Light emitting device including semiconductor nanocrystals

• US 20080001167A1
• Filed: 10/20/2005
• Published: 01/03/2008
• Est. Priority Date: 10/22/2004
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Bawendi, Moungi, Bulovic, Vladimir, Coe-Sullivan, Seth, Steckel, Jonathan, Kim, LeeAnn
• Granted Patent: US 10,225,906 B2
• Time in Patent Office: Days
• US Class Current: 257/146
• CPC Class Codes: B41J 2/0057 where an intermediate transfer member receives the ink before transferring it on the printing material
• CPC Class Codes: B41M 1/02 Letterpress printing, e.g. book printing
• CPC Class Codes: B41M 3/003 on optical devices, e.g. lens elements; for the production of optical devices production by thermal imaging means B41M5/265
• CPC Class Codes: B41M 5/0256 the transferable ink pattern being obtained by means of a computer driven printer, e.g. an ink jet or laser printer, or by electrographic means
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01L 21/6715 Apparatus for applying a liquid, a resin, an ink or the like H01L21/67126 takes precedence
• CPC Class Codes: H05B 33/10 Apparatus or processes specially adapted to the manufacture of electroluminescent light sources
• CPC Class Codes: H05B 33/145 Arrangements of the electroluminescent material
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/115 comprising active inorganic nanostructures, e.g. luminescent quantum dots
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass
• CPC Class Codes: H10K 71/20 Changing the shape of the active layer in the devices, e.g. patterning
• CPC Class Codes: H10K 71/40 Thermal treatment, e.g. annealing in the presence of a solvent vapour

Abstract

A light emitting device includes a semiconductor nanocrystal in a layer. The layer can be a monolayer of semiconductor nanocrystals. The monolayer can form a pattern on a substrate.

Claims

1. A method of forming a device comprising:

placing a nanomaterial on a surface of an applicator;

contacting the surface of the applicator to a substrate including a first electrode, thereby transferring at least a portion of the nanomaterial to the substrate; and

arranging a second electrode opposed to the first electrode.

2. The method of claim 1, wherein the surface of the applicator includes a pattern including an elevation or a depression.

3. The method of claim 1, wherein the nanomaterial includes a plurality of semiconductor nanocrystals.

4. The method of claim 3, wherein the plurality of semiconductor nanocrystals forms a layer on the substrate.

5. The method of claim 4, wherein the layer is a multilayer of semiconductor nanocrystals.

6. The method of claim 4, wherein the layer is a monolayer of semiconductor nanocrystals.

7. The method of claim 4, wherein the layer is a partial monolayer of semiconductor nanocrystals.

8. The method of claim 1, wherein the nanomaterial forms a layer on the substrate.

9. The method of claim 8, wherein the layer is a multilayer of the nanomaterial.

10. The method of claim 8, wherein the layer is a monolayer of the nanomaterial.

11. The method of claim 8, wherein the layer is a partial monolayer of the nanomaterial.

12. The method of claim 1, wherein the nanomaterial forms a pattern on the substrate.

13. The method of claim 1, further comprising modifying the surface of the applicator before placing the nanomaterial on the surface of the applicator.

14. The method of claim 13, wherein modifying the surface of the applicator includes contacting the surface of the applicator with a composition selected to release at least a portion of the nanomaterial from the applicator upon contact with a substrate.

15. The method of claim 14, wherein the composition includes an aromatic organic polymer.

16. The method of claim 1, further comprising placing a second nanomaterial on a surface of a second applicator;

and

contacting the surface of the second applicator to the substrate, thereby transferring at least a portion of the nanomaterial to the substrate.

17. The method of claim 16, wherein the first nanomaterial and the second nanomaterial each independently include a plurality of semiconductor nanocrystals.

18. The method of claim 17, wherein the first plurality of semiconductor nanocrystals have an emission wavelength distinguishable from the second plurality of semiconductor nanocrystals.

19. The method of claim 18, further comprising placing a third plurality of semiconductor nanocrystals on a surface of a third applicator;

and

contacting the surface of the third applicator to the substrate, thereby transferring at least a portion of the third plurality of semiconductor nanocrystals to the substrate.

20. The method of claim 19, wherein the third plurality of semiconductor nanocrystals have an emission wavelength distinguishable from the first plurality of semiconductor nanocrystals, and distinguishable from the second plurality of semiconductor nanocrystals.

21. The method of claim 20, wherein the first, second and third pluralities of semiconductor nanocrystals are applied in non-overlapping predefined regions of the substrate.

22. The method of claim 21, wherein the emission wavelengths of the first, second and third pluralities of semiconductor nanocrystals are selected from an ultraviolet, blue, green, yellow, red, or infrared emission wavelength, or a combination thereof.

23. The method of claim 2, wherein a feature of the pattern has a dimension of less than 10 millimeters.

24. The method of claim 2, wherein a feature of the pattern has a dimension of less than 1 millimeter.

25. The method of claim 2, wherein a feature of the pattern has a dimension of less than 100 micrometers.

26. The method of claim 2, wherein a feature of the pattern has a dimension of less than 1 micrometer.

27. The method of claim 2, wherein a feature of the pattern has a dimension of at least 1 centimeter.

28. The method of claim 2, wherein a feature of the pattern has a dimension of at least 10 centimeters.

29. The method of claim 2, wherein a feature of the pattern has a dimension of at least 100 centimeters.

30. The method of claim 1, wherein the substrate includes a layer including a hole transport material over the first electrode.

31. The method of claim 30, further comprising forming a layer including an electron transporting material over the nanomaterial.

32. The method of claim 31, wherein the second electrode is applied over the layer including the electron transporting material.

33. The method of claim 1, wherein placing the nanomaterial on a surface of the applicator includes spin coating, blade coating, slot coating, dip coating, spray coating, rod coating, reverse roll coating, forward roll coating, air knife coating, knife over roll coating, gravure, microgravure, extrusion coating, slide coating, curtain coating, or a combination thereof.

34. The method of claim 1, wherein the surface of the applicator is substantially free of elevations and depressions.

35. The method of claim 34, wherein applicator is mounted on a rotatable drum.

36. A light emitting device comprising:

a first electrode;

a second electrode opposed to the first electrode; and

a predefined region including a monolayer of semiconductor nanocrystals disposed between the first electrode and the second electrode.

37. The device of claim 36, wherein the predefined region forms a pattern.

38. The device of claim 36, further comprising a second predefined region including a second monolayer of semiconductor nanocrystals.

39. The device of claim 36, further comprising a layer including a hole transport material disposed proximal to the first electrode and between the first electrode and the second electrode.

40. The device of claim 39, further comprising a layer including an electron transport material disposed proximal to the second electrode and between the first electrode and the second electrode.

41. The device of claim 40, wherein the predefined region including the monolayer of semiconductor nanocrystals is disposed between the layer including a hole transport material and the layer including an electron transport material.

42. The device of claim 41, further comprising a second predefined region including a second monolayer of semiconductor nanocrystals.

43. The device of claim 42, wherein the first monolayer of semiconductor nanocrystals has an emission wavelength distinct from an emission wavelength of the second monolayer.

44. A method of generating light comprising:

providing a device including a first electrode, a second electrode opposed to the first electrode, and a predefined region including a monolayer of semiconductor nanocrystals disposed between the first electrode and the second electrode; and

applying a voltage across the first electrode and the second electrode.

45. The method of claim 45, wherein applying a voltage across the first electrode and the second electrode includes passing a current between the first electrode and the second electrode.

46. A display including a plurality of light emitting devices, wherein at least one light emitting device comprises:

a first electrode;

a second electrode opposed to the first electrode; and

a predefined region including a monolayer of semiconductor nanocrystals disposed between the first electrode and the second electrode.

47. The display of claim 46, further comprising a second light emitting device including:

a first electrode;

a second electrode opposed to the first electrode; and

a predefined region including a monolayer of semiconductor nanocrystals disposed between the first electrode and the second electrode.

48. The display of claim 47, wherein the first light emitting device has an emission wavelength distinguishable from an emission wavelength of the second light emitting device.

49. The display of claim 48, further comprising a third light emitting device including:

a first electrode;

a second electrode opposed to the first electrode; and

a predefined region including a monolayer of semiconductor nanocrystals disposed between the first electrode and the second electrode, wherein the third light emitting device has an emission wavelength distinguishable from an emission wavelength of the second light emitting device, and from an emission wavelength of the first light emitting device.

50. The display of claim 49, further comprising a fourth light emitting device including:

a first electrode;

a second electrode opposed to the first electrode; and

a predefined region including a monolayer of semiconductor nanocrystals disposed between the first electrode and the second electrode, wherein the fourth light emitting device has an emission wavelength distinguishable from an emission wavelength of the third light emitting device, from an emission wavelength of the second light emitting device, and from an emission wavelength of the first light emitting device.

51. The display of claim 46, wherein the light emitting device has a dimension of less than 10 millimeters.

52. The display of claim 46, wherein the light emitting device has a dimension of less than 1 millimeter.

53. The display of claim 46, wherein the light emitting device has a dimension of less than 100 micrometers.

54. The display of claim 46, further comprising a backplane.

55. The display of claim 54, wherein the backplane includes active matrix electronics.

56. The display of claim 54, wherein the backplane includes passive matrix electronics.

57. A display including a plurality of light emitting devices comprising:

a first electrode;

a second electrode opposed to the first electrode; and

a predefined region including a monolayer of semiconductor nanocrystals disposed between the first electrode and the second electrode.

58. The display of claim 57, wherein the semiconductor nanocrystals of each light emitting device have an emission wavelength selected from an ultraviolet, blue, green, yellow, red, or infrared emission wavelength, or a combination thereof.