Lighting device having highly luminescent quantum dots

1. A lighting apparatus, comprising:

a housing structure;

a light emitting diode supported within the housing structure; and

a light conversion layer disposed above the light emitting diode, the light conversion layer comprising a plurality of quantum dots, each quantum dot having higher wavelength emission and lower wavelength absorption with little to no overlap between emission and absorption and each quantum dot comprising:

an anisotropic nanocrystalline core comprising a first semiconductor material and having an aspect ratio approximately in the range of 1.01-1.2; and

a nanocrystalline shell comprising a second, different, semiconductor material at least partially surrounding the anisotropic nanocrystalline core.

2. The lighting apparatus of claim 1 , wherein the light emitting diode is a UV or visible spectrum light emitting diode, and wherein the light conversion layer is a down-shifting layer.

3. The lighting apparatus of claim 2 , wherein the light emitting diode is a blue light emitting diode.

4. The lighting apparatus of claim 1 , wherein the quantum dots vary in size and emission color, and wherein the light conversion layer is to provide white light.

5. The lighting apparatus of claim 1 , wherein the housing is a cup-shaped housing.

6. The lighting apparatus of claim 1 , wherein the light conversion layer comprises a combination of red quantum dots with yellow phosphors, green phosphors, or both.

7. The lighting apparatus of claim 6 , wherein the light conversion layer comprises a matrix material, and wherein the combination of red quantum dots with yellow phosphors, green phosphors, or both, is embedded in the matrix material.

8. The lighting apparatus of claim 1 , wherein the light conversion layer comprises red quantum dots and no phosphors, the lighting apparatus further comprising a second light conversion layer disposed on the light conversion layer, the second light conversion layer comprising yellow phosphors, green phosphors, or both.

9. The lighting apparatus of claim 8 , wherein the light conversion layer comprises a first matrix material, and the red quantum dots are embedded in the matrix material, and wherein the second light conversion layer comprises a second matrix material, and the yellow phosphors, green phosphors, or both, are embedded in the second matrix material.

10. The lighting apparatus of claim 1 , wherein the light conversion layer is disposed on the light emitting diode.

11. The lighting apparatus of claim 1 , wherein the light conversion layer is situated remotely from the light emitting diode.

12. The lighting apparatus of claim 1 , wherein each quantum dot further comprises a nanocrystalline outer shell at least partially surrounding the nanocrystalline shell, the nanocrystalline outer shell comprising a third semiconductor material different from the first and second semiconductor materials.

13. The lighting apparatus of claim 1 , wherein each quantum dot further comprises an insulator layer encapsulating the nanocrystalline shell and anisotropic nanocrystalline core.

14. The lighting apparatus of claim 13 , wherein one or more of the quantum dots further comprises a coupling agent covalently bonded to an outer surface of the insulator layer.

15. The lighting apparatus of claim 13 , wherein, for each quantum dot, the anisotropic nanocrystalline core has an aspect ratio approximately in the range of 1.1-1.2.

16. The lighting apparatus of claim 1 , wherein the light conversion layer comprises a matrix material, and wherein the plurality of quantum dots is embedded in the matrix material.

17. The lighting apparatus of claim 16 , wherein each of the plurality of quantum dots is cross-linked with, polarity bound by, or tethered to the matrix material.

18. The lighting apparatus of claim 16 , wherein each of the plurality of quantum dots is bound to the matrix material by a covalent, dative, or ionic bond.

19. The lighting apparatus of claim 1 , wherein, for each quantum dot, the anisotropic nanocrystalline core is positioned off-center within the nanocrystalline shell.

20. The lighting apparatus of claim 19 , wherein the anisotropic nanocrystalline core is off-set along a long axis of the nanocrystalline shell, and is off-set along a short axis of the nanocrystalline shell.

21. The lighting apparatus of claim 1 , wherein, for each quantum dot, the anisotropic nanocrystalline core has an aspect ratio approximately in the range of 1.1-1.2.

22. A lighting apparatus, comprising:

a substrate;

a light emitting diode disposed on the substrate; and

a light conversion layer disposed above the light emitting diode, the light conversion layer comprising a plurality of quantum dots, each quantum dot having higher wavelength emission and lower wavelength absorption with little to no overlap between emission and absorption and each quantum dot comprising:

an anisotropic nanocrystalline core comprising a first semiconductor material and having an aspect ratio approximately in the range of 1.01-1.2; and

a nanocrystalline shell comprising a second, different, semiconductor material at least partially surrounding the anisotropic nanocrystalline core.

23. The lighting apparatus of claim 22 , wherein the light emitting diode is a UV or visible spectrum light emitting diode, and wherein the light conversion layer is a down-shifting layer.

24. The lighting apparatus of claim 23 , wherein the light emitting diode is a blue light emitting diode.

25. The lighting apparatus of claim 22 , wherein the quantum dots vary in size and emission color, and wherein the light conversion layer is to provide white light.

26. The lighting apparatus of claim 22 , wherein the light conversion layer is disposed on and conformal with a top surface of the light emitting diode, but not along sidewalls of the light emitting diode.

27. The lighting apparatus of claim 22 , wherein the light conversion layer is disposed on and conformal with a top surface of the light emitting diode and with sidewalls of the light emitting diode.

28. The lighting apparatus of claim 22 , wherein the light conversion layer is disposed on a top surface of the light emitting diode, but not along sidewalls of the light emitting diode, the light conversion layer having a bulb-like geometry.

29. The lighting apparatus of claim 22 , wherein the light conversion layer comprises a combination of red quantum dots with yellow phosphors, green phosphors, or both.

30. The lighting apparatus of claim 29 , further comprising:

a sealing layer encapsulating the light conversion layer and the light emitting diode, wherein the combination of red quantum dots with yellow phosphors, green phosphors, or both, is embedded in a matrix material of the light conversion layer, and wherein the sealing layer is distinct from the matrix material.

31. The lighting apparatus of claim 29 , wherein the light conversion layer comprises a matrix material, and wherein the combination of red quantum dots with yellow phosphors, green phosphors, or both, is embedded in the matrix material.

32. The lighting apparatus of claim 22 , wherein the light conversion layer comprises red quantum dots and no phosphors, the lighting apparatus further comprising a second light conversion layer disposed on the light conversion layer, the second light conversion layer comprising yellow phosphors, green phosphors, or both.

33. The lighting apparatus of claim 32 , wherein the light conversion layer comprises a first matrix material, and the red quantum dots are embedded in the matrix material, and wherein the second light conversion layer comprises a second matrix material, and the yellow phosphors, green phosphors, or both, are embedded in the second matrix material.

34. The lighting apparatus of claim 32 , further comprising:

a sealing layer encapsulating the light conversion layer, the second light conversion layer, and the light emitting diode, wherein the red quantum dots are embedded in a first matrix material of the first light conversion layer, wherein the yellow phosphors, green phosphors, or both, are embedded in a second matrix material of the second light conversion layer, and wherein the sealing layer is distinct from the first and second matrix materials.

35. The lighting apparatus of claim 22 , wherein the light conversion layer is disposed on the light emitting diode.

36. The lighting apparatus of claim 22 , wherein the light conversion layer is situated remotely from the light emitting diode.

37. The lighting apparatus of claim 22 , wherein each quantum dot further comprises a nanocrystalline outer shell at least partially surrounding the nanocrystalline shell, the nanocrystalline outer shell comprising a third semiconductor material different from the first and second semiconductor materials.

38. The lighting apparatus of claim 22 , wherein each quantum dot further comprises an insulator layer encapsulating the nanocrystalline shell and anisotropic nanocrystalline core.

39. The lighting apparatus of claim 38 , wherein one or more of the quantum dots further comprises a coupling agent covalently bonded to an outer surface of the insulator layer.

40. The lighting apparatus of claim 22 , wherein the light conversion layer comprises a matrix material, and wherein the plurality of quantum dots is embedded in the matrix material.

41. The lighting apparatus of claim 40 , wherein each of the plurality of quantum dots is cross-linked with, polarity bound by, or tethered to the matrix material.

42. The lighting apparatus of claim 40 , wherein each of the plurality of quantum dots is bound to the matrix material by a covalent, dative, or ionic bond.

43. The lighting apparatus of claim 22 , wherein, for each quantum dot, the anisotropic nanocrystalline core is positioned off-center within the nanocrystalline shell.

44. The lighting apparatus of claim 43 , wherein the anisotropic nanocrystalline core is off-set along a long axis of the nanocrystalline shell, and is off-set along a short axis of the nanocrystalline shell.