crystallize. Shows an excellent film forming property, has sufficient driving stability, and a composition for forming an organic electroluminescent device capable of being driven at a low driving voltage, and an organic electroluminescent device and an organic EL using the composition It is an object to provide a display.

  As a result of intensive studies by the present inventors, the nitrogen-containing heterocyclic compound represented by the following formula (1) is a compound that is soluble in various solvents, has a high charge transporting ability, and is difficult to crystallize. It is possible to form a thin film by the method, and has an excellent charge transporting ability. Therefore, when used in an organic electroluminescent device, it has been found that it has high driving stability and can be driven at a low driving voltage. Reached.

  That is, the present invention is a nitrogen-containing heterocyclic compound represented by the following formula (1), an organic electroluminescent element material comprising the compound, and an organic electroluminescent element composition comprising the compound, It exists in organic electroluminescent elements, organic EL displays and organic EL lighting.

(In formula (1), X ^{1 to} X ³ represent CH or a nitrogen atom, provided that any one of X ^{1 to} X ³ represents a nitrogen atom.
R ^{1 to} R ³ each independently represents an organic group having 50 or less carbon atoms, which may have a substituent. L ¹ represents a single bond or an aromatic ring group having 25 or less carbon atoms, which may have a substituent.
n represents an integer of 2 to 6.

m represents an integer of 0 or more and 4 or less.
p, r, and s each independently represent an integer of 0 or more and 4 or less.
Incidentally, in a molecule, if a plurality of ^{R 1 ~R} 3, ^L 1, which and Ar ¹ are included, each independently, may be the same or may be different.
Ar ¹ represents a group selected from the following aromatic hydrocarbon group group A. )
<Aromatic hydrocarbon group A>

(The benzene ring and naphthalene ring in the above formula may have a substituent.)

The nitrogen-containing heterocyclic compound of the present invention is excellent in solubility in various solvents and is a compound that does not crystallize, so that a thin film can be formed by a wet film-forming method and has an excellent charge transport ability.
For this reason, the organic electroluminescent element formed by the wet film-forming method using the composition for organic electroluminescent elements containing the nitrogen-containing heterocyclic compound of the present invention can have a large area.

  According to the organic electroluminescent device containing the nitrogen-containing heterocyclic compound of the present invention, the organic EL display having a large area that has sufficient driving stability due to excellent film forming property and can be driven at a low voltage. Can be created.

It is sectional drawing which shows typically an example of the structure of the organic electroluminescent element of this invention.

Embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention does not exceed the gist thereof. It is not specified in the contents.
[Explanation of phrase]
In the present invention, when the term “heterocycle” or “hydrocarbon ring” is simply used, it includes both a ring having aromaticity and a ring having no aromaticity. In addition, when simply referred to as “aromatic ring”, it includes both hydrocarbon aromatic rings and heteroaromatic rings.

In the present invention, the “aromatic ring group” refers to “a group derived from a monocyclic aromatic ring”, “a group derived from a condensed ring in which two or more rings are condensed”, And / or a group in which two or more of the condensed rings are linked via a single bond.
In the present invention, “may have a substituent” means that one or more substituents may be present.

“(Hetero) aryl” means both “aryl” and “heteroaryl”.
[Nitrogen-containing heterocyclic compound represented by formula (1)]
The nitrogen-containing heterocyclic compound of the present invention is a compound represented by the following formula (1).

(In formula (1), X ^{1 to} X ³ represent CH or a nitrogen atom, provided that any one of X ^{1 to} X ³ represents a nitrogen atom.
R ^{1 to} R ³ each independently represents an organic group having 50 or less carbon atoms, which may have a substituent. L ¹ represents a single bond or an aromatic ring group having 25 or less carbon atoms, which may have a substituent.
n represents an integer of 2 to 6.

m represents an integer of 0 or more and 4 or less.
p, r, and s each independently represent an integer of 0 or more and 4 or less.
Incidentally, in a molecule, if a plurality of ^{R 1 ~R} 3, ^L 1, which and Ar ¹ are included, each independently, may be the same or may be different.
Ar ¹ represents a group selected from the following aromatic hydrocarbon group group A. )
<Aromatic hydrocarbon group A>

(The benzene ring and naphthalene ring in the above formula may have a substituent.)
[1] Structural features The compound represented by the following formula (1) of the present invention has two electron-rich nitrogen atoms in the nitrogen heterocycle portion, and thus exhibits high electron transport ability. Since the molecule has asymmetry due to having a hydrogen group, it exhibits excellent solubility in various solvents and high amorphousness.

[2] Each component in formula (1)
[2-1] About X ^{1 to} X ³ .
X ^{1 to} X ³ represent CH or a nitrogen atom. However, any one of X ¹ to X ³ represents a nitrogen atom.
Among them, any one of X ^{1 to} X ³ is a nitrogen atom in view of having a high electron transport ability, stability of the compound, and ease of synthesis.

[2-2] About n.
n represents the number of partial structures represented by the following formula (i) included in the formula (1). n is
Usually represents an integer of 2 or more, usually 6 or less, preferably 3 or less.
It is particularly preferable that n is 2 in terms of easy purification by sublimation purification.

(In the above formula ^{(i), L 1, Ar} 1, R 2 ~R 3, and, s and r have the same meanings as those in each Formula (1).)
[2-3] for Ar ^1.
In the formula (1), Ar ¹ represents a group selected from the following aromatic hydrocarbon group group A.
<Aromatic hydrocarbon group A>

(The group represented by the above formula may have a substituent.)
The aromatic hydrocarbon group Ar ¹ in the formula (1) is introduced for the purpose of imparting asymmetry to the molecule and improving the solubility in various solvents, and includes o-phenylene group, m-phenylene group, 1, Examples include 2-naphthyl group, 1,4-naphthyl group, 1,6-naphthyl group, 1,7-naphthyl group, and 1,8-naphthyl group. As the aromatic hydrocarbon group Ar ¹ , it is particularly preferable to use an m-phenylene group from the viewpoints of stability of the compound, ease of synthesis, ease of purification, and the like.

In addition, the substituent that the aromatic hydrocarbon group Ar ¹ may have is not particularly limited as long as the carbon number of Ar ¹ including the aromatic hydrocarbon group A is usually 25 or less, below ^{<R 1 ~R 3, m,} r, for s> it may be used selected from those set forth in the specific examples of ^R 1 to R ³ in the section. The substituents are not bonded to form a ring. In terms of redox stability of the compound, the aromatic hydrocarbon group Ar ¹ in the formula (1) preferably has no substituent.

[2-4] R ^{1 to} R ³ , m, r, and s In formula (1), R ^{1 to} R ³ represent an organic group having 50 or less carbon atoms and optionally having a substituent.
R ¹ is a substituent bonded to the nitrogen-containing heterocyclic ring, and m represents the number of R ¹ bonded to the nitrogen-containing heterocyclic ring. m is an integer of usually 0 or more and 4 or less, preferably 2 or less in that it is easy to achieve high purity by sublimation purification. When m is 0, R ¹ is not substituted with a nitrogen-containing heterocyclic ring. Means. When m is 2 or more, the plurality of R ¹ substituted on the nitrogen-containing heterocycle may be the same or different.

R ² is a substituent bonded to the carbazole ring, and r is R ² bonded to the carbazole ring.
Represents the number of r is an integer of usually 0 or more and usually 4 or less, preferably 1 or less in that it is easy to achieve high purity by sublimation purification, and r is 0, and that R ² is not substituted with a carbazole ring. means. When r is 2 or more, the plurality of R ² substituted on the carbazole ring may be the same or different.

R ³ is a substituent bonded to the carbazole ring, and s is R ³ bonded to the carbazole ring.
Represents the number of s is an integer of usually 0 or more and usually 4 or less, preferably 1 or less, in that it is easy to achieve high purity by sublimation purification. When s is 0, R ³ is not substituted with a carbazole ring. means. When s is 2 or more, the plurality of R ³ substituted on the carbazole ring may be the same or different.

R ^{1 to} R ³ each independently represents an organic group having 50 or less carbon atoms, and these may have a substituent. The number of carbon atoms is usually 50 or less, but is preferably 30 or less from the viewpoint of molecular stability and ease of purification.
Specific examples of the organic group include an alkyl group having 1 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 25 carbon atoms, an aromatic heterocyclic group having 3 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, Examples thereof include a (hetero) aryloxy group having 3 to 20 carbon atoms, an alkylthio group having 1 to 20 carbon atoms, a (hetero) arylthio group having 3 to 20 carbon atoms, and a cyano group. An alkyl group, an aromatic hydrocarbon group, and an aromatic heterocyclic group are preferable from the viewpoint of stability of the compound, and an aromatic hydrocarbon group is particularly preferable.

  Examples of the alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, iso-butyl group, sec-butyl group, tert-butyl group, hexyl group, octyl group and cyclohexyl group. Group, decyl group, octadecyl group and the like. Preferably, they are a methyl group, an ethyl group, and an isopropyl group. A methyl group and an ethyl group are preferable from the viewpoint of availability of raw materials and low cost, and an iso-butyl group, a sec-butyl group, and a tert-butyl group are preferable because they have high solubility in nonpolar solvents.

  Examples of the aromatic hydrocarbon group having 6 to 25 carbon atoms include a naphthyl group such as a phenyl group, a 1-naphthyl group and a 2-naphthyl group, a phenanthyl group such as a 9-phenanthyl group and a 3-phenanthyl group, and 1-anthryl. Group, 2-anthryl group, anthryl group such as 9-anthryl group, 1-naphthacenyl group, naphthacenyl group such as 2-naphthacenyl group, 1-chrysenyl group, 2-chrysenyl group, 3-chrysenyl group, 4-chrysenyl group, Examples include a chrycenyl group such as a 5-chrycenyl group and a 6-chrenyl group, a pyrenyl group such as a 1-pyrenyl group, a triphenylenyl group such as a 1-triphenylenyl group, a coronenyl group such as a 1-coronenyl group, and the like. From the aspect, phenyl group, 2-naphthyl group, 1-anthryl group, 9-anthryl group and 9-phenanthryl group are preferred. , Phenyl group, 2-naphthyl group is particularly preferred from the purification ease of the compound.

  Examples of the aromatic heterocyclic group having 3 to 20 carbon atoms include thienyl group such as 2-thienyl group, furyl group such as 2-furyl group, imidazolyl group such as 2-imidazolyl group, and carbazolyl such as 9-carbazolyl group. Groups, pyridyl groups such as 2-pyridyl group, triazin-yl groups such as 1,3,5-triazin-2-yl group, and the like. Of these, a 9-carbazolyl group is preferable from the viewpoint of stability.

Examples of the alkoxy group having 1 to 20 carbon atoms include methoxy group, ethoxy group, isopropyloxy group, cyclohexyloxy group, octadecyloxy group and the like. Of these, a methoxy group and an ethoxy group are preferable from the viewpoints of improved solubility and glass transition point.
Examples of the (hetero) aryloxy group having 3 to 20 carbon atoms include a phenoxy group, a 3-phenoxyphenoxy group, a 2-naphthyloxy group, a 9-anthranyloxy group, and a 2-thienyloxy group. Among these, a phenoxy group, a 3-phenoxyphenoxy group, and a 2-naphthyloxy group are preferable from the viewpoint of improving solubility, and a 3-phenoxyphenoxy group is particularly preferable.

Examples of the alkylthio group having 1 to 20 carbon atoms include methylthio group, ethylthio group, isopropylthio group, cyclohexylthio group and the like. Of these, a methylthio group and an ethylthio group are preferable from the viewpoints of improved solubility and glass transition point.
Examples of the (hetero) arylthio group having 3 to 20 carbon atoms include a phenylthio group, a 1-naphthylthio group, a 9-anthranylthio group, and a 2-thienylthio group. Among these, a phenylthio group is preferable in terms of improving solubility in a solvent.

R ^{1 to} R ³ may further have the above-described group as a substituent.
[2-5] for ^{L 1.}
L ¹ in Formula (1) represents a single bond or an aromatic ring group having 25 or less carbon atoms, which may have a substituent.
Specific examples of the aromatic ring group having 25 or less carbon atoms include an aromatic hydrocarbon group having 6 to 25 carbon atoms and an aromatic heterocyclic group having 3 to 25 carbon atoms. An aromatic hydrocarbon group is preferred from the viewpoint of redox stability of the compound.

Examples of the aromatic hydrocarbon group having 6 to 25 carbon atoms include phenylene groups such as 1,4-phenylene group and 1,3-phenylene group, naphthylene groups such as 1,6-naphthylene group, and 3,9-phenanthylene. Groups such as phenanthylene groups, 2,6-anthranylene groups, anthranylene groups such as 9,10-anthranylene groups, 1, pyrenylene groups such as 1,6-pyrenylene groups, triphenylenyl groups such as 2,7-triphenylenyl groups, 4,4 ′ -Biphenylene group, 3,3'-biphenylene group, biphenylene group such as 4,3'-biphenylene group, etc. are mentioned. From the viewpoint of stability of the compound, 1,4-phenylene group, 1,3-phenylene group, 3 , 3'-biphenylene group, 4,3'-biphenylene group and 1,6-naphthylene group are preferable, 1,3-phenylene group, 3,3'-biphenylene group and 1,6-naphthylene group. From the viewpoint of the solubility of the compound in the solvent, a hydrogen group is particularly preferable.

Examples of aromatic heterocyclic groups having 3 to 25 carbon atoms include thienylene groups such as 2,5-thienylene groups, furylene groups such as 2,5-furylene groups, pyridylene groups such as 2,6-pyridylene groups, 2 Quinolylene groups such as, 6-quinolylene group and the like. Among these, 2,6-pyridylene group and 2,6-quinolylene group are preferable from the viewpoint of stability.
When L ¹ is an aromatic ring which may have a substituent, the substituent is described in the specific examples of R ^{1 to} R ^{3 in} the section of <About R ^{1 to} R ³ , m, r, and s>. You may select from and use.

[3] Regarding formula (2).
Among the compounds represented by the formula (1), a compound represented by the following formula (2) is preferable in that it exhibits high solubility in a solvent by introducing an m-phenylene group.

(In formula (2), X ^{1 to} X ³ represent CH or a nitrogen atom, provided that any one of X ^{1 to} X ³ represents a nitrogen atom. R ^{1 to} R ⁴ each independently represents carbon. An organic group of several 50 or less, which may have a substituent.
L ¹ represents a single bond or an aromatic ring group having 25 or less carbon atoms, which may have a substituent.
n represents an integer of 1 to 6.

m represents an integer of 0 or more and 4 or less.
p, r, and s each independently represent an integer of 0 or more and 4 or less.
In addition, when several R < ² > -R < ⁴ > and L < ¹ > are contained in one molecule, each may be the same and may differ independently. )
[3-1] About X ^{1 to} X ³ .

X ¹ to X in the formula (2) ³ has the same meaning as X ¹ to X ³ in the formula (1). The preferable example is also the same.
[3-2] About R ^{1 to} R ⁴ and m, p, r, and s.
m, r, and s are respectively synonymous with those in the formula (1). The same applies to specific examples and preferred examples.

Moreover, R < ¹ > -R < ³ > is synonymous with the thing in said Formula (1) respectively. The same applies to specific examples, preferred examples, and substituents that may be further included.
R ⁴ is a substituent bonded to the benzene ring bonded to the nitrogen atom of the carbazole ring, and p represents the number of R ⁴ bonded to the benzene ring. p is an integer of usually 0 or more and usually 4 or less, preferably 1 or less in that it is easy to achieve high purity by sublimation purification. When p is 0, it means that R ⁴ is not substituted with a benzene ring. means. When p is 2 or more, the plurality of R ⁴ substituted on the benzene ring may be the same or different.

[3-3] for ^{L 1.}
In formula (2), L ¹ has the same meaning as in formula (1). The same applies to specific examples, preferred examples, and substituents that may be further included.
[4] Regarding formula (3).
Among the compounds represented by the formula (2), a compound represented by the following formula (3) is preferable from the viewpoint of high glass transition temperature and excellent heat resistance.

(In Formula (3), X < ¹ > -X < ³ > represents CH or a nitrogen atom, provided that any one of X < ¹ > -X < ³ > represents a nitrogen atom.
R ^{12 to} R ¹⁴ and R ^{22 to} R ²⁴ each independently represents an organic group having 50 or less carbon atoms and optionally having a substituent. L ¹¹ and L ¹² each independently represents a single bond or an aromatic ring group having 25 or less carbon atoms, which may have a substituent.

p ¹ , r ¹ , s ¹ , p ² , r ² and s ² each independently represent an integer of 0 or more and 4 or less.
In addition, when several R < ¹² > -R < ¹⁴ > and R < ²² > -R < ²⁴ > are contained in one molecule, each may be the same and may differ independently. )
[4-1] Regarding X ^{1 to} X ³ .
X ¹ to X in the formula (3) ³ has the same meaning as X ¹ to X ³ in the formula (2). The preferable example is also the same.

[4-2] About R ^{12 to} R ¹⁴ and R ^{22 to} R ²⁴ , and p ¹ , r ¹ , s ¹ , p ² , r ² and s ² .
P ¹ , r ¹ , s ¹ , p ² , r ² and s ² in the formula (3) have the same meanings as p, r and s in the formula (2), respectively. The preferable range is also the same.
R < ¹² > -R < ¹⁴ > and R < ²² > -R < ²⁴ > in Formula (3) are synonymous with R < ² > -R < ⁴ > of said Formula (2). The specific examples and preferred examples are also the same.

[4-3] About L ¹¹ and L ¹² .
L ¹¹ and L ^{12 in} Formula (3) each independently represent an aromatic ring group having 25 or less carbon atoms, which may have a substituent. L ¹¹ and L ¹² are the same as the specific examples, preferred examples and substituents of L ^{1 in} the formulas (1) and (2).
L ¹¹ and L ¹² may be the same or different, but are preferably different from the viewpoint of increasing the asymmetry of the molecule and improving the solubility in a solvent.

[5] Regarding equation (4).
Among the compounds represented by the formula (3), a compound represented by the following formula (4) is preferred as a nitrogen-containing ring compound in which L ¹¹ and L ¹² which are preferred embodiments are different.

(In Formula (4), X < ¹ > -X < ³ > represents CH or a nitrogen atom, provided that any one of X < ¹ > -X < ³ > represents a nitrogen atom.
R ^{12 to} R ¹⁴ and R ^{22 to} R ²⁴ each independently represents an organic group having 50 or less carbon atoms which may have a substituent. L ¹¹ represents a single bond or an aromatic ring group having 25 or less carbon atoms which may have a substituent. Ring B represents a benzene ring, and L ′ represents a single bond or an aromatic ring group having 19 or less carbon atoms, which may have a substituent.

In addition, when several R < ¹² > -R < ¹⁴ > and R < ²² > -R < ²⁴ > are contained in one molecule, each may be the same and may differ independently. )
[5-1] About X ^{1 to} X ³ .
X < ¹ > -X < ³ > in Formula (4) is synonymous with X < ¹ > -X < ³ > of said Formula (3). The preferable example is also the same.

[5-2] R ^{12 to} R ¹⁴ and R ^{22 to} R ²⁴ , and p ¹ , r ¹ , s ¹ , p ² , r
About ² and ^{s 2.
P 1, r 1, s 1} , p 2, r 2 and ^{s 2} in the formula (4) ^{is, p 1,} r 1 of each Formula (3), s ^1, and p 2, ^{r 2} and ^{s 2} It is synonymous. The preferable range is also the same.
R < ¹² > -R < ¹⁴ > and R < ²² > -R < ²⁴ > in Formula (4) are synonymous with R < ¹² > -R < ¹⁴ > and R < ²² > -R < ²⁴ > of said Formula (3). The specific examples and preferred examples are also the same.

[5-3] About L ¹¹ and L ′.
L ¹¹ in Formula (4) represents an aromatic ring group having 25 or less carbon atoms which may have a substituent. L ¹¹ is the same as the specific examples, preferred examples, and substituents of L ^{1 in} the formulas (1) and (2).
L ′ in Formula (4) represents a single bond or an aromatic ring group having 19 or less carbon atoms, which may have a substituent. Note that L′-ring B corresponds to L ¹² in formula (3).

Specific examples of the aromatic ring group having 19 or less carbon atoms, which may have a substituent, include an aromatic hydrocarbon group having 6 to 25 carbon atoms and an aromatic heterocyclic group having 3 to 25 carbon atoms. . An aromatic hydrocarbon group is preferable from the viewpoint of stability of the compound.
Examples of the aromatic hydrocarbon group having 6 to 19 carbon atoms include phenylene groups such as 1,4-phenylene group and 1,3-phenylene group, naphthylene groups such as 1,6-naphthylene group, and 3,9-phenanthylene. Groups such as phenanthylene groups, 2,6-anthranylene groups, anthranylene groups such as 9,10-anthranylene groups, 1, pyrenylene groups such as 1,6-pyrenylene groups, triphenylenyl groups such as 2,7-triphenylenyl groups, 4,4 ′ -Biphenylene group, 3,3'-biphenylene group, biphenylene group such as 4,3'-biphenylene group, etc. are mentioned. From the viewpoint of stability of the compound, 1,4-phenylene group, 1,3-phenylene group, 3 , 3'-biphenylene group, 4,3'-biphenylene group and 1,6-naphthylene group are preferable, 1,3-phenylene group, 3,3'-biphenylene group and 1,6-naphthylene group. Particularly preferred from the viewpoint of the solubility of the compound.

Examples of the aromatic heterocyclic group having 3 to 19 carbon atoms include thienylene groups such as 2,5-thienylene groups, furylene groups such as 2,5-furylene groups, pyridylene groups such as 2,6-pyridylene groups, Quinolylene groups such as, 6-quinolylene group and the like. Among these, 2,6-pyridylene group and 2,6-quinolylene group are preferable from the viewpoint of stability.
[6] Molecular weight The molecular weight of the nitrogen-containing heterocyclic compound of the present invention is usually 7000 or less, and when considering the ease of purification of the compound, the molecular weight is preferably 5000 or less, particularly when considering solubility in a solvent. It is preferably 3000 or less, and most preferably 1500 or less when considering high purification by sublimation purification.

The molecular weight of the nitrogen-containing heterocyclic compound of the present invention is usually 100 or more. When considering the thermal stability of the compound, the molecular weight is preferably 500 or more.
[7] Physical Properties The glass transition temperature in the nitrogen-containing heterocyclic compound of the present invention is usually 90 ° C or higher, preferably 100 ° C or higher, more preferably 120 ° C or higher, and usually 500 ° C or lower, preferably 250 ° C or lower, more preferably. Is 200 ° C. or lower. Within the above range, heat resistance is excellent and the drive life of the resulting element is long, which is preferable.

Further, the solubility in a solvent is usually 0.1% by weight or more, preferably 1% by weight or more, more preferably 5% by weight or more, and usually 30% by weight or less at room temperature. Within the above range, it is preferable in that a uniform film is obtained when a film is formed by a wet film forming method, and cracking or short-circuiting is less likely to occur when an element is formed.
[8] Illustrative compound Preferred specific examples of the nitrogen-containing heterocyclic compound of the present invention are listed below, but the nitrogen-containing heterocyclic compound of the present invention is not limited to the following exemplary compounds.

[9] Manufacturing method <Synthesis method>
The method for producing the nitrogen-containing heterocyclic compound of the present invention is not particularly limited, and is arbitrary as long as the nitrogen-containing heterocyclic compound of the present invention is obtained. For example, the compound represented by the formula (1) of the present invention can be synthesized by using a coupling reaction using an aminobenzonitrile derivative and a metal catalyst, followed by a coupling reaction with a benzoyl halide derivative.

For example, phenyl carbazole via a linker L to X ^2-position of the nitrogen-containing heterocyclic ring is, in the case of compounds phenyl carbazole is substituted at the 6-position, it can be synthesized according to the following scheme.

(In the above formula, R ¹ is as defined in the above formulas (1), (2) and (3), L is a linker, M is a metal element, and X is a halogen atom or a trifluoromethanesulfonate group. .)
Below, the elementary reaction shown in the said scheme is demonstrated.
<Nitrogen-containing heterocycle formation reaction>
In an inert gas atmosphere, 1 mol of an organometallic reagent and 1 mol of an aminobenzonitrile derivative are reacted, and 0.5 to 10 mol of a compound having an acetyl group is dissolved or suspended in a polar or nonpolar solvent and stirred. While adding a temperature of 0 to 150 ° C., a substrate mixture containing a nitrogen-containing heterocycle is obtained. Purification from the mixture can be performed by a combination of distillation, filtration, extraction, recrystallization, reprecipitation, suspension washing, and chromatographic operations.

  The solvent is not particularly limited as long as it can dissolve the substrate. Non-benzene nonpolar solvents such as hexane and cyclohexane, amide solvents such as N, N-dimethylformamide and N, N-dimethylacetamide, diethyl The reaction is preferably carried out using an ether solvent such as ether, tetrahydrofuran, dioxane or diethylene glycol dimethyl ether, an alcohol solvent such as methanol or ethanol, an acidic solvent such as acetic acid, butyric acid or polyphosphoric acid, and an acidic solvent such as acetic acid. Is particularly preferred.

<Coupling reaction>
In a nonpolar or polar solvent in the presence of a base, 1 mol of a phenylcarbazole boron reagent and a halogenated trifluoromethanesulfonate ester reagent having a nitrogen-containing heterocyclic substrate or 0.75-5 mol of a trifluoromethanesulfonate reagent are used in the presence of a base. Purification from a mixture that can yield a coupled mixture of substrates by reacting can be accomplished by a combination of distillation, filtration, extraction, recrystallization, reprecipitation, suspension washing, and chromatographic operations. .

Examples of transition metal element catalysts include organic palladium catalysts, organic nickel catalysts, organic copper catalysts, organic platinum catalysts, organic rhodium catalysts, organic ruthenium catalysts, and organic iridium catalysts. Organic palladium catalysts are preferred.
The base is not particularly limited, but metal hydroxides, metal salts, organic alkali metal reagents and the like are preferable.

The solvent to be used is not particularly limited as long as it is a solvent that is active with respect to the reaction substrate, but non-aromatic hydrocarbon solvents such as hexane, heptane, and cyclohexane, and aromatic carbonization such as benzene, toluene, and xylene. A hydrogen solvent, ether solvents such as dimethoxyethane, tetrahydrofuran and dioxane, alcohol solvents such as ethanol and propanol, water and the like can be used singly or in combination.
If necessary, 1-100 mol% of a surfactant can be added.

[10] Use of nitrogen-containing compound Since the nitrogen-containing heterocyclic compound of the present invention has a high charge transporting ability, an electrophotographic photoreceptor, an organic electroluminescent element, a photoelectric conversion element, an organic solar cell, an organic rectifier as a charge transporting material. It can be used suitably for an element etc. For example, the nitrogen-containing heterocyclic compound of the present invention is useful as a dopant material, particularly as a host material for a red phosphorescent material, in a light emitting layer of an organic electroluminescent device.

  In particular, the nitrogen-containing heterocyclic compound of the present invention is excellent in solubility in various solvents and has an amorphous property, so that it can be formed into a thin film by a wet film forming method, so that it is applied to a wet film forming method. The organic electroluminescent element material comprising the nitrogen-containing heterocyclic compound of the present invention or the organic electroluminescent element composition comprising the nitrogen-containing heterocyclic compound of the present invention is suitable. An organic electroluminescence device which is excellent in driving stability and can be driven with a low driving voltage can be manufactured by a wet film forming method.

[Composition for organic electroluminescence device]
The composition for an organic electroluminescent device of the present invention contains the above-mentioned nitrogen-containing heterocyclic compound of the present invention, and usually contains the nitrogen-containing heterocyclic compound of the present invention and a solvent, and more preferably a phosphorescent material. It is used for an organic electroluminescent element.
[1] Solvent The composition for organic electroluminescent elements further contains a solvent.

Here, the solvent is a volatile liquid component used for forming a light emitting layer by wet film formation.
The solvent is not particularly limited as long as the solute dissolves well, but the following examples are preferable.
For example, alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane; aromatic hydrocarbons such as toluene, xylene, methicylene, cyclohexylbenzene, and tetralin; halogenated fragrances such as chlorobenzene, dichlorobenzene, and trichlorobenzene Group hydrocarbons: 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethyl Aromatic ethers such as anisole and diphenyl ether; aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; Alicyclic ketones such as Sanone, Cyclooctanone and Fencon; Alicyclic alcohols such as cyclohexanol and cyclooctanol; Aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; Aliphatic alcohols such as butanol and hexanol; Ethylene And aliphatic ethers such as glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA).

Of these, alkanes and aromatic hydrocarbons are preferable. One of these solvents may be used alone, or two or more thereof may be used in any combination and ratio.
The boiling point of the solvent used is usually 100 ° C. or higher, preferably 140 ° C. or higher, more preferably 200 ° C. or higher, and usually 400 ° C. or lower, preferably 300 ° C. or lower, more preferably 260 ° C. or lower. Within this range, the drying rate is moderate, so that good film quality can be obtained, and the heating temperature in the drying step is hardly increased, and other organic layers and glass substrates are hardly affected, which is preferable.

[2] Luminescent Material The composition for organic electroluminescent elements of the present invention preferably contains a luminescent material. The light emitting material in the present invention mainly indicates a component that emits light and corresponds to a dopant component. That is, the amount of light emitted from the composition for organic electroluminescent elements (unit: cd / m ² ) is usually 10 to 100%, preferably 20 to 100%, more preferably 50 to 100%, most preferably 80 to 80%. If 100% is identified as luminescence from a component material, it is defined as the luminescent material.

In measuring the amount of light emitted from the composition, the PL spectrum when an arbitrary voltage at which the photodiode can recognize light is applied to the produced organic electroluminescent element is observed with the photodiode.
As the light-emitting material, known materials can be applied, and a fluorescent light-emitting material or a phosphorescent light-emitting material can be used alone or in combination, and a phosphorescent light-emitting material is preferable from the viewpoint of internal quantum efficiency.

When used in the composition for organic electroluminescent elements of the present invention, the maximum emission peak wavelength of the luminescent material is preferably in the range of 390 to 490 nm.
For the purpose of improving the solubility in a solvent, it is also important to reduce the symmetry and rigidity of molecules in the luminescent material or to introduce lipophilic substituents such as alkyl groups.

Examples of fluorescent dyes that emit blue light include perylene, pyrene, anthracene, coumarin, p-bis (2-phenylethenyl) benzene, and derivatives thereof. Examples of the green fluorescent dye include quinacridone derivatives and coumarin derivatives. Examples of yellow fluorescent dyes include rubrene and perimidone derivatives. Examples of red fluorescent dyes include DCM compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, azabenzothioxanthene and the like.

Examples of the phosphorescent material include organometallic complexes containing a metal selected from Groups 7 to 11 of the periodic table.
Preferred examples of the metal in the phosphorescent organometallic complex containing a metal selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold. Preferred examples of these organometallic complexes include compounds represented by the following general formula (V) or formula (VI).

MQ _{(qj) Q'j} (V)
(In general formula (V), M represents a metal, q represents the valence of the metal, Q and Q ′ represent a bidentate ligand, and j represents 0, 1 or 2.)

(In the general formula (VI), M ^d represents a metal, T represents carbon or nitrogen. R ^{92 to} R ⁹⁵ each independently represents a substituent. However, when T is nitrogen, R ⁹⁴ represents R ^94. And R ⁹⁵ is not present.)
Hereinafter, the compound represented by the general formula (V) will be described first.
In the general formula (V), M represents an arbitrary metal, and specific examples of preferable ones include the metals described above as the metal selected from Groups 7 to 11 of the periodic table.

  Further, the bidentate ligands Q and Q ′ in the general formula (V) each represent a ligand having the following partial structure.

As Q ', the following are particularly preferable from the viewpoint of the stability of the complex.

In the partial structures of Q and Q ′, the ring A1 represents an aromatic hydrocarbon group or an aromatic heterocyclic group, and these may have a substituent. Ring A2 represents a nitrogen-containing aromatic heterocyclic group, and these may have a substituent.
When the rings A1 and A2 have a substituent, preferred substituents include halogen atoms such as fluorine atoms; alkyl groups such as methyl groups and ethyl groups; alkenyl groups such as vinyl groups; methoxycarbonyl groups and ethoxycarbonyl groups. Alkoxycarbonyl groups; alkoxy groups such as methoxy groups and ethoxy groups; aryloxy groups such as phenoxy groups and benzyloxy groups; dialkylamino groups such as dimethylamino groups and diethylamino groups; diarylamino groups such as diphenylamino groups; carbazolyl groups; An acyl group such as an acetyl group; a haloalkyl group such as a trifluoromethyl group; a cyano group; an aromatic hydrocarbon group such as a phenyl group, a naphthyl group, and a phenanthyl group.

  More preferable examples of the compound represented by the general formula (V) include compounds represented by the following general formulas (Va), (Vb), and (Vc).

(In general formula (Va), M ^a represents the same metal as M, w represents the valence of the metal, and ring A1 represents an aromatic hydrocarbon group which may have a substituent. Ring A2 represents a nitrogen-containing aromatic heterocyclic group which may have a substituent.

(In the general formula (Vb), M ^b represents the same metal as M, w represents the valence of the metal. Further, the ring A1 is an aromatic optionally substituted hydrocarbon group or a substituted Represents an aromatic heterocyclic group which may have a group, and ring A2 represents a nitrogen-containing aromatic heterocyclic group which may have a substituent.
)

(In the general formula (Vc), M ^c represents the same metal as M, w represents the valence of the metal, j represents 0, 1 or 2. Furthermore, ring A1 and ring A1 ′ represent Each independently represents an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group, and ring A2 and ring A2 ′ are each independently Represents a nitrogen-containing aromatic heterocyclic group which may have a substituent.
In the general formulas (Va), (Vb), and (Vc), the group of the ring A1 and the ring A1 ′ is preferably a phenyl group, a biphenyl group, a naphthyl group, an anthryl group, a thienyl group, a furyl group, a benzo group, for example. Examples include thienyl group, benzofuryl group, pyridyl group, quinolyl group, isoquinolyl group, carbazolyl group and the like.

In addition, the group of ring A2 and ring A2 ′ is preferably a pyridyl group, pyrimidyl group, pyrazyl group, triazyl group, benzothiazole group, benzoxazole group, benzimidazole group, quinolyl group, isoquinolyl group, quinoxalyl group, A phenanthridyl group and the like can be mentioned.
Furthermore, the substituents that the compounds represented by the general formulas (Va), (Vb), and (Vc) may have include halogen atoms such as fluorine atoms; alkyl groups such as methyl groups and ethyl groups; vinyls Alkenyl groups such as methoxy groups; alkoxycarbonyl groups such as methoxycarbonyl groups and ethoxycarbonyl groups; alkoxy groups such as methoxy groups and ethoxy groups; aryloxy groups such as phenoxy groups and benzyloxy groups; dialkyls such as dimethylamino groups and diethylamino groups An amino group; a diarylamino group such as a diphenylamino group; a carbazolyl group; an acyl group such as an acetyl group; a haloalkyl group such as a trifluoromethyl group; a cyano group;

  When the said substituent is an alkyl group, the carbon number is 1 or more and 6 or less normally. Furthermore, when the substituent is an alkenyl group, the carbon number is usually 2 or more and 6 or less. When the substituent is an alkoxycarbonyl group, the carbon number is usually 2 or more and 6 or less. Further, when the substituent is an alkoxy group, the carbon number is usually 1 or more and 6 or less. Moreover, when a substituent is an aryloxy group, the carbon number is 6 or more and 14 or less normally. Furthermore, when the substituent is a dialkylamino group, the carbon number is usually 2 or more and 24 or less. Further, when the substituent is a diarylamino group, the carbon number is usually 12 or more and 28 or less. Furthermore, when the substituent is an acyl group, the carbon number is usually 1 or more and 14 or less. Moreover, when a substituent is a haloalkyl group, the carbon number is 1 or more and 12 or less normally.

These substituents may be connected to each other to form a ring. As a specific example, a substituent of the ring A1 and a substituent of the ring A2 are bonded, or a substituent of the ring A1 ′ and a substituent of the ring A2 ′ are bonded. Two fused rings may be formed. Examples of such a condensed ring group include a 7,8-benzoquinoline group.
Among them, as a substituent for ring A1, ring A1 ′, ring A2 and ring A2 ′, an alkyl group, alkoxy group, aromatic hydrocarbon group, cyano group, halogen atom, haloalkyl group, diarylamino group, carbazolyl group are more preferable. Is mentioned.

In general formula (Va), (Vb), preferably as ^{M a, M b, M c} in (Vc), ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum or gold.
Specific examples of the organometallic complex represented by the general formula (V), (Va), (Vb) or (Vc) are shown below, but are not limited to the following compounds (in the following, Ph is phenyl Represents a group).

Among the organometallic complexes represented by the general formulas (V), (Va), (Vb), and (Vc), in particular, as the ligand Q and / or Q ′, a 2-arylpyridine-based ligand, , 2-arylpyridine, compounds having an arbitrary substituent bonded thereto, and compounds formed by condensing an arbitrary group thereto are preferable.
Moreover, the compound as described in an international publication 2005/019373 pamphlet can also be used.

Next, the compound represented by the general formula (VI) will be described.
In the general formula (VI), M ^d represents a metal, and specific examples thereof include the metals described above as the metal selected from Groups 7 to 11 of the periodic table. Among these, ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum or gold is preferable, and divalent metals such as platinum and palladium are particularly preferable.

In the general formula (VI), R ⁹² and R ⁹³ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an amino group, an acyl group, an alkoxycarbonyl group, or a carboxyl group. Represents an alkoxy group, an alkylamino group, an aralkylamino group, a haloalkyl group, a hydroxyl group, an aryloxy group, an aromatic hydrocarbon group or an aromatic heterocyclic group.

Further, when T is carbon, R ⁹⁴ and R ⁹⁵ each independently represent a substituent represented by the same examples as R ⁹² and R ⁹³ . Further, as described above, when T is nitrogen, R ⁹⁴ and R ⁹⁵ are absent.
R ^{92 to} R ⁹⁵ may further have a substituent. In this case, the substituent which may further be present is not particularly limited, and any group can be used as the substituent.

Furthermore, R ^{92 to} R ⁹⁵ may be linked to each other to form a ring, and this ring may further have an arbitrary substituent.
Specific examples (T-1, T-10 to T-15) of the organometallic complex represented by the general formula (VI) are shown below, but are not limited to the following exemplified compounds. In the following, Me represents a methyl group, and Et represents an ethyl group.

[3] Other ingredients
In the composition for organic electroluminescent elements of the present invention, various other solvents may be included as necessary in addition to the above-described solvents and light emitting materials. Examples of such other solvents include amides such as N, N-dimethylformamide and N, N-dimethylacetamide, and dimethyl sulfoxide.

Moreover, various additives, such as a leveling agent and an antifoamer, may be included.
In addition, when two or more layers are laminated by a wet film formation method, in order to prevent these layers from being compatible with each other, a photocurable resin or a thermosetting resin is used for the purpose of curing and insolubilizing after film formation. Can also be contained.
[4] Ratio of each in the composition The solid content concentration of the quinazoline compound of the present invention, the luminescent material and components (leveling agents, etc.) that can be added as necessary in the composition for organic electroluminescent elements is usually 0.01% by weight or more,
Preferably it is 0.05% by weight or more, more preferably 0.1% by weight or more, further preferably 0.5% by weight or more, most preferably 1% by weight or more, usually 80% by weight or less, preferably 50% by weight. Below, more preferably 40% by weight or less, still more preferably 30% by weight or less, and most preferably 20% by weight or less. If this concentration is below the lower limit, it is difficult to form a thick film when forming a thin film, and if it exceeds the upper limit, it may be difficult to form a thin film.

  In the composition for organic electroluminescent elements of the present invention, the weight mixing ratio of the light emitting material / nitrogen-containing heterocyclic compound is usually 0.1 / 99.9 or more, more preferably 0.5 / 99. 5 or more, more preferably 1/99 or more, most preferably 2/98 or more, usually 50/50 or less, more preferably 40/60 or less, still more preferably 30/70 or less. And most preferably 20/80 or less. If this ratio falls below the lower limit or exceeds the upper limit, the luminous efficiency may be significantly reduced.

Further, the content of the solvent is preferably 10 parts by weight or more, more preferably 50 parts by weight or more, particularly preferably 80 parts by weight or more, and preferably 100 parts by weight with respect to 100 parts by weight of the nitrogen-containing heterocyclic compound of the present invention. It is 99.95 parts by weight or less, more preferably 99.9 parts by weight or less, and particularly preferably 99.8 parts by weight or less.
Within the above range, when forming a film by a wet film forming method, it is preferable because film uniformity is excellent and a sufficient film thickness can be obtained after film formation.

[5] Properties and physical properties of the composition for organic electroluminescent elements.
Water concentration Specifically, the amount of water contained in the composition for organic electroluminescent elements of the present invention is usually 1% by weight or less, preferably 0.1% by weight or less, more preferably 0.01% by weight or less. It is. Moreover, since it is better that the moisture contained in the composition is less, the lower limit value is ideally 0.

As a method for measuring the moisture concentration in the composition for organic electroluminescent elements, the method described in Japanese Industrial Standard “Method for Measuring Moisture of Chemical Products” (JIS K0068: 2001) is preferable. For example, the Karl Fischer reagent method (JIS K0211). -1348) and the like.
(Physical properties)
Regarding the viscosity of the composition for organic electroluminescent elements of the present invention, when the viscosity is extremely low, for example, coating surface non-uniformity due to excessive liquid film flow in the film forming process, nozzle ejection failure in ink jet film formation, etc. are likely to occur. In the case of extremely high viscosity, nozzle clogging or the like in ink jet film formation is likely to occur. For this reason, the viscosity at 25 ° C. of the composition of the present invention is usually 2 mPa · s or more, preferably 3 mPa · s or more, more preferably 5 mPa · s or more, and usually 1000 mPa · s or less, preferably 100 mPa · s or less. More preferably, it is 50 mPa · s or less.

Further, when the surface tension of the composition for organic electroluminescent elements of the present invention is high, the wettability of the film forming liquid to the substrate is lowered, the leveling property of the liquid film is poor, and the film formation surface is disturbed during drying. Since problems such as being easy to occur may occur, the surface tension of the composition of the present invention at 20 ° C. is usually less than 50 mN / m, preferably less than 40 mN / m.
Furthermore, when the vapor pressure of the composition for organic electroluminescent elements of the present invention is high, problems such as changes in solute concentration due to evaporation of the solvent may easily occur. For this reason, the vapor pressure at 25 ° C. of the composition of the present invention is usually 50 mmHg or less, preferably 10 mmHg or less, more preferably 1 mmHg or less.

[Organic electroluminescent device]
The organic electroluminescent device of the present invention has an anode, a cathode, and an organic layer provided between both electrodes on a substrate, and the organic layer contains the nitrogen-containing heterocyclic compound of the present invention. Features. The layer containing the nitrogen-containing heterocyclic compound is preferably formed using the organic electroluminescent element material or the organic electroluminescent element composition of the present invention. The organic layer containing the nitrogen-containing heterocyclic compound of the present invention is preferably a light emitting layer. The layer containing the nitrogen-containing heterocyclic compound is preferably doped with an organometallic complex. As this organometallic complex, those exemplified as the light emitting material can be used.

FIG. 1 is a schematic cross-sectional view showing a structural example of an organic electroluminescent device according to the present invention. In FIG. 1, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, 5 Represents a light-emitting layer, 6 represents a hole blocking layer, 7 represents an electron transport layer, 8 represents an electron injection layer, and 9 represents a cathode.
In the present invention, the wet film forming method includes, for example, spin coating method, dip coating method, die coating method, bar coating method, blade coating method, roll coating method, spray coating method, capillary coating method, ink jet method, screen printing. This method is a wet film formation method such as a method, a gravure printing method, or a flexographic printing method. Among these film forming methods, a spin coating method, a spray coating method, and an ink jet method are preferable. This is because the liquid property specific to the coating composition used for the organic electroluminescent element is matched.

{substrate}
The substrate 1 serves as a support for the organic electroluminescent element, and a quartz or glass plate, a metal plate or a metal foil, a plastic film, a sheet, or the like is used. In particular, a glass plate or a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, polysulfone or the like is preferable. When using a synthetic resin substrate, it is necessary to pay attention to gas barrier properties. If the gas barrier property of the substrate is too small, the organic electroluminescent element may be deteriorated by the outside air that has passed through the substrate, which is not preferable. For this reason, a method of providing a gas barrier property by providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate is also a preferable method.

{anode}
The anode 2 serves to inject holes into the layer on the light emitting layer side.
This anode 2 is usually a metal such as aluminum, gold, silver, nickel, palladium, or platinum, a metal oxide such as an oxide of indium and / or tin, a metal halide such as copper iodide, carbon black, or It is composed of a conductive polymer such as poly (3-methylthiophene), polypyrrole, or polyaniline.

  In general, the anode 2 is often formed by a sputtering method, a vacuum deposition method, or the like. In addition, when forming the anode 2 using fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, and conductive polymer fine powder, an appropriate binder resin solution It is also possible to form the anode 2 by dispersing it and applying it onto the substrate 1. Furthermore, in the case of a conductive polymer, a thin film can be directly formed on the substrate 1 by electrolytic polymerization, or the anode 2 can be formed by applying a conductive polymer on the substrate 1 (Appl. Phys. Lett. 60, 2711, 1992).

The anode 2 usually has a single-layer structure, but it can also have a laminated structure made of a plurality of materials if desired.
The thickness of the anode 2 varies depending on the required transparency. When transparency is required, the visible light transmittance is usually 60% or more, preferably 80% or more. In this case, the thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and is usually 1000 nm or less, preferably about 500 nm or less. When it may be opaque, the thickness of the anode 2 is arbitrary, and the anode 2 may be the same as the substrate 1. Furthermore, it is also possible to laminate different conductive materials on the anode 2 described above.

For the purpose of removing impurities adhering to the anode 2 and adjusting the ionization potential to improve the hole injection property, the surface of the anode 2 is treated with ultraviolet (UV) / ozone, or with oxygen plasma or argon plasma. It is preferable to do.
{Hole injection layer}
The hole injection layer 3 is a layer that transports holes from the anode 2 to the light emitting layer 5, and is usually formed on the anode 2.

The method for forming the hole injection layer 3 according to the present invention may be a vacuum deposition method or a wet film formation method, and is not particularly limited, but the hole injection layer 3 is formed by a wet film formation method from the viewpoint of reducing dark spots. It is preferable.
The thickness of the hole injection layer 3 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

<Formation of hole injection layer by wet film formation method>
When forming the hole injection layer 3 by wet film formation, the material for forming the hole injection layer 3 is usually mixed with an appropriate solvent (hole injection layer solvent) to form a film-forming composition (positive Hole injecting layer forming composition), and applying the hole injecting layer forming composition on the layer corresponding to the lower layer of the hole injecting layer 3 (usually an anode) by an appropriate technique, The hole injection layer 3 is formed by drying.

(Hole transporting compound)
The composition for forming a hole injection layer usually contains a hole transporting compound and a solvent as a constituent material of the hole injection layer.
The hole transporting compound is a compound having a hole transporting property that is usually used in a hole injection layer of an organic electroluminescence device, and may be a polymer compound or the like, a monomer or the like. Although it may be a low molecular weight compound, it is preferably a high molecular weight compound.

  The hole transporting compound is preferably a compound having an ionization potential of 4.5 eV to 6.0 eV from the viewpoint of a charge injection barrier from the anode 2 to the hole injection layer 3. Examples of hole transporting compounds include aromatic amine derivatives, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, benzylphenyl derivatives, compounds in which tertiary amines are linked by a fluorene group, hydrazone derivatives, silazane derivatives, silanamines Derivatives, phosphamine derivatives, quinacridone derivatives, polyaniline derivatives, polypyrrole derivatives, polyphenylene vinylene derivatives, polythienylene vinylene derivatives, polyquinoline derivatives, polyquinoxaline derivatives, carbon and the like.

In the present invention, the derivative includes, for example, an aromatic amine derivative, and includes an aromatic amine itself and a compound having an aromatic amine as a main skeleton. It may be a mer.
The hole transporting compound used as the material for the hole injection layer 3 may contain any one of these compounds alone, or may contain two or more. When two or more kinds of hole transporting compounds are contained, the combination thereof is arbitrary, but one or more aromatic tertiary amine polymers and one or more other hole transporting compounds are used. It is preferable to use together.

Among the examples exemplified above, an aromatic amine compound is preferable from the viewpoint of amorphousness and visible light transmittance, and an aromatic tertiary amine compound is particularly preferable. Here, the aromatic tertiary amine compound is a compound having an aromatic tertiary amine structure, and includes a compound having a group derived from an aromatic tertiary amine.
The type of the aromatic tertiary amine compound is not particularly limited, but from the viewpoint of uniform light emission due to the surface smoothing effect, a polymer compound having a weight average molecular weight of 1,000 or more and 1,000,000 or less (a polymerizable compound in which repeating units are linked) is further included. preferable. Preferable examples of the aromatic tertiary amine polymer include polymer compounds having a repeating unit represented by the following formula (I).

(In the formula (I), Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. Ar ^{3 to} Ar ⁵ each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. Represents a linking group selected from the group of linking groups, and among Ar ^{1 to} Ar ⁵ , two groups bonded to the same N atom may be bonded to each other to form a ring.

(In the above formulas, Ar ^{6 to} Ar ¹⁶ each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. R ¹ and R ² each independently represents a hydrogen atom or an arbitrary substituent.))
As the aromatic hydrocarbon group and aromatic heterocyclic group of Ar ^{1 to} Ar ¹⁶ , a benzene ring, a naphthalene ring, a phenanthrene ring, a thiophene from the viewpoint of the solubility, heat resistance, hole injection / transport property of the polymer compound A group derived from a ring or a pyridine ring is preferred, and a group derived from a benzene ring or a naphthalene ring is more preferred.

The aromatic hydrocarbon group and aromatic heterocyclic group of Ar ^{1 to} Ar ¹⁶ may further have a substituent. The molecular weight of the substituent is usually 400 or less, preferably about 250 or less. As the substituent, an alkyl group, an alkenyl group, an alkoxy group, an aromatic hydrocarbon group, an aromatic heterocyclic group and the like are preferable.
When R ¹ and R ² are optional substituents, examples of the substituent include alkyl groups, alkenyl groups, alkoxy groups, silyl groups, siloxy groups, aromatic hydrocarbon groups, aromatic heterocyclic groups, and the like. .

Specific examples of the aromatic tertiary amine polymer having a repeating unit represented by the formula (I) include those described in International Publication No. 2005/089024.
In addition, as a hole transporting compound, a conductive polymer (PEDOT / PSS) obtained by polymerizing 3,4-ethylenedioxythiophene (3,4-ethylenedioxythiophene), a polythiophene derivative, in high molecular weight polystyrene sulfonic acid. Is also preferred. Moreover, the end of this polymer may be capped with methacrylate or the like.

  The concentration of the hole transporting compound in the composition for forming a hole injection layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.01% by weight or more, preferably in terms of film thickness uniformity. Is 0.1% by weight or more, more preferably 0.5% by weight or more, and usually 70% by weight or less, preferably 60% by weight or less, more preferably 50% by weight or less. If this concentration is too high, film thickness unevenness may occur, and if it is too low, defects may occur in the formed hole injection layer.

(Electron-accepting compound)
The composition for forming a hole injection layer preferably contains an electron accepting compound as a constituent material of the hole injection layer.
The electron-accepting compound is preferably a compound having an oxidizing power and the ability to accept one electron from the above-described hole transporting compound, specifically, a compound having an electron affinity of 4 eV or more is preferable, and 5 eV or more. The compound which is the compound of these is further more preferable.

Examples of such electron-accepting compounds include triarylboron compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. Examples thereof include one or more compounds selected from the group. More specifically, an onium salt substituted with an organic group such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate and triphenylsulfonium tetrafluoroborate (International Publication No. WO 2005/089024); High valent inorganic compounds such as iron (III) chloride (Japanese Patent Laid-Open No. 11-251067), ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene, tris (pendafluorophenyl) borane (Japanese Patent Laid-Open No. 2003-31365) Aromatic boron compounds such as); fullerene derivatives; iodine; sulfonate ions such as polystyrene sulfonate ions, alkylbenzene sulfonate ions, camphor sulfonate ions, and the like.

These electron accepting compounds can improve the conductivity of the hole injection layer by oxidizing the hole transporting compound.
The content of the electron-accepting compound in the hole-injecting layer or the composition for forming a hole-injecting layer with respect to the hole-transporting compound is usually 0.1 mol% or more, preferably 1 mol% or more. However, it is usually 100 mol% or less, preferably 40 mol% or less.

(Other components)
As a material for the hole injection layer, other components may be further contained in addition to the above-described hole transporting compound and electron accepting compound as long as the effects of the present invention are not significantly impaired. Examples of other components include various light emitting materials, electron transporting compounds, binder resins, and coating property improving agents. In addition, only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and ratios.

(solvent)
At least one of the solvents of the composition for forming a hole injection layer used in the wet film formation method is preferably a compound that can dissolve the constituent material of the hole injection layer. The boiling point of this solvent is usually 110 ° C. or higher, preferably 140 ° C. or higher, particularly 200 ° C. or higher, usually 400 ° C. or lower, and preferably 300 ° C. or lower. If the boiling point of the solvent is too low, the drying speed is too high and the film quality may be deteriorated. Further, if the boiling point of the solvent is too high, it is necessary to increase the temperature of the drying step, which may adversely affect other layers and the substrate.

Examples of the solvent include ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, and the like.
Examples of ether solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole , Phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, aromatic ethers such as 2,4-dimethylanisole, and the like.

Examples of the ester solvent include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate.
Examples of the aromatic hydrocarbon solvent include toluene, xylene, cyclohexylbenzene, 3-isopropylpropylphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, cyclohexylbenzene, and methylnaphthalene. Can be mentioned.

Examples of the amide solvent include N, N-dimethylformamide, N, N-dimethylacetamide, and the like.
In addition, dimethyl sulfoxide and the like can also be used.
These solvent may use only 1 type and may use 2 or more types by arbitrary combinations and a ratio.

(Film formation method)
After preparing the composition for forming the hole injection layer, this composition is applied by wet film formation onto a layer corresponding to the lower layer of the hole injection layer 3 (usually, the anode 2) and dried. The hole injection layer 3 is formed.
The temperature in the coating step is preferably 10 ° C. or higher and preferably 50 ° C. or lower in order to prevent film loss due to the formation of crystals in the composition.

Although the relative humidity in an application | coating process is not limited unless the effect of this invention is impaired remarkably, it is 0.01 ppm or more normally, and usually 80% or less.
After coating, the film of the composition for forming a hole injection layer is usually dried by heating or the like. Examples of the heating means used in the heating step include a clean oven, a hot plate, infrared rays, a halogen heater, microwave irradiation and the like. Among them, a clean oven and a hot plate are preferable in order to uniformly apply heat to the entire film.

The heating temperature in the heating step is preferably heated at a temperature equal to or higher than the boiling point of the solvent used in the composition for forming a hole injection layer as long as the effects of the present invention are not significantly impaired. In the case of a mixed solvent containing two or more types of solvents used in the hole injection layer, at least one type is preferably heated at a temperature equal to or higher than the boiling point of the solvent. In consideration of an increase in the boiling point of the solvent, the heating step is preferably performed at 120 ° C. or higher, preferably 410 ° C. or lower.

  In the heating step, the heating time is not limited as long as the heating temperature is not lower than the boiling point of the solvent of the composition for forming a hole injection layer and sufficient insolubilization of the coating film does not occur. Is less than a minute. If the heating time is too long, the components of the other layers tend to diffuse, and if it is too short, the hole injection layer tends to be inhomogeneous. Heating may be performed in two steps.

<Formation of hole injection layer by vacuum deposition>
When the hole injection layer 3 is formed by vacuum deposition, one or more of the constituent materials of the hole injection layer 3 (the aforementioned hole transporting compound, electron accepting compound, etc.) are placed in a vacuum vessel. Put in crucibles installed (in case of using two or more materials, put them in each crucible), evacuate the inside of the vacuum vessel to about 10 ⁻⁴ Pa with a suitable vacuum pump, and then heat the crucible (two types When using the above materials, heat each crucible) and control the evaporation amount to evaporate (when using two or more materials, control each evaporation amount independently) and face the crucible Then, the hole injection layer 3 is formed on the anode 2 of the substrate placed on the substrate. In addition, when using 2 or more types of materials, the hole injection layer 3 can also be formed by putting those mixtures into a crucible, heating and evaporating.

The degree of vacuum at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 × 10 ⁻⁶ Torr (0.13 × 10 ⁻⁴ Pa) or more, usually 9.0 × 10 ⁻⁶ Torr. (12.0 × 10 ⁻⁴ Pa) or less. The deposition rate is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 Å / second or more and usually 5.0 Å / second or less. The film forming temperature at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 10 ° C. or higher, preferably 50 ° C. or lower.

{Hole transport layer}
The method for forming the hole transport layer 4 according to the present invention may be a vacuum deposition method or a wet film formation method, and is not particularly limited, but the hole transport layer 4 is formed by a wet film formation method from the viewpoint of reducing dark spots. It is preferable.
The hole transport layer 4 can be formed on the hole injection layer 3 when there is a hole injection layer and on the anode 2 when there is no hole injection layer 3. The organic electroluminescent device of the present invention may have a configuration in which the hole transport layer is omitted.

  The material for forming the hole transport layer 4 is preferably a material having a high hole transport capability and capable of efficiently transporting injected holes. Therefore, it is preferable that the ionization potential is small, the transparency to visible light is high, the hole mobility is large, the stability is high, and impurities that become traps are not easily generated during manufacturing or use. In many cases, it is preferable not to quench the light emitted from the light emitting layer 5 or to form an exciplex with the light emitting layer 5 to reduce the efficiency because it is in contact with the light emitting layer 5.

  Such a material for the hole transport layer 4 may be any material conventionally used as a constituent material for the hole transport layer. For example, the hole transport property used for the hole injection layer 3 described above. What was illustrated as a compound is mentioned. In addition, arylamine derivatives, fluorene derivatives, spiro derivatives, carbazole derivatives, pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, phthalocyanine derivatives, porphyrin derivatives, silole derivatives, oligothiophene derivatives, condensed polycyclic aromatics Group derivatives, metal complexes and the like.

In addition, for example, polyvinylcarbazole derivatives, polyarylamine derivatives, polyvinyltriphenylamine derivatives, polyfluorene derivatives, polyarylene derivatives, polyarylene ether sulfone derivatives containing tetraphenylbenzidine, polyarylene vinylene derivatives, polysiloxane derivatives, polythiophenes Derivatives, poly (p-phenylene vinylene) derivatives, and the like. These may be any of an alternating copolymer, a random polymer, a block polymer, or a graft copolymer. Further, it may be a polymer having a branched main chain and three or more terminal portions, or a so-called dendrimer.

Of these, polyarylamine derivatives and polyarylene derivatives are preferred.
The polyarylamine derivative is preferably a polymer containing a repeating unit represented by the following formula (II). In particular, the polymer is preferably composed of a repeating unit represented by the following formula (II). In this case, Ar ^a or Ar ^b may be different in each repeating unit.

(In formula (II), Ar ^a and Ar ^b each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent.)
Examples of the aromatic hydrocarbon group which may have a substituent include, for example, a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, and acenaphthene. Examples include a group derived from a 6-membered monocyclic ring or a 2-5 condensed ring, such as a ring, a fluoranthene ring, a fluorene ring, and a group in which these rings are linked by a direct bond.

  Examples of the aromatic heterocyclic group which may have a substituent include a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, and a carbazole ring. , Pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine Ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring, etc. ring Are those groups group and the rings of from 2-4 fused ring is linked by a direct bond or two or more rings.

Ar ^a and Ar ^b are each independently composed of a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a triphenylene ring, a pyrene ring, a thiophene ring, a pyridine ring, and a fluorene ring from the viewpoint of solubility in solvents and heat resistance. A group derived from a ring selected from the group or a group formed by linking two or more benzene rings (for example, a biphenyl group (biphenylene group) or a terphenyl group (terphenylene group)) is preferable.

Among these, a group derived from a benzene ring (phenyl group), a group formed by connecting two benzene rings (biphenyl group), and a group derived from a fluorene ring (fluorenyl group) are preferable.
Examples of the substituent that the aromatic hydrocarbon group and aromatic heterocyclic group in Ar ^a and Ar ^b may have include an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, and a dialkyl. Examples thereof include an amino group, a diarylamino group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, a cyano group, an aromatic hydrocarbon ring group, and an aromatic heterocyclic group.

As the polyarylene derivative, an arylene group such as an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent exemplified as Ar ^a or Ar ^b in the formula (II) is used as ^a repeating unit. The polymer which has is mentioned.
As a polyarylene derivative, the polymer which has a repeating unit which consists of following formula (III-1) and / or following formula (III-2) is preferable.

(In formula (III-1), R ^a , R ^b , R ^c and R ^d are each independently an alkyl group, an alkoxy group, a phenylalkyl group, a phenylalkoxy group, a phenyl group, a phenoxy group, an alkylphenyl group, Represents an alkoxyphenyl group, an alkylcarbonyl group, an alkoxycarbonyl group, or a carboxy group, and t and s each independently represent an integer of 0 to 3. When t or s is 2 or more, they are contained in one molecule. A plurality of R ^a or R ^b may be the same or different, and adjacent R ^a or R ^b may form a ring.)

(In formula (III-2), R ^e and R ^f are each independently the same as R ^a , R ^b , R ^c or R ^d in formula (III-1). Independently represents an integer of 0 to 3. When r or u is 2 or more, a plurality of R ^e and R ^f contained in one molecule may be the same or different, and adjacent R ^e or R ^f may form a ring, and X represents an atom or a group of atoms constituting a 5-membered ring or a 6-membered ring.)
Specific examples of X are —O—, —BR—, —NR—, —SiR ₂ —, —PR—, —SR—, —CR ₂ —, or a group formed by bonding thereof. R represents a hydrogen atom or an arbitrary organic group. The organic group in the present invention is a group containing at least one carbon atom.

  The polyarylene derivative has a repeating unit represented by the following formula (III-3) in addition to the repeating unit consisting of the formula (III-1) and / or the formula (III-2). Is preferred.

(In formula (III-3), Ar ^{c to} Ar ^j each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent, and v and w each represent Independently represents 0 or 1.)
Specific examples of Ar ^{c to} Ar ^j are the same as Ar ^a and Ar ^b in the formula (II).
Specific examples of the above formulas (III-1) to (III-3) and specific examples of polyarylene derivatives include those described in JP-A-2008-98619.

When the hole transport layer 4 is formed by a wet film forming method, a hole transport layer forming composition is prepared in the same manner as the formation of the hole injection layer 3, and then wet-coated and then heat-dried. Form a film.
The composition for forming a hole transport layer contains a solvent in addition to the above hole transport compound. The solvent used is the same as that used for the composition for forming a hole injection layer. In addition, the application conditions, the heat drying conditions, and the like are the same as in the case of forming the hole injection layer 3.

In the case where the hole transport layer is formed by the vacuum deposition method, the film forming conditions are the same as those in the case of forming the hole injection layer 3.
The hole transport layer 4 may contain various light emitting materials, electron transport compounds, binder resins, coating property improving agents, and the like in addition to the hole transport compound.
The hole transport layer 4 may also be a layer formed by crosslinking a crosslinkable compound. The crosslinkable compound is a compound having a crosslinkable group, and forms a network polymer compound by crosslinking.

Examples of this crosslinkable group include groups derived from cyclic ethers such as oxetane and epoxy; groups derived from unsaturated double bonds such as vinyl, trifluorovinyl, styryl, acrylic, methacryloyl and cinnamoyl; benzo And a group derived from a cyclobutene ring.
The crosslinkable compound may be any of a monomer, an oligomer, and a polymer. The crosslinkable compound may have only 1 type, and may have 2 or more types by arbitrary combinations and ratios.

  As the crosslinkable compound, a hole transporting compound having a crosslinkable group is preferably used. Examples of the hole transporting compound include those exemplified above, and those having a crosslinkable group bonded to the main chain or side chain with respect to these hole transporting compounds. In particular, the crosslinkable group is preferably bonded to the main chain via a linking group such as an alkylene group. In particular, the hole transporting compound is preferably a polymer containing a repeating unit having a crosslinkable group, and the above formula (II) and formulas (III-1) to (III-3) can be used as a crosslinkable group. Is preferably a polymer having a repeating unit bonded directly or via a linking group.

As the crosslinkable compound, a hole transporting compound having a crosslinkable group is preferably used. Examples of hole transporting compounds include nitrogen-containing aromatic compound derivatives such as pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, carbazole derivatives, phthalocyanine derivatives, porphyrin derivatives; triphenylamine derivatives Silole derivatives; oligothiophene derivatives, condensed polycyclic aromatic derivatives, metal complexes and the like. Among them, nitrogen-containing aromatic derivatives such as pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, carbazole derivatives; triphenylamine derivatives, silole derivatives, condensed polycyclic aromatic derivatives, metal complexes, etc. Particularly preferred are triphenylamine derivatives.

In order to form a hole transport layer 4 by crosslinking a crosslinkable compound, a composition for forming a hole transport layer in which a crosslinkable compound is dissolved or dispersed in a solvent is usually prepared and deposited by wet film formation. To crosslink.
The composition for forming a hole transport layer may contain an additive for promoting a crosslinking reaction in addition to the crosslinking compound. Examples of additives that promote the crosslinking reaction include polymerization initiators and polymerization accelerators such as alkylphenone compounds, acylphosphine oxide compounds, metallocene compounds, oxime ester compounds, azo compounds, onium salts; condensed polycyclic hydrocarbons, And photosensitizers such as porphyrin compounds and diaryl ketone compounds.

Further, it may contain a coating property improving agent such as a leveling agent and an antifoaming agent; an electron accepting compound; a binder resin;
In the composition for forming a hole transport layer, the crosslinkable compound is usually 0.01% by weight or more, preferably 0.05% by weight or more, more preferably 0.1% by weight or more, usually 50% by weight or less, preferably 20%. It is contained by weight% or less, more preferably 10% by weight or less.

After forming a composition for forming a hole transport layer containing a crosslinkable compound at such a concentration on the lower layer (usually the hole injection layer 3), the composition is crosslinked by heating and / or irradiation with active energy such as light. Are crosslinked to form a network polymer compound.
Conditions such as temperature and humidity at the time of application are the same as those at the time of wet application of the hole injection layer 3.
The heating method after application is not particularly limited. As heating temperature conditions, it is 120 degreeC or more normally, Preferably it is 400 degrees C or less.

The heating time is usually 1 minute or longer, preferably 24 hours or shorter. The heating means is not particularly limited, and means such as placing a laminated body having a deposited layer on a hot plate or heating in an oven is used. For example, conditions such as heating on a hot plate at 120 ° C. or more for 1 minute or more can be used.
In the case of irradiation with active energy such as light, a method of irradiating directly using an ultraviolet / visible / infrared light source such as an ultra-high pressure mercury lamp, a high-pressure mercury lamp, a halogen lamp, an infrared lamp, or the above-mentioned light source is incorporated. Examples include a mask aligner and a method of irradiation using a conveyor type light irradiation device. In active energy irradiation other than light, for example, there is a method of irradiation using a so-called microwave oven that irradiates a microwave generated by a magnetron. As the irradiation time, it is preferable to set conditions necessary for reducing the solubility of the film, but irradiation is usually performed for 0.1 seconds or longer, preferably 10 hours or shorter.

The irradiation of active energy such as heating and light may be performed alone or in combination. When combined, the order of implementation is not particularly limited.
The film thickness of the hole transport layer 4 thus formed is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 100 nm or less.
{Light emitting layer}
A light emitting layer 4 is usually provided on the hole injection layer 3. The light emitting layer 4 is a layer containing a light emitting material, and between the electrodes to which an electric field is applied, holes injected from the anode 2 through the hole injection layer 3 and electrons injected from the cathode 6 through the electron injection layer 5 It is a layer that is excited by recombination and becomes a main light emitting source. The light emitting layer 4 preferably contains a light emitting material (dopant) and one or more host materials, and the light emitting layer 4 more preferably contains the nitrogen-containing heterocyclic compound of the present invention as a host material. However, it is particularly preferable that the layer be formed by a wet film-forming method using the composition for organic electroluminescent elements of the present invention.

Here, the wet film-forming method is a method in which the composition for organic electroluminescent elements of the present invention containing the above-mentioned solvent is applied by spin coating, spray coating, dip coating, die coating, flexographic printing, screen printing, or inkjet method. It is a film.
In addition, the light emitting layer 4 may contain other materials and components as long as the performance of the present invention is not impaired.

  In general, when the same material is used in the organic electroluminescent element, the thinner the film thickness between the electrodes, the larger the effective electric field, so that the injected current increases, so the driving voltage decreases. For this reason, the driving voltage of the organic electroluminescence device decreases when the total film thickness between the electrodes is thin, but if it is too thin, a short circuit occurs due to the protrusion caused by the electrode such as ITO. Necessary.

In the present invention, in addition to the light emitting layer 4, when the organic layer such as the hole injection layer 3 and the electron transport layer 7 described later is provided, the light emitting layer 4 and other organic materials such as the hole injection layer 3 and the electron transport layer 7 The total film thickness combined with the layers is usually 30 nm or more, preferably 50 nm or more, more preferably 100 nm or less.
Above, it is 1000 nm or less normally, Preferably it is 500 nm or less, More preferably, it is 300 nm or less. In addition, when the conductivity of the hole injection layer 3 other than the light emitting layer 4 and the electron injection layer 5 described later is high, the amount of charge injected into the light emitting layer 4 increases. It is also possible to reduce the drive voltage while increasing the thickness to reduce the thickness of the light emitting layer 4 and maintaining the total thickness to some extent.

Therefore, the thickness of the light emitting layer 4 is usually 10 nm or more, preferably 20 nm or more, and usually 300 nm or less, preferably 200 nm or less. When the element of the present invention has only the light emitting layer 4 between the anode and the cathode, the thickness of the light emitting layer 4 is usually 30 nm or more, preferably 50 nm or more, usually 500 nm or less, preferably 300 nm or less. is there.
{Hole blocking layer}
A hole blocking layer 6 may be provided between the light emitting layer 5 and an electron injection layer 8 described later. The hole blocking layer 6 is a layer laminated on the light emitting layer 5 so as to be in contact with the interface of the light emitting layer 5 on the cathode 9 side.

The hole blocking layer 6 has a role of blocking holes moving from the anode 2 from reaching the cathode 9 and a role of efficiently transporting electrons injected from the cathode 9 toward the light emitting layer 5. Have

The physical properties required for the material constituting the hole blocking layer 6 include high electron mobility, low hole mobility, a large energy gap (difference between HOMO and LUMO), and excited triplet level (T1). Is high. Examples of the material for the hole blocking layer satisfying such conditions include bis (2-methyl-8-quinolinolato) (phenolato) aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum, and the like. Mixed metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum binuclear metal complexes, distyrylbiphenyl derivatives, etc. Triazole derivatives such as styryl compounds (JP-A-11-242996), 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole (JP-A-7 -41759), phenanthroline derivatives such as bathocuproine (JP-A-10-79297), and the like. That. Further, a compound having at least one pyridine ring substituted at the 2,4,6-position described in International Publication No. 2005-022962 is also preferable as the material for the hole blocking layer 6.

In addition, the material of the hole-blocking layer 6 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
There is no restriction | limiting in the formation method of the hole-blocking layer 6. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.
The thickness of the hole blocking layer 6 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

{Electron transport layer}
An electron transport layer 7 may be provided between the light emitting layer 5 and an electron injection layer 8 described later.
The electron transport layer 7 is provided for the purpose of further improving the light emission efficiency of the device, and efficiently transports electrons injected from the cathode 9 between the electrodes to which an electric field is applied in the direction of the light emitting layer 5. Formed from a compound capable of

  As an electron transporting compound used for the electron transport layer 7, usually, the electron injection efficiency from the cathode 9 or the electron injection layer 8 is high, and the injected electrons having high electron mobility are efficiently transported. The compound which can be used is used. Examples of the compound satisfying such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, oxadiazole derivatives , Distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), quinoxaline compounds ( JP-A-6-207169), phenanthroline derivative (JP-A-5-331459), 2-t-butyl-9,10-N, N'-dicyanoanthraquinonediimine, n-type hydrogenated amorphous silicon carbide , N-type zinc sulfide, n-type zinc Such as emissions of zinc, and the like.

In addition, the material of the electron carrying layer 7 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
There is no restriction | limiting in the formation method of the electron carrying layer 7. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.
The thickness of the electron transport layer 7 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.
{Electron injection layer}
The electron injection layer 8 plays a role of efficiently injecting electrons injected from the cathode 9 into the light emitting layer 5. In order to perform electron injection efficiently, the material for forming the electron injection layer 8 is preferably a metal having a low work function. Examples include alkali metals such as sodium and cesium, alkaline earth metals such as barium and calcium, and the film thickness is preferably from 0.1 nm to 5 nm.

  Furthermore, an organic electron transport compound represented by a metal complex such as a nitrogen-containing heterocyclic compound such as bathophenanthroline or an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium, or rubidium ( (As described in JP-A-10-270171, JP-A-2002-1000047, JP-A-2002-1000048, etc.), it is possible to improve the electron injection / transport properties and achieve excellent film quality. preferable. In this case, the film thickness is usually 5 nm or more, preferably 10 nm or more, and is usually 200 nm or less, preferably 100 nm or less.

In addition, the material of the electron injection layer 8 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
There is no restriction | limiting in the formation method of the electron injection layer 8. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.
{cathode}
The cathode 9 plays a role of injecting electrons into a layer on the light emitting layer 5 side (such as the electron injection layer 8 or the light emitting layer 5).

  As the material of the cathode 9, the material used for the anode 2 can be used. However, in order to perform electron injection efficiently, a metal having a low work function is preferable. For example, tin, magnesium, indium, A suitable metal such as calcium, aluminum, silver, or an alloy thereof is used. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

In addition, the material of the cathode 9 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The film thickness of the cathode 9 is usually the same as that of the anode 2.
Further, for the purpose of protecting the cathode 9 made of a low work function metal, it is preferable to further stack a metal layer having a high work function and stable to the atmosphere because the stability of the device is increased. For this purpose, for example, metals such as aluminum, silver, copper, nickel, chromium, gold and platinum are used. In addition, these materials may be used only by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

{Other layers}
The organic electroluminescent element according to the present invention may have another configuration without departing from the gist thereof. For example, as long as the performance is not impaired, an arbitrary layer may be provided between the anode 2 and the cathode 9 in addition to the layers described above, and an arbitrary layer may be omitted. .
<Electron blocking layer>
Examples of the layer that may be included include an electron blocking layer.

  The electron blocking layer is provided between the hole injection layer 3 or the hole transport layer 4 and the light emitting layer 5 and prevents electrons moving from the light emitting layer 5 from reaching the hole injection layer 3. Thus, the probability of recombination of holes and electrons in the light emitting layer 5 is increased, the excitons generated are confined in the light emitting layer 5, and the holes injected from the hole injection layer 3 are efficiently collected. There is a role to transport in the direction of. In particular, when a phosphorescent material or a blue light emitting material is used as the light emitting material, it is effective to provide an electron blocking layer.

  The characteristics required for the electron blocking layer include high hole transportability, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1). Furthermore, in the present invention, when the light emitting layer 5 is formed as an organic layer according to the present invention by a wet film formation method, the electron blocking layer is also required to be compatible with the wet film formation. Examples of the material used for such an electron blocking layer include a copolymer of dioctylfluorene and triphenylamine typified by F8-TFB (International Publication No. 2004/084260).

In addition, the material of an electron blocking layer may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
There is no restriction | limiting in the formation method of an electron blocking layer. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

Further, at the interface between the cathode 9 and the light emitting layer 5 or the electron transport layer 7, for example, lithium fluoride (LiF), magnesium fluoride (MgF ₂ ), lithium oxide (Li ₂ O), cesium carbonate (II) (CsCO ₃ ). Inserting an ultrathin insulating film (0.1 to 5 nm) formed by the above method is also an effective method for improving the efficiency of the device (Applied Physics Letters, 1997, Vol. 70, pp. 152; Kaihei 10-74586; IEEE Transactions on Electron Devices, 1
997, Vol. 44, pp. 1245; SID 04 Digest, pp. 154 etc.).

Moreover, in the layer structure demonstrated above, it is also possible to laminate | stack components other than a board | substrate in reverse order. For example, in the case of the layer configuration of FIG. 1, the other components on the substrate 1 are the cathode 9, the electron injection layer 8, the electron transport layer 7, the hole blocking layer 6, the light emitting layer 5, the hole transport layer 4, the positive layer. The hole injection layer 3 and the anode 2 may be provided in this order.
Furthermore, it is also possible to constitute the organic electroluminescent element according to the present invention by laminating components other than the substrate between two substrates, at least one of which is transparent.

In addition, a structure in which a plurality of components (light emitting units) other than the substrate are stacked in a plurality of layers (a structure in which a plurality of light emitting units are stacked) may be employed. In that case, instead of the interface layer between the steps (between the light emitting units) (when the anode is ITO and the cathode is Al, these two layers), for example, a charge made of vanadium pentoxide (V ₂ O ₅ ) or the like. When a generation layer (Carrier Generation Layer: CGL) is provided, a barrier between steps is reduced, which is more preferable from the viewpoint of light emission efficiency and driving voltage.

Furthermore, the organic electroluminescent device according to the present invention may be configured as a single organic electroluminescent device, or may be applied to a configuration in which a plurality of organic electroluminescent devices are arranged in an array. You may apply to the structure by which the cathode is arrange | positioned at XY matrix form.
Each layer described above may contain components other than those described as materials unless the effects of the present invention are significantly impaired.

[Organic EL display and organic EL lighting]
The organic electroluminescent element of the present invention is used for an organic EL display or organic EL illumination. The organic electroluminescent device obtained by the present invention is described in, for example, “Organic EL Display” (Ohm, August 20, 2004, written by Shizushi Tokito, Chiba Adachi, and Hideyuki Murata). An organic EL display and organic EL illumination can be formed by the method.

EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to description of a following example, unless the summary is exceeded.
(Synthesis Example 1: Synthesis of Compound 1)

<Synthesis of Intermediate 1>
Grinded magnesium (145 mg, 6.0 mmol) was added to THF (3 mL), and a THF solution (1 mL) of bromobenzene (973 mg, 6.2 mmol) was gently added dropwise at room temperature. After completion of the dropwise addition, the reaction mixture was stirred for 1 hour while refluxing. Then, under reflux conditions 2-amino-5-bromobenzonitrile (1.18
g, 6.0 mmol) in THF (1 mL) was gently added dropwise, followed by further stirring for 30 minutes. Thereafter, the reaction mixture was cooled to 0 ° C., a THF solution (1 mL) of 3-bromobenzoyl chloride (658 mg, 3.0 mmol) was added gently, and the mixture was stirred for 1 hour while refluxing the reaction mixture. After completion of the reaction, the reaction mixture was poured into purified water and extracted with methylene chloride. The organic layer was washed with purified water and then dried over sodium sulfate. The solvent was distilled off under reduced pressure, and the residue was recrystallized from chloroform / hexane to obtain Intermediate 1 (444 mg).

<Synthesis of Compound 1>
Under a nitrogen atmosphere, Intermediate 1 (400 mg, 0.901 mmol), 3- (9-carbazolyl) phenylboronic acid (625 mg, 2.17 mmol) in toluene (2.7 mL) solution and 2M aqueous sodium carbonate solution (1.4 mL) , Ethanol (1.4 mL) was added and degassed with nitrogen for 10 minutes. Tetrakis (triphenylphosphine) palladium (0) (63 mg, 0.055 mmol) was added to the mixture, and the mixture was stirred for 3 hours while refluxing. After completion of the reaction, the mixture was poured into water and extracted with toluene. The organic layer was washed with purified water and dried over magnesium sulfate, and then the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography to obtain compound 1 (649 mg).

The mass spectral value of this product was 764 (M ⁺ ), and the glass transition temperature was 135 ° C.
(Synthesis Example 2: Synthesis of Compound 2)

Grinded magnesium (471 mg, 19.4 mmol) was added to THF (50 mL), and a THF solution (5 mL) of 3-bromobiphenyl (4.89 g, 21.0 mmol) was gently added dropwise at room temperature. After completion of the dropwise addition, the reaction mixture was stirred for 1 hour while refluxing. Next, a THF solution (12.5 mL) of 2-amino-5-bromobenzonitrile (3.17 g, 16.1 mmol) was gently added dropwise under reflux conditions, and the mixture was further stirred for 30 minutes. Thereafter, the reaction mixture was cooled to 0 ° C., a THF solution (12.5 mL) of 3-bromobenzoyl chloride (4.25 g, 19.4 mmol) was gently added, and then the reaction mixture was stirred for 1 hour while refluxing. After completion of the reaction, the reaction mixture was poured into purified water and extracted with methylene chloride. The organic layer was washed with purified water and then dried over sodium sulfate. The solvent was distilled off under reduced pressure, and hexane was added to the residue to precipitate a solid, yielding intermediate 2 (4.8 g).

<Synthesis of Compound 2>
Intermediate 2 (1.0 g, 1.94 mmol), 3- (9-carbazolyl) phenylboronic acid (1.22 g, 4.26 mmol) in toluene (5 mL), 2M aqueous sodium carbonate solution (2.5 mL) under nitrogen atmosphere
, Ethanol (2.5 mL) was added and degassed with nitrogen for 10 minutes. Tetrakis (triphenylphosphine) palladium (0) (115 mg, 0.10 mmol) was added to the mixture and stirred for 3 hours while refluxing. After completion of the reaction, the mixture was poured into water and extracted with toluene. The organic layer was washed with purified water and dried over magnesium sulfate, and then the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography to obtain compound 2 (1.01 g).

The mass spectral value of this product was 840 (M ⁺ ), and the glass transition temperature was 135 ° C.
[Production of organic electroluminescence device]
{Measuring method}
<Luminance half-life>
As a method for measuring the luminance half-life, a change in luminance was observed with a photodiode when a constant direct current with a luminance of 3000 nit at the start of the test was applied to the produced organic electroluminescent device. The time (luminance half-life) until the luminance value reached half of the test start, that is, 1500 nit was obtained. The energization test was performed in a room where the room temperature was controlled to 23 ± 1.5 ° C. by air conditioning.

<Drive voltage>
The driving voltage was measured by measuring the voltage at which the luminance was 1000 nit when a constant DC current was first applied to the produced organic electroluminescent device.
<Luminous efficiency>
As a method for measuring the luminous efficiency, a current value of 1000 nit was measured on the produced organic electroluminescent element to calculate the luminous efficiency. Hereinafter, the present invention will be described in more detail with reference to production examples and examples. In addition, the following examples are shown in order to explain the present invention in detail, and the present invention is not limited to the following examples unless it is contrary to the gist thereof.

<substrate>
The organic electroluminescent element shown in FIG. 1 was produced.
An indium tin oxide (ITO) transparent conductive film deposited on a glass substrate 1 with a thickness of 120 nm (manufactured by Sanyo Vacuum Co., Ltd., sputtered film product) using ordinary photolithography technology and hydrochloric acid etching Then, the anode 2 was formed by patterning into stripes having a width of 2 mm.

<Preprocessing>
The patterned ITO substrate is cleaned in the order of ultrasonic cleaning with an aqueous surfactant solution, water cleaning with ultrapure water, ultrasonic cleaning with ultrapure water, and water cleaning with ultrapure water, followed by drying with compressed air, and finally UV irradiation. Ozone cleaning was performed.

<Film formation of hole injection layer>
First, 2% by weight of a hole transporting polymer having a repeating structure represented by the following structural formula (P1) and 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate represented by the structural formula (A1) After dissolving 0.4% by weight in ethyl benzoate as a solvent, it was filtered using a PTFE (polytetrafluoroethylene) membrane filter having a pore size of 0.2 μm to prepare a coating composition. This coating composition was spin-coated on the glass substrate. As spin coating conditions, spinner rotation speed was 500 rpm, 2 seconds, and 2250 rpm, 30 seconds. Drying conditions go through the following two heating steps. After heating at 80 ° C. for 1 minute as the first heating step, drying at 230 ° C. for 1 hour as the second heating step and cooling to room temperature forms a uniform thin film with a thickness of 30 nm did. In this way, a hole injection layer 3 having a thickness of 30 nm was formed. The apparatus used for heating is an oven.

<Deposition of hole transport layer>
Next, the hole transport layer 4 was formed by a wet film formation method as follows. As the material for the hole transport layer, a composition in which 1.4% by weight of a polymer compound having a repeating structure of the following formula (HT-1) is dissolved in cyclohexylbenzene is prepared, and a membrane filter made of PTFE having a pore size of 0.2 μm is used. It filtered using, and spin-coated on the said positive hole injection layer 3 on the conditions shown below. Spin coating was performed in a nitrogen atmosphere glove box, and spin coating conditions were performed in two stages: spinner rotation speed 500 rpm, 2 seconds, and 1500 rpm, 120 seconds. Thereafter, drying was performed at 230 ° C. for 1 hour in a nitrogen atmosphere glove box to form a uniform thin film having a thickness of 18.2 nm. The apparatus used for heating is a hot plate.

<Deposition of light emitting layer>
Subsequently, the light emitting layer (organic layer) was formed by the wet film-forming method as follows. The material of the light-emitting layer is the following materials H-1, H-2, D-1, and D-2 mixed at a ratio of 50: 50: 5: 7, and 4.8% by weight of this mixture is dissolved in cyclohexylbenzene. The prepared composition was prepared, filtered using a membrane filter made of PTFE having a pore size of 0.2 μm, and spin-coated on the hole transport layer 4 under the following conditions.

  Spin coating was performed in a nitrogen atmosphere glove box, and spin coating conditions were performed in two stages: spinner rotation speed 500 rpm, 2 seconds, and 1500 rpm, 120 seconds. Thereafter, vacuum drying was performed at 130 ° C. for 1 hour in a nitrogen atmosphere glove box to form a thin film having a uniform film thickness of 57.2 nm. The apparatus used for heating is a hot plate.

Next, the substrate on which the hole injection layer 3, the hole transport layer 4, and the light emitting layer 5 are formed is transferred into a chamber-type vacuum vapor deposition apparatus, the apparatus is roughly evacuated by an oil rotary pump, and then the vacuum inside the apparatus is The hole blocking layer 6 was obtained by evacuating using a cryopump until the degree became 1.8 × 10 ⁻⁶ Torr or less, and laminating a compound represented by the following structural formula (HB-1) by a vacuum deposition method. . The degree of vacuum during deposition is 1.6 to 1.5 × 10 ⁻⁶ Torr, the deposition rate is controlled in the range of 0.7 to 0.9 kg / sec, and a film with a thickness of 10.0 nm is formed on the light emitting layer. The hole blocking layer 6 was formed by stacking.

Next, tris (8-quinolinato) aluminum was heated and evaporated to form an electron transport layer 7. The degree of vacuum during deposition is 1.3 to 1.2 × 10 ⁻⁶ Torr, the deposition rate is controlled within the range of 1.0 to 1.1 Å / sec, and a film with a thickness of 30.0 nm is formed as the hole blocking layer 6. The electron transport layer 7 was formed by stacking on the substrate.
Here, the element on which the electron transport layer 7 has been deposited is moved from the organic layer deposition chamber on which the electron transport layer has been deposited to the metal deposition chamber, and a 2 mm wide striped shadow mask is used as a mask for cathode deposition. The element is in close contact with the ITO stripe of the anode 2 and installed in another vacuum deposition apparatus, and the degree of vacuum in the apparatus is 3.7 × 10 ⁻⁴ Pa or less in the same manner as in the organic layer deposition. It exhausted until it became.

As the electron injection layer 8, first, lithium fluoride (LiF) was controlled using a molybdenum boat at a deposition rate of 0.13 to 0.16 Å / sec and a degree of vacuum of 3.7 × 10 ⁻⁴ Pa, 0.5 nm. Was formed on the electron transport layer. Next, aluminum was similarly heated by a molybdenum boat and controlled at a deposition rate of 0.8 to 5.2 liters / second and a degree of vacuum of 3.3 to 3.8 × 10 ⁻⁴ Pa to a film thickness of 80.1 nm. A cathode 9 was formed by forming an aluminum layer. The substrate temperature at the time of vapor deposition of the above two-layer cathode was kept at room temperature.

Subsequently, in order to prevent the element from being deteriorated by moisture in the atmosphere during storage, a sealing process was performed by the method described below.
In a nitrogen glove box connected to a vacuum deposition apparatus, a photocurable resin 30Y-437 (manufactured by ThreeBond Co., Ltd.) with a width of about 1 mm is applied to the outer periphery of a 23 mm × 23 mm glass plate, and moisture is applied to the center. A getter sheet (manufactured by Dynic) was installed. On this, the board | substrate which complete | finished cathode formation was bonded together so that the vapor-deposited surface might oppose a desiccant sheet. Then, only the area | region where the photocurable resin was apply | coated was irradiated with ultraviolet light, and resin was hardened.

  As described above, an organic electroluminescent element having a light emitting area portion having a size of 2 mm × 2 mm was obtained.

The efficiency of this device was 3.9 lm / W, and the device half life when driven at 1000 cd / m ² was 3000 hours.

  The present invention relates to various fields in which organic electroluminescent elements are used, for example, flat panel displays (for example, for OA computers and wall-mounted televisions), and light sources that make use of characteristics as surface light emitters (for example, light sources for copying machines). , Liquid crystal displays and backlights for instruments), display panels, marker lamps, and the like.

1 Substrate
2 Anode
3 Hole injection layer
4 hole transport layer
5 Light emitting layer
6 Hole blocking layer
7 Electron transport layer
8 Electron injection layer
9 Cathode

Claims (11)

A nitrogen-containing heterocyclic compound represented by the following formula (1):

(Equation (1) Medium ^{R 1} represents an aromatic hydrocarbon group having 6 to 25 carbon atoms. L represents a single bond or an aromatic hydrocarbon group having 6 to 25 carbon atoms.) In the above formula (1), R ¹ The nitrogen-containing heterocyclic compound according to claim 1, wherein is selected from a phenyl group, a 2-naphthyl group, a 1-anthryl group, a 9-anthryl group, a 9-phenanthryl group, or a biphenylyl group. In the above formula (1), L is a single bond, 1,4-phenylene group, 1,3-phenylene group, 3,3′-biphenylene group, 4,3′-biphenylene group, or 1,6-naphthylene. The nitrogen-containing heterocyclic compound according to claim 1 or 2, which is selected from a group. In the above formula (1), R ¹ The nitrogen-containing heterocyclic compound according to any one of claims 1 to 3, wherein is a phenyl group or a biphenylyl group. The nitrogen-containing heterocyclic compound according to any one of claims 1 to 4, wherein L in the formula (1) is a 1,3-phenylene group.   An organic electroluminescent element material comprising the nitrogen-containing heterocyclic compound according to any one of claims 1 to 5.   The composition for organic electroluminescent elements characterized by containing the nitrogen-containing heterocyclic compound as described in any one of Claims 1-5, and an organic solvent. An organic electroluminescent device having an anode, a cathode, and an organic layer between the anode and the cathode, wherein the organic layer is formed by a wet film formation method using the composition for an organic electroluminescent device according to claim 7. An organic electroluminescent device comprising a layer formed of   The said organic layer contains the nitrogen-containing heterocyclic compound as described in any one of Claims 1-5, The organic electroluminescent element characterized by the above-mentioned.   An organic EL display comprising the organic electroluminescent element according to claim 8.   An organic EL illumination comprising the organic electroluminescence device according to claim 8.

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