CERAMIC COMPOSITION HAVING DISPERSION OF NANO-PARTICLES THEREIN AND METHODS OF FABRICATING SAME

• US 20140170789A1
• Filed: 10/16/2013
• Published: 06/19/2014
• Est. Priority Date: 12/13/2012
• Status: Active Grant

• Current Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Original Assignee: Georgeta Masson, Juanita N. Kurtin
• Inventors: KURTIN, Juanita N., MASSON, Georgeta
• Granted Patent: US 9,337,368 B2
• Time in Patent Office: Days
• US Class Current: 438/27
• 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: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: H01L 31/0264 Inorganic materials
• CPC Class Codes: H01L 31/055 where light is absorbed and re-emitted at a different wavelength by the optical element directly associated or integrated with the PV cell, e.g. by using luminescent material, fluorescent concentrators or up-conversion arrangements
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y10S 977/774 Exhibiting three-dimensional carrier confinement, e.g. quantum dots
• CPC Class Codes: Y10S 977/779 Possessing nanosized particles, powders, flakes, or clusters other than simple atomic impurity doping

Abstract

Ceramic compositions having a dispersion of nano-particles therein and methods of fabricating ceramic compositions having a dispersion of nano-particles therein are described. In an example, a method of forming a composition having a dispersion of nano-particles therein includes forming a mixture of semiconductor nano-particles and ceramic precursor molecules. A ceramic matrix is formed from the ceramic precursor molecules. The ceramic matrix includes a dispersion of the semiconductor nano-particles therein. In another example, a composition includes a medium including ceramic precursor molecules. The medium is a liquid or gel at 25 degrees Celsius. A plurality of semiconductor nano-particles is suspended in the medium.

Claims

1. A method of applying a light-conversion layer to a surface of a light-emitting diode (LED), the method comprising:

forming a ceramic matrix from a mixture of quantum dots and ceramic precursor molecules, the ceramic matrix comprising a dispersion of the quantum dots therein; and

applying the ceramic matrix to the surface of the LED.

2. The method of claim 1, wherein applying the ceramic matrix to the surface of the LED comprises using a technique selected from the group consisting of spraying, dip-coating, spin-coating, and drop-casting.

3. The method of claim 1, wherein applying the ceramic matrix to the surface of the LED further comprises curing the ceramic matrix with ultra-violet (UV) light exposure or heating.

4. The method of claim 1, wherein the ceramic precursor molecules are discrete molecules, and forming the ceramic matrix comprises forming an infinite inorganic network.

5. The method of claim 1, wherein the ceramic precursor molecules are linear metal oxide polymers, and forming the ceramic matrix comprises forming a metal oxide matrix via cross-linking mechanisms.

6. The method of claim 1, wherein the ceramic precursor molecules are thermal or ultra-violet (UV) labile polysilsequioxane molecules having one or more β

-electron withdrawing groups, and forming the ceramic matrix comprises forming a silica-rich or silicate matrix via heating or UV-light exposure.

7. The method of claim 1, wherein the quantum dots are hetero-structure quantum dots having an outer insulator coating.

8. The method of claim 7, wherein the quantum dots each comprise an anisotropic nano-crystalline core comprising a first semiconductor material and having an aspect ratio between, but not including, 1.0 and 2.0, and a nano-crystalline shell comprising a second, different, semiconductor material at least partially surrounding the anisotropic nano-crystalline core.

9. The method of claim 7, wherein the quantum dots each comprise a nano-crystalline core comprising a first semiconductor material, a nano-crystalline shell comprising a second, different, semiconductor material at least partially surrounding the nano-crystalline core, and a compositional transition layer disposed between, and in contact with, the nano-crystalline core and nano-crystalline shell, the compositional transition layer having a composition intermediate to the first and second semiconductor materials.

10. The method of claim 7, wherein the quantum dots each comprise a nano-crystalline core comprising a first semiconductor material, a nano-crystalline shell comprising a second, different, semiconductor material at least partially surrounding the nano-crystalline core, a nano-crystalline outer shell at least partially surrounding the nano-crystalline shell, the nano-crystalline outer shell comprising a third semiconductor material different from the first and second semiconductor materials, and a compositional transition layer disposed between, and in contact with, the nano-crystalline shell and the nano-crystalline outer shell, the compositional transition layer having a composition intermediate to the second and third semiconductor materials.

11. The method of claim 7, wherein the outer insulator coating comprises a layer of material selected from the group consisting of silica (SiO_x), titanium oxide (TiO_x), zirconium oxide (ZrO_x), alumina (AlO_x), and hafnia (HfO_x).

12. A method of applying a light-conversion layer to a surface of a light-emitting diode (LED), the method comprising:

applying a mixture of quantum dots and ceramic precursor molecules to the surface of the LED; and

forming, from the mixture, a ceramic matrix on the surface of the LED, the ceramic matrix comprising a dispersion of the quantum dots therein.

13. The method of claim 12, wherein applying the mixture to the surface of the LED comprises using a technique selected from the group consisting of spraying, dip-coating, spin-coating, and drop-casting.

14. The method of claim 12, wherein forming the ceramic matrix on the surface of the LED further comprises curing the ceramic matrix with ultra-violet (UV) light exposure or heating.

15. The method of claim 12, wherein the ceramic precursor molecules are discrete molecules, and forming the ceramic matrix comprises forming an infinite inorganic network.

16. The method of claim 12, wherein the ceramic precursor molecules are linear metal oxide polymers, and forming the ceramic matrix comprises forming a metal oxide matrix via cross-linking mechanisms.

17. The method of claim 12, wherein the ceramic precursor molecules are thermal or ultra-violet (UV) labile polysilsequioxane molecules having one or more β

-electron withdrawing groups, and forming the ceramic matrix comprises forming a silica-rich or silicate matrix via heating or UV-light exposure.

18. The method of claim 12, wherein the quantum dots are hetero-structure quantum dots having an outer insulator coating.

19. The method of claim 18, wherein the quantum dots each comprise an anisotropic nano-crystalline core comprising a first semiconductor material and having an aspect ratio between, but not including, 1.0 and 2.0, and a nano-crystalline shell comprising a second, different, semiconductor material at least partially surrounding the anisotropic nano-crystalline core.

20. The method of claim 18, wherein the quantum dots each comprise a nano-crystalline core comprising a first semiconductor material, a nano-crystalline shell comprising a second, different, semiconductor material at least partially surrounding the nano-crystalline core, and a compositional transition layer disposed between, and in contact with, the nano-crystalline core and nano-crystalline shell, the compositional transition layer having a composition intermediate to the first and second semiconductor materials.

21. The method of claim 18, wherein the quantum dots each comprise a nano-crystalline core comprising a first semiconductor material, a nano-crystalline shell comprising a second, different, semiconductor material at least partially surrounding the nano-crystalline core, a nano-crystalline outer shell at least partially surrounding the nano-crystalline shell, the nano-crystalline outer shell comprising a third semiconductor material different from the first and second semiconductor materials, and a compositional transition layer disposed between, and in contact with, the nano-crystalline shell and the nano-crystalline outer shell, the compositional transition layer having a composition intermediate to the second and third semiconductor materials.

22. The method of claim 18, wherein the outer insulator coating comprises a layer of material selected from the group consisting of silica (SiO_x), titanium oxide (TiO_x), zirconium oxide (ZrO_x), alumina (AlO_x), and hafnia (HfO_x).

23. The method of claim 12, wherein the mixture of quantum dots and ceramic precursor molecules is applied to the surface of the LED prior to dicing the LED from a wafer comprising a plurality of LED dies.