Light-emitting element and iridium complex

1. A light-emitting material comprising a compound represented by a following formula (III):

wherein Z 3 represents an atomic group for forming a nitrogen-containing heteroaryl group or a nitrogen-containing heterocycloalkenyl group;

Y represents an atomic group for forming pyrroline, pyrrole, indole, isothiazole, oxazole, isoxazole or 1,2,3-triazole;

each of R 3 and R 4 represents a hydrogen atom or a substituent;

R 5 represents a C 1 -C 6 alkyl group;

R 6 represents an electron-withdrawing group;

R 7 represents an aryl group or a C 1 -C 20 alkyl group;

R 8 represents an alkyl group or a hydrogen;

m is 1 or 2;

c is an integer of from 0 to 2; and

d is 0 or any positive integer depending upon a size of the Z 3 atomic group.

2. The light-emitting material according to claim 1 , wherein a net effect of the (R 3 ) c group is not electron donating.

3. The light-emitting material according to claim 1 , wherein a net effect of the (R 4 ) d group is not electron withdrawing.

4. The light-emitting material according to claim 1 , wherein the R 6 group is selected from the group consisting of a halogen atom, a nitrile group, a nitro group, a carbonyl group, a cyano group and a trifluoromethyl group.

5. The light-emitting material according to claim 1 , wherein the aryl group is selected from the group consisting of a phenyl group, a benzyl group, a naphthyl group, a diphenyl group, an anthryl group, a pyrenyl group, a phenanthryl group and fluorene.

6. The light-emitting material according to claim 1 , wherein, in Z 3 , the nitrogen-containing heterocycloalkenyl group is selected from the group consisting of pyrroline, pyridine, quinoline, isoquinoline, pyrazine, pyrimidine, pyrrole, pyrazole, imidazole, indole, thiazole, isothiazole, oxazole, isoxazole, benzothiazole, benzoxazole, and phenanthroline.

7. An OLED device which includes an anode, a cathode and an electroluminescent region interposed between the anode and the cathode, wherein the electroluminescent region includes an emitter layer comprising a phosphorescent iridium complex represented by a following formula (III):

wherein Z 3 represents an atomic group for forming a nitrogen-containing heteroaryl group or a nitrogen-containing heterocycloalkenyl group;

Y represents an atomic group for forming pyrroline, pyrrole, indole, isothiazole, oxazole, isoxazole or 1,2,3-triazole;

each of R 3 and R 4 represents a hydrogen atom or a substituent;

R 5 represents a C 1 -C 6 alkyl group;

R 6 represents an electron-withdrawing group;

R 7 represents an aryl group or a C 1 -C 20 alkyl group;

R 8 represents an alkyl group or a hydrogen;

m is 1 or 2;

c is an integer of from 0 to 2; and

d is 0 or any positive integer depending upon a size of the Z 3 atomic group.

8. The OLED device according to claim 7 , wherein a net effect of the (R 3 ) c group is not electron donating.

9. The OLED device according to claim 7 , wherein a net effect of the (R 4 ) d is not electron withdrawing.

10. The OLED device according to claim 7 , wherein the R 6 group is selected from the group consisting of a halogen atom, a nitrile group, a nitro group, a carbonyl group, a cyano group and a trifluoromethyl group.

11. The OLED device according to claim 7 , wherein the aryl group is selected from the group consisting of a phenyl group, a benzyl group, a naphthyl group, a diphenyl group, an anthryl group, a pyrenyl group, a phenanthryl group and fluorene.

12. The OLED device according to claim 7 , wherein, in Z 3 , the nitrogen-containing heterocycloalkenyl group is selected from the group consisting of pyrroline, pyridine, quinoline, isoquinoline, pyrazine, pyrimidine, pyrrole, pyrazole, imidazole, indole, thiazole, isothiazole, oxazole, isoxazole, benzothiazole, benzoxazole, and phenanthroline.

13. The OLED device according to claim 7 , wherein the emitter layer further includes a host luminescent compound doped with the iridium complex.

14. The OLED device according to claim 7 , wherein the host luminescent compound is represented by a following structural formula:

15. The OLED device according to claim 7 , wherein the electroluminescent region further includes a hole transfer layer interposed between the anode and the emitter layer, and the hole transfer layer comprises a compound represented by a following structural formula of H1 or H2:

16. The OLED device according to claim 7 , wherein the electroluminescent region further includes a hole-blocking layer interposed between the cathode and the emitter layer and in contact with the emitter layer, and the hole-blocking layer comprises a compound represented by a following structural formula:

wherein the Ph group is a phenyl group, and the Me group is a methyl group.

17. The OLED device according to claim 7 , wherein the electroluminescent region further includes an electron-transporting layer interposed between the hole-blocking layer and the cathode, and the hole-blocking layer comprises a compound represented by a following structural formula:

18. A light-emitting material comprising a compound selected from the group consisting of the following formulas II-8, II-14, II-15, II-16, II-17, II-18, II-19, II-20, II-23, II-26, II-27, II-28 and II-29:

19. An organic light-emitting diode (OLED) device which includes an anode, a cathode and an electroluminescent region interposed between the anode and the cathode, wherein the electroluminescent region includes an emitter layer comprising a phosphorescent iridium complex selected from the group consisting of the following formulas II-8, II-14, II-15, II-16, II-17, II-18, II-19, II-20, II-22, II-23, II-25, II-26, II-27, II-28, and II-29:

20. The OLED device according to claim 19 , wherein the electroluminescent region further includes a hole transfer layer interposed between the anode and the emitter layer, and the hole transfer layer comprises a compound represented by a following structural formula of H1 or H2: