Intersystem crossing agents for efficient utilization of excitons in organic light emitting devices

• US 6,894,307 B2
• Filed: 01/31/2003
• Issued: 05/17/2005
• Est. Priority Date: 07/21/1999
• Status: Expired due to Term

• Current Assignee: The Trustees of Princeton University (Princeton University)
• Original Assignee: The Trustees of Princeton University (Princeton University)
• Inventors: Baldo, Marc A., Forrest, Stephen R., Thompson, Mark E.
• Primary Examiner(s): Thomas, Tom
• Assistant Examiner(s): Richards, N. Drew
• Application Number:
  US10/355,316
• Publication Number:
  US 20030178619A1
• Time in Patent Office: 837 Days
• Field of Search: 257/40, 257/87, 257/89, 257/102, 257/103, 438/22, 438/29, 438/47, 438/99, 313/458, 313/502, 313/503, 313/504, 313/505
• US Class Current: 257/40
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 2102/103 comprising indium oxides, e.g. ITO
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/121 for assisting energy transfer, e.g. sensitization
• CPC Class Codes: H10K 50/18 Carrier blocking layers
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/341 Transition metal complexes, e.g. Ru(II)polypyridine complexes H10K85/331 takes precedence
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/348 comprising osmium
• CPC Class Codes: H10K 85/631 Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine
• CPC Class Codes: H10K 85/649 Aromatic compounds comprising a hetero atom

Abstract

Organic light emitting devices are described wherein the emissive layer comprises a host material containing a fluorescent or phosphorescent emissive molecule, which molecule is adapted to luminesce when a voltage is applied across the heterostructure, wherein an intersystem crossing molecule of optical absorption spectrum matched to the emission spectrum of the emissive molecule enhances emission efficiency.

Claims

1. An organic light emitting device, comprising:

an anode,

a cathode, and

an emissive layer between the anode and cathode, wherein the emissive layer comprises a host material, a luminescent emissive molecule present as a dopant in said host material, and an intersystem crossing agent which transfers energy to the luminescent emissive molecule, wherein the luminescent emissive molecule exhibits luminescence when a voltage is applied across the anode and the cathode.

2. The device of claim 1, wherein the intersystem crossing agent is selected from the group consisting of acridines, acridones, brominated polycyclic aromatic compounds, anthraquinones, alpha-beta-diketones, phenazines, benzoquinones, biacetyls, fullerenes, thiophenes, pyrazines, quinoxalines and thianthrenes.

3. The device of claim 2, wherein the intersystem crossing agent is an acridine.

4. The device of claim 2, wherein the intersystem crossing agent is an acridone.

5. The device of claim 2, wherein the intersystem crossing agent is a brominated polycyclic aromatic compound.

6. The device of claim 2, wherein the intersystem crossing agent is an anthraquinone.

7. The device of claim 2, wherein the intersystem crossing agent is an alpha-beta-diketone.

8. The device of claim 2, wherein the intersystem crossing agent is a phenazine.

9. The device of claim 2, wherein the intersystem crossing agent is a benzoquinone.

10. The device of claim 2, wherein the intersystem crossing agent is a biacetyl.

11. The device of claim 2, wherein the intersystem crossing agent is a fullerene.

12. The device of claim 2, wherein the intersystem crossing agent is a thiophene.

13. The device of claim 2, wherein the intersystem crossing agent is a pyrazine.

14. The device of claim 2, wherein the intersystem crossing agent is a quinoxaline.

15. The device of claim 2, wherein the intersystem crossing agent is a thianthrene.

16. An organic light emitting device comprising:

an anode;

a cathode; and

an emissive layer between the anode and the cathode, wherein the emissive layer comprises a fluorescent emissive molecule and an intersystem crossing agent which transfers energy to the fluorescent emissive molecule, wherein the fluorescent emissive molecule exhibits fluorescence when a voltage is applied across the anode and the cathode.

17. The device of claim 16, wherein the intersystem crossing agent comprises a phosphorescent organometallic compound.

18. The device of claim 17, wherein the phosphorescent organometallic compound comprises a metal selected from the group consisting of tungsten, platinum, gold, iridium and osmium.

19. The device of claim 17, wherein the phosphorescent organometallic compound comprises iridium.