An OLED device comprises an anode, a light emitting layer, a first layer, a second layer contiguous to the first layer, and a cathode, in that order. The first layer includes a first complex comprising gallium or another group 13 metal and the second layer includes a second complex also comprising gallium and wherein the second complex has a more negative LUMO than the first complex. Such materials can provide an improvement in one or more of luminance, drive voltage, and stability.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a schematic cross-sectional view of an OLED device that represents one embodiment of the present invention.
Claims
1. An OLED device comprising an anode, a light emitting layer, a first layer, a second layer contiguous to the first layer, and a cathode, in that order, and wherein the first layer includes a first complex comprising gallium and the second layer includes a second complex also comprising gallium and wherein the second complex has a more negative LUMO than the first complex.
2. The device of claim 1 wherein the first layer also contains a second gallium complex having an equal or more positive LUMO than the second layer gallium complex.
3. The device of claim 1 wherein the first complex is a gallium complex that comprises a 2-phenylimidazole group
4. The device of claim 1 wherein the second complex is a gallium complex that comprises a 2-phenylbenzimidazole group.
5. The device of claim 1 wherein the difference in the LUMO value of the first and second complexes is 0.1 eV or greater.
6. The device of claim 1 wherein the difference in the LUMO value of the first and second complexes is 0.2 eV or greater.
7. The device of claim 1 wherein the first layer is contiguous to a light-emitting layer.
8. The device of claim 1 wherein the light-emitting layer includes a host material, and wherein the host material has a LUMO value that is more negative than the LUMO value of the first complex.
9. The device of claim 1 wherein the light-emitting layer includes a host material, and wherein the difference in LUMO values between the host material and the first complex is 0.1 eV or less.
10. The device of claim 1 wherein the second layer is contiguous to an electron-injecting layer.
11. The device of claim 1 wherein the first or second complex is represented by Formula (1):
12. The device of claim 11 wherein each Za and each Zb represents the atoms necessary to form an independently selected aromatic ring group.
13. The device of claim 11 wherein the first complex and the second complex are both represented by Formula (1), provided at least one Za or Zb in the first complex is different in the second complex.
14. The device of claim 1 wherein the first or second complex is represented by Formula (2):
15. The device of claim 14 wherein at least one of Z1 through Z3 represents N and wherein Z1 through Z3 represent C—Y.
16. The device of claim 1 wherein the first complex is represented by Formula (3a) and the second complex is represented by Formula (3b):
17. The device of claim 1 wherein the second layer comprises an alkali metal material.
18. The device of claim 17 wherein the alkali metal material comprises lithium.
19. The device of claim 1 wherein the light-emitting layer includes a material that emits blue or blue-green light.
20. The device of claim 1 wherein the light-emitting layer includes a host material that comprises an anthracene group.
21. The device of claim 1 wherein the light-emitting layer includes a host material that comprises an anthracene group bearing independently selected aromatic substituents in the 2-, 9-, and 10-positions.
22. The device of claim 1 wherein the first layer also contains any group 13 metal complex having an equal or more positive LUMO than the second layer gallium complex.
23. An OLED device comprising an anode, a light emitting layer, a first layer, a second layer contiguous to the first layer, and a cathode, in that order, and wherein the first layer includes a first complex comprising a group 13 metal complex and the second layer includes a complex comprising gallium and wherein the gallium complex has a more negative LUMO than the group 13 metal complex.
24. The device of claim 23 wherein the group 13 metal is aluminum.
25. The device of claim 23 wherein the first complex is represented by Formula (E):
26. The device of claim 25 where the first complex is tris(8-quinolinolato)aluminum (III) (Alq).
27. The device of claim 23 wherein the second layer further comprises an alkali metal material.
28. The device of claim 23 wherein there is a thin layer of between 5 to 25 angstroms contiguous to the 2nd gallium containing layer on the cathode side.
29. The device of claim 28 wherein the thin layer comprises tris(8-quinolinolato)aluminum (III) (Alq).
Patent Application
20070207345
