Organic electroluminescent device

1. An organic electroluminescent device comprising:

a pair of electrodes; and

an organic layer between the pair of electrodes, which comprises a light-emitting layer,

wherein the organic layer contains a compound represented by the following formula (I); and

the light-emitting layer contains an iridium complex phosphorescent material:

wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 each represents a hydrogen atom or a substituent, and contiguous substituents of R 1 to R 8 may be bonded to each other to form a condensed ring;

R 9 represents an alkyl group, an alkenyl group, an aryl group, a hetero-aryl group, or a silyl group, and each of which group may be substituted with a substituent; and

at least one of R 1 to R 9 represents a deuterium atom or a substituent containing a deuterium atom,

wherein the iridium complex phosphorescent material contains a ligand bonding to an iridium atom via a carbene carbon.

2. The organic electroluminescent device of claim 1 , wherein the iridium complex phosphorescent material containing a ligand bonding to an iridium atom via a carbene carbon is represented by the following formula (II):

wherein R 21 , R 22 , R 23 , R 25 , R 26 , R 27 and R 28 each represents a hydrogen atom or a substituent;

L 21 represents a ligand;

n 22 represents an integer of from to 1 to 3

n 21 represents an integer of from 0 to 4; and

C represents the carbene carbon coordinating to the iridium atom.

3. The organic electroluminescent device of claim 2 , wherein the iridium complex phosphorescent material containing a ligand bonding to an iridium atom via a carbene carbon is represented by the following formula (III):

wherein R 31 represents an alkyl group or an aryl group;

R 35 , R 36 and R 37 each represents a hydrogen atom, a fluorine atom, an alkyl group, or a cyano group, and R 35 and R 36 or R 36 and R 37 may be bonded to each other to form a condensed ring structure;

L 31 represents a ligand;

n 32 represents an integer of from 1 to 3;

n 31 represents an integer of from 0 to 4; and

C represents the carbene carbon coordinating to the iridium atom.

4. An organic electroluminescent device comprising:

a pair of electrodes; and

an organic layer between the pair of electrodes, which comprises a light-emitting layer,

wherein the organic layer contains a compound represented by the following formula (I); and

the light-emitting layer contains an iridium complex phosphorescent material:

wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 each represents a hydrogen atom or a substituent, and contiguous substituents of R 1 to R 8 may be bonded to each other to form a condensed ring;

R 9 represents an alkyl group, an alkenyl group, an aryl group, a hetero-aryl group, or a silyl group, and each of which group may be substituted with a substituent; and

at least one of R 1 to R 9 represents a deuterium atom or a substituent containing a deuterium atom,

wherein the iridium complex phosphorescent material contains a ligand bonding to an iridium atom via a nitrogen atom of a pyrazole structure.

5. The organic electroluminescent device of claim 4 , wherein the iridium complex phosphorescent material containing a ligand bonding to an iridium atom via a nitrogen atom of a pyrazole structure is represented by the following formula (IV):

wherein R 41 , R 42 , R 43 , R 45 , R 46 , R 47 and R 48 each represents a hydrogen atom or a substituent;

L 41 represents a ligand;

n 42 represents an integer of from 1 to 3; and

n 41 represents an integer of from 0 to 4.

6. The organic electroluminescent device of claim 5 , wherein the iridium complex phosphorescent material containing a ligand bonding to an iridium atom via a nitrogen atom of a pyrazole structure is represented by the following formula (V):

wherein R 52 and R 53 each represents a hydrogen atom, an alkyl group, or an aryl group;

R 55 , R 56 and R 57 each represents a hydrogen atom, a fluorine atom, an alkyl group, or a cyano group, and R 55 and R 56 or R 56 and R 57 may be bonded to each other to form a condensed ring structure;

L 51 represents a ligand;

n 52 represents an integer of from 1 to 3; and

n 51 represents an integer of from 0 to 4.

7. An organic electroluminescent device comprising:

a pair of electrodes; and

an organic layer between the pair of electrodes, which comprises a light-emitting layer,

wherein the organic layer contains a compound represented by the following formula (I), and

the light-emitting layer contains an iridium complex phosphorescent material which contains a ligand bonding to an iridium atom via the nitrogen atom of a pyridine structure and is represented by the formula (VI):

wherein R′, R 3 , R 4 , R 5 , R 6 , and R 8 each represents a hydrogen atom or a substituent, and contiguous substituents of R 1 , R 3 to R 6 , and R 8 may be bonded to each other to form a condensed ring;

R 2 and R 7 each independently represents a hydrogen atom, a deuterium atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a hetero-aryl group, an amino group, an alkoxyl group, an aryloxy group, a heterocyclic oxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxyl group, a mercapto group, a halogen group, a cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, a heterocyclic group, a silyl group, a silyloxy group, wherein these substituents may further be substituted with other substituents, and these substituents may be bonded to each other to form a ring;

R 9 represents an alkyl group, an alkenyl group, an aryl group, a hetero-aryl group, or a silyl group, and each of which group may be substituted with a substituent; and

at least one of R 1 to R 9 represents a deuterium atom or a substituent containing a deuterium atom,

wherein R 61 , R 62 , R 63 , R 64 , R 65 , R 66 , R 67 , and R 68 each independently represents a hydrogen atom or a substituent;

L 61 represents a ligand, wherein the ligand is

n 62 represents an integer of 2; and

n 61 represents an integer of 1.

8. The organic electroluminescent device of claim 7 , wherein the iridium complex phosphorescent material has a maximum emission wavelength of smaller than 470 nm.

9. The organic electroluminescent device according to claim 7 , wherein the compound represented by formula (I) is represented by the formula (VIII):

wherein R 81 , R 83 , R 84 , R 85 , R 86 , and R 88 each represents a hydrogen atom or a substituent, and contiguous substituents of R 81 , R 83 to R 86 , and R 88 may be bonded to each other to form a condensed ring structure

R 82 and R 87 each independently represents a hydrogen atom, a deuterium atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a hetero-aryl group, an amino group, an alkoxyl group, an aryloxy group, a heterocyclic oxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxyl group, a mercapto group, a halogen group, a cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, a heterocyclic group, a silyl group, a silyloxy group, wherein these substituents may further be substituted with other substituents, and these substituents may be bonded to each other to form a ring;

A represents a linking group;

n 81 represents an integer of from 2 to 6; and

the compound represented by the formula (VIII) contains at least one deuterium atom.

10. The organic electroluminescent device of claim 7 , wherein the compound represented by the formula (I) is contained in the light-emitting layer.