Organic electroluminescent device

1. An organic electroluminescent device comprising:

a pair of electrodes; and

at least one organic layer between the pair of electrodes, the at least one organic layer including a light-emitting layer,

wherein the at least one organic layer contains an indole compound represented by formula (3):

wherein R 301 represents an aryl group or a hetero ring group, R 302 to R 306 each represents a hydrogen atom, L 301 represents a substituted carbon atom where an alkyl group or aryl group is connected to the carbon atom, and n 301 represents an integer of 2 or 3.

2. The organic electroluminescent device according to claim 1 , wherein R 301 is an aryl group.

3. The organic electroluminescent device according to claim 1 , wherein the at least one organic layer contains a platinum complex having a tetradentate ligand.

4. The organic electroluminescent device according to claim 3 , wherein the platinum complex is a compound represented by one of formulae (A), (C) and (D):

wherein R A3 and R A4 each independently represents a hydrogen atom, an aryl group or a heterocyclic group; and R A1 and R A2 each independently represents an aryl group or a heterocyclic group, and a plurality of R A1 s and R A2 s are present, the plurality of R A1 s and R A2 s may be the same or different and may be connected to each other to form a ring; n A1 and n A2 each independently represents an integer of from 0 to 4; and Y A1 represents a linking group selected from the group consisting of an alkylene group, an arylene group, a hetero arylene group, an imino group, an oxy group, a thio group, a phosphinidene group, and a silylene group,

wherein A C1 to A C6 each independently represents C—R, Rs may be connected to form a ring, R in each of A C2 and A C5 is a hydrogen atom, an alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine atom or a cyano group, R in each of A C1 , A C3 , A C4 , and A C6 is a hydrogen atom, an alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine atom or a cyano group, A C7 to A C14 each independently represents C—R or N, R in each of A C8 and A C12 is a hydrogen atom, an alkyl group, a polyfluoroalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine atom or a cyano group, R in each of A C7 , A C9 , A C11 , and A C13 is a hydrogen atom, an alkyl group, a polyfluoroalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine atom or a cyano group, and R in each of A C10 and A C14 is a hydrogen atom or a fluorine atom; and L C1 represents a single bond or a divalent linking group selected from the group consisting of an alkylene group, an arylene group and an imino group, and

wherein A D1 to A D6 each independently represents C—R, Rs may be connected to form a ring, R in each of A D2 and A D5 is a hydrogen atom, an alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine atom or a cyano group, R in each of A D1 , A D3 , A D4 , and A D6 is a hydrogen atom, an alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine atom or a cyano group, A D7 to A D12 each independently represents C—R or N, R in each of A D8 and A D11 is a hydrogen atom, an alkyl group, a polyfluoroalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine atom or a cyano group, and R in each of A D7 , A D9 , A 10 , and A D12 is a hydrogen atom, an alkyl group, a polyfluoroalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine atom or a cyano group; and L D1 represents a single bond or a divalent linking group selected from the group consisting of an alkylene group, an arylene group and an imino group.

5. The organic electroluminescent device according to claim 1 , wherein the light-emitting layer contains at least one indole compound represented by formula (3).

6. The organic electroluminescent device according to claim 1 , wherein the at least one organic layer includes an electron transporting layer containing a metal complex material.

7. An indole compound represented by formula (4):

wherein R 401 represents an aryl group or a hetero ring group, R402 to R 406 each represents a hydrogen atom, L 401 represents a substituted carbon atom where an alkyl group or aryl group is connected to the carbon atom, and n 401 represents an integer of 2 or 3;

wherein the substituted or unsubstituted atom represented by L 401 is selected from the group consisting of a carbon atom, a silicon atom, a boron atom (in the case where n 401 ≦3), a nitrogen atom (in the case where n 401 ≦3), a phosphorus atom (in the case where n 401 ≦3), an oxygen atom (in the case where n 401 =2), and a sulfur atom (in the case where n 401 =2), and wherein the substituent for the substituted atom represented by L 401 is selected from the group consisting of an alkyl group, an aryl group, a heterocyclic group, a silyl group, and a halogen atom.