High efficiency transparent organic light emitting devices

• US 6,639,357 B1
• Filed: 03/09/2000
• Issued: 10/28/2003
• Est. Priority Date: 02/28/2000
• Status: Expired due to Fees

• Current Assignee: The Trustees of Princeton University (Princeton University)
• Original Assignee: The Trustees of Princeton University (Princeton University)
• Inventors: Parthasarathy, Gautam, Burrows, Paul E., Forrest, Stephen R., Adachi, Chihaya
• Primary Examiner(s): Patel, Ashok
• Assistant Examiner(s): Guharay, Karabi
• Application Number:
  US09/522,155
• Time in Patent Office: 1,328 Days
• Field of Search: 313/504, 313/503, 313/506, 428/690, 428/691
• US Class Current: 313/504
• CPC Class Codes: A61B 18/00 Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body eye surgery A61F9/007; ear surgery A61F11/00
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/22051 with an inflatable part, e.g. balloon, for positioning, blocking, or immobilisation A61B2017/22048, A61B2017/3486 take precedence
• CPC Class Codes: A61B 2018/00095 high, i.e. heat conducting
• CPC Class Codes: A61F 2007/126 for invasive application, e.g. for introducing into blood vessels
• CPC Class Codes: A61F 7/123 using a flexible balloon containing the thermal element
• CPC Class Codes: A61M 2025/1072 having balloons with two or more compartments
• CPC Class Codes: A61M 2025/1086 having a special balloon surface topography, e.g. pores, protuberances, spikes or grooves
• CPC Class Codes: A61M 25/00 Catheters; Hollow probes dilators A61M29/00; peritoneal catheters A61M1/285; tracheal tubes A61M16/04; for drainage A61M27/00; for uterus, vagina or rectum A61M31/00 ; for measuring or testing A61B; materials for catheters A61L29/00
• CPC Class Codes: A61M 25/1011 Multiple balloon catheters
• CPC Class Codes: H10K 2102/3031 Two-side emission, e.g. transparent OLEDs [TOLED]
• CPC Class Codes: H10K 2102/351 Thickness
• CPC Class Codes: H10K 50/165 comprising dopants
• CPC Class Codes: H10K 50/171 Electron injection layers
• CPC Class Codes: H10K 50/18 Carrier blocking layers
• CPC Class Codes: H10K 50/828 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 85/311 Phthalocyanine
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3

Abstract

A highly transparent non-metallic cathode is disclosed that comprises a metal-doped organic electron injection layer that is in direct contact with a transparent non-metallic electron injecting cathode layer, such as indium tin oxide (ITO), wherein the metal-doped organic electron injection layer also functions as an exciton blocking or hole blocking layer. The metal-doped organic electron injection layer is created by diffusing an ultra-thin layer of about 5-10 Å of a highly electropositive metal such as Li throughout the layer. A representative embodiment of the highly transparent non-metallic cathode comprises a layer of ITO, a layer of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), which acts as an electron injection, exciton blocking, and hole blocking layer, and an ultra-thin layer of lithium, which degenerately dopes the layer of BCP, improving the electron injecting properties of the BCP layer. This cathode is demonstrated for use in an OLED having a transparency of about 90% or higher combined with a device external quantum efficiency of about 1% or higher.

Claims

1. A highly transparent and highly efficient organic light emitting device comprising, in the following order:

an anode layer comprising ITO;

a hole transporting layer comprising 4,4-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl;

an electron transporting layer comprising tris-(8-hydroxyquinoline) aluminum; and

a cathode, further comprising a lithium-doped electron injection layer comprising 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, and an ITO layer in contact with said lithium-doped electron injection layer.

2. A compound cathode comprising a transparent, non-metallic, electron injecting material in contact with an organic electron injection layer doped with a metal, wherein the organic electron injection layer comprises a transparent organic material that acts as a hole blocking layer, wherein the transparent organic material is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline.

3. The compound cathode of claim 2, wherein said metal is selected from the group consisting of Li, Sr and Sm.

4. The compound cathode of claim 2, wherein said metal is Li.

5. The compound cathode of claim 2, wherein said metal produces an electronic density of at least about 10¹⁵/cm³.

6. The compound cathode of claim 2, wherein said metal produces an electronic density of at least about 10²¹/cm³.

7. The compound cathode of claim 2, wherein said transparent, non-metallic, electron injecting material comprises indium tin oxide.

8. The compound cathode of claim 2, wherein said compound cathode is incorporated in an organic optoelectronic device.

9. The compound cathode of claim 8, wherein said optoelectronic device is an organic light emitting device.

10. The compound cathode of claim 9, wherein said organic light emitting device is incorporated in a device selected from the group consisting of a vehicle, a computer, a television, a printer, a screen, a billboard, a display and a telephone.

11. The compound cathode of claim 2, wherein said organic electron injection layer has a thickness of about 20 angstroms to about 500 angstroms.

12. The compound cathode of claim 2, wherein said organic electron injection layer has a thickness of about 70 angstroms.

13. The compound cathode of claim 2, wherein said metal diffuses throughout said organic electron injection layer.

14. A compound cathode comprising a transparent, non-metallic, electron injecting material in contact with an organic electron injection layer comprising 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline doped with Li.

15. The compound cathode of claim 14, wherein said transparent, non-metallic, electron injecting material comprises indium tin oxide.