JP2007027587A - Organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent element that has a high luminous efficiency and a long life. <P>SOLUTION: The present invention solves the problem by an organic electroluminescent element that has: a luminescent layer arranged between an anode and a cathode; an electron transport layer arranged between the cathode and the luminescent layer; a positive hole transport layer arranged between the anode and the luminescent layer; and a buffer layer that is arranged between the electron transport layer and the luminescent layer, and includes at least one kind of chemical compound expressed by the following general formula (I). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic electroluminescent device. More specifically, the present invention relates to an organic electroluminescence device having improved luminous efficiency, lifetime, etc. by using a buffer layer containing a specific compound.

  The organic electroluminescent element is a self-luminous light emitting element and is expected as a light emitting element for display or illumination. As an organic electroluminescent element, for example, a fluorescent light emitting element using fluorescent light emission, or an organic electroluminescent phosphor element using phosphorescent light emission (hereinafter sometimes referred to as a phosphorescent light emitting element) is known (for example, the United States). (Japanese Patent No. 6097147: Patent Document 1). In the case of emitting light using only fluorescence as in a fluorescent light emitting element, an excited singlet state is used. On the other hand, in the phosphorescent light emitting element, the excitation energy in the triplet state contributes to light emission.

  In order to improve the luminous efficiency of the organic electroluminescence device or control the emission color to a desired one, a hole blocking layer that restricts the movement of holes from the light emitting layer is provided between the light emitting layer and the cathode. It has been proposed. With this hole blocking layer, holes can be accumulated in the light emitting layer, the recombination probability with electrons can be improved, and high efficiency of light emission can be achieved. It has been reported that phenanthroline derivatives (see JP-A-10-79297: see Patent Document 2) and triazole derivatives (see JP-A-10-233284: see Patent Document 3) are effective as hole blocking materials. Also in phosphorescent light emitting devices, phenanthroline (Appl. Phys. Lett. 75, 4 (1999): see Non-Patent Document 1) and aluminum chelates such as BAlq (Proc. SPIE, Vol. 4105, p175-182 (2000) : See Non-Patent Document 2) is used as a hole blocking layer.

US Pat. No. 6,097,147 Japanese Patent Laid-Open No. 10-79297 JP-A-10-233284 JP 2005-93425 A JP-T-2004-525878 JP 2005-501372 A JP 2001-93670 A JP 2000-294373 A Appl. Phys. Lett. 75, 4 (1999) Proc. SPIE, Vol. 4105, p175-182 (2000)

  However, even when these hole blocking materials are used in organic electroluminescent elements, organic electroluminescent elements having sufficient luminous efficiency and long life have not been obtained, and the driving voltage becomes high as an adverse effect. There is a problem. This problem is particularly noticeable when a blue light emitting material is used for the light emitting layer. Under such circumstances, it is desired to develop an organic electroluminescence device improved in light emission efficiency, device life, drive voltage, and the like.

  As a result of intensive studies to solve the above problems, the present inventors have included at least one of the compounds represented by the general formulas (I) to (III) between the electron transport layer and the light emitting layer. The present inventors have found that an organic electroluminescence device improved in luminous efficiency, device lifetime, driving voltage, and the like can be obtained by providing a buffer layer.

That is, the present invention provides the following organic electroluminescence device.
[1]
A light-emitting layer disposed between the anode and the cathode;
An electron transport layer disposed between the cathode and the light emitting layer;
A hole transport layer disposed between the anode and the light emitting layer;
A buffer layer which is disposed between the electron transport layer and the light emitting layer and contains at least one compound represented by the following general formula (I);
An organic electroluminescent device comprising:
(Where
R ¹¹ and R ¹² are each independently at least one of a hydrogen atom, an alkyl group, an optionally substituted aryl group, a substituted silyl group, an optionally substituted nitrogen-containing heterocyclic group, or a cyano group. And
R ^{13 to} R ¹⁶ are each independently an optionally substituted alkyl group or an optionally substituted aryl group;
X is an optionally substituted arylene group,
Y is an optionally substituted aryl group having 16 or less carbon atoms, a substituted boryl group, or an optionally substituted carbazole group, and
n is an integer of 0-3 each independently. )

[2]
The organic electroluminescent element according to the above [1], wherein the organic electroluminescent element is an organic electroluminescent element.

[3]
The organic electroluminescence according to the above [2], wherein the light emitting layer contains at least one material containing at least one anthracene ring in the molecular structure, and a fluorescent light emitting material having an emission wavelength having a peak at 400 to 500 nm. element.

[4]
The organic electroluminescence according to the above [2], wherein the light emitting layer contains at least one material containing at least one pyrene ring in the molecular structure and a fluorescent light emitting material having a light emission wavelength having a peak at 400 to 500 nm. element.

[5]
The organic electroluminescent element according to the above [3], wherein the fluorescent light-emitting material having a peak at an emission wavelength of 400 to 500 nm contains at least one substituted amino group in the molecular structure.

[6]
The organic electroluminescent element according to the above [4], wherein the fluorescent light-emitting material having a peak at an emission wavelength of 400 to 500 nm contains at least one substituted amino group in the molecular structure.

[7]
The organic electroluminescence device according to [3] above, wherein the fluorescent light-emitting material having a peak at an emission wavelength of 400 to 500 nm includes at least one perylene ring in the molecular structure.

[8]
The organic electroluminescent element according to the above [4], wherein the fluorescent light-emitting material having a peak at 400 to 500 nm in the emission wavelength contains at least one perylene ring in the molecular structure.

[9]
The organic electroluminescent element according to the above [3], wherein the fluorescent light-emitting material having a peak at an emission wavelength of 400 to 500 nm contains at least one coumarin skeleton in the molecular structure.

[10]
The organic electroluminescence device according to the above [4], wherein the fluorescent light-emitting material having a peak at an emission wavelength of 400 to 500 nm contains at least one coumarin skeleton in the molecular structure.

[11]
The organic electroluminescence device according to any one of [2] to [10], wherein the buffer layer contains at least one compound represented by the following general formula (II).
(Where
R ¹¹ and R ¹² are each independently at least one of a hydrogen atom, an alkyl group, an optionally substituted aryl group, a substituted silyl group, an optionally substituted nitrogen-containing heterocyclic group, or a cyano group. And
R ^{13 to} R ¹⁶ are each independently an optionally substituted alkyl group or an optionally substituted aryl group;
R ²¹ and R ²² are each independently a hydrogen atom, an alkyl group, an optionally substituted aryl group, a substituted silyl group, an optionally substituted nitrogen-containing heterocyclic group, or cyano. At least one of the groups,
X ¹ is an optionally substituted arylene group having 20 or less carbon atoms,
each n is independently an integer from 0 to 3, and
m is an integer of 0-4 each independently. )

[12]
The organic electroluminescence device according to any one of [2] to [10], wherein the buffer layer contains at least one compound represented by the following general formula (III).
(Where
R ¹¹ and R ¹² are each independently at least one of a hydrogen atom, an alkyl group, an optionally substituted aryl group, a substituted silyl group, an optionally substituted nitrogen-containing heterocyclic group, or a cyano group. And
R ^{13 to} R ¹⁶ are each independently an optionally substituted alkyl group or an optionally substituted aryl group;
X ¹ is an optionally substituted arylene group having 20 or less carbon atoms, and
n is an integer of 0-3 each independently. )

[13]
The organic electroluminescence device according to any one of [2] to [10], wherein the buffer layer contains at least one compound represented by the following general formula (IV).
(Where
R ¹¹ and R ¹² are each independently at least one of a hydrogen atom, an alkyl group, an optionally substituted aryl group, a substituted silyl group, an optionally substituted nitrogen-containing heterocyclic group, or a cyano group. And
R ^{13 to} R ¹⁶ are each independently an optionally substituted alkyl group or an optionally substituted aryl group;
X ¹ is an optionally substituted arylene group having 10 or less carbon atoms,
Y ¹ is an optionally substituted aryl group having 14 or less carbon atoms, and
n is an integer of 0-3 each independently. )

[14]
Among the optionally substituted arylene groups represented by X ¹ and having 20 or less carbon atoms, the arylene moiety is independently any one of the following formulas (X-1) to (X-9): The organic electroluminescent element according to the above [11] or [12].
(Where
R ^a is each independently an alkyl group or an optionally substituted phenyl group. )

[15]
Among the optionally substituted arylene groups represented by X ¹ and having 10 or less carbon atoms, the aryl moiety is a phenylene group or a naphthylene group, and
Of the optionally substituted aryl group represented by Y ¹ having 14 or less carbon atoms, the aryl moiety is any one of the following formulas (Y-1) to (Y-3), [13] The organic electroluminescent element of description.

[16]
The organic electroluminescent element according to the above [11], wherein the compound represented by the general formula (II) is a compound represented by the following formula (II-1).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. )

[17]
The organic electroluminescent element according to the above [16], wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. )

[18]
The organic electroluminescent element according to the above [16], wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. )

[19]
The organic electroluminescent element according to the above [16], wherein the electron transport layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. )

[20]
The organic electroluminescent element according to the above [16], wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. )

[21]
The organic electroluminescent element according to the above [11], wherein the compound represented by the general formula (II) is a compound represented by the following formula (II-2).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. )

[22]
The organic electroluminescent element according to the above [21], wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. )

[23]
The organic electroluminescent element according to the above [21], wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. )

[24]
The organic electroluminescent element according to the above [21], wherein the electron transport layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. )

[25]
The organic electroluminescent element according to the above [21], wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. )

[26]
The organic electroluminescent element according to the above [11], wherein the compound represented by the general formula (II) is a compound represented by the following formula (II-3).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. )

[27]
The organic electroluminescent element according to the above [26], wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. )

[28]
The organic electroluminescent element according to the above [26], wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. )

[29]
The organic electroluminescent element according to the above [26], wherein the electron transport layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. )

[30]
The organic electroluminescent element according to the above [26], wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. )

[31]
The organic electroluminescent element according to the above [11], wherein the compound represented by the general formula (II) is a compound represented by the following formula (II-4).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. )

[32]
The organic electroluminescent element according to the above [31], wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. )

[33]
The organic electroluminescent element according to the above [31], wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. )

[34]
The organic electroluminescence device according to the above [31], wherein the electron transporting layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. )

[35]
The organic electroluminescent element according to the above [31], wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. )

[36]
The organic electroluminescent element according to the above [12], wherein the compound represented by the general formula (III) is a compound represented by the following formula (III-1).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. )

[37]
The organic electroluminescent element according to the above [36], wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. )

[38]
The organic electroluminescent element according to the above [36], wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. )

[39]
The organic electroluminescence device according to the above [36], wherein the electron transport layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. )

[40]
The organic electroluminescent element according to the above [36], wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. )

[41]
The organic electroluminescent element according to the above [13], wherein the compound represented by the general formula (IV) is a compound represented by the following formula (IV-1).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. )

[42]
The organic electroluminescent element according to the above [41], wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. )

[43]
The organic electroluminescent element according to the above [41], wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. )

[44]
The organic electroluminescence device according to the above [41], wherein the electron transporting layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. )

[45]
The organic electroluminescence device according to the above [41], wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. )

[46]
The organic electroluminescent element according to the above [13], wherein the compound represented by the general formula (IV) is a compound represented by the following formula (IV-2).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. )

[47]
The organic electroluminescent element according to the above [46], wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. )

[48]
The organic electroluminescent element according to the above [46], wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. )

[49]
The organic electroluminescent element according to the above [46], wherein the electron transport layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. )

[50]
The organic electroluminescence device according to the above [46], wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. )

[51]
A display device comprising the organic electroluminescent element according to any one of [1] to [50].

[52]
A lighting device comprising the organic electroluminescent element according to any one of [1] to [50].

  According to a preferred embodiment of the present invention, it is possible to provide an organic electroluminescent device having high luminous efficiency, long device lifetime, and reduced driving voltage. In particular, when it is applied as a blue fluorescent light emitting element, it is possible to solve the problems such as a short element lifetime at a conventional high driving voltage. Furthermore, it is possible to provide a display device, a lighting device, and the like provided with this effective organic electroluminescent element.

An organic electroluminescence device according to an embodiment of the present invention will be described in detail.
An organic electroluminescent device according to the present invention includes a light emitting layer disposed between an anode and a cathode, an electron transport layer disposed between the cathode and the light emitting layer, and the anode and the light emitting layer. An organic electroluminescence device comprising: a hole transport layer disposed therebetween; and a buffer layer disposed between the electron transport layer and the light emitting layer and including at least one compound represented by formula (I) It is an element.
The organic electroluminescent device according to this embodiment is not particularly limited as long as it is an organic electroluminescent device, but a fluorescent light emitting device is preferable.

Hereinafter, the compound represented by the general formula (I) and the organic electroluminescent element will be described in detail.
1. Compound represented by formula (I) First, the compound represented by formula (I) will be described.

The “alkyl group” in R ¹¹ and R ¹² of the general formula (I) may be linear, branched or cyclic, for example, a linear or branched alkyl group having 1 to 20 carbon atoms. Or a cyclic | annular alkyl group is mention | raise | lifted. Specific examples of the “alkyl group” include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, t-butyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, Examples include heptyl group, cycloheptyl group, octyl group, and cyclooctyl group. A preferred “alkyl group” is an alkyl group having 1 to 12 carbon atoms. A more preferable “alkyl group” is an alkyl group having 1 to 6 carbon atoms. Particularly preferred “alkyl groups” are alkyl groups having 1 to 4 carbon atoms.

Examples of the “aryl group” in the optionally substituted aryl group in R ¹¹ and R ¹² include an aryl group having 6 to 18 carbon atoms. Specific examples of the “aryl group” include phenyl group, naphthyl group, anthracenyl group, phenanthryl group and the like. A preferred “aryl group” is an aryl group having 6 to 12 carbon atoms. More preferable “aryl group” is an aryl group having 6 to 10 carbon atoms. A particularly preferred “aryl group” is a phenyl group.

Examples of the “substituted silyl group” in R ¹¹ and R ¹² include a trimethylsilyl group, a t-butyldimethylsilyl group, a t-butyldiphenylsilyl group, and a triphenylsilyl group.

The “heterocyclic group” in the optionally substituted nitrogen-containing heterocyclic group for R ¹¹ and R ¹² includes, for example, at least one nitrogen atom in addition to the carbon atom as a ring-constituting atom, Examples thereof include a heterocyclic group which may contain a hetero atom selected from sulfur atoms.

  Examples of the “heterocyclic group” include pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, triazolyl, tetrazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl Group, triazinyl group, indolyl group, isoindolyl group, 1H-indazolyl group, benzimidazolyl group, benzoxazolyl group, benzothiazolyl group, 1H-benzotriazolyl group, quinolyl group, isoquinolyl group, cinnolyl group, quinazolyl group, quinoxalinyl Group, phthalazinyl group, naphthyridinyl group, purinyl group, pteridinyl group, carbazolyl group, acridinyl group, phenoxazinyl group, phenothiazinyl group, phenazinyl group, indolizinyl group, etc. Is, oxazolyl group, isoxazolyl group, an imidazolyl group, a pyrazolyl group, a pyridyl group, pyrimidinyl group, pyridazinyl group, pyrazinyl group, indolyl group, isoindolyl group, quinolyl group, isoquinolyl group, quinazolyl group, and the like are preferable.

The “alkyl group” in R ^{13 to} R ¹⁶ (R ¹³ , R ¹⁴ , R ^15, and R ¹⁶ ) may be linear, branched, or cyclic. Examples thereof include a branched alkyl group and a cyclic alkyl group. Specific examples of the “alkyl group” include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, t-butyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, Examples include heptyl group, cycloheptyl group, octyl group, and cyclooctyl group. A preferred “alkyl group” is an alkyl group having 1 to 12 carbon atoms. More preferable “alkyl group” is an alkyl group having 1 to 6 carbon atoms. Particularly preferred “alkyl groups” are alkyl groups having 1 to 4 carbon atoms.

Examples of the “aryl group” in the optionally substituted aryl group for R ^{13 to} R ¹⁶ include an aryl group having 6 to 18 carbon atoms. Specific examples of the “aryl group” include phenyl group, naphthyl group, anthracenyl group, phenanthryl group and the like. A preferred “aryl group” is an aryl group having 6 to 12 carbon atoms. More preferable “aryl group” is an aryl group having 6 to 10 carbon atoms. A particularly preferred “aryl group” is a phenyl group.

Examples of the “substituent” in R ¹¹ and R ¹² include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, t-butyl group, pentyl group, cyclopentyl group, and hexyl. Group, cyclohexyl group, heptyl group, cycloheptyl group, octyl group, cyclooctyl group, trifluoromethyl group and other alkyl groups; phenyl group, naphthyl group, anthracenyl group, phenanthryl group and other aryl groups; methylphenyl group, ethylphenyl Group, s-butylphenyl group, t-butylphenyl group, 1-methylnaphthyl group, 2-methylnaphthyl group, 4-methylnaphthyl group, 1,6-dimethylnaphthyl group, alkyl such as 4-t-butylnaphthyl group Aryl group; pyridyl group, quinazolinyl group, quinolyl group, pyrimidinyl , Furyl group, a thienyl group, a pyrrolyl group, an imidazolyl group, a tetrazolyl group, a heterocyclic group such as phenanthrolinyl group; and a cyano group. The number of substituents is, for example, a maximum replaceable number, and preferably one.

Examples of the “substituent” in R ^{13 to} R ¹⁶ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a s-butyl group, a t-butyl group, a pentyl group, a cyclopentyl group, and hexyl. Group, cyclohexyl group, heptyl group, cycloheptyl group, octyl group, cyclooctyl group, trifluoromethyl group and other alkyl groups; phenyl group, naphthyl group, anthracenyl group, phenanthryl group and other aryl groups; methylphenyl group, ethylphenyl Group, s-butylphenyl group, t-butylphenyl group, 1-methylnaphthyl group, 2-methylnaphthyl group, 4-methylnaphthyl group, 1,6-dimethylnaphthyl group, alkyl such as 4-t-butylnaphthyl group An aryl group etc. are mention | raise | lifted.

  Preferred “substituents” in the optionally substituted aryl group are an alkyl group and an aryl group. More preferable “substituents” are an alkyl group having 1 to 12 carbon atoms and an aryl group having 6 to 10 carbon atoms. Particularly preferred “substituents” are a methyl group, a t-butyl group and a phenyl group.

Preferable R ¹¹ and R ¹² are a hydrogen atom, an alkyl group, or an aryl group. Further preferred R ¹¹ and R ¹² are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an optionally substituted aryl group having 6 to 10 carbon atoms. Particularly preferred R ¹¹ and R ¹² are a hydrogen atom, a methyl group, an isopropyl group, and an aryl group having 6 to 10 carbon atoms which may be substituted with an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms. It is. Particularly preferred R ¹¹ and R ¹² are a hydrogen atom, a methyl group and an isopropyl group.

  n is each independently an integer of 0 to 3, and each independently takes a value of 0, 1, 2, or 3, and is preferably 1. In particular, n is preferably 1, and when n is 1, it is preferable to have substituents at two ortho positions and para positions on the basis of the position at which boron is bonded.

  Examples of the “arylene group” in X include an arylene group having 6 to 70 carbon atoms. Specific examples of the “arylene group” include a phenylene group, a naphthylene group, an anthrylene group, a phenanthrylene group, a pyrenylene group, and a triphenylenylene group. A preferred “arylene group” is an arylene group having 6 to 44 carbon atoms. More preferable “arylene group” is an arylene group having 6 to 20 carbon atoms.

  In addition, examples of the “arylene group” in X include a heterocyclic group.

  Examples of the “heterocyclic group” include an aromatic heterocyclic group containing 1 to 5 heteroatoms selected from an oxygen atom, a sulfur atom and a nitrogen atom in addition to a carbon atom as a ring constituent atom.

  As the “aromatic heterocyclic group”, for example, a furylene group, a thienylene group, a pyrrolylene group, an oxazolylene group, an isoxazolylene group, a thiazolylene group, an isothiazolylene group, an imidazolylene group, a pyrazolylene group, an oxadiazolylene group, a flazanylene group, Thiadiazolylene group, triazolylene group, tetrazolylene group, pyridylene group, pyrimidinylene group, pyridazinylene group, pyrazinylene group, triazinylene group, benzofuranylene group, isobenzofuranylene group, benzo [b] thienylene group, indolinylene group, isoindolylene group, 1H- Indazolylene group, benzimidazolylene group, benzoxazolylene group, benzothiazolylene group, 1H-benzotriazolylene group, quinolylene group, isoquinolylene group, cinnolylene group, quinazolylene group, quinoxa Nylene group, phthalazinylene group, naphthyridinylene group, plinylene group, pteridinylene group, carbazolinylene group, acridinylene group, phenoxazinylene group, phenothiazinylene group, phenazinylene group, phenoxathiinylene group, thiantrenylene group, indolizinylene group Etc.

  Examples of the “substituent” in X include an optionally substituted alkyl group, an optionally substituted aryl group, a substituted silyl group, an optionally substituted heterocyclic group, and a cyano group. .

  The “alkyl group” in the alkyl group which may be substituted may be linear, branched or cyclic, for example, a linear or branched alkyl group having 1 to 20 carbon atoms or a cyclic group. And an alkyl group. Specific examples of the “alkyl group” include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, t-butyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, Examples include heptyl group, cycloheptyl group, octyl group, and cyclooctyl group. A preferred “alkyl group” is an alkyl group having 1 to 12 carbon atoms. More preferable “alkyl group” is an alkyl group having 1 to 6 carbon atoms. Particularly preferred “alkyl groups” are alkyl groups having 1 to 4 carbon atoms.

  Examples of the “aryl group” in the optionally substituted aryl group include an aryl group having 6 to 18 carbon atoms. Specific examples of the “aryl group” include phenyl group, naphthyl group, anthracenyl group, phenanthryl group and the like. A preferred “aryl group” is an aryl group having 6 to 12 carbon atoms. More preferable “aryl group” is an aryl group having 6 to 10 carbon atoms. A particularly preferred “aryl group” is a phenyl group.

  Examples of the “substituted silyl group” include a trimethylsilyl group, a t-butyldimethylsilyl group, a t-butyldiphenylsilyl group, and a triphenylsilyl group.

  Examples of the “heterocyclic group” in the optionally substituted heterocyclic group include aromatic heterocyclic groups.

  Examples of the “aromatic heterocyclic group” include aromatic heterocyclic groups containing 1 to 5 heteroatoms selected from oxygen atoms, sulfur atoms and nitrogen atoms in addition to carbon atoms as ring constituent atoms.

  Examples of the “aromatic heterocyclic group” include a furyl group, a thienyl group, a pyrrolyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, an imidazolyl group, a pyrazolyl group, an oxadiazolyl group, a furazanyl group, a thiadiazolyl group, and a triazolyl group. , Tetrazolyl group, pyridyl group, pyrimidinyl group, pyridazinyl group, pyrazinyl group, triazinyl group, benzofuranyl group, isobenzofuranyl group, benzo [b] thienyl group, indolyl group, isoindolyl group, 1H-indazolyl group, benzimidazolyl group, Benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolyl, isoquinolyl, cinnolyl, quinazolyl, quinoxalinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl Group, carbazolyl group, acridinyl group, phenoxazinyl group, phenothiazinyl group, phenazinyl group, phenoxathiinyl group, thianthrenyl group, such as indolizinyl group.

Examples of the “substituent” in the optionally substituted alkyl group, the optionally substituted aryl group, the optionally substituted alkoxy group, the substituted silyl group, and the optionally substituted heterocyclic group include R Examples of the “substituent” in ¹¹ and R ¹² are the same.

  Preferred “substituents” for X are an alkyl group, an optionally substituted aryl group, and a cyano group. More preferable “substituent” is an aryl group having 6 to 12 carbon atoms which may be substituted. In particular, the state having no substituent is most preferable.

  Examples of the “aryl group” of the aryl group which may be substituted in Y include an aryl group having 6 to 16 carbon atoms. Specific examples of the “aryl group” include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a pyrenyl group. A preferred “aryl group” is an aryl group having 6 to 10 carbon atoms.

  Examples of the “substituent” of the optionally substituted aryl group in Y include, for example, an optionally substituted alkyl group, an optionally substituted aryl group, a substituted silyl group, and an optionally substituted heterocyclic ring. Group or a cyano group.

  The “alkyl group” in the alkyl group which may be substituted may be linear, branched or cyclic, for example, a linear or branched alkyl group having 1 to 20 carbon atoms or a cyclic group. And an alkyl group. Specific examples of the “alkyl group” include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, t-butyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, Examples include heptyl group, cycloheptyl group, octyl group, and cyclooctyl group. A preferred “alkyl group” is an alkyl group having 1 to 12 carbon atoms. More preferable “alkyl group” is an alkyl group having 1 to 6 carbon atoms. Particularly preferred “alkyl groups” are alkyl groups having 1 to 4 carbon atoms.

  Examples of the “aryl group” in the optionally substituted aryl group include an aryl group having 6 to 18 carbon atoms. Specific examples of the “aryl group” include phenyl group, naphthyl group, anthracenyl group, phenanthryl group and the like. A preferred “aryl group” is an aryl group having 6 to 12 carbon atoms. More preferable “aryl group” is an aryl group having 6 to 10 carbon atoms. A particularly preferred “aryl group” is a phenyl group.

  Examples of the “substituted silyl group” include a trimethylsilyl group, a t-butyldimethylsilyl group, a t-butyldiphenylsilyl group, and a triphenylsilyl group.

  Examples of the “heterocyclic group” in the optionally substituted heterocyclic group include aromatic heterocyclic groups.

  Examples of the “aromatic heterocyclic group” include aromatic heterocyclic groups containing 1 to 5 heteroatoms selected from oxygen atoms, sulfur atoms and nitrogen atoms in addition to carbon atoms as ring constituent atoms.

  Examples of the “aromatic heterocyclic group” include a furyl group, a thienyl group, a pyrrolyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, an imidazolyl group, a pyrazolyl group, an oxadiazolyl group, a furazanyl group, a thiadiazolyl group, and a triazolyl group. , Tetrazolyl group, pyridyl group, pyrimidinyl group, pyridazinyl group, pyrazinyl group, triazinyl group, benzofuranyl group, isobenzofuranyl group, benzo [b] thienyl group, indolyl group, isoindolyl group, 1H-indazolyl group, benzimidazolyl group, Benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolyl, isoquinolyl, cinnolyl, quinazolyl, quinoxalinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl Group, carbazolyl group, acridinyl group, phenoxazinyl group, phenothiazinyl group, phenazinyl group, phenoxathiinyl group, thianthrenyl group, such as indolizinyl group.

Examples of the “substituent” in the optionally substituted alkyl group, the optionally substituted aryl group, the optionally substituted alkoxy group, the substituted silyl group, and the optionally substituted heterocyclic group include R Examples of the “substituent” in ¹¹ and R ¹² are the same.

  Preferred “substituents” in Y are an alkyl group, an optionally substituted aryl group, and a cyano group. More preferable “substituent” is an aryl group having 6 to 12 carbon atoms which may be substituted. In particular, the state having no substituent is most preferable.

  Examples of the “substituent” of the substituted boryl group in Y include an ortho-disubstituted phenyl group. Specific “substituents” include xylyl, mesityl, diisopropylphenyl, triisopropylphenyl, terphenyl and the like. Preferred “substituents” are a xylyl group, a mesityl group, and a terphenyl group.

  Examples of the “carbazolyl group” of the optionally substituted carbazolyl group in Y include a 9-carbazolyl group and an N-phenylcarbazolyl group. Specific examples of the “carbazolyl group” include a 9-carbazolyl group and an N-phenyl-2-carbazolyl group. A preferred “carbazolyl group” is a 9-carbazolyl group.

  Examples of the “substituent” of the optionally substituted carbazolyl group in Y include, for example, an optionally substituted alkyl group, an optionally substituted aryl group, a substituted silyl group, and an optionally substituted heterocyclic ring. Group or a cyano group.

  The “alkyl group” in the alkyl group which may be substituted may be linear, branched or cyclic, for example, a linear or branched alkyl group having 1 to 20 carbon atoms or a cyclic group. And an alkyl group. Specific examples of the “alkyl group” include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, t-butyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, Examples include heptyl group, cycloheptyl group, octyl group, and cyclooctyl group. A preferred “alkyl group” is an alkyl group having 1 to 12 carbon atoms. More preferable “alkyl group” is an alkyl group having 1 to 6 carbon atoms. Particularly preferred “alkyl groups” are alkyl groups having 1 to 4 carbon atoms.

  Examples of the “aryl group” in the optionally substituted aryl group include an aryl group having 6 to 18 carbon atoms. Specific examples of the “aryl group” include phenyl group, naphthyl group, anthracenyl group, phenanthryl group and the like. A preferred “aryl group” is an aryl group having 6 to 12 carbon atoms. More preferable “aryl group” is an aryl group having 6 to 10 carbon atoms. A particularly preferred “aryl group” is a phenyl group.

  Examples of the “substituted silyl group” include a trimethylsilyl group, a t-butyldimethylsilyl group, a t-butyldiphenylsilyl group, and a triphenylsilyl group.

  Examples of the “heterocyclic group” in the optionally substituted heterocyclic group include aromatic heterocyclic groups.

  Examples of the “aromatic heterocyclic group” include aromatic heterocyclic groups containing 1 to 5 heteroatoms selected from oxygen atoms, sulfur atoms and nitrogen atoms in addition to carbon atoms as ring constituent atoms.

  Examples of the “aromatic heterocyclic group” include a furyl group, a thienyl group, a pyrrolyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, an imidazolyl group, a pyrazolyl group, an oxadiazolyl group, a furazanyl group, a thiadiazolyl group, and a triazolyl group. , Tetrazolyl group, pyridyl group, pyrimidinyl group, pyridazinyl group, pyrazinyl group, triazinyl group, benzofuranyl group, isobenzofuranyl group, benzo [b] thienyl group, indolyl group, isoindolyl group, 1H-indazolyl group, benzimidazolyl group, Benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolyl, isoquinolyl, cinnolyl, quinazolyl, quinoxalinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl Group, carbazolyl group, acridinyl group, phenoxazinyl group, phenothiazinyl group, phenazinyl group, phenoxathiinyl group, thianthrenyl group, such as indolizinyl group.

Examples of the “substituent” in the optionally substituted alkyl group, the optionally substituted aryl group, the optionally substituted alkoxy group, the substituted silyl group, and the optionally substituted heterocyclic group include R Examples of the “substituent” in ¹¹ and R ¹² are the same.

  Preferred “substituents” in Y are an alkyl group, an optionally substituted aryl group, and a cyano group. More preferable “substituent” is an aryl group having 6 to 12 carbon atoms which may be substituted. In particular, the state having no substituent is most preferable.

Specific examples of the compound represented by the general formula (I) include compounds represented by the above formulas (II) to (IV). In the formula, R ^{11 to} R ¹⁶ (R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ ) are the same as R ^{11 to} R ¹⁶ exemplified for the general formula (I). Similar ones are preferred. Moreover, as R <^21> and R < ²² >, the thing similar to R < ¹¹ > -R < ¹⁶ > illustrated about the said general formula (I) is mention | raise | lifted.

  In the above formulas (II) to (IV), n is preferably the same as n exemplified for the general formula (I). M is independently an integer of 0 to 4, and each independently takes a value of 0, 1, 2, 3 or 4, and is preferably 0 to 2. In particular, m is preferably 0.

Of the optionally substituted arylene groups represented by X ¹ in the above formulas (II) to (IV), the arylene moiety is represented by the above formulas (X-1) to (X-9). An arylene moiety represented by formulas (X-1) to (X-4) is particularly preferred. In the formula, the R ^a, an alkyl group or an optionally substituted aryl group and the like also, a methyl group, hexyl group and phenyl group are preferred. Further, as represented by Y ^1, of even an aryl group substituted, the aryl moiety is an aryl moiety represented by the formula (Y-1) ~ (Y -3) is preferred.

As further specific examples of the compound represented by the general formula (I), for example, the above formulas (II-1) to (II-4), (III-1), and (IV-1) to (IV) -2) can be mentioned. In the formula, R ^{31 to} R ³⁶ (R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ ) are the same as R ^{11 to} R ¹⁶ exemplified for the general formula (I). Similar ones are preferred. Particularly preferably, they are each independently a hydrogen atom, a methyl group, an ethyl group, an isopropyl group or a phenyl group.

2. Production Method of Compound Represented by General Formula (I) The compound represented by general formula (I) can be produced by a known synthesis method using a known compound. For example, it can be synthesized by reacting a borane derivative represented by the general formula (b) after allowing a base to act on the aryl halide represented by the following general formula (a). The compounds represented by the formula (a) and the formula (b) can be produced by a known synthesis method using a known compound or a known compound, respectively.

In the formula, X and Y represent the same meaning as described above, W ¹ represents a halogen atom, and W ² represents chlorine, fluorine, a methoxy group, and an isopropoxy group. The base used in this production method is an organic lithium reagent such as n-butyllithium, t-butyllithium or phenyllithium, a magnesium reagent such as magnesium or magnesium bromide, or the like.

  Further, in the case where Y is an optionally substituted aryl group having 16 or less carbon atoms, a base is allowed to act on the aryl halide represented by the following general formula (c), and then a borane derivative of the general formula (b) Can also be synthesized by reacting a compound of the general formula (d) with the compound of the following general formula (e). The compounds represented by the formula (c) and the formula (e) can each be a known compound or can be produced by a known synthesis method using a known compound.

In the formula, X and Y represent the same meaning as described above, and W ¹ represents a halogen atom. W ³ represents a halogen atom or a halogen atom, triflate, boronic acid or boronic acid ester. W ⁴ is a halogen atom, triflate, boronic acid, boronic acid ester or the like. In addition, although Suzuki coupling reaction and Negishi coupling reaction can be utilized for reaction of general formula (d) and general formula (e), it does not restrict | limit in particular to this synthesis method.

  As for various substituents bonded to the compound of the general formula (I), the substituent is first bonded as in the compounds of the formula (a), the formula (b), the formula (c) and the formula (e). The above reaction may be carried out in a state where these substituents are bonded, or these substituents may be bonded after the above reaction.

  Regarding the reaction temperature and reaction time, when the halogen and the base are reacted, the reaction temperature is, for example, -120 ° C to 0 ° C, preferably -90 to -50 ° C, and the reaction time is about 10 minutes to 1 hour. The reaction time can be adjusted according to the reaction rate. In the case of Suzuki coupling reaction or Negishi coupling reaction, the reaction temperature is, for example, reflux temperature, for example, 150 ° C. to 0 ° C., preferably 100 to 40 ° C., and the reaction time is about 30 minutes to 2 hours. Yes, the reaction time can be adjusted according to the reaction rate.

  The solvent used in these reactions is not particularly limited as long as it is an inert solvent for the base, such as ethers such as diethyl ether and tetrahydrofuran, aromatics such as benzene and toluene, hydrocarbons such as hexane, Or DMF and NMP are mentioned and can be used suitably.

  The compounds represented by the general formulas (II) to (IV) are compounds prepared by a known synthesis method using a known compound or a known compound as appropriate for X and Y in the synthesis method of the general formula (I). Can be synthesized.

3. Organic Electroluminescent Device Next, the organic electroluminescent device according to this embodiment will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an organic electroluminescent element according to this embodiment.

<Structure of organic electroluminescence device>
An organic electroluminescent device 100 shown in FIG. 1 includes a substrate 101, an anode 102 provided on the substrate 101, a hole injection layer 103 provided on the anode 102, and a hole injection layer 103. The hole transport layer 104 provided on the light-emitting layer 105, the light-emitting layer 105 provided on the hole-transport layer 104, the buffer layer 106 provided on the light-emitting layer 105, and the buffer layer 106. An electron transport layer 107 and a cathode 108 provided on the electron transport layer 107 are included.

  Note that it is preferable to provide at least one of the hole injection layer 103 and the hole transport layer 104, and it is preferable to provide both of them. The organic electroluminescent element 100 further includes an electron injection layer between the cathode 108 and the light emitting layer 105, between the cathode 108 and the buffer layer 106, or between the cathode 108 and the electron transport layer 107. May be. Moreover, each said layer may consist of a single layer, respectively, and may consist of multiple layers.

  The organic electroluminescent element 100 is manufactured in the reverse order, for example, the substrate 101, the cathode 108 provided on the substrate 101, the electron transport layer 107 provided on the cathode 108, and the electron transport layer. A buffer layer 106 provided on 107, a light-emitting layer 105 provided on the buffer layer 106, a hole transport layer 104 provided on the light-emitting layer 105, and a hole transport layer 104. A structure including the hole injection layer 103 provided and the anode 102 provided on the hole injection layer 103 may be employed. Also in this case, it is preferable to provide one or more of the hole injection layer 103 and the hole transport layer 104, and it is preferable to provide both of them. The organic electroluminescent element 100 further includes an electron injection layer between the cathode 108 and the light emitting layer 105, between the cathode 108 and the buffer layer 106, or between the cathode 108 and the electron transport layer 107. May be. Moreover, each said layer may consist of a single layer, respectively, and may consist of multiple layers.

  As an aspect of the layer constituting the organic electroluminescent element, in addition to the above-described structural aspect of “substrate / anode / hole injection layer / hole transport layer / light emitting layer / buffer layer / electron transport layer / cathode”, Substrate / anode / hole injection layer / hole transport layer / light emitting layer / buffer layer / cathode ”,“ substrate / anode / hole injection layer / light emitting layer / buffer layer / electron transport layer / cathode ”,“ substrate / anode / Hole transport layer / light emitting layer / buffer layer / electron transport layer / cathode ”,“ substrate / anode / hole injection layer / light emitting layer / buffer layer / cathode ”or“ substrate / anode / hole transport layer / light emitting layer ” / Buffer layer / cathode "may be employed.

<Substrate in organic electroluminescence device>
The substrate 101 serves as a support for the organic electroluminescent device 100, and usually quartz, glass, metal, plastic, or the like is used. The substrate 101 is formed into a plate shape, a film shape, or a sheet shape according to the purpose. For example, a glass plate, a metal plate, a metal foil, a plastic film, a plastic sheet, or the like is used. Of these, glass plates and transparent synthetic resin plates such as polyester, polymethacrylate, polycarbonate, polysulfone and the like are preferable. In the case of a glass substrate, soda lime glass, non-alkali glass, or the like is used, and the thickness only needs to be sufficient to maintain the mechanical strength. The upper limit value of the thickness is, for example, 2 mm or less, preferably 1 mm or less. The glass material is preferably alkali-free glass because it is better to have less ions eluted from the glass. However, soda lime glass with a barrier coat such as SiO ₂ is also commercially available, so it can be used. it can. Further, the substrate 101 may be provided with a gas barrier film such as a dense silicon oxide film on at least one surface in order to improve the gas barrier property, and a synthetic resin plate, film or sheet having a low gas barrier property is used as the substrate 101. When used, it is preferable to provide a gas barrier film.

<Anode in organic electroluminescence device>
The anode 102 serves to inject holes into the light emitting layer 105. When the hole injection layer 103 and / or the hole transport layer 104 are provided between the anode 102 and the light emitting layer 105, holes are injected into the light emitting layer 105 through these layers. .

  Examples of the material for forming the anode 102 include inorganic compounds and organic compounds. Examples of inorganic compounds include metals (aluminum, gold, silver, nickel, palladium, chromium, etc.), metal oxides (indium oxide, tin oxide, indium-tin oxide (ITO), etc.), halogenated compounds. Examples thereof include metals (such as copper iodide), copper sulfide, carbon black, ITO glass, and nesa glass. Examples of the organic compound include polythiophene such as poly (3-methylthiophene), conductive polymer such as polypyrrole and polyaniline, and the like. In addition, it can select suitably from the substances currently used as an anode of an organic electroluminescent element, and can use it.

The resistance of the transparent electrode is not limited as long as a current sufficient for light emission of the light emitting element can be supplied. For example, an ITO substrate of 300 Ω / cm ² or less functions as an element electrode, but since it is now possible to supply a substrate of about 10 Ω / cm ² , for example, 100 to 5 Ω / cm ² , preferably It is particularly desirable to use a low resistance product of 50-5 Ω / cm ² . The thickness of ITO can be arbitrarily selected according to the resistance value, but is usually used in a range of 100 to 300 nm.

<Hole injection layer and hole transport layer in organic electroluminescence device>
The hole injection layer 103 plays a role of efficiently injecting holes moving from the anode 102 into the light emitting layer 105 or the hole transport layer 104. The hole transport layer 104 plays a role of efficiently transporting holes injected from the anode 102 or holes injected from the anode 102 through the hole injection layer 103 to the light emitting layer 105. The hole injection layer 103 and the hole transport layer 104 are each formed by laminating and mixing one kind or two or more kinds of hole injection / transport materials or a mixture of the hole injection / transport material and the polymer binder. Is done. In addition, an inorganic salt such as iron (III) chloride may be added to the hole injection / transport material to form a layer.

  As a hole injection / transport material, it is necessary to efficiently inject and transport holes from the positive electrode between electrodes to which an electric field is applied. The hole injection efficiency is high, and the injected holes are transported efficiently. It is desirable to do. For this purpose, it is preferable to use a substance that has a low ionization potential, a high hole mobility, excellent stability, and is less likely to generate trapping impurities during production and use.

  As a material for forming the hole injection layer 103 and the hole transport layer 104, in a photoconductive material, a compound conventionally used as a charge transport material for holes, a p-type semiconductor, and a hole injection of an organic electroluminescent element are used. Any known material used for the layer and the hole transport layer can be selected and used. Specific examples thereof include carbazole derivatives (N-phenylcarbazole, polyvinylcarbazole, etc.), biscarbazole derivatives such as bis (N-allylcarbazole) or bis (N-alkylcarbazole), triarylamine derivatives (aromatic tertiary class). Polymer having amine in main chain or side chain, 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane, N, N′-diphenyl-N, N′-di (3-methylphenyl) -4 , 4'-diaminobiphenyl, N, N'-diphenyl-N, N'-dinaphthyl-4,4'-diaminobiphenyl (hereinafter abbreviated as NPD), N, N'-diphenyl-N, N'- Di (3-methylphenyl) -4,4′-diphenyl-1,1′-diamine, N, N′-dinaphthyl-N, N′-diphenyl- , 4′-diphenyl-1,1′-diamine, triphenylamine derivatives such as 4,4 ′, 4 ″ -tris (3-methylphenyl (phenyl) amino) triphenylamine, starburst amine derivatives, and stilbene derivatives Phthalocyanine derivatives (metal-free, copper phthalocyanine, etc.), pyrazoline derivatives, hydrazone compounds, benzofuran derivatives, thiophene derivatives, oxadiazole derivatives, porphyrin derivatives, and other heterocyclic compounds, polysilanes, etc. Polycarbonate, styrene derivatives, polyvinyl carbazole, polysilane, and the like are preferably used as long as they are compounds capable of forming a thin film necessary for the production of a light-emitting element, injecting holes from the anode, and further transporting holes. It is not particularly limited.

  It is also known that the conductivity of organic semiconductors is strongly influenced by the doping. Such an organic semiconductor matrix material is composed of a compound having a good electron donating property or a compound having a good electron accepting property. Strong electron acceptors such as tetracyanoquinone dimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-1,4-benzoquinone dimethane (F4TCNQ) are known for doping of electron donor materials. (For example, the document “M. Pfeiffer, A. Beyer, T. Fritz, K. Leo, Appl. Phys. Lett., 73 (22), 3202-3204 (1998)”) and the document “J. Blochwitz, M Pheiffer, T. Fritz, K. Leo, Appl. Phys. Lett., 73 (6), 729-731 (1998)). M. Pfeiffer, A. Beyer, T. Fritz, K. Leo, Appl. Phys. Lett., 73 (22), 3202-3204 (1998). And J. Blochwitz, M. Pheiffer, T. Fritz, K. Leo, Appl. Phys. Lett., 73 (6), 729-731 (1998). These generate so-called holes by an electron transfer process in an electron donating base material (hole transport material). Depending on the number and mobility of holes, the conductivity of the base material varies considerably. Known matrix substances having hole transporting properties include, for example, benzidine derivatives (TPD and the like), starburst amine derivatives (TDATA and the like), and specific metal phthalocyanines (particularly zinc phthalocyanine ZnPc and the like). 2005-167175).

<Light emitting layer in organic electroluminescent element>
The light emitting layer 105 emits light by recombining holes injected from the anode 102 and electrons injected from the cathode 108 between electrodes to which an electric field is applied. The material for forming the light-emitting layer 105 may be a compound that emits light by being excited by recombination of holes and electrons (a light-emitting compound), can form a stable thin film shape, and is in a solid state And a compound exhibiting strong luminous efficiency.

  The light emitting layer may be either a single layer or a plurality of layers, each formed of a light emitting material (host material, dopant material), which may be a mixture of a host material and a dopant material or a host material alone. Or either. That is, in each layer of the light emitting layer, only the host material or the dopant material may emit light, or both the host material and the dopant material may emit light. Each of the host material and the dopant material may be one kind or a plurality of combinations. The dopant material may be included in the host material as a whole, or may be included partially. If the amount of the dopant material is too large, a concentration quenching phenomenon occurs, so that it is preferably used in an amount of 10 to 1% by weight, more preferably 5 to 2% by weight, based on the host material. As a doping method, it can be formed by a co-evaporation method with a host material, but it may be pre-mixed with the host material and then simultaneously deposited.

  Preferable blue light emission may have a peak wavelength of 400 to 500 nm, preferably 400 to 480 nm, more preferably 420 to 480 nm, still more preferably 430 to 480 nm. Examples of the fluorescent light-emitting material having an emission wavelength having a peak at 400 to 500 nm include a material containing at least one substituted amino group in the molecular structure, a material containing at least one perylene ring in the molecular structure, or at least one coumarin skeleton. Examples include materials included in the molecular structure. When these materials are used, it is preferable that the light emitting layer includes a material containing at least one anthracene ring in the molecular structure or a material containing at least one pyrene ring in the molecular structure. Note that fluorescence emission refers to light emission caused by transition between states having the same spin multiplicity, and phosphorescence emission refers to light emission caused by transition between states having different spin multiplicity. For example, light emission associated with a transition from a singlet excited state to a ground state (in general, the ground state of an organic compound is a singlet) is fluorescence, and light emission associated with a transition from a triplet excited state to a ground state is phosphorescence. It is luminescence.

  The dopant material is not particularly limited, and a known compound can be used, and can be selected from various materials according to a desired emission color. Specifically, for example, condensed ring derivatives such as phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopylene, dibenzopyrene and rubrene, benzoxazole derivatives, benzthiazole derivatives, benzimidazole derivatives, benztriazole derivatives, oxazole derivatives, Bisstyryl derivatives such as oxadiazole derivatives, thiazole derivatives, imidazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazoline derivatives, stilbene derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives and distyrylbenzene derivatives Kaihei 1-245087), bisstyrylarylene derivatives (Japanese Patent Laid-Open No. 2-247278) Isobenzofuran derivatives such as diazaindacene derivatives, furan derivatives, benzofuran derivatives, phenylisobenzofuran, dimesitylisobenzofuran, di (2-methylphenyl) isobenzofuran, di (2-trifluoromethylphenyl) isobenzofuran, phenylisobenzofuran, Dibenzofuran derivatives, 7-dialkylaminocoumarin derivatives, 7-piperidinocoumarin derivatives, 7-hydroxycoumarin derivatives, 7-methoxycoumarin derivatives, 7-acetoxycoumarin derivatives, 3-benzthiazolylcoumarin derivatives, 3-benzimidazolylcoumarin derivatives Derivatives, coumarin derivatives such as 3-benzoxazolyl coumarin derivatives, dicyanomethylenepyran derivatives, dicyanomethylenethiopyran derivatives, polymethine derivatives, cyanine derivatives , Oxobenzanthracene derivatives, xanthene derivatives, rhodamine derivatives, fluorescein derivatives, pyrylium derivatives, carbostyril derivatives, acridine derivatives, oxazine derivatives, phenylene oxide derivatives, quinacridone derivatives, quinazoline derivatives, pyrrolopyridine derivatives, furopyridine derivatives, 1,2, 5-thiadiazolopyrene derivatives, pyromethene derivatives, perinone derivatives, pyrrolopyrrole derivatives, squarylium derivatives, violanthrone derivatives, phenazine derivatives, acridone derivatives, diazaflavin derivatives, and the like.

  Illustratively for each color light, blue to blue-green dopant materials include naphthalene, anthracene, phenanthrene, pyrene, triphenylene, perylene, fluorene, indene and other aromatic hydrocarbon compounds and derivatives thereof, furan, pyrrole, thiophene, silole, Aromatic heterocyclic compounds such as 9-silafluorene, 9,9'-spirobisilafluorene, benzothiophene, benzofuran, indole, dibenzothiophene, dibenzofuran, imidazopyridine, phenanthroline, pyrazine, naphthyridine, quinoxaline, pyrrolopyridine, thioxanthene And its derivatives, distyrylbenzene derivatives, tetraphenylbutadiene derivatives, stilbene derivatives, aldazine derivatives, coumarin derivatives, imidazole, thiazole, thiadiazole, cal Azole derivatives such as sol, oxazole, oxadiazole, triazole and metal complexes thereof, and N, N′-diphenyl-N, N′-di (3-methylphenyl) -4,4′-diphenyl-1,1′- Examples thereof include aromatic amine derivatives represented by diamine.

  Examples of the green to yellow dopant material include coumarin derivatives, phthalimide derivatives, naphthalimide derivatives, perinone derivatives, pyrrolopyrrole derivatives, cyclopentadiene derivatives, acridone derivatives, quinacridone derivatives, and naphthacene derivatives such as rubrene, and the above blue A compound in which a substituent capable of increasing the wavelength such as an aryl group, a heteroaryl group, an arylvinyl group, an amino group, or a cyano group is introduced into the compound exemplified as a blue-green dopant material is also a suitable example.

  Further, examples of the orange to red dopant material include naphthalimide derivatives such as bis (diisopropylphenyl) perylenetetracarboxylic imide, perinone derivatives, rare earth complexes such as Eu complexes having acetylacetone, benzoylacetone and phenanthroline as ligands, 4 -(Dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran and its analogs, metal phthalocyanine derivatives such as magnesium phthalocyanine and aluminum chlorophthalocyanine, rhodamine compounds, deazaflavin derivatives, coumarin derivatives, quinacridone Derivatives, phenoxazine derivatives, oxazine derivatives, quinazoline derivatives, pyrrolopyridine derivatives, squarylium derivatives, violanthrone derivatives, phenazine derivatives, phenoxazones Conductors and thiadiazolopyrene derivatives, etc. can be used. In addition, the compounds exemplified above as blue to blue-green and green to yellow dopant materials can increase the wavelength of aryl groups, heteroaryl groups, arylvinyl groups, amino groups, cyano groups, etc. A compound into which a substituent is introduced is also a suitable example.

  In addition, as a dopant, it can select and use suitably from the compound etc. which were described in the chemical industry June, 2004 issue page 13, and the reference cited up.

  In addition, the host material is not particularly limited, but metal chelated oxinoid compounds such as fused ring derivatives such as anthracene and pyrene, tris (8-quinolinolato) aluminum, which have been known as light emitters for a long time. Bisstyryl derivatives such as bisstyryl anthracene derivatives and distyrylbenzene derivatives, tetraphenylbutadiene derivatives, coumarin derivatives, oxadiazole derivatives, pyrrolopyridine derivatives, perinone derivatives, cyclopentadiene derivatives, oxadiazole derivatives, thiadiazolopyridine derivatives, For pyrrolopyrrole derivatives and polymer systems, polyphenylene vinylene derivatives, polyparaphenylene derivatives, and polythiophene derivatives are preferably used.

  In addition, as a host material, it can select and use suitably from the compound etc. which were described in the chemical industry June, 2004 issue page 13, and the reference cited up.

<Buffer layer in organic electroluminescence device>
The buffer layer 106 is a layer that can have various functions described below. For example, the buffer layer 106 is a layer having an energy blocking effect that confines an energy state formed from holes and electrons in the light emitting layer 105 in the light emitting layer. Further, the buffer layer 106 may have a function of blocking holes, which serves to confine holes and electrons in the light emitting layer 105 and improve luminous efficiency. Further, the buffer layer 106 has a function of a “second electron transport layer” having a role of efficiently transmitting electrons from the first electron transport layer to the light emitting layer as disclosed in JP-A-2005-93425. You may do it.

  The buffer layer 106 in the present embodiment includes a compound represented by the general formula (I), the general formula (II), the general formula (III), or the general formula (IV), and may further include other substances. As a material for forming the buffer layer 106 together with the compound represented by the general formula (I), the general formula (II), the general formula (III), or the general formula (IV), for example, a metal complex (mixed ligand complex, Binuclear metal complexes), styryl compounds (such as distyrylbiphenyl derivatives), triazole derivatives, phenanthroline derivatives, and the like. In the case of having a function of blocking holes, the buffer layer 106 prevents holes moving from the anode 102 from reaching the cathode 108, and efficiently injects electrons injected from the cathode 108 into the light emitting layer 105. A substance that can be transported in the direction may be used.

  The content of the compound represented by the general formula (I), the general formula (II), the general formula (III), or the general formula (IV) in the buffer layer 106 is 1 to 100% by weight, further 10 to 100% by weight, In particular, 50 to 100% by weight, particularly 80 to 100% by weight is preferable.

<Electron injection layer and electron transport layer in organic electroluminescence device>
The electron transport layer 107 plays a role of efficiently transporting electrons injected from the cathode 108 to the light emitting layer 105 or the buffer 106. The electron injection layer serves to efficiently inject electrons moving from the cathode 108 into the light emitting layer 105, the buffer layer 106, or the electron transport layer 107.

  The electron injecting / transporting layer is a layer that administers electrons injected from the cathode and further transports electrons. It is desirable that the electron injecting electrons have high efficiency and efficiently transport the injected electrons. For this purpose, it is preferable to use a substance that has a high electron affinity, a high electron mobility, excellent stability, and is unlikely to generate trapping impurities during production and use. However, considering the transport balance between holes and electrons, if the role of effectively preventing the holes from the anode from flowing to the cathode side without recombination is mainly played, the electron transport capability is much higher. Even if it is not high, the effect of improving the luminous efficiency is equivalent to that of a material having a high electron transport capability. Therefore, the electron injection / transport layer in this embodiment may include a function of a layer that can efficiently block the movement of holes.

  As a material for forming the electron transport layer and the electron injection layer, a compound conventionally used as an electron transport compound in a photoconductive material, a known compound used for an electron injection layer and an electron transport layer of an organic electroluminescence device Any of these can be selected and used.

  As a material used for the electron transport layer and the electron injection layer, a compound comprising an aromatic ring or a heteroaromatic ring composed of one or more atoms selected from carbon, hydrogen, oxygen, sulfur, silicon and phosphorus, a pyrrole derivative And at least one selected from the condensed ring derivatives thereof and metal complexes having electron-accepting nitrogen. Specifically, condensed ring aromatic ring derivatives such as naphthalene and anthracene, styryl aromatic ring derivatives represented by 4,4′-bis (diphenylethenyl) biphenyl, perinone derivatives, coumarin derivatives, naphthalimide derivatives, anthraquinones And quinone derivatives such as diphenoquinone, phosphorus oxide derivatives, carbazole derivatives, and indole derivatives. Examples of metal complexes having electron-accepting nitrogen include quinolinol complexes such as tris (8-quinolinolato) aluminum, hydroxyazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and benzoquinoline metal complexes. Etc. These materials can be used alone or in combination with different materials. Among them, quinolinol complexes such as tris (8-quinolinolato) aluminum, anthracene derivatives such as 9,10-bis (2-naphthyl) anthracene, styryl aromatic ring derivatives such as 4,4′-bis (diphenylethenyl) biphenyl, Carbazole derivatives such as 4,4′-bis (N-carbazolyl) biphenyl and 1,3,5-tris (N-carbazolyl) benzene are preferably used from the viewpoint of durability.

  Specific examples of other electron transfer compounds include pyridine derivatives, phenanthroline derivatives, diphenylquinone derivatives, perylene derivatives, oxadiazole derivatives, thiophene derivatives, triazole derivatives, thiadiazole derivatives, metal complexes of oxine derivatives, quinolinol metal complexes, Quinoxaline derivatives, polymers of quinoxaline derivatives, benzazole compounds, gallium complexes, pyrazole derivatives, perfluorinated phenylene derivatives, triazine derivatives, pyrazine derivatives, benzoquinoline derivatives, imidazopyridine derivatives, borane derivatives, benzimidazole derivatives, benzoxazole derivatives, benz Thiazole derivatives, quinoline derivatives, oligopyridine derivatives such as bipyridine and terpyridine, naphthyridine derivatives, aldazine derivatives, Such as Susuchiriru derivatives.

Among them, pyridine derivatives (for example, 2,5-bis (6 ′-(2 ′, 2 ″ -bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (hereinafter abbreviated as PyPySPyPy), 9,10 -Di (2 ', 2 "-bipyridyl) anthracene, 2,5-di (2', 2" -bipyridyl) thiophene, 2,5-di (3 ', 2 "-bipyridyl) thiophene, 6'6"- Di (2-pyridyl) 2,2 ′: 4 ′, 3 ″: 2 ″, 2 ″ -quaterpyridine, etc.), phenanthroline derivatives (for example, 4,7-diphenyl-1,10-phenanthroline, 2,9- Dimethyl-4,7-diphenyl-1,10-phenanthroline, 9,10-di (1,10-phenanthroline-2-yl) anthracene, 2,6-di (1,10-phenanthroline-5-yl) pyridine, , 3, -Tri (1,10-phenanthroline-5-yl) benzene, 9,9'-difluoro-bis (1,10-phenanthroline-5-yl), bathocuproine or 1,3-bis (2-phenyl-1,10 -Phenanthroline-9-yl) benzene), quinolinol-based metal complexes (for example, tris (8-hydroxyquinoline) aluminum (hereinafter abbreviated as Alq3), bis (10-hydroxybenzo [h] quinoline) beryllium, tris Imidazoles such as (4-methyl-8-hydroxyquinoline) aluminum, bis (2-methyl-8-hydroxyquinoline)-(4-phenylphenol) aluminum), tris (N-phenylbenzimidazol-2-yl) benzene Derivative 1,3-bis [(4-tert-butylphenyl) 1,3,4- Oxadiazole derivatives such as oxadiazolyl] phenylene, triazole derivatives such as N-naphthyl-2,5-diphenyl-1,3,4-triazole, 2,2′-bis (benzo [h] quinolin-2-yl)- Benzoquinoline derivatives such as 9,9′-spirobifluorene, terpyridine derivatives such as 1,3-bis (4 ′-(2,2 ′: 6′2 ″ -terpyridinyl)) benzene, bis (1-naphthyl)- Naphthyridine derivatives such as 4- (1,8-naphthyridin-2-yl) phenylphosphine oxide are preferred.
In particular, when a pyridine derivative or a phenanthroline derivative is used for the electron transport layer or the electron injection layer, low voltage and high efficiency can be realized.

  A case where an organic phosphor having a phenanthroline skeleton is used for the electron transport layer will be described. In order to obtain stable light emission over a long period of time, a material excellent in thermal stability and thin film formation is desired, and among organic phosphors having a phenanthroline skeleton, the substituent itself has a three-dimensional structure, Those having a three-dimensional structure by steric repulsion with a phenanthroline skeleton or adjacent substituents, or those having a plurality of phenanthroline skeletons linked to each other are preferred. Furthermore, when linking a plurality of phenanthroline skeletons, a compound containing a conjugated bond, a substituted or unsubstituted aromatic hydrocarbon, or a substituted or unsubstituted aromatic heterocycle in the linking unit is more preferable. Specific examples of the organic phosphor having the phenanthroline skeleton include structures represented by the following formulas (ETM-1) to (ETM-31), but are not limited thereto.

<Cathode in organic electroluminescence device>
The cathode 108 plays a role of injecting electrons into the light emitting layer 105 through the electron transport layer 107 and the buffer layer 106. Note that in the case where an electron injection layer is provided, electrons are injected into the light emitting layer 105 through this layer.

  The material for forming the cathode 108 is not particularly limited as long as it can efficiently inject electrons into the organic layer, but the same material as that for forming the anode 102 can be used. Among them, metals such as tin, magnesium, indium, calcium, aluminum, silver, copper, nickel, chromium, gold, platinum, iron, tin, zinc, lithium, sodium, potassium, cesium and magnesium or their alloys (magnesium- Silver alloys, magnesium-indium alloys, aluminum-lithium alloys such as lithium fluoride / aluminum) are preferred. Lithium, sodium, potassium, cesium, calcium, magnesium, or alloys containing these low work function metals are effective for increasing the electron injection efficiency and improving device characteristics. However, these low work function metals are generally unstable in the atmosphere. For example, the organic layer is doped with a small amount of lithium, cesium, or magnesium (1 nm or less in vacuum vapor deposition thickness gauge display). Although a method using a highly stable electrode can be given as a preferred example, it is particularly limited to these because inorganic salts such as lithium fluoride, cesium fluoride, lithium oxide and cesium oxide can also be used. It is not something.

  Furthermore, for electrode protection, metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium, or alloys using these metals, and inorganic substances such as silica, titania and silicon nitride, polyvinyl alcohol, vinyl chloride Lamination of hydrocarbon polymer compounds and the like is a preferred example. The method for producing these electrodes is not particularly limited as long as conduction can be achieved, such as resistance heating, electron beam, sputtering, ion plating, and coating.

<Binder that may be used in each layer>
The materials used for the above hole injection layer, hole transport layer, light emitting layer, buffer layer and electron transport layer can form each layer alone, but as a polymer binder, polyvinyl chloride, polycarbonate, polystyrene , Poly (N-vinylcarbazole), polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, hydrocarbon resin, ketone resin, phenoxy resin, polysulfone, polyamide, ethyl cellulose, vinyl acetate, ABS resin, polyurethane Used in a solvent-soluble resin such as resin, or curable resin such as phenol resin, xylene resin, petroleum resin, urea resin, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin, or silicone resin. It is also possible.

<Method for producing organic electroluminescent element>
Each layer constituting the organic electroluminescent element is formed by a method such as vapor deposition, resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular lamination method, printing method, spin coating method or casting method, coating method, etc. It can be formed by using a thin film. The thickness of each layer formed in this way is not particularly limited and can be appropriately set according to the properties of the material, but is usually in the range of 2 nm to 5000 nm. The film thickness can usually be measured with a crystal oscillation type film thickness measuring device or the like. When a thin film is formed using a vapor deposition method, the vapor deposition conditions vary depending on the type of material, the intended crystal structure and association structure of the film, and the like. Deposition conditions generally include boat heating temperature of 50 to 400 ° C., vacuum degree of 10 ⁻⁶ to 10 ⁻³ Pa, deposition rate of 0.01 to 50 nm / second, substrate temperature of −150 to + 300 ° C., and film thickness of 2 nm to 5 μm. It is preferable to set appropriately within the range.

  Next, as an example of a method for producing an organic electroluminescence device, organic electroluminescence comprising an anode / hole injection layer / hole transport layer / light emitting host material and a light emitting layer comprising a dopant / buffer layer / electron transport layer / cathode A method for manufacturing the element will be described. A thin film of an anode material is formed on a suitable substrate by vapor deposition or the like to produce an anode, and then a thin film of a hole injection layer and a hole transport layer is formed on the anode. A light-emitting host material and a dopant are co-evaporated to form a thin film to form a light-emitting layer. A buffer layer and an electron transport layer are formed on the light-emitting layer, and a thin film made of a cathode material is formed by vapor deposition. By making it into a cathode, the target organic electroluminescent element is obtained. In the preparation of the above-mentioned organic electroluminescence device, the order of preparation can be reversed, and the cathode, the electron transport layer, the buffer layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode can be prepared in this order. It is. Further, when an electron injection layer is provided, after forming a lower layer of the electron injection layer, the electron injection layer may be formed thereon by a vapor deposition method or the like.

  When a DC voltage is applied to the organic electroluminescent device thus obtained, the anode may be applied with a positive polarity and the cathode with a negative polarity. When a voltage of about 2 to 40 V is applied, the organic electroluminescent device is transparent or translucent. Luminescence can be observed from the electrode side (anode or cathode, and both). The organic electroluminescence device emits light when a pulse current or an alternating current is applied. The alternating current waveform to be applied may be arbitrary.

<Application examples of organic electroluminescent devices>
The present invention also relates to a display device including an organic electroluminescent element or a lighting device including an organic electroluminescent element.
A display device or an illuminating device including an organic electroluminescent element can be manufactured by a known method such as connecting the organic electroluminescent element according to the present embodiment and a known driving device, such as direct current driving, pulse driving, or alternating current. It can be driven by appropriately using a known driving method such as driving.

  Examples of the display device include a panel display such as a color flat panel display, and a flexible display such as a flexible color organic electroluminescence (EL) display (for example, JP-A-10-335066 and JP-A-2003-321546). Gazette, Japanese Patent Application Laid-Open No. 2004-281086, etc.). Examples of the display method of the display include a matrix and / or segment method. Note that the matrix display and the segment display may coexist in the same panel.

  A matrix means a pixel in which pixels for display are two-dimensionally arranged such as a lattice or a mosaic, and displays a character or an image with a set of pixels. The shape and size of the pixel are determined by the application. For example, a square pixel with a side of 300 μm or less is usually used for displaying images and characters on a personal computer, monitor, TV, and a pixel with a side of mm order for a large display such as a display panel. become. In monochrome display, pixels of the same color may be arranged. However, in color display, red, green, and blue pixels are displayed side by side. In this case, there are typically a delta type and a stripe type. The matrix driving method may be either a line sequential driving method or an active matrix. The line-sequential driving has an advantage that the structure is simple. However, the active matrix may be superior in consideration of the operation characteristics, so that it is necessary to properly use it depending on the application.

  In the segment method (type), a pattern is formed so as to display predetermined information, and a predetermined region is caused to emit light. For example, the time and temperature display in a digital clock or a thermometer, the operation state display of an audio device or an electromagnetic cooker, the panel display of an automobile, and the like can be mentioned.

  Examples of the illuminating device include an illuminating device such as indoor lighting, a backlight of a liquid crystal display device, and the like (for example, Japanese Patent Application Laid-Open Nos. 2003-257621, 2003-277741, and 2004-119211). Etc.) The backlight is used mainly for the purpose of improving the visibility of a display device that does not emit light, and is used for a liquid crystal display device, a clock, an audio device, an automobile panel, a display panel, a sign, and the like. In particular, as a backlight for liquid crystal display devices, especially personal computers for which thinning is an issue, considering that conventional methods are made of fluorescent lamps and light guide plates, it is difficult to reduce the thickness. The backlight using the light emitting element according to the embodiment is thin and lightweight.

The electroluminescent elements according to Examples 1 to 4 and the electroluminescent elements according to Comparative Examples 1 to 5 were produced, and the applied voltage (V) and luminance (cd / m ² ) when a current of 10 mA / cm ² flows, respectively. The performance evaluation of the luminous efficiency (Lm / W) and the luminance half time (hour) and the measurement of the emission wavelength were performed. Hereinafter, each example and comparative example will be described in detail.

[Example 1]
A transparent support substrate was obtained by depositing ITO on a glass substrate to a thickness of 150 nm. This transparent support substrate is fixed to a substrate holder of a commercially available vapor deposition apparatus, and a molybdenum vapor deposition boat containing copper phthalocyanine (hereinafter referred to as the symbol CuPc), N, N′-di (1-naphthyl) -N, Molybdenum vapor deposition boat containing N′-diphenylbenzidine (hereinafter referred to as symbol NPD), the following compound (1) 9-phenyl-10- [6-([1,1 ′; 3,1 ″] Terphenyl-5′-yl) naphthalen-2-yl] anthracene (hereinafter referred to as symbol BH1), a molybdenum vapor deposition boat, and N, N, N which is a styrylamine derivative represented by the following compound (2) Molybdenum evaporation boat containing ', N'-tetra (4-biphenylyl) -4,4'-diaminostilbene (hereinafter referred to as symbol BD1), the following compound (4) 9- [4- (4- Dimeschi Borylnaphthalen-1-yl) phenyl] carbazole (hereinafter referred to as symbol buffer1), molybdenum vapor deposition boat, compound (6) 2,5-bis (6 ′-(2 ′, 2 ″ -bipyridyl) ) -Molybdenum deposition boat containing 1,1-dimethyl-3,4-dimethylsylsilole (hereinafter referred to as ETM1), molybdenum deposition boat containing lithium fluoride, and tungsten containing aluminum A boat for vapor deposition was installed.

The following layers were sequentially formed on the ITO film of the transparent support substrate. The vacuum chamber was depressurized to 1 × 10 ⁻³ Pa, first, the vapor deposition boat containing CuPc was heated to form a hole injection layer by vapor deposition to a film thickness of 20 nm, and then NPD entered. The vapor deposition boat was heated and vapor-deposited so that it might become a film thickness of 30 nm, and the positive hole transport layer was formed. Next, the vapor deposition boat containing BH1 and the vapor deposition boat containing BD1 were heated at the same time to form a light emitting layer by vapor deposition to a film thickness of 20 nm. The deposition rate was adjusted so that the weight ratio of BH1 to BD1 was approximately 95: 5. Next, the evaporation boat containing the buffer 1 was heated and evaporated to a thickness of 10 nm to obtain a buffer layer. Thereafter, the evaporation boat containing ETM1 was heated to a film thickness of 15 nm to form an electron transport layer. The deposition rate of each layer was 0.001 to 3.0 nm / sec.

  Thereafter, the evaporation boat containing lithium fluoride is heated to deposit at a deposition rate of 0.003 to 0.01 nm / second so that the film thickness becomes 0.5 nm, and then the evaporation boat containing aluminum is heated. The cathode was formed by vapor deposition at a vapor deposition rate of 0.1 to 1 nm / second so that the film thickness was 100 nm, and an electroluminescent element was obtained.

When a direct current voltage of 4.29 V is applied with the ITO electrode as the anode and the lithium fluoride / aluminum electrode as the cathode, a current of 10 mA / cm ² flows, the luminance is 800 cd / m ² , and the luminous efficiency is 5.95 Lm / W. Blue light emission having a spectrum with a peak at a wavelength of 455 nm was obtained. When continuously driven at a current density of 11 mA / cm ² , the initial luminance was about 1000 cd / m ² and the luminance half time was 1000 hours or more.

[Comparative Example 1]
Instead of buffer 1 forming the buffer layer used in Example 1, bis- (2-methyl-8-quinolinolato) -4- (phenyl-phenolate) -aluminum (hereinafter referred to as symbol BAlq) was used. Obtained an electroluminescent device in exactly the same manner as in Example 1.

When a direct current voltage of 4.31 V is applied with the ITO electrode as the anode and the lithium fluoride / aluminum electrode as the cathode, a current of 10 mA / cm ² flows, the luminance is 625 cd / m ² , and the luminous efficiency is 4.55 Lm / W. Blue light emission having a spectrum with a peak at a wavelength of 455 nm was obtained. When continuously driven at a current density of 16 mA / cm ² , the initial luminance was about 1000 cd / m ² and the luminance half time was about 150 hours.

[Comparative Example 2]
An electroluminescent device was obtained in exactly the same manner as in Example 1 except that the buffer layer in Example 1 was eliminated and the light emitting layer was changed from 20 nm to 30 nm.

When a direct current voltage of 3.8 V is applied with the ITO electrode as the anode and the lithium fluoride / aluminum electrode as the cathode, a current of 10 mA / cm ² flows, the luminance is 560 cd / m ² , and the luminous efficiency is 4.64 Lm / W. Blue light emission having a spectrum with a peak at a wavelength of 455 nm was obtained. When continuously driven at a current density of 17 mA / cm ² , the initial luminance was about 1000 cd / m ² and the luminance half time was about 100 hours.

[Example 2]
In place of ETM1 forming the electron transport layer used in Example 1, the above compound (7) 9,10-di (2 ′, 2 ″ -bipyridyl) anthracene (hereinafter referred to as symbol ETM2) was used. Except for the above, an electroluminescent device was obtained in exactly the same manner as in Example 1.

When a direct current voltage of 4.18 V is applied with the ITO electrode as the anode and the lithium fluoride / aluminum electrode as the cathode, a current of 10 mA / cm ² flows, the luminance is 709 cd / m ² , and the luminous efficiency is 5.33 Lm / W. Blue light emission having a spectrum with a peak at a wavelength of 455 nm was obtained. When continuously driven at a current density of 13 mA / cm ² , the initial luminance was about 1000 cd / m ² and the luminance half time was 1000 hours or more.

[Comparative Example 3]
An electroluminescent device was obtained in exactly the same manner as in Example 2, except that the buffer layer in Example 2 was eliminated and the light emitting layer was changed from 20 nm to 30 nm.

When a direct current voltage of 3.52 V is applied with the ITO electrode as the anode and the lithium fluoride / aluminum electrode as the cathode, a current of 10 mA / cm ² flows, the luminance is 383 cd / m ² , and the luminous efficiency is 3.42 Lm / W. Blue light emission having a spectrum with a peak at a wavelength of 455 nm was obtained. When continuously driven at a current density of 23 mA / cm ² , the initial luminance was about 1000 cd / m ² and the luminance half time was about 150 hours.

[Example 3]
Instead of buffer 1 forming the buffer layer used in Example 1, the above compound (5) 9- [4- (4-Dimesitylborylnaphthalen-1-yl) naphthalen-1-yl] carbazole (hereinafter referred to as symbol) An electroluminescent element was obtained in exactly the same manner as in Example 1 except that (denoted as buffer 2) was used.

When a direct current voltage of 4.17 V is applied with the ITO electrode as the anode and the lithium fluoride / aluminum electrode as the cathode, a current of 10 mA / cm ² flows, the luminance is 650 cd / m ² , and the luminous efficiency is 4.89 Lm / W. Blue light emission having a spectrum with a peak at a wavelength of 455 nm was obtained. When continuously driven at a current density of 16 mA / cm ² , the initial luminance was about 1000 cd / m ² and the luminance half time was about 300 hours.

[Comparative Example 4]
An electroluminescent device was obtained in the same manner as in Example 3 except that 10- (dimesitylboryl) anthracene (hereinafter referred to as symbol MBA) was used instead of buffer 2 forming the buffer layer used in Example 3. It was.

When a direct current voltage of 3.74 V is applied with the ITO electrode as the anode and the lithium fluoride / aluminum electrode as the cathode, a current of 10 mA / cm ² flows, the luminance is 544 cd / m ² , and the luminous efficiency is 4.56 Lm / W. Blue light emission having a spectrum with a peak at a wavelength of 455 nm was obtained. When continuously driven at a current density of 18 mA / cm ² , the initial luminance was about 1000 cd / m ² and the luminance half time was about 150 hours.

[Example 4]
Implementation was performed except that the above compound (3) 3,10-bis (2,6-dimethylphenyl) perylene (hereinafter referred to as symbol BD2) was used in place of BD1 constituting the dopant used in Example 1. An electroluminescent device was obtained in exactly the same manner as in Example 1.

When a direct current voltage of 4.22 V is applied with the ITO electrode as the anode and the lithium fluoride / aluminum electrode as the cathode, a current of 10 mA / cm ² flows, the luminance is 600 cd / m ² , and the luminous efficiency is 4.46 Lm / W. Blue light emission having a spectrum with a peak at a wavelength of 468 nm was obtained. When continuously driven at a current density of 17 mA / cm ² , the initial luminance was about 1000 cd / m ² and the luminance half time was about 600 hours.

[Comparative Example 5]
An electroluminescent device was obtained in exactly the same manner as in Example 4 except that the buffer layer in Example 4 was eliminated and the light emitting layer was changed from 20 nm to 30 nm.

When a direct current voltage of 4.19 V is applied with the ITO electrode as the anode and the lithium fluoride / aluminum electrode as the cathode, a current of 10 mA / cm ² flows, the luminance is 580 cd / m ² , and the luminous efficiency is 4.34 Lm / W. Blue light emission having a spectrum with a peak at a wavelength of 468 nm was obtained. When continuously driven at a current density of 18 mA / cm ² , the initial luminance was about 1000 cd / m ² and the luminance half time was about 290 hours.

Table 1 below summarizes the performance evaluation and measured emission wavelengths of the electroluminescent elements according to Examples 1 to 4 and the electroluminescent elements according to Comparative Examples 1 to 5 described above.

Reference example

  In addition, a manufacture example is demonstrated about some of the compounds which can be used for the buffer layer which concerns on embodiment.

(A) 9- [4- (4-Dimesitylborylnaphthalen-1-yl) phenyl] carbazole (compound system represented by general formula (II-1)) Nitrogen gas stream, 1-bromo 50 ml of a tetrahydrofuran solution containing 2.5 g of -4-dimesitylborylnaphthalene was cooled to −78 ° C., and 5 ml of a 1.6 mol / L hexane solution of n-butyllithium was added thereto. This solution was stirred at −78 ° C. for 30 minutes, 2.1 g of zinc chloride tetramethylethylenediamine was added, and the mixture was stirred at room temperature for 15 minutes. Next, 116 mg of PdCl ₂ (PPh ₃ ) ₂ and 3 g of 9- (4-iodophenyl) -carbazole were added, followed by stirring at reflux temperature for 1 hour. After completion of the reaction, the mixture was cooled to room temperature and concentrated with an evaporator, and purified by column chromatography and recrystallization to obtain 1 g of the desired product.

In addition, it is as follows about the manufacturing method of 1-bromo-4- dimesitylboryl naphthalene.
A 350 mL solution of t-butyl methyl ether containing 15 g of 1,4-dibromonaphthalene was cooled to −50 ° C., and 36 mL of a 1.6 mol / L hexane solution of n-butyl lithium was added to this solution. This solution was stirred at −70 ° C. for 30 minutes, and 20 g of dimesitylborane fluoride was added. Next, after stirring at room temperature for 16 hours, pure water was added to extract the organic layer. What condensed this organic layer with the evaporator was refine | purified by column chromatography, and 18g of target objects were obtained.

(B) 9- [4- (4- dimesityl boryl naphthalen-1-yl) naphthalen-1-yl] carbazole (formula (compound type represented by II-2)) production process 1- dimesitylboryl - 4- (4,4,5,5-tetramethyl-1,3-dioxaboran-2-yl) naphthalene 2 g, 9- (4-bromonaphthalen-1-yl) -carbazole 1.5 g, palladium acetate 54 mg, 2 A mixed solution of 40 mL of toluene, 10 mL of ethanol and 10 mL of pure water containing 198 mg of dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl and 3.4 g of potassium phosphate was stirred at reflux temperature for 16 hours. After completion of the reaction, the mixture was cooled to room temperature, pure water was added, and the organic layer was extracted. What condensed this organic layer with the evaporator was refine | purified by column chromatography and recrystallization, and 1.4g of target objects were obtained.

In addition, the manufacturing method of 1-dimesitylboryl-4- (4,4,5,5-tetramethyl-1,3-dioxaboran-2-yl) naphthalene is as follows.
14 g of 1-bromo-4-dimesitylborylnaphthalene, 9.5 g of bis (pinacolato) diboron, 760 mg of [1,1′-bis (diphenylphosphino) ferrocene] palladium (II) dichloride, and 9.1 g of potassium acetate The 175 ml solution containing dimethyl sulfoxide was heated at 80 ° C. and stirred for 2 hours. After completion of the reaction, the mixture was cooled to room temperature, pure water was added, and the organic layer was extracted. What condensed the organic layer with the evaporator was refine | purified by column chromatography, and 13g of target objects were obtained.

In addition, a method for producing 9- (4-bromonaphthalen-1-yl) -carbazole is as follows.
A 100 mL solution of dimethyl sulfoxide containing nitrogen gas stream, 3.1 g carbazole, 5 g 1-bromo-4-fluoronaphthalene, and 7.2 g cesium carbonate was heated to 150 ° C. and stirred for 3 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, the deposited precipitate was filtered off, and the filtrate was concentrated with an evaporator. Next, it refine | purified by column chromatography and recrystallization, and obtained 5.8g of target objects.

(C) 9- (4-Dimesitylborylnaphthalen-1-yl) -carbazole (compound system represented by the general formula (II-3)) In the production method (A), “9- ( 4-bromonaphthalen-1-yl) -carbazole "and" dimesitylborane fluoride ".

(D) Method for producing 4,4′-bisdimesitylboryl-1,1′-binaphthyl (compound system in which arylene moiety (X-2) is applied to general formula (III)) 1-bromo-4-di A tetrahydrofuran solution containing 0.91 g of mesitylborylnaphthalene was cooled to −78 ° C., and 1.25 mL of a 1.6 mol / L hexane solution of n-butyllithium was added. The solution was stirred at −78 ° C. for 30 minutes, 0.5 g of zinc chloride tetramethylethylenediamine was added, and the mixture was stirred at room temperature for 25 minutes. Next, 28 mg of PdCl ₂ (PPh ₃ ) ₂ and 0.91 g of 1-bromo-4-dimesitylborylnaphthalene were added, followed by stirring at reflux temperature for 2 hours. After completion of the reaction, the mixture was cooled to room temperature, pure water was added, and the organic layer was extracted. What condensed this organic layer with the evaporator was refine | purified by column chromatography and recrystallization, and 475 mg of target objects were obtained.

(E) Method for producing 1,4-bisdimesitylborylnaphthalene (compound system in which arylene moiety (X-3) is applied to general formula (III)) 1-Bromo-4-dimesitylborylnaphthalene is included. The t-butyl methyl ether 120 mL solution was cooled to −78 ° C., and n-butyl lithium 1.6 mol / L hexane solution 8.3 mL was added thereto. This solution was stirred at −78 ° C. for 40 minutes, and then 5.9 g of dimesitylborane fluoride was added. Next, after stirring at room temperature for 17 hours, pure water was added to extract the organic layer. The organic layer concentrated by an evaporator was purified by column chromatography and recrystallization to obtain 2.1 g of the desired product.

(F) Production method of 9- (4-Dimesitylborylnaphthalen-1-yl) -anthracene (compound system in which aryl moiety (Y-2) is applied to general formula (IV)) 1-bromo-4-di 0.64 g of sodium carbonate was dissolved in 5 mL of pure water in a mixed solution of 20 mL of toluene and 5 mL of ethanol containing 1.37 g of mesitylborylnaphthalene, 0.73 g of 9-anthraceneboronic acid, and Pd (PPh ₃ ) ₄ . The solution was added. Next, it stirred at reflux temperature for 3 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, purified water was added, and the organic layer was extracted and purified by recrystallization to obtain 550 mg of the desired product.

(G) Manufacturing method of 9- (4-Dimesitylborylnaphthalen-1-yl) -10-phenylanthracene (compound system in which aryl moiety (Y-3) is applied to general formula (IV)) In F), “9-anthraceneboronic acid” was replaced with “9- (10-phenyl) anthraceneboronic acid”.

  According to a preferable aspect of the present invention, for example, an organic electroluminescent element (in particular, a fluorescent light emitting element) having high luminous efficiency and a long lifetime, a display device including the same, a lighting device including the same, and the like are provided. Can do.

It is a schematic sectional drawing which shows the organic electroluminescent element which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Organic electroluminescent element 101 Substrate 102 Anode 103 Hole injection layer 104 Hole transport layer 105 Light emitting layer 106 Buffer layer 107 Electron transport layer 108 Cathode

Claims (52)

A light-emitting layer disposed between the anode and the cathode;
An electron transport layer disposed between the cathode and the light emitting layer;
A hole transport layer disposed between the anode and the light emitting layer;
A buffer layer which is disposed between the electron transport layer and the light emitting layer and contains at least one compound represented by the following general formula (I);
An organic electroluminescent device comprising:
(Where
R ¹¹ and R ¹² are each independently at least one of a hydrogen atom, an alkyl group, an optionally substituted aryl group, a substituted silyl group, an optionally substituted nitrogen-containing heterocyclic group, or a cyano group. And
R ^{13 to} R ¹⁶ are each independently an optionally substituted alkyl group or an optionally substituted aryl group;
X is an optionally substituted arylene group,
Y is an optionally substituted aryl group having 16 or less carbon atoms, a substituted boryl group, or an optionally substituted carbazole group, and
n is an integer of 0-3 each independently. )   The organic electroluminescent device according to claim 1, wherein the organic electroluminescent device is an organic electroluminescent device.   The organic electroluminescent element according to claim 2, wherein the light emitting layer includes at least one material including at least one anthracene ring in a molecular structure and a fluorescent light emitting material having an emission wavelength having a peak at 400 to 500 nm. .   The organic electroluminescent element according to claim 2, wherein the light emitting layer includes at least one material including at least one pyrene ring in a molecular structure and a fluorescent light emitting material having an emission wavelength having a peak at 400 to 500 nm. .   The organic electroluminescent element according to claim 3, wherein the fluorescent light-emitting material having a light emission wavelength having a peak at 400 to 500 nm contains at least one substituted amino group in a molecular structure.   The organic electroluminescent element according to claim 4, wherein the fluorescent light emitting material having a peak at an emission wavelength of 400 to 500 nm contains at least one substituted amino group in a molecular structure.   The organic electroluminescent element according to claim 3, wherein the fluorescent light-emitting material having a peak at an emission wavelength of 400 to 500 nm contains at least one perylene ring in the molecular structure.   The organic electroluminescent element according to claim 4, wherein the fluorescent light-emitting material having a peak at an emission wavelength of 400 to 500 nm contains at least one perylene ring in the molecular structure.   The organic electroluminescent element according to claim 3, wherein the fluorescent light-emitting material having a peak at an emission wavelength of 400 to 500 nm includes at least one coumarin skeleton in a molecular structure.   The organic electroluminescent element according to claim 4, wherein the fluorescent light-emitting material having a peak at an emission wavelength of 400 to 500 nm includes at least one coumarin skeleton in a molecular structure. The organic electroluminescent element according to claim 2, wherein the buffer layer contains at least one compound represented by the following general formula (II).
(Where
R ¹¹ and R ¹² are each independently at least one of a hydrogen atom, an alkyl group, an optionally substituted aryl group, a substituted silyl group, an optionally substituted nitrogen-containing heterocyclic group, or a cyano group. And
R ^{13 to} R ¹⁶ are each independently an optionally substituted alkyl group or an optionally substituted aryl group;
R ²¹ and R ²² are each independently a hydrogen atom, an alkyl group, an optionally substituted aryl group, a substituted silyl group, an optionally substituted nitrogen-containing heterocyclic group, or cyano. At least one of the groups,
X ¹ is an optionally substituted arylene group having 20 or less carbon atoms,
each n is independently an integer from 0 to 3, and
m is an integer of 0-4 each independently. ) The organic electroluminescent element according to claim 2, wherein the buffer layer contains at least one compound represented by the following general formula (III).
(Where
R ¹¹ and R ¹² are each independently at least one of a hydrogen atom, an alkyl group, an optionally substituted aryl group, a substituted silyl group, an optionally substituted nitrogen-containing heterocyclic group, or a cyano group. And
R ^{13 to} R ¹⁶ are each independently an optionally substituted alkyl group or an optionally substituted aryl group;
X ¹ is an optionally substituted arylene group having 20 or less carbon atoms, and
n is an integer of 0-3 each independently. ) The organic electroluminescent element according to claim 2, wherein the buffer layer contains at least one compound represented by the following general formula (IV).
(Where
R ¹¹ and R ¹² are each independently at least one of a hydrogen atom, an alkyl group, an optionally substituted aryl group, a substituted silyl group, an optionally substituted nitrogen-containing heterocyclic group, or a cyano group. And
R ^{13 to} R ¹⁶ are each independently an optionally substituted alkyl group or an optionally substituted aryl group;
X ¹ is an optionally substituted arylene group having 10 or less carbon atoms,
Y ¹ is an optionally substituted aryl group having 14 or less carbon atoms, and
n is an integer of 0-3 each independently. ) Among the optionally substituted arylene groups represented by X ¹ and having 20 or less carbon atoms, the arylene moiety is independently any one of the following formulas (X-1) to (X-9): The organic electroluminescent element according to claim 11 or 12.
(Where
R ^a is each independently an alkyl group or an optionally substituted phenyl group. ) Among the optionally substituted arylene groups represented by X ¹ and having 10 or less carbon atoms, the aryl moiety is a phenylene group or a naphthylene group, and
The aryl moiety in the optionally substituted aryl group represented by Y ¹ having 14 or less carbon atoms is any one of the following formulas (Y-1) to (Y-3): The organic electroluminescent element as described.
The organic electroluminescent element according to claim 11, wherein the compound represented by the general formula (II) is a compound represented by the following formula (II-1).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. ) The organic electroluminescent element according to claim 16, wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. ) The organic electroluminescent element according to claim 16, wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. ) The organic electroluminescent element according to claim 16, wherein the electron transport layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. ) The organic electroluminescent element according to claim 16, wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. ) The organic electroluminescent element according to claim 11, wherein the compound represented by the general formula (II) is a compound represented by the following formula (II-2).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. ) The organic electroluminescent element according to claim 21, wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. ) The organic electroluminescent element according to claim 21, wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. ) The organic electroluminescent element according to claim 21, wherein the electron transport layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. ) The organic electroluminescent element according to claim 21, wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. ) The organic electroluminescent element according to claim 11, wherein the compound represented by the general formula (II) is a compound represented by the following formula (II-3).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. ) 27. The organic electroluminescent element according to claim 26, wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. ) 27. The organic electroluminescent element according to claim 26, wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. ) 27. The organic electroluminescent element according to claim 26, wherein the electron transporting layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. ) 27. The organic electroluminescent element according to claim 26, wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. ) The organic electroluminescent element according to claim 11, wherein the compound represented by the general formula (II) is a compound represented by the following formula (II-4).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. ) The organic electroluminescent element according to claim 31, wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. ) 32. The organic electroluminescent element according to claim 31, wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. ) 32. The organic electroluminescence device according to claim 31, wherein the electron transport layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. ) 32. The organic electroluminescent element according to claim 31, wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. ) The organic electroluminescence device according to claim 12, wherein the compound represented by the general formula (III) is a compound represented by the following formula (III-1).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. ) The organic electroluminescent element according to claim 36, wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. ) The organic electroluminescent element according to claim 36, wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. ) The organic electroluminescent element according to claim 36, wherein the electron transport layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. ) The organic electroluminescent element according to claim 36, wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. ) The organic electroluminescent element according to claim 13, wherein the compound represented by the general formula (IV) is a compound represented by the following formula (IV-1).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. ) The organic electroluminescent element according to claim 41, wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. ) 42. The organic electroluminescent element according to claim 41, wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. ) 42. The organic electroluminescent element according to claim 41, wherein the electron transporting layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. ) The organic electroluminescent element according to claim 41, wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. ) The organic electroluminescent element according to claim 13, wherein the compound represented by the general formula (IV) is a compound represented by the following formula (IV-2).
(Where
R ^{31 to} R ³⁴ are each independently any of a methyl group, an isopropyl group, or a phenyl group, and
R ³⁵ and R ³⁶ are each independently any one of a hydrogen atom, a methyl group, an isopropyl group, and a phenyl group. ) The organic electroluminescent element according to claim 46, wherein the electron transport layer contains at least one quinolinol complex represented by the following formula (V).
(Where
R _{1 to} R ₆ are a hydrogen atom, fluorine, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an alkoxy group, an optionally substituted aryl group, or an optionally substituted aromatic heterocyclic group. ,
M is Al, Ga, or Zn, and
n is an integer of 2 or 3. ) The organic electroluminescent element according to claim 46, wherein the electron transport layer contains at least one bipyridyl compound represented by the following formula (VI).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent, or G.
However, at least one of R _{1 to} R ₈ represents G. In addition, n 2,1'-bipyridyl residues formed by R _{1 to} R ₈ and 2,2'-bipyridyl nucleus may be the same or different, and R _{1 to} R ₈ Adjacent substituents may be condensed with each other to form a ring. ) 47. The organic electroluminescent element according to claim 46, wherein the electron transporting layer contains at least one phenanthroline compound represented by the following formula (VII).
(Where
G represents a simple bond or an n-valent linking group,
n is an integer from 2 to 8 and
R _{1 to} R ₈ each independently represents a hydrogen atom, a substituent or G.
However, at least one of R _{1 to} R ₈ represents G. The n phenanthroline residues formed by R _{1 to} R ₈ and the phenanthroline nucleus may be the same or different, and adjacent substituents of R _{1 to} R ₈ are condensed with each other. A ring may be formed. ) 47. The organic electroluminescent element according to claim 46, wherein the electron transport layer contains at least one imidazole compound represented by the following formula (VIII).
(Where
n is an integer of 2 to 8,
R and R ′ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or heteroatom-substituted aryl, and
L is an aryl group which may be substituted. )   The display apparatus provided with the organic electroluminescent element in any one of Claims 1 thru | or 50.   An illumination device comprising the organic electroluminescent element according to any one of claims 1 to 50.