TANDEM OLED DEVICE

• US 20090001885A1
• Filed: 06/27/2007
• Published: 01/01/2009
• Est. Priority Date: 06/27/2007
• Status: Abandoned Application

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Inventors: Spindler, Jeffrey P., Hatwar, Tukaram K., Royster, Tommie L. JR.
• Application Number:
  US11/769,349
• Publication Number:
  US 20090001885A1
• Time in Patent Office: Days
• US Class Current: 313/506
• 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 85/321 Metal complexes comprising a group IIIA element, e.g. Tris (8-hydroxyquinoline) gallium [Gaq3]
• CPC Class Codes: H10K 85/326 comprising gallium

Abstract

A tandem OLED device having two spaced electrodes comprising first and second light-emitting units disposed between the electrodes wherein each light emitting unit has at least one light emitting layer with an intermediate connector disposed between each of the light-emitting units. The intermediate connector includes an electron accepting organic layer in contact with the first light emitting unit and an n-type doped organic layer in contact with the electron accepting organic layer and the second light-emitting unit. The n-type doped organic layer includes an organic gallium complex. The devices exhibit improved stability and little change in color when current density is varied.

Claims

1. A tandem OLED device having two spaced electrodes comprising:

a) first and second light-emitting units disposed between the electrodes wherein each light emitting unit has at least one light emitting layer; and

b) an intermediate connector disposed between each of the light-emitting units and having;

i) an electron accepting organic layer in contact with the first light emitting unit and an n-type doped organic layer in contact with the electron accepting organic layer and the second light emitting unit and wherein the n-type doped organic layer includes an organic gallium complex.

2. The tandem OLED device of claim 1 wherein the n-type doped organic layer further includes a phenanthroline derivative and lithium metal.

3. The tandem OLED device of claim 1 wherein the gallium complex is according to Formula (1):

GaL₃  

 

Formula (1)

wherein;

the gallium is in a +3 valence state; and

each L represents a monoionic ligand such that the complex has an overall neutral charge and where at least one L must be organic.

4. The tandem OLED device of claim 3 wherein the n-type doped organic layer further includes a phenanthroline derivative and lithium metal.

5. The tandem OLED device of claim 3 wherein at least two of the L groups of the gallium complex are bidentate and contain at least one nitrogen that can form a dative bond to the gallium.

6. The tandem OLED device of claim 5 where the gallium complex is according to Formula (2):

7. The tandem OLED of claim 6 wherein the gallium complex is according to Formula (3).

8. The tandem OLED of claim 2 wherein the thickness of the n-doped organic layer is between 3 and 100 nm and the thickness of the electron accepting layer is between 3 and 100 nm.

9. The tandem OLED of claim 2 wherein the electron accepting organic layer includes a hexaazatriphenylene derivative.

10. The tandem OLED of claim 2 wherein the hexaazatriphenylene derivative is according to Formula (HATP):

11. The tandem OLED device of claim 1 where the n-type doped organic layer is divided into two sublayers in contact with each other;

the sublayer which is in contact with the second light emitting unit includes a material having a LUMO energy level less negative than the LUMO energy level of the primary host material in the closest light emitting layer of the second light emitting unit.

17. The tandem OLED device of claim 1 wherein one of the spaced electrodes is reflective and the other is transmissive and the first light-emitting unit is disposed closer to the reflective electrode than the second light-emitting unit.

12. A tandem OLED device having two spaced electrodes comprising:

a) first and second light-emitting units disposed between the electrodes that produce different emission spectra, the first light-emitting unit produces light that has multiple peaks at wavelengths longer than 500 nm and substantially no emission at wavelengths shorter than 480 nm, and the second light-emitting unit produces light that has substantial emission at wavelengths shorter than 500 nm; and

b) an intermediate connector disposed between each of the light-emitting units and having an electron accepting organic layer and an n-type doped organic layer and wherein the n-type doped organic layer includes an organic gallium complex.

13. The tandem OLED device of claim 12 wherein the n-type doped organic layer further includes a phenanthroline derivative and lithium metal.

14. The tandem OLED of claim 12 wherein the gallium complex is according to Formula (3).

15. The tandem OLED of claim 12 wherein the thickness of the n-doped organic layer is between 3 and 100 nm and the thickness of the electron accepting layer is between 3 and 100 nm.

16. The tandem OLED of claim 12 wherein the electron accepting organic layer includes a hexaazatriphenylene derivative.