JP6189296B2 - Organic electroluminescence device - Google Patents

Description

  The present invention relates to an organic electroluminescence element.

Organic electroluminescence (EL) elements include a fluorescent type and a phosphorescent type, and an optimum element design has been studied according to each light emission mechanism. With respect to phosphorescent organic EL elements, it is known from their light emission characteristics that high-performance elements cannot be obtained by simple diversion of fluorescent element technology. The reason is generally considered as follows.
Since phosphorescent light emission is light emission using triplet excitons, the energy gap of the compound used for the light emitting layer needs to be large. This is because the value of the energy gap (hereinafter also referred to as singlet energy) of a compound usually refers to the triplet energy of the compound (in the present invention, the energy difference between the lowest excited triplet state and the ground state). This is because it is larger than the value of).

  In order to efficiently confine the triplet energy of the phosphorescent dopant material in the light emitting layer, a host material having a triplet energy larger than the triplet energy of the phosphorescent dopant material must first be used for the light emitting layer. .

  In order to reduce the driving voltage of the organic EL element, it is necessary to use a material excellent in charge injection property or charge transport property. However, in the case of using such a material excellent in charge injection property and charge transport property, there is a case in which, instead of reducing the driving voltage, the charge balance in the light emitting layer is deteriorated and the life of the device is shortened. That is, a charge transport material that reduces the driving voltage while maintaining the lifetime of the element is required.

For the above reasons, material selection and device design different from those of the fluorescent organic EL device are required for improving the performance of the phosphorescent organic EL device.
Material research has been conducted earnestly and several reports have been made (Patent Documents 1 to 3).

  In Patent Document 1 and Patent Document 2, benzimidazole compounds are exemplified and used as an electron transport layer material. However, the triplet energy of the host material of the combined light emitting layer is small and the efficiency is low. In addition, since the host material to be combined has a structure that does not include a dibenzofuran ring or a dibenzothiophene ring, the charge injecting / transporting property is low and the voltage tends to be high.

  Patent Document 3 exemplifies benzimidazole compounds and is used as an electron transport layer material, but their triplet energy is small, and the energy of the light emitting layer leaks to the electron transport layer side, so the efficiency is low. Become.

JP 2009-155300 A JP 2009-158848 A JP 2010-118591 A

  An object of the present invention is to provide an organic EL device having a low voltage and a long lifetime.

  As a result of diligent research, the inventors of the present invention have used a benzimidazole compound having a specific structure excellent in electron injecting and transporting properties for a layer adjacent to the light emitting layer, and a combination using a compound having a specific structure for the light emitting layer. It was found that leakage of the term energy to the electron transport layer side can be suppressed, and an organic EL element having low voltage, high efficiency, and long life can be obtained.

According to the present invention, the following organic EL elements and the like are provided.
1. Having two or more organic thin film layers including a light emitting layer between the anode and the cathode;
The light emitting layer contains at least one compound represented by the following formula (1),
The organic thin film layer in contact with the light emitting layer on the cathode side of the light emitting layer contains at least one benzimidazole compound represented by the following formula (A),
Organic electroluminescence device.
(In the formula (1),
G _{1 to} G ₆ are each independently C—R ₁ or a nitrogen atom.
G _{11 to} G ₁₈ are each independently C—R ₂ or a nitrogen atom.
R and R ₁ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon. An alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkoxy group having 3 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, a substituted or unsubstituted ring group Aryloxy group having 6 to 18 ring carbon atoms, substituted or unsubstituted heteroaryloxy group having 5 to 18 ring atoms, substituted or unsubstituted arylthio group having 6 to 18 ring carbon atoms, substituted or unsubstituted A heteroarylthio group having 5 to 18 ring atoms, a substituted or unsubstituted arylsulfonyl group having 6 to 18 ring carbon atoms, and a substituted or unsubstituted ring atom number 5-18 heteroarylsulfonyl group, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted fluoroalkyl group, substituted or An unsubstituted fluoroalkoxy group or a cyano group.
When a plurality of C—R ₁ are present, the plurality of R ₁ may be the same as or different from each other.
However, if _{G 2} and / or _{G 5} is a _{C-R 1, R 1} of _{G 2} and _{G 5} are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, A substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or An unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms.
R ₂ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C—R ₂ are present, each R ₂ may be the same or different.
When R, R ₁ and R ₂ have a substituent, the substituent R ′ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 ring carbon atoms, or 1 to 20 carbon atoms. Alkoxy groups having 3 to 20 ring carbon atoms, aromatic hydrocarbon ring groups having 6 to 18 ring carbon atoms, aryloxy groups having 6 to 18 ring carbon atoms, and 5 to 18 ring atoms. A heteroaromatic ring group, a silyl group, a fluorine atom, a fluoroalkyl group having 1 to 20 carbon atoms, a fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
X represents an oxygen atom or a sulfur atom. )
(In the formula (A), Ra to Rd, Re to Rf, Rh to Ri, Rj to Rk and Rm to Rn are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and a substituted group. Or an unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted Substituted aromatic hydrocarbon ring group having 6 to 18 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 18 ring carbon atoms, substituted or unsubstituted heteroaromatic group having 5 to 18 ring atoms A cyclic group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon number of 1 to 2 It is a fluoroalkoxy group or a cyano group.
Rg and Rl are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number. 1 to 20 alkoxy groups, substituted or unsubstituted cycloalkoxy groups having 3 to 20 ring carbon atoms, substituted or unsubstituted silyl groups, fluorine atoms, substituted or unsubstituted fluoroalkyl groups having 1 to 20 carbon atoms, Alternatively, it is a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms.
Provided that at least one of Re to Rf, Rh to Ri, Rj to Rk, and Rm to Rn is a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted azacarbazolyl group, a substituted or unsubstituted dibenzofuranyl group, or A substituted or unsubstituted dibenzothiophenyl group;
Ar ₁ is a single bond, a substituted or unsubstituted alkyl group or alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted phenyl group or a metaphenylene group, a substituted or unsubstituted metabiphenylyl group or a metabiphenylylene group. Substituted or unsubstituted metaterphenylyl group or metaterphenylylene group, substituted or unsubstituted 3-pyridyl group or 3,5-pyridylene group, substituted or unsubstituted 2-pyridyl group or 2,6-pyridylene group Group, substituted or unsubstituted 2-pyridyl group or 2,4-pyridylene group, substituted or unsubstituted 2-dibenzofuranyl group or 2,8-dibenzofuranylene group, substituted or unsubstituted 2-dibenzothiophenyl Group or 2,8-dibenzothiophenylene group, or substituted or unsubstituted 3-carbazolyl group or 3,6-carbazolylene group.
Ar ₂ is a single bond, a substituted or unsubstituted alkyl group or alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted phenyl group or a metaphenylene group, a substituted or unsubstituted paraphenylene group, a substituted or unsubstituted group. Metabiphenylyl group or metabiphenylylene group, substituted or unsubstituted metaterphenylyl group or metaterphenylylene group, substituted or unsubstituted 3-pyridyl group or 3,5-pyridylene group, substituted or unsubstituted 2 -Pyridyl group or 2,6-pyridylene group, substituted or unsubstituted 2-pyridyl group or 2,4-pyridylene group, substituted or unsubstituted 2-dibenzofuranyl group or 2,8-dibenzofuranylene group, substituted Or an unsubstituted 2-dibenzothiophenyl group or 2,8-dibenzothio It is a phenylene group, or a substituted or unsubstituted 3-carbazolyl group or 3,6-carbazolylene group.
When Ra to Rn, Ar ₁ and Ar ₂ have a substituent, the substituent R ″ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 ring carbon atoms, or a carbon number. An alkoxy group having 1 to 20 carbon atoms, a cycloalkoxy group having 3 to 20 ring carbon atoms, an aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, an aryloxy group having 6 to 18 ring carbon atoms, and the number of ring forming atoms They are a 5-18 heteroaromatic ring group, a silyl group, a fluorine atom, a C1-C20 fluoroalkyl group, a C1-C20 fluoroalkoxy group, or a cyano group.
m and n are each 0 or 1.
o and p are each an integer of 0 to 3.
However, m, n, o, and p satisfy m + o ≧ 1 and n + p ≧ 1.
When o is 2 or 3, the plurality of Ar ₁ may be the same as or different from each other.
When p is 2 or 3, the plurality of Ar ₂ may be the same as or different from each other. )
2. 2. The organic electroluminescence according to 1, wherein the compound represented by the formula (1) is a compound represented by the following formula (2a), a compound represented by the following formula (2b), or a compound represented by the following formula (2c). element.
(In the formulas (2a) to (2c),
G ₂₁₁ ~G ₂₁₄ are each independently _{C-R 21} or a nitrogen atom.
G _{221 to} G ₂₂₈ are each independently C—R ₂₂ or a nitrogen atom.
Ga to Gk are each independently C—R ₂₃ or a nitrogen atom.
R ₂₁ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C-R ₂₁ are present, the plurality of R ₂₁ may be the same or different from each other.
R ₂₂ is independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C—R ₂₂ are present, the plurality of R ₂₂ may be the same or different from each other.
R ₂₃ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C—R ₂₃ are present, the plurality of R ₂₃ may be the same or different from each other.
When R ₂₁ , R ₂₂ and R ₂₃ have a substituent, the substituent R ′ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 ring carbon atoms, or 1 to 1 carbon atoms. 20 alkoxy groups, cycloalkoxy groups having 3 to 20 ring carbon atoms, aromatic hydrocarbon ring groups having 6 to 18 ring carbon atoms, aryloxy groups having 6 to 18 ring carbon atoms, 5 to 5 ring atoms An 18 heteroaromatic ring group, a silyl group, a fluorine atom, a fluoroalkyl group having 1 to 20 carbon atoms, a fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
X ₁ is an oxygen atom or a sulfur atom.
X ₂ is an oxygen atom, a sulfur atom, or ═C (CH ₃ ) ₂ . )
3. 2. The organic electroluminescence according to 1, wherein the compound represented by the formula (1) is a compound represented by the following formula (3a), a compound represented by the following formula (3b), or a compound represented by the following formula (3c). element.
(In Formula (3a)-Formula (3c),
Y represents a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, a substituted or unsubstituted monocyclic heteroaromatic ring group having 5 to 7 ring atoms, or the following formula (3- It is group represented by 1).
G _{311 to} G ₃₁₇ , G _{321 to} G ₃₂₇ , and G _{331 to} G ₃₃₇ are each independently C—R ₃₁ or a nitrogen atom.
R ₃₁ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C—R ₃₁ are present, the plurality of R ₃₁ may be the same or different from each other.
L ₃ is a single bond, a divalent linking group containing an oxygen atom, a divalent linking group containing a silicon atom, a divalent linking group containing a sulfur atom, an alkylene group having 1 to 5 carbon atoms, or the number of ring-forming carbon atoms. A cycloalkylene group having 3 to 6 carbon atoms, an aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, or a heteroaromatic ring group having 5 to 18 ring atoms.
When R ₃₁ has a substituent, the substituent R ′ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 ring carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a ring Cycloalkoxy group having 3 to 20 carbon atoms, aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, aryloxy group having 6 to 18 ring carbon atoms, heteroaromatic ring having 5 to 18 ring atoms Group, silyl group, fluorine atom, fluoroalkyl group, fluoroalkoxy group or cyano group.
X ₃ is an oxygen atom or a sulfur atom. )
(In Formula (3-1),
* Indicates a bond with a nitrogen atom.
G ₃₄₁ ~G ₃₄₇ are each independently a _{C-R 31} or a nitrogen _{atom, R 31} is the same as _{R 31} in the formula (3a) ~ formula (3c).
X ₃₁ is a nitrogen atom, oxygen atom or sulfur atom having a substituent. )
4). 2. The organic electroluminescence device according to 1, wherein the compound represented by the formula (1) is a compound represented by the following formula (4).
(In formula (4),
R ₄₁ , R ₄₂ and R ₄₃ are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted group. It is an aromatic hydrocarbon group having 6 to 18 ring carbon atoms, or a substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms.
R ₄₁ , R ₄₂ and R ₄₃ may be directly bonded to each other to form a ring, may be bonded through an oxygen atom to form a ring, or may be bonded through a sulfur atom to form a ring. Or may be bonded via a silicon atom to form a ring.
G _{41 to} G ₄₄ are each independently C—R ₄₄ or a nitrogen atom.
R ₄₄ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms. Group, substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 ring carbon atoms, substituted or unsubstituted ring carbon atoms having 6 to 18 carbon atoms An aryloxy group, a substituted or unsubstituted heteroaromatic cyclic group having 5 to 18 ring atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, A substituted or unsubstituted C1-C20 fluoroalkoxy group or cyano group.
When a plurality of C—R ₄₄ are present, the plurality of R ₄₄ may be the same or different from each other.
G ₄₁₁ ~G ₄₁₈ are each independently _{C-R 45} or a nitrogen atom.
R ₄₅ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms. Group, substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 ring carbon atoms, substituted or unsubstituted ring carbon atoms having 6 to 18 carbon atoms An aryloxy group, a substituted or unsubstituted heteroaromatic cyclic group having 5 to 18 ring atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, A substituted or unsubstituted C1-C20 fluoroalkoxy group or cyano group.
When a plurality of C-R ₄₅ are present, the plurality of R ₄₅ may be the same or different from each other.
When R ₄₁ , R ₄₂ , R ₄₃ , R ₄₄ and R ₄₅ have a substituent, the substituent R ′ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a cycloalkyl having 3 to 20 ring carbon atoms. Group, an alkoxy group having 1 to 20 carbon atoms, a cycloalkoxy group having 3 to 20 ring carbon atoms, an aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, an aryloxy group having 6 to 18 ring carbon atoms, A heteroaromatic cyclic group having 5 to 18 ring atoms, a silyl group, a fluorine atom, a fluoroalkyl group having 1 to 20 carbon atoms, a fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
X ₄ is an oxygen atom or a sulfur atom. )
5. In the formula (A), at least one of Rf, Rh, Rk and Rm is a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted azacarbazolyl group, a substituted or unsubstituted 2-dibenzofuranyl group, substituted or unsubstituted The organic electroluminescence device according to any one of 1 to 4, which is a 4-dibenzofuranyl group, a substituted or unsubstituted 2-dibenzothiophenyl group, or a substituted or unsubstituted 4-dibenzothiophenyl group.
6). Both Rf and Rh in the formula (A), or both Rk and Rm in the formula (A) are substituted or unsubstituted carbazolyl groups, substituted or unsubstituted azacarbazolyl groups, substituted or unsubstituted 2- Any one of 1 to 5 which is a dibenzofuranyl group, a substituted or unsubstituted 4-dibenzofuranyl group, a substituted or unsubstituted 2-dibenzothiophenyl group, or a substituted or unsubstituted 4-dibenzothiophenyl group The organic electroluminescent element of description.
7). Ar _{1 in the} formula (A) is a single bond, a substituted or unsubstituted alkyl group or alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted phenyl group or a metaphenylene group, substituted or unsubstituted 2-dibenzo. The organic electroluminescence device according to any one of 1 to 6, which is a furanyl group, a 2,8-dibenzofuranylene group, a substituted or unsubstituted 2-dibenzothiophenyl group, or a 2,8-dibenzothiophenylene group.
8). Ar _{2 in the} formula (A) is a single bond, a substituted or unsubstituted alkyl group or alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted phenyl group or a metaphenylene group, a substituted or unsubstituted paraphenylene group. Any one of 1 to 7 which is a substituted or unsubstituted 2-dibenzofuranyl group or 2,8-dibenzofuranylene group, or a substituted or unsubstituted 2-dibenzothiophenyl group or 2,8-dibenzothiophenylene group An organic electroluminescence device according to any one of the above.
9. The light emitting layer includes a phosphorescent material;
The organic electroluminescence device according to any one of 1 to 8, wherein the phosphorescent material is an orthometalated complex of one or more metal atoms selected from iridium (Ir), osmium (Os), and platinum (Pt). .
10. The organic electroluminescent element in any one of 1-9 in which the interface area | region of the said cathode and the said organic thin film layer contains an electron-donating dopant.
11. A compound represented by the following formula (a).
(In formula (a), R is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms.
Ra to Rd and Rj to Rn are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted group. Unsubstituted alkoxy group having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, substituted Or an unsubstituted aryloxy group having 6 to 18 carbon atoms, a substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group A fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
However, at least one of Rm and Rk is a substituted or unsubstituted carbazolyl group, substituted or unsubstituted azacarbazolyl group, substituted or unsubstituted dibenzofuranyl group, substituted or unsubstituted dibenzothiophenyl group, substituted or unsubstituted A substituted azadibenzofuranyl group, or a substituted or unsubstituted azadibenzothiophenyl group.
Ar ₂ is a single bond, a substituted or unsubstituted alkyl group or alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted phenyl group or a metaphenylene group, a substituted or unsubstituted paraphenylene group, a substituted or unsubstituted group. Metabiphenylyl group or metabiphenylylene group, substituted or unsubstituted metaterphenylyl group or metaterphenylylene group, substituted or unsubstituted 3-pyridyl group or 3,5-pyridylene group, substituted or unsubstituted 2 -Pyridyl group or 2,6-pyridylene group, substituted or unsubstituted 2-pyridyl group or 2,4-pyridylene group, substituted or unsubstituted 2-dibenzofuranyl group or 2,8-dibenzofuranylene group, substituted Or an unsubstituted 2-dibenzothiophenyl group or 2,8-dibenzothio It is a phenylene group, or a substituted or unsubstituted 3-carbazolyl group or 3,6-carbazolylene group.
n is 0 or 1.
p is 0 or 1.
n + p ≧ 1. )
12 In the formula (a), each of Rm and Rk independently represents a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted azacarbazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted group. 12. The compound according to 11, which is a dibenzothiophenyl group, a substituted or unsubstituted azadibenzofuranyl group, or a substituted or unsubstituted azadibenzothiophenyl group.
13. 12. The compound according to 11, wherein in the formula (a), at least one of Rm and Rk is a substituted or unsubstituted carbazolyl group.

  According to the present invention, an organic EL element having a low voltage, high efficiency, and long life can be provided.

It is a figure which shows one Embodiment of the organic EL element of this invention. It is a figure which shows other embodiment of the organic EL element of this invention.

The organic EL device of the present invention has two or more organic thin film layers including a light emitting layer between an anode and a cathode, and the light emitting layer contains at least one compound represented by the following formula (1). The organic thin film layer in contact with the light emitting layer on the cathode side of the light emitting layer contains at least one benzimidazole compound represented by the following formula (A).
Hereinafter, these compounds will be described.

[Compound represented by formula (A)]
The compound represented by the formula (A) is the following compound having a benzimidazole skeleton.
(In the formula (A), Ra to Rd, Re to Rf, Rh to Ri, Rj to Rk and Rm to Rn are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and a substituted group. Or an unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted Substituted aromatic hydrocarbon ring group having 6 to 18 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 18 ring carbon atoms, substituted or unsubstituted heteroaromatic group having 5 to 18 ring atoms A cyclic group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon number of 1 to 2 It is a fluoroalkoxy group or a cyano group.
Rg and Rl are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number. 1 to 20 alkoxy groups, substituted or unsubstituted cycloalkoxy groups having 3 to 20 ring carbon atoms, substituted or unsubstituted silyl groups, fluorine atoms, substituted or unsubstituted fluoroalkyl groups having 1 to 20 carbon atoms, Alternatively, it is a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms.
Provided that at least one of Re and Rf, Rh and Ri, Rj and Rk, and Rm and Rn is a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted azacarbazolyl group, a substituted or unsubstituted dibenzofuranyl group, Or a substituted or unsubstituted dibenzothiophenyl group.
Ar ₁ is a single bond, a substituted or unsubstituted alkyl group or alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted phenyl group or a metaphenylene group, a substituted or unsubstituted metabiphenylyl group or a metabiphenylylene group. Substituted or unsubstituted metaterphenylyl group or metaterphenylylene group, substituted or unsubstituted 3-pyridyl group or 3,5-pyridylene group, substituted or unsubstituted 2-pyridyl group or 2,6-pyridylene group Group, substituted or unsubstituted 2-pyridyl group or 2,4-pyridylene group, substituted or unsubstituted 2-dibenzofuranyl group or 2,8-dibenzofuranylene group, substituted or unsubstituted 2-dibenzothiophenyl Group or 2,8-dibenzothiophenylene group, or substituted or unsubstituted 3-carbazolyl group or 3,6-carbazolylene group.
Ar ₂ is a single bond, a substituted or unsubstituted alkyl group or alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted phenyl group or a metaphenylene group, a substituted or unsubstituted paraphenylene group, a substituted or unsubstituted group. Metabiphenylyl group or metabiphenylylene group, substituted or unsubstituted metaterphenylyl group or metaterphenylylene group, substituted or unsubstituted 3-pyridyl group or 3,5-pyridylene group, substituted or unsubstituted 2 -Pyridyl group or 2,6-pyridylene group, substituted or unsubstituted 2-pyridyl group or 2,4-pyridylene group, substituted or unsubstituted 2-dibenzofuranyl group or 2,8-dibenzofuranylene group, substituted Or an unsubstituted 2-dibenzothiophenyl group or 2,8-dibenzothio It is a phenylene group, or a substituted or unsubstituted 3-carbazolyl group or 3,6-carbazolylene group.
When Ra to Rn, Ar ₁ and Ar ₂ have a substituent, the substituent R ″ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 ring carbon atoms, or a carbon number. An alkoxy group having 1 to 20 carbon atoms, a cycloalkoxy group having 3 to 20 ring carbon atoms, an aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, an aryloxy group having 6 to 18 ring carbon atoms, and the number of ring forming atoms They are a 5-18 heteroaromatic ring group, a silyl group, a fluorine atom, a C1-C20 fluoroalkyl group, a C1-C20 fluoroalkoxy group, or a cyano group.
m and n are each 0 or 1.
o and p are each an integer of 0 to 3.
However, m, n, o, and p satisfy m + o ≧ 1 and n + p ≧ 1.
When o is 2 or 3, the plurality of Ar ₁ may be the same as or different from each other.
When p is 2 or 3, the plurality of Ar ₂ may be the same as or different from each other. )

  In the compound represented by the formula (A), preferably at least one of Rf, Rh, Rk, and Rm is a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted azacarbazolyl group, a substituted or unsubstituted 2-dibenzofuranyl Group, a substituted or unsubstituted 4-dibenzofuranyl group, a substituted or unsubstituted 2-dibenzothiophenyl group, or a substituted or unsubstituted 4-dibenzothiophenyl group, and more preferably Rf, Rh, Rk, At least one of Rm is a substituted or unsubstituted N-carbazolyl group, a substituted or unsubstituted 2-dibenzofuranyl group, or a substituted or unsubstituted 2-dibenzothiophenyl group.

  In the compound represented by the formula (A), preferably both Rf and Rh, or both Rk and Rm are substituted or unsubstituted carbazolyl group, substituted or unsubstituted azacarbazolyl group, substituted or unsubstituted 2- A dibenzofuranyl group, a substituted or unsubstituted 4-dibenzofuranyl group, a substituted or unsubstituted 2-dibenzothiophenyl group, or a substituted or unsubstituted 4-dibenzothiophenyl group.

In the compound represented by the formula (A), Ar ₁ is preferably a single bond, a substituted or unsubstituted alkyl group or alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted phenyl group or a metaphenylene group, substituted or An unsubstituted 2-dibenzofuranyl group or 2,8-dibenzofuranylene group, or a substituted or unsubstituted 2-dibenzothiophenyl group or 2,8-dibenzothiophenylene group, more preferably a single bond or a substituted group Alternatively, it is an unsubstituted alkyl group or alkylene group having 1 to 5 carbon atoms, or a substituted or unsubstituted phenyl group or metaphenylene group.

In the compound represented by the formula (A), Ar ₂ is preferably a single bond, a substituted or unsubstituted alkyl group or alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group or a metaphenylene group, substituted or unsubstituted An unsubstituted paraphenylene group, a substituted or unsubstituted 2-dibenzofuranyl group or 2,8-dibenzofuranylene group, or a substituted or unsubstituted 2-dibenzothiophenyl group or 2,8-dibenzothiophenylene group; More preferably a single bond, a substituted or unsubstituted alkyl group or alkylene group having 1 to 5 carbon atoms, a substituted or unsubstituted phenyl group or metaphenylene group, or a substituted or unsubstituted paraphenylene group.

  In the compound represented by the formula (A), m and n preferably satisfy m + n ≧ 1.

The compound represented by the formula (A) is preferably a compound represented by the following formula (a).
The compound of the present invention is represented by the following formula (a).
(In formula (a), R is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms.
Ra to Rd, Rj to Rn, and Ar ₂ are the same as in the formula (A).
At least one of Rm and Rk is a substituted or unsubstituted carbazolyl group, substituted or unsubstituted azacarbazolyl group, substituted or unsubstituted dibenzofuranyl group, substituted or unsubstituted dibenzothiophenyl group, substituted or unsubstituted An azadibenzofuranyl group, or a substituted or unsubstituted azadibenzothiophenyl group;
n is 0 or 1.
p is 0 or 1.
n + p ≧ 1. )

  In the formula (a), each of Rm and Rk independently represents a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted azacarbazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted group. A dibenzothiophenyl group, a substituted or unsubstituted azadibenzofuranyl group, or a substituted or unsubstituted azadibenzothiophenyl group is preferable.

  In the formula (a), it is preferable that at least one of Rm and Rk is a substituted or unsubstituted carbazolyl group.

  The triplet energy of the benzimidazole compound represented by the formula (A) is preferably 2.85 eV or more, more preferably 2.90 eV or more.

Specific examples of the compound represented by the formula (A) are shown below. However, the compound represented by the formula (A) is not limited to the following specific examples.

  The compound represented by the formula (A) can be produced by a known method. For example, it can be produced by a method described in JP2009-155300A, JP2009-158848A, or the like.

[Compound represented by Formula (1)]
The compound represented by Formula (1) is the following compound.
(In the formula (1),
G _{1 to} G ₆ are each independently C—R ₁ or a nitrogen atom.
G _{11 to} G ₁₈ are each independently C—R ₂ or a nitrogen atom.
R and R ₁ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon. An alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkoxy group having 3 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, a substituted or unsubstituted ring group Aryloxy group having 6 to 18 ring carbon atoms, substituted or unsubstituted heteroaryloxy group having 5 to 18 ring atoms, substituted or unsubstituted arylthio group having 6 to 18 ring carbon atoms, substituted or unsubstituted A heteroarylthio group having 5 to 18 ring atoms, a substituted or unsubstituted arylsulfonyl group having 6 to 18 ring carbon atoms, and a substituted or unsubstituted ring atom number 5-18 heteroarylsulfonyl group, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted 1 to 20 carbon atoms A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C—R ₁ are present, the plurality of R ₁ may be the same as or different from each other.
However, if _{G 2} and / or _{G 5} is a _{C-R 1, R 1} of _{G 2} and _{G 5} are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, A substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or An unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms.
R ₂ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C—R ₂ are present, each R ₂ may be the same or different.
When R, R ₁ and R ₂ have a substituent, the substituent R ′ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 ring carbon atoms, or 1 to 20 carbon atoms. Alkoxy groups having 3 to 20 ring carbon atoms, aromatic hydrocarbon ring groups having 6 to 18 ring carbon atoms, aryloxy groups having 6 to 18 ring carbon atoms, and 5 to 18 ring atoms. A heteroaromatic ring group, a silyl group, a fluorine atom, a fluoroalkyl group having 1 to 20 carbon atoms, a fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
X represents an oxygen atom or a sulfur atom. )

The compound represented by the formula (1) is preferably any one of the compounds represented by the following formulas (2a) to (2c), (3a) to (3c) and (4).
(In the formulas (2a) to (2c),
G ₂₁₁ ~G ₂₁₄ are each independently _{C-R 21} or a nitrogen atom.
G _{221 to} G ₂₂₈ are each independently C—R ₂₂ or a nitrogen atom.
Ga to Gk are each independently C—R ₂₃ or a nitrogen atom.
R ₂₁ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C-R ₂₁ are present, the plurality of R ₂₁ may be the same or different from each other.
R ₂₂ is independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C—R ₂₂ are present, the plurality of R ₂₂ may be the same or different from each other.
R ₂₃ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C—R ₂₃ are present, the plurality of R ₂₃ may be the same or different from each other.
When R ₂₁ , R ₂₂ and R ₂₃ have a substituent, the substituent R ′ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 ring carbon atoms, or 1 to 1 carbon atoms. 20 alkoxy groups, cycloalkoxy groups having 3 to 20 ring carbon atoms, aromatic hydrocarbon ring groups having 6 to 18 ring carbon atoms, aryloxy groups having 6 to 18 ring carbon atoms, 5 to 5 ring atoms An 18 heteroaromatic ring group, a silyl group, a fluorine atom, a fluoroalkyl group having 1 to 20 carbon atoms, a fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
X ₁ is an oxygen atom or a sulfur atom.
X ₂ is an oxygen atom, a sulfur atom, or ═C (CH ₃ ) ₂ . )

(In Formula (3a)-Formula (3c),
Y represents a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, a substituted or unsubstituted monocyclic heteroaromatic ring group having 2 to 5 ring carbon atoms, or the following formula (3- It is group represented by 1).
G _{311 to} G ₃₁₇ , G _{321 to} G ₃₂₇ , and G _{331 to} G ₃₃₇ are each independently C—R ₃₁ or a nitrogen atom.
R ₃₁ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C—R ₃₁ are present, the plurality of R ₃₁ may be the same or different from each other.
L ₃ is a single bond, a divalent linking group containing an oxygen atom, a divalent linking group containing a silicon atom, a divalent linking group containing a sulfur atom, an alkylene group having 1 to 5 carbon atoms, or the number of ring-forming carbon atoms. A cycloalkylene group having 3 to 6 carbon atoms, an aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, or a heteroaromatic ring group having 5 to 18 ring atoms.
When R ₃₁ has a substituent, the substituent R ′ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 ring carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a ring Cycloalkoxy group having 3 to 20 carbon atoms, aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, aryloxy group having 6 to 18 ring carbon atoms, heteroaromatic ring having 5 to 18 ring atoms A group, a silyl group, a fluorine atom, a fluoroalkyl group having 1 to 20 carbon atoms, a fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
X ₃ is an oxygen atom or a sulfur atom. )
(In Formula (3-1),
* Indicates a bond with a nitrogen atom.
G ₃₄₁ ~G ₃₄₇ are each independently a _{C-R 31} or a nitrogen _{atom, R 31} is the same as _{R 31} in the formula (3a) ~ formula (3c).
X ₃₁ is a nitrogen atom, oxygen atom or sulfur atom having a substituent. )

(In formula (4),
R ₄₁ , R ₄₂ and R ₄₃ are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted group. It is an aromatic hydrocarbon group having 6 to 18 ring carbon atoms, or a substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms.
R ₄₁ , R ₄₂ and R ₄₃ may be directly bonded to each other to form a ring, may be bonded through an oxygen atom to form a ring, or may be bonded through a sulfur atom to form a ring. Or may be bonded via a silicon atom to form a ring.
G _{41 to} G ₄₄ are each independently C—R ₄₄ or a nitrogen atom.
R ₄₄ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms. Group, substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 ring carbon atoms, substituted or unsubstituted ring carbon atoms having 6 to 18 carbon atoms An aryloxy group, a substituted or unsubstituted heteroaromatic cyclic group having 5 to 18 ring atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, A substituted or unsubstituted C1-C20 fluoroalkoxy group or cyano group.
When a plurality of C—R ₄₄ are present, the plurality of R ₄₄ may be the same or different from each other.
G ₄₁₁ ~G ₄₁₈ are each independently _{C-R 45} or a nitrogen atom.
R ₄₅ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms. Group, substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 ring carbon atoms, substituted or unsubstituted ring carbon atoms having 6 to 18 carbon atoms An aryloxy group, a substituted or unsubstituted heteroaromatic cyclic group having 5 to 18 ring atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, A substituted or unsubstituted C1-C20 fluoroalkoxy group or cyano group.
When a plurality of C-R ₄₅ are present, the plurality of R ₄₅ may be the same or different from each other.
When R ₄₁ , R ₄₂ , R ₄₃ , R ₄₄ and R ₄₅ have a substituent, the substituent R ′ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a cycloalkyl having 3 to 20 ring carbon atoms. Group, an alkoxy group having 1 to 20 carbon atoms, a cycloalkoxy group having 3 to 20 ring carbon atoms, an aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, an aryloxy group having 6 to 18 ring carbon atoms, A heteroaromatic cyclic group having 5 to 18 ring atoms, a silyl group, a fluorine atom, a fluoroalkyl group having 1 to 20 carbon atoms, a fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
X ₄ is an oxygen atom or a sulfur atom. )

  The compounds represented by formulas (1), (2a) to (2c), (3a) to (3c) and (4) preferably have a triplet energy of 2.9 eV or more.

Specific examples of the compounds represented by the formulas (1), (2a) to (2c), (3a) to (3c) and (4) are shown below. However, the compounds represented by the formulas (1), (2a) to (2c), (3a) to (3c) and (4) are not limited to the following specific examples.
X represents an oxygen atom or a sulfur atom.

Hereinafter, the compound represented by the formula (A) and each substituent of the compounds represented by the formulas (1), (2a) to (2c), (3a) to (3c) and (4) will be described.
The “ring-forming carbon” means a carbon atom constituting a saturated ring, an unsaturated ring, or an aromatic ring, and the “ring-forming atom” includes a hetero ring (including a saturated ring, an unsaturated ring, and an aromatic ring). ) Is a carbon atom and a hetero atom.
In the present application, the hydrogen atom includes isotopes having different neutron numbers such as light hydrogen (protium), deuterium (deuterium), and tritium.

Specific examples of the aryl group (aromatic hydrocarbon group) include phenyl group, tolyl group, xylyl group, naphthyl group, phenanthryl group, pyrenyl group, chrysenyl group, benzo [c] phenanthryl group, benzo [g] chrysenyl group, Benzoanthryl group, triphenylenyl group, fluorenyl group, 9,9-dimethylfluorenyl group, benzofluorenyl group, dibenzofluorenyl group, biphenyl group, terphenyl group, fluoranthenyl group, and the like are preferable. Are a phenyl group, a biphenyl group, and a naphthyl group.
Examples of the aromatic hydrocarbon group having a substituent include a tolyl group, a xylyl group, and a 9,9-dimethylfluorenyl group.
As specific examples indicate, aryl groups include both fused and non-fused aryl groups.

  Specific examples of the heteroaryl group (aromatic heterocyclic group, heteroaromatic ring group, heterocyclic group) include pyrrolyl group, pyrazolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, pyridyl group, triazinyl group, indolyl group, Isoindolyl group, imidazolyl group, benzimidazolyl group, indazolyl group, imidazo [1,2-a] pyridinyl group, furyl group, benzofuranyl group, isobenzofuranyl group, dibenzofuranyl group, azadibenzofuranyl group, thiophenyl group, Benzothiophenyl group, dibenzothiophenyl group, azadibenzothiophenyl group, quinolyl group, isoquinolyl group, quinoxalinyl group, quinazolinyl group, naphthyridinyl group, carbazolyl group, azacarbazolyl group, phenanthridinyl group, acridinyl group, phenanthrolinyl Group, fe Examples include a dinyl group, a phenothiazinyl group, a phenoxazinyl group, an oxazolyl group, an oxadiazolyl group, a furanyl group, a benzoxazolyl group, a thienyl group, a thiazolyl group, a thiadiazolyl group, a benzthiazolyl group, a triazolyl group, and a tetrazolyl group. A dibenzofuranyl group, a dibenzothiophenyl group, and a carbazolyl group.

The azacarbazolyl group is, for example, an azacarbazolyl group containing 2 to 5 nitrogen atoms, and examples thereof include monovalent groups derived from the following azacarbazole. The bond may be present on any nitrogen atom or any carbon atom, and any nitrogen atom or any carbon atom may be substituted.

Examples of the alkyl group include linear, branched and cyclic alkyl groups. Examples of linear and branched alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl. Group, n-heptyl group, n-octyl group and the like, preferably methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group and tert-butyl group. More preferred are methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group and t-butyl group.
Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a 1-adamantyl group, a 2-adamantyl group, a 1-norbornyl group, and a 2-norbornyl group. Preferred are a cyclopentyl group and a cyclohexyl group.

The alkoxy group is represented as -OY, and examples of Y include the above alkyl examples. Specific examples of the alkoxy group include a methoxy group and an ethoxy group.
The cycloalkoxy group is represented as —OY ^2, and examples of Y ² include the above cycloalkyl groups. The cycloalkoxy group is, for example, a cyclopentyloxy group or a cyclohexyloxy group.

The aryloxy group is represented by -OZ, and examples of Z include the above aryl groups. Specific examples of the aryloxy group include a phenoxy group and a naphthyloxy group.
A heteroaryloxy group is represented by —OZ ′, and examples of Z ′ include the above heteroaryl groups. Specific examples of the heteroaryloxy group include (carbazol-3-yl) oxy group, (carbazol-4-yl) oxy group, (dibenzofuran-2-yl) oxy group, and the like.
The arylcarbonyl group is represented by —COZ, and examples of Z include the above aryl groups.

The arylthio group is represented by -SZ, and examples of Z include the above aryl groups.
The heteroarylthio group is represented by —SZ ′, and examples of Z ′ include the above heteroaryl groups. Specific examples of the heteroaryloxy group include (carbazol-3-yl) thio group, (carbazol-4-yl) thio group, (dibenzofuran-2-yl) thio group, and the like.
The arylsulfonyl group is represented by —SO ₂ Z, and examples of Z include the above aryl groups.
The heteroarylsulfonyl group is represented by —SO ₂ Z ′, and examples of Z ′ include the above heteroaryl groups. Specific examples of the heteroaryloxy group include (carbazol-3-yl) sulfonyl group, (carbazol-4-yl) sulfonyl group, (dibenzofuran-2-yl) sulfonyl group, and the like.

  The aralkyl group is represented as —Y—Z. Examples of Y include alkylene examples corresponding to the above alkyl examples, and examples of Z include the above aryl examples. The aryl part of the aralkyl group preferably has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms. The alkyl moiety preferably has 1 to 10 carbon atoms, particularly preferably 1 to 6 carbon atoms. For example, benzyl group, phenylethyl group, 2-phenylpropan-2-yl group and the like can be mentioned.

Examples of the halogenated alkyl group include groups in which one or more halogen atoms (a fluorine atom, a chlorine atom and a bromine atom are included, preferably a fluorine atom) are substituted on the above-described alkyl group. Specific examples include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a 2,2,2-trifluoroethyl group, and a pentafluoroethyl group. Preferably, they are a trifluoromethyl group and a pentafluoroethyl group.
Examples of the fluoroalkyl group include groups in which one or more fluorine atoms are substituted on the above-described alkyl group. Specific examples include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a 2,2,2-trifluoroethyl group, and a pentafluoroethyl group. Preferably, they are a trifluoromethyl group and a pentafluoroethyl group.
Examples of the fluoroalkoxy group include groups in which the alkyl portion of the alkoxy group described above is substituted with one or more fluorine atoms. Specific examples include a fluoromethoxy group, a difluoromethoxy group, a trifluoromethoxy group, a fluoroethoxy group, a 2,2,2-trifluoroethoxy group, and a pentafluoroethoxy group. Preferably, they are a trifluoromethoxy group and a pentafluoroethoxy group.

The substituted or unsubstituted silyl group includes, for example, a silyl group, an alkylsilyl group, a dialkylarylsilyl group, an alkyldiarylsilyl group, and a triarylsilyl group.
The substituted silyl group is represented as —Si (R ^a ) (R ^b ) (R ^c ), and examples of (R ^a ), (R ^b ) and (R ^c ) include the above-described alkyl groups, aryl groups, hetero groups. An aryl group etc. are mentioned.

The substituted or unsubstituted amino group includes, for example, an arylamino group, an alkylamino group, and an aralkylamino group.
The substituted amino group is represented as —N (Q ^a ) (Q ^b ), and examples of (Q ^a ) and (Q ^b ) include the alkyl group, aryl group, and aralkyl group described above.

Examples of the alkylene group, cycloalkylene group, arylene group, and heteroarylene group include divalent residues corresponding to the above-described alkyl group, cycloalkyl group, aryl group, and heteroaryl group.
In addition, a metabiphenylyl group, a metabiphenylylene group, a metaterphenylyl group, and a metaterphenylylene group are groups represented by the following formulas, respectively.

The compound represented by the formula (A) is a material for an organic thin film layer of an organic EL device, and can be suitably used as an electron transport band layer material. Among the electron transport band layers, the compound is particularly suitable as an electron transport layer material. Can be used.
The compounds represented by the formulas (1) to (4) are materials for a light emitting layer of an organic EL device, can be suitably used as a host material for a light emitting layer, and are particularly suitably used as a host material for a blue phosphorescent light emitting layer. be able to. This is because the triplet energy of the compounds represented by the formulas (1) to (4) is sufficiently large, so that the triplet energy of the phosphorescent dopant material is efficiently used even when a blue phosphorescent dopant material is used. This is because it can be confined in the light emitting layer.
The compounds represented by the formulas (1) to (4) can be used not only in the blue light emitting layer but also in the light emitting layer of longer wavelength light (such as green to red).

[Element structure]
In the organic EL device of the present invention, other configurations are not particularly limited as long as the organic thin film layer and the light emitting layer are configured as described above, and the organic thin film layer containing the compound represented by the formula (A) emits light. Adjacent on the cathode side of the layer.
In addition, the light emitting layer may contain one or more of the compounds represented by formulas (1) to (4), preferably one of the compounds represented by formulas (1) to (4). Including only.

The organic EL element of the present invention can employ a known element configuration. Hereinafter, the example of an organic EL element is demonstrated using drawing.
FIG. 1 is a schematic view showing a layer structure of an embodiment of the organic EL device of the present invention.
The organic EL element 1 has a configuration in which an anode 20, a hole transport zone 30, a phosphorescent light emitting layer 40, an electron transport zone 50, and a cathode 60 are laminated on a substrate 10 in this order.
The hole transport zone 30 means a hole transport layer and / or a hole injection layer. Similarly, the electron transport zone 50 means an electron transport layer and / or an electron injection layer. These need not be formed, but preferably one or more layers are formed.
In this element 1, the organic thin film layer is each organic layer provided in the hole transport zone 30, each phosphor layer and the organic layer provided in the electron transport zone 50.

FIG. 2 is a schematic view showing the layer structure of another embodiment of the organic EL element of the present invention. The organic EL element 2 is an example of a hybrid organic EL element in which a phosphorescent light emitting layer and a fluorescent light emitting layer are laminated. is there.
The organic EL element 2 has the same configuration as the organic EL element 1 except that a space layer 42 and a fluorescent light emitting layer 44 are formed between the phosphorescent light emitting layer 40 and the electron transport zone 50. In the configuration in which the phosphorescent light emitting layer 40 and the fluorescent light emitting layer 44 are laminated, the excitons formed in the phosphorescent light emitting layer 40 are not diffused into the fluorescent light emitting layer 44. May be provided.
In addition, since the compound represented by Formula (1)-(4) has a large triplet energy, it can function as a space layer.

  In the organic EL element 2, for example, when the phosphorescent light emitting layer 40 emits yellow light and the fluorescent light emitting layer 44 forms a blue light emitting layer, a white light emitting organic EL element can be obtained. In the present embodiment, the phosphorescent light emitting layer 40 and the fluorescent light emitting layer 44 are formed one by one. However, the present invention is not limited to this, and two or more layers may be formed. it can. For example, when a full color light emitting device is formed using a white light emitting element and a color filter, a plurality of wavelength regions such as red, green, blue (RGB), red, green, blue, yellow (RGBY) are used from the viewpoint of color rendering. In some cases, it may be preferable to include luminescence.

  In addition to the above-described embodiments, the organic EL element of the present invention can employ various known configurations. In addition, light emission of the light emitting layer can be extracted from the anode side, the cathode side, or both sides.

Hereinafter, materials of each layer will be described. The organic thin film layer in contact with the light emitting layer of the organic EL element on the cathode side contains the compound represented by the formula (A), and the light emitting layer has the formulas (1) to (4). It is not particularly limited as long as it contains one or more of the compounds represented by A known material etc. can be used for each layer of an organic EL element.
In addition, when an organic EL element has two or more light emitting layers, the organic thin film layer which touches the cathode side of any one light emitting layer should just contain the compound represented by Formula (A).

[Electron injection layer and electron transport layer]
The electron injection / transport layer is a layer that assists the injection of electrons into the light emitting layer and transports it to the light emitting region and has a high electron mobility. The compound represented by the formula (A) includes the electron injection / transport layer. It can be suitably used as an electron transporting material used for the transport layer.
As the electron transporting material other than the compound represented by the formula (A), an aromatic heterocyclic compound containing at least one hetero atom in the molecule is preferably used, and a nitrogen-containing ring derivative is particularly preferable. The nitrogen-containing ring derivative is preferably an aromatic ring having a nitrogen-containing 6-membered ring or 5-membered ring skeleton, or a condensed aromatic ring compound having a nitrogen-containing 6-membered ring or 5-membered ring skeleton, such as a pyridine ring. , Pyrimidine ring, triazine ring, benzimidazole ring, phenanthroline ring, quinazoline ring and the like.

  In addition, an organic layer having semiconducting properties may be formed by doping a donor material (n) and acceptor material (p). A typical example of N doping is to dope a metal such as Li or Cs into an electron transporting material, and a typical example of P doping is F4TCNQ (2,3,5,6-Tetrafluoro- 7,7,8,8-tetracyanoquinodimethane) and the like (see, for example, Patent 3695714).

In the organic EL element, since emitted light is reflected by an electrode (for example, a cathode), it is known that light emitted directly from the anode interferes with light emitted via reflection by the electrode. To efficiently utilize the interference, although the electron injecting and transporting layer is suitably selected in a film thickness of several nm~ number [mu] m, especially when thick film thickness, in order to avoid a voltage rise, 10 ⁴ to 10 ⁶ It is preferable that the electron mobility is at least 10 ⁻⁵ cm ² / Vs or more when an electric field of V / cm is applied.

[Light emitting layer]
The phosphorescent layer containing one or more compounds represented by formulas (1) to (4) as a host contains a phosphorescent dopant (phosphorescent material).
Examples of the phosphorescent dopant include metal complex compounds, preferably a compound having a metal atom selected from Ir, Pt, Os, Au, Cu, Re and Ru and a ligand. The ligand preferably has an ortho metal bond.
The phosphorescent dopant is preferably a compound containing a metal atom selected from Ir, Os and Pt in that the phosphorescent quantum yield is high and the external quantum efficiency of the light-emitting element can be further improved, and an iridium complex, It is more preferable that it is a metal complex such as an osmium complex and a platinum complex, among which an iridium complex and a platinum complex are more preferable, and an orthometalated iridium complex is most preferable.
The dopant may be a single type or a mixture of two or more types.

  The addition concentration of the phosphorescent dopant in the phosphorescent light emitting layer is not particularly limited, but is preferably 0.1 to 30% by mass, more preferably 0.1 to 20% by mass.

The light emitting layer may be a double host (also referred to as a host / cohost). Specifically, the carrier balance in the light emitting layer may be adjusted by combining an electron transporting host and a hole transporting host in the light emitting layer.
Moreover, it is good also as a double dopant. In the light emitting layer, each dopant emits light by adding two or more dopant materials having a high quantum yield. For example, a yellow light emitting layer may be realized by co-evaporating a host, a red dopant, and a green dopant.

When the phosphorescent light emitting layer is formed of a material other than the compounds represented by the formulas (1) to (4), a known material can be used as the material of the phosphorescent light emitting layer. Specifically, Japanese Patent Application No. 2005-517938 may be referred to.
The organic EL device of the present invention may have a fluorescent light emitting layer like the device shown in FIG. A known material can be used for the fluorescent light emitting layer.

As the host material of the light emitting layer other than the compounds represented by the formulas (1) to (4), a compound containing any of a carbazole ring, a dibenzofuran ring and a dibenzothiophene ring is preferable.
Preferred examples of the host material for the light emitting layer other than the compounds represented by the formulas (1) to (4) include compounds represented by the following formula (a).
(In the formula, L ¹¹ represents a single bond, a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, or a heteroarylene group having 5 to 30 ring atoms.
X ¹¹ represents O, S, Se, or Te.
R ¹⁴ and R ¹⁵ each independently represents a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a heteroaryl group having 5 to 30 ring atoms, or a substituted or unsubstituted carbon atom having 1 to 30 carbon atoms. An alkyl group, a substituted or unsubstituted alkylsilyl group, a substituted or unsubstituted arylsilyl group, or a substituted or unsubstituted heteroarylsilyl group is represented.
s represents an integer of 0 to 3.
t represents an integer of 0 to 4.
Cz represents a group represented by the following formula (a-1) or the following formula (a-2). )
(Wherein, * ^represents a bonding position to ^{L 11.}
R ¹¹ represents a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a heteroaryl group having 5 to 30 ring atoms, or a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms. Represent.
R ¹² and R ¹³ are each independently a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a heteroaryl group having 5 to 30 ring atoms, or a substituted or unsubstituted carbon atom having 1 to 30 carbon atoms. Represents an alkyl group.
p and q represent the integer of 0-4 each independently.
r represents an integer of 0 to 3. )

Examples of the arylene group having 6 to 30 ring carbon atoms and the heteroarylene group having 5 to 30 ring atoms of L ^{11 in} the formula (a) include those similar to L in the formula (1).
The aryl group having 6 to 30 ring carbon atoms, the heteroaryl group having 5 to 30 ring atoms, and the alkyl group having 1 to 30 carbon atoms of R ^{11 in} formula (a) are represented by R _{401 in} formula (4) and The same thing as _Ra is mentioned. The alkylsilyl group, arylsilyl group, and heteroarylsilyl group of R ¹¹ are groups obtained by arbitrarily combining the alkyl group, the aryl group, the heteroaryl group, and the silyl group, respectively.
The aryl group having 6 to 30 ring carbon atoms, the heteroaryl group having 5 to 30 ring atoms, and the alkyl group having 1 to 30 carbon atoms of R ^{12 to} R ^{15 in} the formula (a) are represented by the formula (4). The same thing as _Ra is mentioned.

Specific examples of the compound represented by the formula (a) are shown below.
However, the compound represented by the formula (a) is not limited to the following. In the compounds shown below, X represents an oxygen atom or a sulfur atom, and R ′ represents a hydrogen atom or a methyl group.

  The light emitting layer may be a single layer or a laminated structure. When the light emitting layer is stacked, the recombination region can be concentrated on the light emitting layer interface by accumulating electrons and holes at the light emitting layer interface. Thereby, quantum efficiency can be improved.

[Blocking layer]
It is also preferable to use the compounds represented by the formulas (1) to (4) in a layer adjacent to the phosphorescent light emitting layer 40. For example, when a layer containing the material of the present invention (an anode side adjacent layer) is formed between the hole transport zone 30 and the phosphorescent light emitting layer 40 of the device of FIG. 1, the layer functions as an electron barrier layer. It functions as an exciton blocking layer.

When a layer containing the compounds represented by the formulas (1) to (4) (cathode side adjacent layer) is formed between the phosphorescent light emitting layer 40 and the electron transport zone 50, the layer functions as a hole blocking layer. It can also function as an exciton blocking layer.
The barrier layer (blocking layer) is a layer having a function of a carrier movement barrier or an exciton diffusion barrier. The organic layer for preventing electrons from leaking from the light-emitting layer to the hole transport zone can be defined mainly as an electron barrier layer, and the organic layer for preventing holes from leaking from the light-emitting layer to the electron transport zone is defined as a hole barrier. Can be defined as a layer. In addition, an exciton blocking layer (triplet barrier layer) is an organic layer for preventing triplet excitons generated in the light emitting layer from diffusing into a peripheral layer having triplet energy lower than that of the light emitting layer. May be defined.
Further, the compounds represented by the formulas (1) to (4) may be used for a layer adjacent to the phosphorescent light emitting layer 40 and further used for another organic thin film layer bonded to the adjacent layer.
In addition, when two or more light emitting layers are formed, the compounds represented by the formulas (1) to (4) can be suitably used as a space layer material formed between the light emitting layers.

The organic EL device of the present invention preferably has at least one of an electron donating dopant and an organometallic complex in an interface region between the cathode and the organic thin film layer.
According to such a configuration, it is possible to improve the light emission luminance and extend the life of the organic EL element.
Moreover, it is preferable that the organic EL element of this invention contains the compound and electron donating dopant which are represented by Formula (1)-(4) in the electron carrying layer or electron injection layer in the electron carrying zone 50. Thereby, the drive voltage of an organic EL element can further be reduced.

Examples of the electron donating dopant include at least one selected from alkali metals, alkali metal compounds, alkaline earth metals, alkaline earth metal compounds, rare earth metals, rare earth metal compounds, and the like.
Examples of the organometallic complex include at least one selected from an organometallic complex containing an alkali metal, an organometallic complex containing an alkaline earth metal, an organometallic complex containing a rare earth metal, and the like.

  Examples of the alkali metal include lithium (Li) (work function: 2.93 eV), sodium (Na) (work function: 2.36 eV), potassium (K) (work function: 2.28 eV), rubidium (Rb) (work Function: 2.16 eV), cesium (Cs) (work function: 1.95 eV), and the like, and those having a work function of 2.9 eV or less are preferable. Of these, K, Rb, and Cs are preferred, Rb and Cs are more preferred, and Cs is most preferred.

  Examples of the alkaline earth metal include calcium (Ca) (work function: 2.9 eV), strontium (Sr) (work function: 2.0 eV to 2.5 eV), barium (Ba) (work function: 2.52 eV). A work function of 2.9 eV or less is particularly preferable.

  Examples of the rare earth metal include scandium (Sc), yttrium (Y), cerium (Ce), terbium (Tb), ytterbium (Yb) and the like, and those having a work function of 2.9 eV or less are particularly preferable.

  Among the above metals, preferred metals are particularly high in reducing ability, and by adding a relatively small amount to the electron injection region, it is possible to improve the light emission luminance and extend the life of the organic EL element.

Examples of the alkali metal compound include lithium oxide (Li ₂ O), cesium oxide (Cs ₂ O), alkali oxides such as potassium oxide (K ₂ O), lithium fluoride (LiF), sodium fluoride (NaF), fluorine. Examples thereof include alkali halides such as cesium fluoride (CsF) and potassium fluoride (KF), and lithium fluoride (LiF), lithium oxide (Li ₂ O), and sodium fluoride (NaF) are preferable.

Examples of the alkaline earth metal compound include barium oxide (BaO), strontium oxide (SrO), calcium oxide (CaO), and barium strontium oxide (Ba _x Sr _1-x O) (0 <x <1), Examples thereof include barium calcium acid (Ba _x Ca _1-x O) (0 <x <1), and BaO, SrO, and CaO are preferable.

The rare earth metal compound, ytterbium fluoride _(YbF 3), scandium fluoride _(ScF 3), scandium oxide _(ScO 3), yttrium oxide _{(Y 2 O} 3), cerium oxide _{(Ce 2 O} 3), gadolinium fluoride _(GdF 3), include such terbium fluoride (TbF _{3) is, YbF 3, ScF 3, TbF} 3 are preferable.

  As described above, the organometallic complex is not particularly limited as long as it contains at least one of alkali metal ions, alkaline earth metal ions, and rare earth metal ions as metal ions. The ligands include quinolinol, benzoquinolinol, acridinol, phenanthridinol, hydroxyphenyl oxazole, hydroxyphenyl thiazole, hydroxydiaryl thiadiazole, hydroxydiaryl thiadiazole, hydroxyphenylpyridine, hydroxyphenylbenzimidazole, hydroxybenzotriazole, Hydroxyfulborane, bipyridyl, phenanthroline, phthalocyanine, porphyrin, cyclopentadiene, β-diketones, azomethines, and derivatives thereof are preferred, but are not limited thereto.

  The addition form of the electron donating dopant and the organometallic complex is preferably formed in a layered or island shape in the interface region. As a forming method, while depositing at least one of an electron donating dopant and an organometallic complex by a resistance heating vapor deposition method, an organic material as a light emitting material or an electron injection material for forming an interface region is simultaneously deposited, and an electron is deposited in the organic material. A method of dispersing at least one of the donor dopant and the organometallic complex is preferable. The dispersion concentration is usually an organic substance: electron-donating dopant and / or organometallic complex in a molar ratio of 100: 1 to 1: 100, preferably 5: 1 to 1: 5.

  In the case where at least one of the electron donating dopant and the organometallic complex is formed in a layered form, after forming the light emitting material or the electron injecting material that is the organic layer at the interface in a layered form, at least one of the electron donating dopant and the organometallic complex is formed. These are vapor-deposited by a resistance heating vapor deposition method alone, preferably with a layer thickness of 0.1 nm to 15 nm.

  In the case where at least one of an electron donating dopant and an organometallic complex is formed in an island shape, a light emitting material or an electron injecting material which is an organic layer at the interface is formed in an island shape, and then the electron donating dopant and the organometallic complex are formed. At least one of them is vapor-deposited by a resistance heating vapor deposition method, preferably with an island thickness of 0.05 nm to 1 nm.

  In the organic EL device of the present invention, the ratio of at least one of the main component and the electron donating dopant and the organometallic complex is, as a molar ratio, the main component: the electron donating dopant and / or the organometallic complex = 5. Is preferably 1: 1 to 1: 5, and more preferably 2: 1 to 1: 2.

[Hole injection layer and hole transport layer (hole injection / transport layer)]
The hole injection / transport layer is a layer that assists hole injection into the light emitting layer and transports it to the light emitting region, and has a high hole mobility and a small ionization energy of usually 5.6 eV or less.
In addition, inorganic compounds such as p-type Si and p-type SiC can also be used as the hole injection material.

[substrate]
As the substrate, a glass plate, a polymer plate or the like can be used.
Examples of the glass plate include soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfone, and polysulfone.

[anode]
The anode is made of, for example, a conductive material, and a conductive material having a work function larger than 4 eV is suitable.
Examples of the conductive material include carbon, aluminum, vanadium, iron, cobalt, nickel, tungsten, silver, gold, platinum, palladium, and their alloys, ITO substrate, tin oxide used for NESA substrate, indium oxide, and the like. Examples thereof include metal oxides and organic conductive resins such as polythiophene and polypyrrole.
The anode may be formed with a layer structure of two or more layers if necessary.

[cathode]
The cathode is made of, for example, a conductive material, and a conductive material having a work function smaller than 4 eV is suitable.
Examples of the conductive material include, but are not limited to, magnesium, calcium, tin, lead, titanium, yttrium, lithium, ruthenium, manganese, aluminum, lithium fluoride, and alloys thereof.
Examples of the alloy include magnesium / silver, magnesium / indium, lithium / aluminum, and the like, but are not limited thereto. The ratio of the alloy is controlled by the temperature of the vapor deposition source, the atmosphere, the degree of vacuum, etc., and is selected to an appropriate ratio.
If necessary, the cathode may be formed with a layer structure of two or more layers, and the cathode can be produced by forming a thin film from the conductive material by a method such as vapor deposition or sputtering.

When light emitted from the light emitting layer is taken out from the cathode, the transmittance of the cathode for light emission is preferably greater than 10%.
Further, the sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually 10 nm to 1 μm, preferably 50 to 200 nm.

  For the formation of each layer of the organic EL device of the present invention, a known method such as a dry film forming method such as vacuum deposition, sputtering, plasma, or ion plating, or a wet film forming method such as spin coating, dipping, or flow coating is applied. be able to.

  The thickness of each layer is not particularly limited, but must be set to an appropriate thickness. If the film thickness is too thick, a large applied voltage is required to obtain a constant light output, resulting in poor efficiency. If the film thickness is too thin, pinholes and the like are generated, and sufficient light emission luminance cannot be obtained even when an electric field is applied. The normal film thickness is suitably in the range of 5 nm to 10 μm, but more preferably in the range of 10 nm to 0.2 μm.

Synthesis Example 1 (Synthesis of Compound 6)
(1) Synthesis of intermediate A
Under an argon atmosphere, 35.0 g (253 mmol) of 2-nitroaniline, 86.1 g (304 mmol) of 1-bromo-3-iodobenzene, 4.8 g (25.3 mmol) of copper iodide, trans-1,2-diaminocyclohexane 5.8 g (50.6 mmol) and tripotassium phosphate 118.2 g (557 mmol) were added to dehydrated 1,4-dioxane 400 ml, and the mixture was heated and stirred at 90 ° C. for 20 hours. Water was added to the reaction solution, and the precipitated solid was collected, and this solid was washed with water and methanol to obtain 71.1 g of Intermediate A (yield 95%).

(2) Synthesis of intermediate B
Under an argon atmosphere, 84.3 g (484 mmol) of hydrosulfite sodium dissolved in 300 ml of water was added dropwise at room temperature over 1 hour to a reaction solution in which 71.1 g (242 mmol) of Intermediate A, 280 ml of tetrahydrofuran and 60 ml of methanol were added. did. After stirring for 2 hours, 42.1 g (242 mmol) of hydrosulfite sodium was further added and stirred for 24 hours. The organic phase was separated, ethyl acetate and aqueous sodium hydrogen carbonate solution were added to the aqueous phase, and the organic phase was separated and combined. This organic phase was purified by silica gel column chromatography to obtain 30.2 g of intermediate B (yield 47%). As developing solvents for silica gel column chromatography, heptane alone, heptane: toluene = 1: 1 solvent, and toluene: ethyl acetate = 10: 1 solvent were used in this order.

(3) Synthesis of intermediate C
Under an argon atmosphere, 11.7 g (126 mmol) of propionyl chloride was added dropwise at 10 to 15 ° C. to a reaction solution in which 30.2 g (115 mmol) of the intermediate B was added to 170 ml of N-methylpyrrolidone (NMP). Stir for hours. 200 ml of water was added and the precipitated solid was collected and washed with water to obtain 39.4 g of Intermediate C. It was used in the next step without further purification.

(4) Synthesis of intermediate D
Under an argon atmosphere, intermediate C39.4 g, p-toluenesulfonic acid hydrate 6.5 g (34.2 mmol) and xylene 300 ml were added, and water generated in a reaction vessel equipped with a Dean-Stark tube was removed. The mixture was heated and stirred at 140 ° C. for 2 hours. After returning to room temperature, 3 L of water was added for liquid separation, and the organic phase was concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography (developing solvent: toluene), and further recrystallized with a toluene solvent to obtain 25.5 g of intermediate D (yield from intermediate B: 74%). .

(5) Synthesis of compound 6
Under an argon atmosphere, Intermediate D 3.0 g (10 mmol), Intermediate E (for example, synthesized by the method described in US2013 / 082591) 4.5 g (10 mmol), Pd (PPh ₃ ) ₄ 0.23 g (0 0.2 mmol), 10 ml of 2M aqueous sodium carbonate solution was added to 50 ml of 1,2-dimethoxyethane (DME), and the mixture was heated and stirred under reflux conditions. Methanol was added and the precipitated solid was collected, and the oil dissolved in dichloromethane was purified by silica gel column chromatography to obtain 4.3 g of Compound 6 (yield 68%). As developing solvents for silica gel column chromatography, a solvent of hexane: dichloromethane = 10: 1 and a solvent of hexane: dichloromethane = 3: 1 were used in this order.
As a result of FD-MS analysis, it was m / e = 628 with respect to molecular weight 628.

Synthesis Example 2 (Synthesis of Compound 8)
(1) Synthesis of intermediate G
Under an argon atmosphere, 4.95 g (8.6 mmol) of Pd (dba) _{2 and} 5.8 g (21 mmol) of tricyclohexylphosphine were added to 1.5 L of 1,4-dioxane, and then 80.2 g of bis (pinacolato) diboron ( 316 mmol), 42.2 g (420 mmol) of potassium acetate, and 100 g (286 mmol) of intermediate F were sequentially charged to the reaction solution at room temperature. Intermediate F was synthesized in the same manner as in Synthesis Examples 1 (1) to (4) except that benzoyl chloride was used instead of propionyl chloride in Synthesis Example 1 (3).
After charging, the mixture was heated and stirred for 8 hours under reflux conditions, and after returning to room temperature, toluene and water were added to separate the organic phase. The organic phase was washed with an aqueous sodium hydrogen carbonate solution until neutral, and the solvent was distilled off under reduced pressure. The obtained solid was washed with heptane to obtain 91 g of intermediate G (yield 80%).

(2) Synthesis of intermediate I
Under an argon atmosphere, Intermediate G 4.0 g (10 mmol), Intermediate H (for example, can be synthesized by the method described in Tetrahedron Letters, pages 6942-6947 (2011)) 4.0 g (10 mmol), Pd (PPh ₃ ) ₄ 0.23 g (0.2 mmol), 10 ml of 2M aqueous sodium carbonate solution was added to 50 ml of 1,2-dimethoxyethane (DME), and the mixture was heated and stirred under reflux conditions. Methanol was added and the precipitated solid was collected, and the oil dissolved in dichloromethane was purified by silica gel column chromatography to obtain 1.6 g of intermediate I (yield 27%). As developing solvents for silica gel column chromatography, a solvent of hexane: dichloromethane = 10: 1 and a solvent of hexane: dichloromethane = 3: 1 were used in this order.

(3) Synthesis of Compound 8
Under an argon atmosphere, 1 g of Intermediate I 1.6 g (2.7 mmol), dibenzofuran-2-boronic acid 0.57 g (2.7 mmol), Pd (PPh ₃ ) ₄ 94 mg (0.081 mmol), and 2 M aqueous sodium carbonate solution 5 ml , 2-Dimethoxyethane (DME) was added to 20 ml, and the mixture was heated and stirred under reflux conditions. Methanol was added, and the precipitated solid was collected, and an oily substance dissolved in dichloromethane was purified by silica gel column chromatography to obtain 1.5 g of Compound 8 (yield 82%). As developing solvents for silica gel column chromatography, a solvent of hexane: dichloromethane = 10: 1 and a solvent of hexane: dichloromethane = 3: 1 were used in this order.
As a result of FD-MS analysis, it was m / e = 677 with respect to molecular weight 677.

Synthesis Example 3 (Synthesis of Compound 9)
Similar to Synthesis Example 2 (3) except that Intermediate J (for example, synthesized by the method described in WO2013-038650) was used instead of dibenzofuran-2-boronic acid in Synthesis Example 2 (3). Compound 9 was synthesized by this method.
As a result of FD-MS analysis, it was m / e = 678 with respect to molecular weight 678.

Synthesis Example 4 (Synthesis of Compound 13)
Compound 13 was synthesized in the same manner as in Synthesis Examples 1 (1) to (5) except that n-butyryl chloride was used instead of propionyl chloride in Synthesis Example 1 (3).
As a result of FD-MS analysis, it was m / e = 642 with respect to the molecular weight 642.

Synthesis Example 5 (Synthesis of Compound 15)
In Synthesis Example 1 (3), Compound 15 was synthesized in the same manner as in Synthesis Examples 1 (1) to (5) except that isobutyryl chloride was used instead of propionyl chloride.
As a result of FD-MS analysis, it was m / e = 642 with respect to the molecular weight 642.

Synthesis Example 6 (Synthesis of Compound 20)
In Synthesis Example 1 (3), Compound 20 was synthesized in the same manner as in Synthesis Examples 1 (1) to (5) except that pivaloyl chloride was used instead of propionyl chloride.
As a result of FD-MS analysis, it was m / e = 656 with respect to molecular weight 656.

Synthesis Example 7 (Synthesis of Compound 21)
Compound 21 was synthesized in the same manner as in Synthesis Examples 1 (1) to (5) except that 2-methylbutyryl chloride was used instead of propionyl chloride in Synthesis Example 1 (3).
As a result of FD-MS analysis, it was m / e = 656 with respect to molecular weight 656.

Synthesis Example 8 (Synthesis of Compound 5)
In Synthesis Example 1 (5), the compound was prepared in the same manner as in Synthesis Example 1 (5), except that Intermediate K (for example, synthesized by the method described in EP2477172) was used instead of Intermediate E. 5 was synthesized.
As a result of FD-MS analysis, it was m / e = 539 with respect to the molecular weight of 539.

Synthesis Example 9 (Synthesis of Compound 3)
In Synthesis Example 2 (2), 8- (dibenzofuran-2-yl) dibenzofuran-2-boronic acid (for example, synthesized by the method described in WO2013-038650) was used in place of Intermediate H. Compound 3 was synthesized in the same manner as in Synthesis Example 2 (2).
As a result of FD-MS analysis, it was m / e = 602 with respect to the molecular weight 602.

Synthesis Example 10 (Synthesis of Compound 4)
In Synthesis Example 1 (1), 1-bromo-4-iodobenzene was used instead of 1-bromo-3-iodobenzene, and in Synthesis Example 1 (3), n-butyryl chloride was used instead of propionyl chloride. Except for the above, compound 4 was synthesized in the same manner as in Synthesis Examples 1 (1) to (5).
As a result of FD-MS analysis, it was m / e = 642 with respect to the molecular weight 642.

Example 1
A glass substrate with a transparent electrode of 25 mm × 75 mm × 1.1 mm (manufactured by Geomatic) was subjected to ultrasonic cleaning for 5 minutes in isopropyl alcohol, and further subjected to UV (Ultraviolet) ozone cleaning for 30 minutes. .
The glass substrate with the transparent electrode thus cleaned is attached to the substrate holder of the vacuum evaporation apparatus, and first, on the surface of the glass substrate on which the transparent electrode line is formed, the transparent electrode is covered, HTM1 was deposited with a thickness of 20 nm to obtain a hole injection layer. Subsequently, HTM2 was vapor-deposited with a thickness of 60 nm on this film to obtain a hole transport layer.
On the hole transport layer, H-1 as a phosphorescent host material and D-1 as a phosphorescent material were co-evaporated at a thickness of 50 nm to obtain a phosphorescent layer. The concentration of H-1 in the phosphorescent light emitting layer was 80% by mass, and the concentration of D-1 was 20% by mass.
Subsequently, Compound 1 was deposited on the phosphorescent light emitting layer with a thickness of 10 nm to obtain a first electron transporting layer. Furthermore, after depositing ETM1 with a thickness of 10 nm to obtain a second electron transporting layer, 1 nm thick LiF and 80 nm thick metal Al were sequentially laminated to obtain a cathode. Note that LiF, which is an electron injecting electrode, was formed at a rate of 1 Å / min.

The compounds used in the examples are as follows.

[Light-emitting performance evaluation of organic EL elements]
The produced organic EL element was caused to emit light by direct current drive, the luminance and current density were measured, and the voltage and luminous efficiency (external quantum efficiency) at a current density of 1 mA / cm ² were determined. Furthermore, the brightness | luminance 70% lifetime (time when a brightness | luminance falls to 70%) in initial stage brightness | luminance 3,000 cd / m < ² > was calculated | required. The evaluation results of these light emitting performances are shown in Table 1.

Example 2
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that Compound 1 was used instead of ETM1 as the material for the second electron transport layer. The results are shown in Table 1.

Example 3
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that the following compound 2 was used instead of compound 1 as a material for the first electron transport layer. The results are shown in Table 1.

Example 4
An organic EL device was produced in the same manner as in Example 1, except that Compound 2 was used instead of Compound 1 as the material for the first electron transport layer, and Compound 2 was used instead of ETM1 as the material for the second electron transport layer. And evaluated. The results are shown in Table 1.

Example 5
An organic EL device was prepared in the same manner as in Example 1 except that the following compound H-2 was used instead of H-1 as the phosphorescent host material, and compound 2 was used instead of compound 1 as the material of the first electron transport layer. Prepared and evaluated. The results are shown in Table 1.

Example 6
An organic EL device was prepared in the same manner as in Example 1, except that the following compound H-3 was used instead of H-1 as the phosphorescent host material, and compound 2 was used instead of compound 1 as the material of the first electron transport layer. Prepared and evaluated. The results are shown in Table 1.

Comparative Example 1
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that Compound A was used instead of Compound 1 as the material for the first electron transport layer. The results are shown in Table 1.

Comparative Example 2
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that Compound B was used instead of Compound 1 as the material for the first electron transport layer. The results are shown in Table 1.

Comparative Example 3
An organic EL device was produced in the same manner as in Example 1 except that the following HA was used instead of H-1 as the phosphorescent host material and compound 2 was used instead of compound 1 as the material of the first electron transport layer. And evaluated. The results are shown in Table 1.

  Further, triplet energies of the host material and the first electron transport layer material used in Examples and Comparative Examples were measured. The results are shown in Table 2.

Triplet energy (E ^T (eV)) was evaluated by the following method.
First, a sample was dissolved in an EPA solvent (diethyl ether: isopentane: ethanol = 5: 5: 2 (volume ratio)) at 10 μmol / L to obtain a sample for phosphorescence measurement. This phosphorescence measurement sample was placed in a quartz cell, irradiated with excitation light at a temperature of 77 K, and the emitted phosphorescence spectrum was measured. Based on this, a value obtained by the conversion formula E ^T (eV) = 1239.85 / λ _edge was defined as triplet energy. The above-mentioned “λ _edge ” means that when the phosphorescence spectrum is represented by taking the phosphorescence intensity on the vertical axis and the wavelength on the horizontal axis, the tangent line is drawn with respect to the rising _edge on the short wavelength side of the phosphorescence spectrum. Means the wavelength value (unit: nm) of the intersection.
For measurement of the phosphorescence spectrum, an F-4500 type spectrofluorometer main body manufactured by Hitachi High-Technology Co., Ltd. and an optional part for low temperature measurement were used.

  From the results shown in Tables 1 and 2, it was found that the device of the example obtained a device having a lower voltage, higher efficiency, and longer life than the device of the comparative example. In particular, it can be seen that the effect of lowering the voltage and increasing the efficiency is great. This is because a benzimidazole compound having a high triplet energy is used as an electron transport layer material, and a host material having a carbazole ring and a dibenzofuran ring (or dibenzothiophene ring) in the same skeleton and having a high triplet energy is suitable. This is due to the effect of the combination. That is, the high triplet energy necessary for blue phosphorescence emission is confined in the device and the carrier balance in the device is appropriately adjusted.

Examples 7-25
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that Compound 3 to Compound 21 were used instead of Compound 1 as the material for the first electron transport layer. The results are shown in Table 3.

Examples 26-29
As in Example 1, except that H-2 was used instead of H-1 as the phosphorescent host material, and compounds 4, 6, 9, and 19 were used instead of compound 1 as the material for the first electron transport layer, respectively. Thus, an organic EL device was produced and evaluated. The results are shown in Table 3.

  Further, the triplet energy of the first electron transport layer material used in Examples 7 to 29 was measured in the same manner as described above. The results are shown in Table 4.

  From the results of Table 3 and Table 4, it was found that the device of the example can obtain a device having low voltage, high efficiency, and long life. In particular, it can be seen that the effect of lowering the voltage and increasing the efficiency is great. This is because a benzimidazole compound having a high triplet energy is used as an electron transport layer material, and a host material having a carbazole ring and a dibenzofuran ring (or dibenzothiophene ring) in the same skeleton and having a high triplet energy is suitable. This is due to the effect of the combination. That is, the high triplet energy necessary for blue phosphorescence emission is confined in the device and the carrier balance in the device is appropriately adjusted.

  The organic EL device of the present invention can be used for a flat light emitter such as a flat panel display of a wall-mounted television, a light source such as a copying machine, a printer, a backlight of a liquid crystal display or instruments, a display board, a marker lamp, and an illumination.

Although several embodiments and / or examples of the present invention have been described in detail above, those skilled in the art will appreciate that these exemplary embodiments and / or embodiments are substantially without departing from the novel teachings and advantages of the present invention. It is easy to make many changes to the embodiment. Accordingly, many of these modifications are within the scope of the present invention.
All the contents of the Japanese application specification that is the basis of the priority of Paris in this application are incorporated herein.

Claims (19)

Having two or more organic thin film layers including a light emitting layer between the anode and the cathode;
The light emitting layer contains at least one compound represented by the following formula (1),
The organic thin film layer in contact with the light emitting layer on the cathode side of the light emitting layer contains at least one benzimidazole compound represented by the following formula (A),
Organic electroluminescence device.
(In the formula (1),
G _{1 to} G ₆ are each independently C—R ₁ or a nitrogen atom.
G _{11 to} G ₁₈ are each independently C—R ₂ or a nitrogen atom.
R and R ₁ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon. An alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkoxy group having 3 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, a substituted or unsubstituted ring group Aryloxy group having 6 to 18 ring carbon atoms, substituted or unsubstituted heteroaryloxy group having 5 to 18 ring atoms, substituted or unsubstituted arylthio group having 6 to 18 ring carbon atoms, substituted or unsubstituted A heteroarylthio group having 5 to 18 ring atoms, a substituted or unsubstituted arylsulfonyl group having 6 to 18 ring carbon atoms, and a substituted or unsubstituted ring atom number 5-18 heteroarylsulfonyl group, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted fluoroalkyl group, substituted or An unsubstituted fluoroalkoxy group or a cyano group.
When a plurality of C—R ₁ are present, the plurality of R ₁ may be the same as or different from each other.
However, if _{G 2} and / or _{G 5} is a _{C-R 1, R 1} of _{G 2} and _{G 5} are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, A substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or An unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms.
R ₂ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C—R ₂ are present, each R ₂ may be the same or different.
When R, R ₁ and R ₂ have a substituent, the substituent R ′ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 ring carbon atoms, or 1 to 20 carbon atoms. Alkoxy groups having 3 to 20 ring carbon atoms, aromatic hydrocarbon ring groups having 6 to 18 ring carbon atoms, aryloxy groups having 6 to 18 ring carbon atoms, and 5 to 18 ring atoms. A heteroaromatic ring group, a silyl group, a fluorine atom, a fluoroalkyl group having 1 to 20 carbon atoms, a fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
X represents an oxygen atom or a sulfur atom. )
(In the formula (A), Ra to Rd, Re to Rf, Rh to Ri, Rj to Rk and Rm to Rn are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and a substituted group. Or an unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted Substituted aromatic hydrocarbon ring group having 6 to 18 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 18 ring carbon atoms, substituted or unsubstituted heteroaromatic group having 5 to 18 ring atoms A cyclic group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon number of 1 to 2 It is a fluoroalkoxy group or a cyano group.
Rg and Rl are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number. 1 to 20 alkoxy groups, substituted or unsubstituted cycloalkoxy groups having 3 to 20 ring carbon atoms, substituted or unsubstituted silyl groups, fluorine atoms, substituted or unsubstituted fluoroalkyl groups having 1 to 20 carbon atoms, Alternatively, it is a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms.
Provided that at least one of Re to Rf, Rh to Ri, Rj to Rk, and Rm to Rn is a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted azacarbazolyl group, a substituted or unsubstituted dibenzofuranyl group, or A substituted or unsubstituted dibenzothiophenyl group;
Ar ₁ is a single bond, a substituted or unsubstituted alkyl group or alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted phenyl group or a metaphenylene group, a substituted or unsubstituted metabiphenylyl group or a metabiphenylylene group. Substituted or unsubstituted metaterphenylyl group or metaterphenylylene group, substituted or unsubstituted 3-pyridyl group or 3,5-pyridylene group, substituted or unsubstituted 2-pyridyl group or 2,6-pyridylene group Group, substituted or unsubstituted 2-pyridyl group or 2,4-pyridylene group, substituted or unsubstituted 2-dibenzofuranyl group or 2,8-dibenzofuranylene group, substituted or unsubstituted 2-dibenzothiophenyl Group or 2,8-dibenzothiophenylene group, or substituted or unsubstituted 3-carbazolyl group or 3,6-carbazolylene group.
Ar ₂ is a single bond, a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted metaphenylene group, a substituted or unsubstituted paraphenylene group, a substituted or unsubstituted metabiphenylylene group, a substituted Or an unsubstituted metaterphenylylene group, a substituted or unsubstituted 3,5-pyridylene group, a substituted or unsubstituted 2,6-pyridylene group, a substituted or unsubstituted 2,4-pyridylene group, or a substituted or unsubstituted group A substituted 3,6-carbazolylene group.
When Ra to Rn, Ar ₁ and Ar ₂ have a substituent, the substituent R ″ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 ring carbon atoms, or a carbon number. An alkoxy group having 1 to 20 carbon atoms, a cycloalkoxy group having 3 to 20 ring carbon atoms, an aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, an aryloxy group having 6 to 18 ring carbon atoms, and the number of ring forming atoms They are a 5-18 heteroaromatic ring group, a silyl group, a fluorine atom, a C1-C20 fluoroalkyl group, a C1-C20 fluoroalkoxy group, or a cyano group.
m is 0 or 1.
o and p are each an integer of 0 to 3.
However, m and o satisfy m + o ≧ 1.
When o is 2 or 3, the plurality of Ar ₁ may be the same as or different from each other.
When p is 2 or 3, the plurality of Ar ₂ may be the same as or different from each other. ) The organic compound according to claim 1, wherein the compound represented by the formula (1) is a compound represented by the following formula (2a), a compound represented by the following formula (2b), or a compound represented by the following formula (2c). Electroluminescence element.
(In the formulas (2a) to (2c),
G ₂₁₁ ~G ₂₁₄ are each independently _{C-R 21} or a nitrogen atom.
G _{221 to} G ₂₂₈ are each independently C—R ₂₂ or a nitrogen atom.
Ga to Gk are each independently C—R ₂₃ or a nitrogen atom.
R ₂₁ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C-R ₂₁ are present, the plurality of R ₂₁ may be the same or different from each other.
R ₂₂ is independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C—R ₂₂ are present, the plurality of R ₂₂ may be the same or different from each other.
R ₂₃ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C—R ₂₃ are present, the plurality of R ₂₃ may be the same or different from each other.
When R ₂₁ , R ₂₂ and R ₂₃ have a substituent, the substituent R ′ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 ring carbon atoms, or 1 to 1 carbon atoms. 20 alkoxy groups, cycloalkoxy groups having 3 to 20 ring carbon atoms, aromatic hydrocarbon ring groups having 6 to 18 ring carbon atoms, aryloxy groups having 6 to 18 ring carbon atoms, 5 to 5 ring atoms An 18 heteroaromatic ring group, a silyl group, a fluorine atom, a fluoroalkyl group having 1 to 20 carbon atoms, a fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
X ₁ is an oxygen atom or a sulfur atom.
X ₂ is an oxygen atom, a sulfur atom, or ═C (CH ₃ ) ₂ . ) The organic compound according to claim 1, wherein the compound represented by the formula (1) is a compound represented by the following formula (3a), a compound represented by the following formula (3b), or a compound represented by the following formula (3c). Electroluminescence element.
(In Formula (3a)-Formula (3c),
Y represents a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, a substituted or unsubstituted monocyclic heteroaromatic ring group having 5 to 7 ring atoms, or the following formula (3- It is group represented by 1).
G _{311 to} G ₃₁₇ , G _{321 to} G ₃₂₇ , and G _{331 to} G ₃₃₇ are each independently C—R ₃₁ or a nitrogen atom.
R ₃₁ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation Aryloxy group having 6 to 18 carbon atoms, substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, substituted or unsubstituted silyl group, fluorine atom, substituted or unsubstituted carbon atoms of 1 to 20 A fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
When a plurality of C—R ₃₁ are present, the plurality of R ₃₁ may be the same or different from each other.
L ₃ is a single bond, a divalent linking group containing an oxygen atom, a divalent linking group containing a silicon atom, a divalent linking group containing a sulfur atom, an alkylene group having 1 to 5 carbon atoms, or the number of ring-forming carbon atoms. A cycloalkylene group having 3 to 6 carbon atoms, an aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, or a heteroaromatic ring group having 5 to 18 ring atoms.
When R ₃₁ has a substituent, the substituent R ′ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 ring carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a ring Cycloalkoxy group having 3 to 20 carbon atoms, aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, aryloxy group having 6 to 18 ring carbon atoms, heteroaromatic ring having 5 to 18 ring atoms Group, silyl group, fluorine atom, fluoroalkyl group, fluoroalkoxy group or cyano group.
X ₃ is an oxygen atom or a sulfur atom. )
(In Formula (3-1),
* Indicates a bond with a nitrogen atom.
G ₃₄₁ ~G ₃₄₇ are each independently a _{C-R 31} or a nitrogen _{atom, R 31} is the same as _{R 31} in the formula (3a) ~ formula (3c).
X ₃₁ is a nitrogen atom, oxygen atom or sulfur atom having a substituent. ) The organic electroluminescence device according to claim 1, wherein the compound represented by the formula (1) is a compound represented by the following formula (4).
(In formula (4),
R ₄₁ , R ₄₂ and R ₄₃ are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted group. It is an aromatic hydrocarbon group having 6 to 18 ring carbon atoms, or a substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms.
R ₄₁ , R ₄₂ and R ₄₃ may be directly bonded to each other to form a ring, may be bonded through an oxygen atom to form a ring, or may be bonded through a sulfur atom to form a ring. Or may be bonded via a silicon atom to form a ring.
G _{41 to} G ₄₄ are each independently C—R ₄₄ or a nitrogen atom.
R ₄₄ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms. Group, substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 ring carbon atoms, substituted or unsubstituted ring carbon atoms having 6 to 18 carbon atoms An aryloxy group, a substituted or unsubstituted heteroaromatic cyclic group having 5 to 18 ring atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, A substituted or unsubstituted C1-C20 fluoroalkoxy group or cyano group.
When a plurality of C—R ₄₄ are present, the plurality of R ₄₄ may be the same or different from each other.
G ₄₁₁ ~G ₄₁₈ are each independently _{C-R 45} or a nitrogen atom.
R ₄₅ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms. Group, substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 ring carbon atoms, substituted or unsubstituted ring carbon atoms having 6 to 18 carbon atoms An aryloxy group, a substituted or unsubstituted heteroaromatic cyclic group having 5 to 18 ring atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, A substituted or unsubstituted C1-C20 fluoroalkoxy group or cyano group.
When a plurality of C-R ₄₅ are present, the plurality of R ₄₅ may be the same or different from each other.
When R ₄₁ , R ₄₂ , R ₄₃ , R ₄₄ and R ₄₅ have a substituent, the substituent R ′ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a cycloalkyl having 3 to 20 ring carbon atoms. Group, an alkoxy group having 1 to 20 carbon atoms, a cycloalkoxy group having 3 to 20 ring carbon atoms, an aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, an aryloxy group having 6 to 18 ring carbon atoms, A heteroaromatic cyclic group having 5 to 18 ring atoms, a silyl group, a fluorine atom, a fluoroalkyl group having 1 to 20 carbon atoms, a fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
X ₄ is an oxygen atom or a sulfur atom. ) In the formula (1), R is a hydrogen atom, an unsubstituted alkyl group having 1 to 20 carbon atoms, an unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, or an unsubstituted alkoxy having 1 to 20 carbon atoms. A group, an unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, an unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, an aryloxy group having 6 to 18 unsubstituted ring carbon atoms, Unsubstituted heteroaryloxy group having 5 to 18 ring atoms, unsubstituted arylthio group having 6 to 18 ring carbon atoms, unsubstituted heteroarylthio group having 5 to 18 ring atoms, unsubstituted ring An arylsulfonyl group having 6 to 18 carbon atoms, an unsubstituted heteroarylsulfonyl group having 5 to 18 ring atoms, an unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, an unsubstituted silyl group, Fluorine atom, unsubstituted fluoroa The organic electroluminescence device according to claim 1 which is killed group, unsubstituted fluoroalkoxy group or a cyano group. Ga, Gb, Gc and Gd in the formula (2a), and Ga, Gb, Gc, Gd, Gi and Gk in the formula (2c) are C—R, respectively. ₂₃ R when ₂₃ Are each independently a hydrogen atom, an unsubstituted alkyl group having 1 to 20 carbon atoms, an unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, an unsubstituted alkoxy group having 1 to 20 carbon atoms, or unsubstituted. A cycloalkoxy group having 3 to 20 ring carbon atoms, an unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, an aryloxy group having 6 to 18 ring carbon atoms and an unsubstituted ring Heteroaromatic cyclic group having 5 to 18 atoms, unsubstituted silyl group, fluorine atom, unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or cyano group The organic electroluminescence element according to claim 2. G in the formula (3a) ₃₂₄ ~ G ₃₂₇ Are each CR ₃₁ R when ₃₁ Are each independently a hydrogen atom, an unsubstituted alkyl group having 1 to 20 carbon atoms, an unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, an unsubstituted alkoxy group having 1 to 20 carbon atoms, or unsubstituted. A cycloalkoxy group having 3 to 20 ring carbon atoms, an unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, an aryloxy group having 6 to 18 ring carbon atoms and an unsubstituted ring Heteroaromatic cyclic group having 5 to 18 atoms, unsubstituted silyl group, fluorine atom, unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or cyano group The organic electroluminescence device according to claim 3. In the formula (A), at least one of Rf, Rh, Rk and Rm is a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted azacarbazolyl group, a substituted or unsubstituted 2-dibenzofuranyl group, substituted or unsubstituted of 4-dibenzofuranyl group, an organic electroluminescent device according to any one of claims 1 to 7 which is a substituted or unsubstituted 2-dibenzothiophenyl group, or a substituted or unsubstituted 4-dibenzothiophenyl group. Both Rf and Rh in the formula (A), or both Rk and Rm in the formula (A) are substituted or unsubstituted carbazolyl groups, substituted or unsubstituted azacarbazolyl groups, substituted or unsubstituted 2- dibenzofuranyl group, a substituted or unsubstituted 4-dibenzofuranyl group, any of claims 1-8 which is substituted or unsubstituted 2-dibenzothiophenyl group, or a substituted or unsubstituted 4-dibenzothiophenyl group An organic electroluminescence device according to any one of the above. Ar _{1 in the} formula (A) is a single bond, a substituted or unsubstituted alkyl group or alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted phenyl group or a metaphenylene group, substituted or unsubstituted 2-dibenzo. The organic electroluminescence according to any one of claims 1 to 9 , which is a furanyl group, a 2,8-dibenzofuranylene group, or a substituted or unsubstituted 2-dibenzothiophenyl group or a 2,8-dibenzothiophenylene group. element. _2. Ar _{2 in the} formula (A) is a single bond, a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted metaphenylene group, or a substituted or unsubstituted paraphenylene group. the organic electroluminescent device according to any one of 1-10. Ar in the formula (A) ₂ Is a substituted or unsubstituted metaphenylene group, or a substituted or unsubstituted paraphenylene group, The organic electroluminescent element in any one of Claims 1-11. The light emitting layer includes a phosphorescent material;
The phosphorescent material, iridium (Ir), osmium (Os) and platinum organic electroluminescence according to any one of claims 1 to 12 (Pt) is ortho-metalated complex of at least one metal atom selected Luminescence element. The organic electroluminescent device according to any one of claims 1 to 13 interface region between the organic thin film layer and the cathode comprises an electron donating dopant. A compound represented by the following formula (a).
(In formula (a), R is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms.
Ra to Rd and Rj to Rn are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted group. Unsubstituted alkoxy group having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, substituted Or an unsubstituted aryloxy group having 6 to 18 carbon atoms, a substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group A fluorine atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, or a cyano group.
However, at least one of Rm and Rk is a substituted or unsubstituted carbazolyl group, substituted or unsubstituted azacarbazolyl group, substituted or unsubstituted dibenzofuranyl group, substituted or unsubstituted dibenzothiophenyl group, substituted or unsubstituted A substituted azadibenzofuranyl group, or a substituted or unsubstituted azadibenzothiophenyl group.
Ar ₂ is a single bond, a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted metaphenylene group, a substituted or unsubstituted paraphenylene group, a substituted or unsubstituted metabiphenylylene group, a substituted Or an unsubstituted metaterphenylylene group, a substituted or unsubstituted 3,5-pyridylene group, a substituted or unsubstituted 2,6-pyridylene group, a substituted or unsubstituted 2,4-pyridylene group, substituted or unsubstituted 2,8-dibenzofuranylene group, a substituted or unsubstituted 2,8-dibenzothiophenylene group, or a substituted or unsubstituted 3,6-carbazolylene group.
p is 0 or 1. ) In the formula (a), when Rm and Rk are each independently a substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms, the number of substituted or unsubstituted ring atoms is 5 -18 heteroaromatic ring group is a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted azadibenzofuranyl group, or The compound according to claim 15, which is a substituted or unsubstituted azadibenzothiophenyl group. In the formula (a), each of Rm and Rk independently represents a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted azacarbazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted group. The compound according to claim 15 , which is a dibenzothiophenyl group, a substituted or unsubstituted azadibenzofuranyl group, or a substituted or unsubstituted azadibenzothiophenyl group. The compound according to any one of claims 15 to 17, wherein in the formula (a), at least one of Rm and Rk is a substituted or unsubstituted carbazolyl group. In the formula (a), p is 1. The compound according to any one of claims 15 to 18.