Phosphorescent OLED with interlayer

• US 20070116983A1
• Filed: 11/23/2005
• Published: 05/24/2007
• Est. Priority Date: 11/23/2005
• Status: Active Grant

• Current Assignee: The Trustees of Princeton University (Princeton University)
• Original Assignee: The Trustees of Princeton University (Princeton University)
• Inventors: Forrest, Stephen, Kanno, Hiroshi
• Granted Patent: US 8,021,763 B2
• Time in Patent Office: Days
• US Class Current: 428/690
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 50/18 Carrier blocking layers
• CPC Class Codes: H10K 50/19 Tandem OLEDs
• CPC Class Codes: H10K 59/32 Stacked devices having two or more layers, each emitting at different wavelengths
• CPC Class Codes: Y10S 428/917 Electroluminescent
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree

Abstract

The present invention relates to phosphorescent stacked OLEDs having an interlayer.

Claims

1. A device comprising:

an anode;

a cathode;

a first interlayer disposed between the anode and the cathode;

a first organic phosphorescent unit disposed between and electrically

connected to the anode and the first interlayer; and

a second organic phosphorescent unit disposed between and electrically

connected to the first interlayer and the cathode;

wherein each of the first and second phosphorescent units further comprises a first organic emissive layer, the first organic emissive layer comprising a first organic host material and a first organic dopant material; and

wherein;

(i) the first organic dopant material has a HOMO at least about 0.3 eV higher than the HOMO of the first organic host material, a LUMO at least about 0.3 eV lower than the LUMO of the first organic host material, or both;

(ii) each of the first and second organic phosphorescent units further comprises an exciton blocking layer;

or

(iii) both (i) and (ii).

2. The device of claim 1 wherein the first organic dopant material has a HOMO at least about 0.3 eV higher than the HOMO of the first organic host material.

3. The device of claim 2 wherein:

the anode comprises ITO;

the cathode comprises Al;

the first interlayer comprises MoO₃;

each of the organic host materials comprises mCP; and

each of the organic emissive dopant materials comprises FlzIr.

4. The device of claim 2, wherein the organic host material has a HOMO at least about 0.3 eV lower than the HOMO of a layer adjacent to the anode side of the phosphorescent unit.

5. The device of claim 4, wherein the layer adjacent to the anode side of the phosphorescent layer is a hole transport layer.

6. The device of claim 2, wherein each of the phosphorescent units has a relaxation time of not more than about 1 ns.

7. The device of claim 2, wherein the device emits white light having a CRI of at least about 60.

8. The device of claim 1, wherein the organic emissive dopant material has a LUMO at least about 0.3 eV lower than the LUMO of the host material.

9. The device of claim 8, wherein the organic host material has a LUMO at least about 0.3 eV higher than the LUMO of an adjacent layer.

10. The device of claim 9, wherein the adjacent layer is an electron transport layer.

11. The device of claim 8, wherein each of the phosphorescent units has a relaxation time of not more than about 1 ns.

12. The device of claim 8, wherein the device emits white light having a CRI of at least about 60.

13. The device of claim 1, wherein the organic host material has a HOMO at least about 0.3 eV lower than the HOMO of an adjacent layer, a LUMO at least about 0.3 eV higher than the LUMO of an adjacent layer, or both.

14. The device of claim 1, wherein each of the first and second phosphorescent units further comprises a second organic host material and a second organic dopant material.

15. The device of claim 14, wherein:

the anode comprises ITO;

the cathode comprises al;

the first interlayer comprises MoO₃;

each of the first organic blocking layers comprises Ir(ppz)₃;

each of the second organic blocking layers comprises BPhen;

each of the first organic host materials comprises mCP;

each of the second organic host materials comprises CBP;

each of the first organic emissive dopant materials comprises FlzIr; and

each of the second organic emissive dopant materials comprises Ir(ppy)₃, PQIr, or both.

20. The device of claim 1 wherein each of the first and second organic phosphorescent units further comprises an exciton blocking layer.

21. The device of claim 20 wherein:

the anode comprises ITO;

the cathode comprises Al;

the first interlayer comprises MoO₃;

each of the first organic blocking layers comprises Ir(ppz)₃;

each of the second organic blocking layers comprises Bphen; and

the emissive layer comprise mCP, CBP, or both.

22. The device of claim 20 further comprising:

a second interlayer disposed between the first interlayer and the cathode; and

a third organic phosphorescent unit disposed between and electrically connected to the first interlayer and the second interlayer;

wherein the second organic phosphorescent unit is disposed between and electrically connected to the second interlayer and the cathode.

23. The device of claim 20 wherein the interlayer comprises a layer of metal oxide.

24. The device of claim 23 wherein the interlayer comprises MoO₃.

25. The device of claim 20 wherein, for each of the first and second organic phosphorescent units, the organic blocking layer is either an electron blocking layer disposed on an anode side of the emissive layer, or a hole blocking layer disposed on a cathode side of the emissive layer.

26. The device of claim 20, wherein each of the first and second organic phosphorescent units further comprises an exciton blocking layer on each side of the emissive layer.

27. The device of claim 20 wherein the device emits white light.

28. The device of claim 27 wherein the device emits light with a CRI of at least about 55.

29. The device of claim 28 wherein the device emits light with a CRE in the range (0.33±

0.20, 0.33±

0.20).

30. The device of claim 20 wherein the device has an efficiency of at least about 10 lm/W.

31. The device of claim 20 wherein the device has an efficiency of at least about 20 lm/W.

32. The device of claim 20 wherein the device produces light with a brightness of at least about 500 cd/m² lumens.

16. A device comprising:

an anode;

a cathode;

a first interlayer disposed between the anode and the cathode;

a first organic phosphorescent unit disposed between and electrically

connected to the anode and the first interlayer; and

a second organic phosphorescent unit disposed between and electrically

connected to the first interlayer and the cathode; and

a means for confining emission to the emissive layers of an OLED device;

wherein each of the first and second phosphorescent units further comprises a first organic emissive layer, the first organic emissive layer comprising a first organic host material and a first organic dopant material.

17. The device of claim 16, wherein the means comprises providing an exciton blocking layer.

18. The device of claim 16, wherein the means comprises providing an emissive layer having an organic host material and an organic dopant material, the organic dopant material having a HOMO at least about 0.3 eV higher than the HOMO of the organic host material,

19. The means of claim 16, wherein the means comprises providing an emissive layer having an organic host material and an organic dopant material, the organic dopant material having a LUMO at least about 0.3 eV lower than the LUMO of the organic host material.