White OLEDs with a color-compensated electroluminescent unit

• US 20060087225A1
• Filed: 10/22/2004
• Published: 04/27/2006
• Est. Priority Date: 10/22/2004
• Status: Active Grant

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Eastman Kodak Company
• Inventors: Hatwar, Tukaram K., Liao, Liang-Sheng, Tang, Ching W., Klubek, Kevin P., Comfort, Dustin L.
• Granted Patent: US 7,560,862 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 50/19 Tandem OLEDs
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/615 Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
• CPC Class Codes: H10K 85/621 Aromatic anhydride or imide compounds, e.g. perylene tetra-carboxylic dianhydride or perylene tetracarboxylic di-imide
• CPC Class Codes: H10K 85/622 containing four rings, e.g. pyrene
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

A tandem white OLED includes an anode; a cathode; at least one broadband electroluminescent unit disposed between the anode and the cathode, wherein the broadband electroluminescent unit includes at least one light-emitting layer and produces at least one color component having an intensity less than desired; at least one color-compensating electroluminescent unit disposed between the anode and the cathode, wherein the color-compensating electroluminescent unit is selected to produce the at least one color component and to increase the color component intensity; and an intermediate connector disposed between each adjacent electroluminescent unit, wherein the intermediate connector has no direct connection to an external power source.

Claims

1. A tandem white OLED comprising:

a) an anode;

b) a cathode;

c) at least one broadband electroluminescent unit disposed between the anode and the cathode, wherein the broadband electroluminescent unit includes at least one light-emitting layer and produces at least one color component having an intensity less than desired;

d) at least one color-compensating electroluminescent unit disposed between the anode and the cathode, wherein the color-compensating electroluminescent unit is selected to produce the at least one color component and to increase the color component intensity; and

e) an intermediate connector disposed between each adjacent electroluminescent unit, wherein the intermediate connector has no direct connection to an external power source.

2. The tandem white OLED of claim 1 includes a single broadband electroluminescent unit, a single color-compensating electroluminescent unit, and a single intermediate connector.

4. The tandem white OLED of claim 1 wherein one of the broadband electroluminescent units includes at least three light-emitting layers, and wherein each of the light-emitting layers has a different color of emission.

5. The tandem white OLED of claim 1 wherein one of the broadband electroluminescent units includes at least two light-emitting layers, and wherein each of the light-emitting layers has a different color of emission.

6. The tandem white OLED of claim 1 wherein one of the broadband electroluminescent units includes at least one light-emitting layer.

7. The tandem white OLED of claim 1 wherein the number of the color-compensating electroluminescent units is equal to or less than the number of the broadband electroluminescent units, and wherein the number of the color-compensating electroluminescent units is equal to or larger than 1.

8. The tandem white OLED of claim 1 wherein each of the color-compensating electroluminescent units includes at least one light-emitting layer.

9. The tandem white OLED of claim 1 wherein each of the color-compensating electroluminescent units can have the same color emission.

10. The tandem white OLED of claim 1 wherein the color-compensating electroluminescent unit(s) have red color emission, and wherein the broadband electroluminescent units have a red color component with an intensity less than desired.

11. The tandem white OLED of claim 1 wherein the color-compensating electroluminescent unit(s) have green color emission, and wherein the broadband electroluminescent units have a green color component with an intensity less than desired.

12. The tandem white OLED of claim 1 wherein the color-compensating electroluminescent unit(s) have blue color emission, and wherein the broadband electroluminescent units have a blue color component with an intensity less than desired.

13. The tandem white OLED of claim 1 wherein each of the color-compensating electroluminescent units can have different color emission.

14. The tandem white OLED of claim 1 wherein the color-compensating electroluminescent unit can be disposed in contact with the anode.

15. The tandem white OLED of claim 1 wherein the color-compensating electroluminescent unit can be disposed in contact with the cathode.

16. The tandem white OLED of claim 1 wherein the color-compensating electroluminescent unit can be disposed between two broadband electroluminescent units.

17. The tandem white OLED of claim 1 wherein the color-compensating electroluminescent unit can be disposed between two other color-compensating electroluminescent units.

18. The tandem white OLED of claim 1 wherein each intermediate connector includes at least an n-type doped organic layer disposed adjacent to the electron-transporting layer of the preceding electroluminescent unit and a p-type doped organic layer disposed over the n-type doped organic layer.

19. The tandem white OLED of claim 18 wherein each intermediate connector includes a metal compound layer disposed between the n-type organic layer and the p-type organic layer.

20. The tandem white OLED of claim 18 wherein each intermediate connector includes a high work function metal layer disposed between the n-type organic layer and the p-type organic layer.

21. The tandem white OLED of claim 1 wherein each intermediate connector has a sheet resistance of higher than 100 kΩ

per square including at least an n-type doped organic layer disposed adjacent to the electron-transporting layer of the preceding electroluminescent unit and a metal compound layer disposed over the n-type doped organic layer.

22. The tandem white OLED of claim 21 wherein each intermediate connector includes a high work function metal layer disposed between the n-type organic layer and the metal compound layer.

23. The tandem white OLED of claim 1 wherein each intermediate connector has a sheet resistance of higher than 100 kΩ

per square including at least a low work function metal layer disposed adjacent to the electron-transporting layer of the preceding electroluminescent unit and a metal compound layer disposed over the low work function metal layer.

24. The tandem white OLED of claim 23 wherein each intermediate connector includes a high work function metal layer disposed between the low work function metal layer and the metal compound layer.

25. The tandem white OLED of claim 1 wherein each intermediate connector has a sheet resistance of higher than 100 kΩ

per square including at least an n-type inorganic semiconductor layer disposed adjacent to the electron-transporting layer in the preceding electroluminescent unit and a metal compound layer disposed over the n-type inorganic semiconductor layer.

26. The tandem white OLED of claim 25 wherein each intermediate connector includes a high work function metal layer disposed between the n-type inorganic semiconductor layer and the metal compound layer.

27. The tandem white OLED of claim 1 wherein each of the intermediate connectors can have the same or different layer structures.

3. A tandem white-OLED comprising:

a) an anode;

b) a cathode;

c) two broadband electroluminescent units disposed between the anode and the cathode, wherein each of the broadband electroluminescent units includes at least one light-emitting layer and produces at least one color component having an intensity less than desired;

d) one color-compensating electroluminescent unit disposed between the anode and the cathode, wherein the color-compensating electroluminescent unit is selected to produce the at least one color component and to increase the color component intensity; and

e) two intermediate connectors, each disposed between each adjacent electroluminescent unit, wherein the intermediate connector has no direct connection to an external power source.