Device including quantum dots

Patent metadata

Field	Value
Publication number	US-9525148-B2
Application number	US-201213441394-A
Country	US
Kind code	B2
Filing date	Apr 6, 2012
Priority date	Apr 3, 2008
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

A device including an emissive material comprising quantum dots is disclosed. In one embodiment, the device includes a first electrode and a second electrode, a layer comprising quantum dots disposed between the first electrode and the second electrodes, and a first interfacial layer disposed at the interface between a surface of the layer comprising quantum dots and a first layer in the device. In certain embodiments, a second interfacial layer is optionally further disposed on the surface of the layer comprising quantum dots opposite to the first interfacial layer. In certain embodiments, a device comprises a light-emitting device. Other light emitting devices and methods are disclosed.

First claim

The invention claimed is:

1. A light emitting device including a first electrode and a second electrode, an emissive layer comprising quantum dots disposed between the first and second electrodes, a first layer comprising a first charge transport material comprising an inorganic material disposed between the first electrode and the emissive layer, and a first interfacial layer disposed between the emissive layer and the first layer, wherein the first interfacial layer protects quantum dots from charge quenching sites in a contiguous device layer and is a distinct layer, the first interfacial layer comprising a material that is non-quenching to quantum dot photoluminescent emission and does not impede charge flow, wherein the inorganic material comprises a metal chalcogenide, and wherein the first interfacial layer has a thickness in a range from a monolayer thickness to about 5 nm.

2. A light emitting device in accordance with claim 1 wherein the device further includes a second layer comprising a second charge transport material between the emissive layer and the second electrode.

3. A light emitting device in accordance with claim 1 wherein the inorganic material comprises a metal oxide.

4. A light emitting device in accordance with claim 1 wherein the inorganic material comprises a zinc oxide.

5. A light emitting device in accordance with claim 1 wherein the inorganic material comprises a metal sulfide.

6. A light emitting device in accordance with claim 1 wherein the inorganic material comprises a mixture of two or more inorganic materials.

7. A light emitting device in accordance with claim 1 wherein the thickness of the first interfacial layer is effective to reduce quenching of quantum dot emission due to interaction of the quantum dots in the emissive layer with the first layer comprising a first charge transport material.

8. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises an inorganic material.

9. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises an organic material.

10. A light emitting device in accordance with claim 1 wherein the first interfacial layer fills voids that may exist between quantum dots.

11. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises a surfactant.

12. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises a silicon-containing coupling agent.

13. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises a metal oxide.

14. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises an organic small molecule material.

15. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises a material non-quenching to quantum dot emission.

16. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises a material that is non-crystallizing.

17. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises material with a glass transition temperature (Tg) greater than 150° C.

18. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises a spiro compound.

19. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises non-light-emitting nanoparticles having a bandgap that is the same or similar to the bandgap of quantum dots included in the layer comprising quantum dots.

20. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises non-light-emitting nanoparticles having a bandgap that is higher than the bandgap of quantum dots included in the layer comprising quantum dots.

21. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises non-light-emitting semiconductor nanoparticles that have been chemically treated to give them intrinsic semiconductor properties.

22. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises non-light-emitting semiconductor nanoparticles that have been chemically treated to give them n-type (electron transporting) semiconductor properties.

23. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises non-light-emitting semiconductor nanoparticles that have been chemically treated to give them p-type (hole transporting) semiconductor properties.

24. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises non-light-emitting nanoparticles that have been chemically treated to include a chemical linker capable of attaching to the layer comprising quantum dots.

25. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises organic small molecules having a dipole moment that modifies the work function of the first layer.

26. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises organic small molecules that chemically stabilizes the surface of the first layer.

27. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises an inorganic material that chemically stabilizes the surface of the first layer.

28. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises an adhesion promoting moiety.

29. A light emitting device in accordance with claim 1 wherein the first interfacial layer comprises a bipolar transport material.

30. A light emitting device in accordance with claim 1 wherein the quantum dots comprise semiconductor nanocrystals.

31. A light emitting device in accordance with claim 1 wherein the emissive layer includes two or more different types of quantum dots, wherein each type is selected to emit light having a predetermined distinct color.

32. A light emitting device in accordance with claim 1 wherein the first electrode is a cathode, the second electrode is an anode, and the first charge transport material comprises a material that transports electrons.

33. A light emitting device in accordance with claim 1 wherein the first electrode is an anode, the second electrode is cathode, and the first charge transport material comprises a material that transports holes.

34. A light emitting device in accordance with claim 2 wherein the device further includes a second interfacial layer between the emissive layer and the second layer comprising a second charge transport material in the device, wherein the second interfacial layer protects quantum dots from charge quenching sites in another device layer, wherein the second interfacial layer has a thickness in a range from a monolayer thickness to about 5 nm.

35. A light emitting device in accordance with claim 2 wherein the first electrode is an anode, the first charge transport material comprises a material that transports holes, the second charge transport material comprises a material that transports electrons, and the second electrode is a cathode.

36. A light emitting device in accordance with claim

Assignees

• Kazlas Peter T
• Zhou Zhaoqun
• Niu Yuhua
• Kim Sang-Jin
• Mashford Benjamin S
• Qd Vision Inc

Inventors

• Kazlas Peter T
• Zhou Zhaoqun
• Niu Yuhua
• Kim Sang-Jin
• Mashford Benjamin S

Classifications

• H10K50/171

  Electron injection layers · CPC title

• H10K50/115

  comprising active inorganic nanostructures, e.g. luminescent quantum dots · CPC title

• H01L51/50 Primary

  Electricity · mapped topic

• H01L2251/5369

  Electricity · mapped topic

• H01L2251/552

  Electricity · mapped topic