Quantum dots having a nanocrystalline core, a nanocrystalline shell surrounding the core, and an insulator coating for the shell
View Patent ↗Semiconductor nanocrystal structures having silica insulator coatings encapsulating the nanocrystals and methods of fabricating semiconductor nanocrystal structures having silica insulator coatings encapsulating the nanocrystals involve adding a silicon-containing silica precursor species to a solution of nanocrystals, subsequently forming a silica-based insulator layer on the nanocrystals from a reaction involving the silicon-containing silica precursor species, and adding additional amounts of the silicon-containing silica precursor species after initial formation of the silica-based insulator layer while continuing to form the silica-based insulator layer to finally encapsulate each of the nanocrystals.
1. A semiconductor structure, comprising:
an oblong-shaped semiconductor nanocrystal; and
a non-oblong-shaped insulator coating formed by two bulbous portions separated by a waist portion encapsulating the oblong-shaped semiconductor nanocrystal.
2. The semiconductor structure of claim 1 , wherein the non-oblong-shaped insulator coating is a silica coating.
3. The semiconductor structure of claim 1 , wherein the non-oblong-shaped insulator coating is bonded directly to the semiconductor nanocrystal.
4. The semiconductor structure of claim 1 , wherein the oblong-shaped semiconductor nanocrystal comprises an anisotropic nanocrystalline core comprising a first semiconductor material, and comprises a nanocrystalline shell comprising a second, different, semiconductor material at least partially surrounding the anisotropic nanocrystalline core.
5. The semiconductor structure of claim 4 , wherein the anisotropic nanocrystalline core has an aspect ratio between, but not including, 1.0 and 2.0.
6. 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 comprising:
an oblong-shaped semiconductor nanocrystal; and
a non-oblong-shaped insulator coating formed by two bulbous portions separated by a waist portion encapsulating the oblong-shaped semiconductor nanocrystal.
7. The lighting apparatus of claim 6 , wherein the light emitting diode is a UV or visible spectrum light emitting diode, and wherein the light conversion layer is a down- or up-shifting layer.
8. The lighting apparatus of claim 7 , wherein the light emitting diode is a blue light emitting diode, and wherein the light conversion layer is a down-shifting layer.
9. The lighting apparatus of claim 6 , wherein the quantum dots vary in size and emission color, and wherein the light conversion layer is to provide white light.
10. The lighting apparatus of claim 6 , wherein the housing is a cup-shaped housing.
11. The lighting apparatus of claim 6 , wherein the light conversion layer comprises a combination of red quantum dots with yellow phosphors, green phosphors, or both.
12. The lighting apparatus of claim 6 , 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.
13. The lighting apparatus of claim 6 , wherein the light conversion layer is disposed on the light emitting diode.
14. The lighting apparatus of claim 6 , wherein the light conversion layer is situated remotely from the light emitting diode.
15. The lighting apparatus of claim 6 , wherein, for each quantum dot, the non-oblong-shaped insulator coating is a silica coating.
16. The lighting apparatus of claim 6 , wherein, for each quantum dot, the non-oblong-shaped insulator coating is bonded directly to the oblong-shaped semiconductor nanocrystal.
17. The lighting apparatus of claim 6 , wherein the oblong-shaped semiconductor nanocrystal of each quantum dot comprises an anisotropic nanocrystalline core comprising a first semiconductor material, and comprises a nanocrystalline shell comprising a second, different, semiconductor material at least partially surrounding the anisotropic nanocrystalline core.
18. The lighting apparatus of claim 6 , wherein the light conversion layer comprises a matrix material, and wherein the plurality of quantum dots is embedded in the matrix material.
19. 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 comprising:
an oblong-shaped semiconductor nanocrystal; and
a non-oblong-shaped insulator coating formed by two bulbous portions separated by a waist portion encapsulating the oblong-shaped semiconductor nanocrystal.
20. The lighting apparatus of claim 19 , wherein the light emitting diode is a UV or visible spectrum light emitting diode, and wherein the light conversion layer is a down- or up-shifting layer.
21. The lighting apparatus of claim 20 , wherein the light emitting diode is a blue light emitting diode, and wherein the light conversion layer is a down-shifting layer.
22. The lighting apparatus of claim 19 , wherein the quantum dots vary in size and emission color, and wherein the light conversion layer is to provide white light.
23. The lighting apparatus of claim 19 , 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.
24. The lighting apparatus of claim 19 , 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.
25. The lighting apparatus of claim 19 , 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.
26. The lighting apparatus of claim 19 , wherein the light conversion layer comprises a combination of red quantum dots with yellow phosphors, green phosphors, or both.
27. The lighting apparatus of claim 26 , further comprising:
a protective cover encapsulating the light conversion layer and the light emitting diode.
28. The lighting apparatus of claim 19 , 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.
29. The lighting apparatus of claim 28 , further comprising:
a protective cover encapsulating the light conversion layer, the second light conversion layer, and the light emitting diode.
30. The lighting apparatus of claim 19 , wherein the light conversion layer is disposed on the light emitting diode.
31. The lighting apparatus of claim 19 , wherein the light conversion layer is situated remotely from the light emitting diode.
32. The lighting apparatus of claim 19 , wherein, for each quantum dot, the non-oblong-shaped insulator coating is a silica coating.
33. The lighting apparatus of claim 19 , wherein, for each quantum dot, the non-oblong-shaped insulator coating is bonded directly to the oblong-shaped semiconductor nanocrystal.
34. The lighting apparatus of claim 19 , wherein the oblong-shaped semiconductor nanocrystal of each quantum dot comprises an anisotropic nanocrystalline core comprising a first semiconductor material, and comprises a nanocrystalline shell comprising a second, different, semiconductor material at least partially surrounding the anisotropic nanocrystalline core.
35. The lighting apparatus of claim 19 , wherein the light conversion layer comprises a matrix material, and wherein the plurality of quantum dots is embedded in the matrix material.