Material for organic electroluminescent device, organic electroluminescent device, and organic electroluminescent display

1. A material for an organic electroluminescent device comprising an imine derivative represented by the following formula (Ia) or (Ib),

wherein Y 1 to Y 4 are independently a carbon atom or a nitrogen atom; R 1 to R 4 are independently hydrogen, an alkyl group, an aryl group, a heterocycle, a halogen atom, a fluoroalkyl group or a cyano group; and R 1 and R 2 , or R 3 and R 4 may be bonded together to form a ring.

2. The material for an organic electroluminescent device according to claim 1 wherein the imine derivative is represented by the following formula (IIa) or (IIb),

wherein R 5 to R 8 are independently hydrogen, an alkyl group, fluorine, a fluoroalkyl group or a cyano group; provided that at least one of R 5 to R 8 is fluorine or a fluoroalkyl group; and ms are independently an integer of 1 to 5.

3. The material for an organic electroluminescent device according to claim 1 wherein the reduction potential of an acetonitrile solution is −1.0V (vs Fc + /Fc wherein Fc represents ferrocene) or more.

4. The material for an organic electroluminescent device according to claim 1 which is a hole-injecting material.

5. An organic electroluminescent device comprising an organic layer between an anode and a cathode wherein the organic layer comprises the material for an organic electroluminescent device according claim 1 .

6. An organic electroluminescent device comprising an organic layer between an anode and a cathode,

wherein the organic layer is a thin-layer stack comprising a hole-injecting layer, a hole-transporting layer, an emitting layer and an electron-transporting layer in sequential order from the anode; and

the hole-injecting layer comprises the material for an organic electroluminescent device according claim 1 .

7. The organic electroluminescent device according to claim 6 wherein the hole-injecting layer further comprises a phenylenediamine compound represented by the following formula (III);

wherein R 11 to R 16 are independently hydrogen, a halogen atom, a trifluoromethyl group, an alkyl group, an aryl group or a heterocycle; R 11 to R 16 may each form a naphthalene skeleton, a carbazole skeleton, or a fluorene skeleton with its bonding phenyl group; and n represents 1 or 2.

8. The organic electroluminescent device according to claim 5 wherein the anode comprises a metal formed of aluminum or an aluminum alloy.

9. The organic electroluminescent device according to claim 8 wherein the anode comprises a stack of the metal formed of aluminum or an aluminum alloy, and a metal oxide or nitride.

10. An imine derivative represented by the following formula (IIa) or (IIb),

wherein R 5 to R 8 are independently hydrogen, an alkyl group, fluorine, a fluoroalkyl group or a cyano group; provided that at least one of R 5 to R 8 is a fluorine or a fluoroalkyl group; and ms are independently an integer of 1 to 5.

11. An organic electroluminescent display wherein a plurality of organic electroluminescent devices in which an anode, an organic layer comprising an emitting layer and a transparent cathode are stacked in sequential order are arranged on a substrate, and

the organic layer comprises an imine derivative represented by the following formula (Ia) or (Ib),

wherein Y 1 to Y 4 are independently a carbon atom or a nitrogen atom; R 1 to R 4 are independently hydrogen, an alkyl group, an aryl group, a heterocycle, a halogen atom, a fluoroalkyl group or a cyano group; and R 1 and R 2 , or R 3 and R 4 may be bonded together to form a ring.

12. An organic electroluminescent display wherein a plurality of organic electroluminescent devices in which an anode, an organic layer comprising an emitting layer and a transparent cathode are stacked in sequential order are arranged on a substrate, and

the organic layer comprises an imine derivative represented by the following formula (IIa) or

wherein R 5 to R 8 are independently hydrogen, an alkyl group, fluorine, a fluoroalkyl group or a cyano group; provided that at least one of R 5 to R 8 is a fluorine or a fluoroalkyl group; and ms are independently an integer of 1 to 5.

13. The organic electroluminescent display according to claim 11 wherein the anode comprises a metal formed of aluminum or an aluminum alloy.

14. The organic electroluminescent display according to claim 13 wherein the anode comprises a stack of the metal formed of aluminum or an aluminum alloy, and a metal oxide or nitride.

15. The organic electroluminescent display according to claim 12 wherein the anode comprises a metal formed of aluminum or an aluminum alloy.

16. The organic electroluminescent display according to claim 15 wherein the anode comprises a stack of the metal formed of aluminum or an aluminum alloy, and a metal oxide or nitride.