Ceramic composition having dispersion of nano-particles therein and methods of fabricating same

• US 9,337,368 B2
• Filed: 10/16/2013
• Issued: 05/10/2016
• Est. Priority Date: 12/13/2012
• Status: Active Grant

• Current Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Original Assignee: Pacific Light Technologies Corp. (Ams-Osram AG)
• Inventors: Kurtin, Juanita N., Masson, Georgeta
• Primary Examiner(s): Everhart, Caridad
• Application Number:
  US14/055,727
• Publication Number:
  US 20140170789A1
• Time in Patent Office: 937 Days
• Field of Search: 977/847, 977/892, 257/87, 257/17, 257/12, 257/E31.051, 257/E51.026, 438/63
• US Class Current: 1/1
• 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:

applying a mixture of quantum dots and discrete ceramic precursor molecules to the surface of the LED, wherein the quantum dots are hetero-structure quantum dots having an outer insulator coating already formed thereon prior to forming the mixture, 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), and wherein the discrete ceramic precursor molecules are thermal or ultra-violet (UV) labile polysilsequioxane molecules having one or more β

-electron withdrawing groups; and

subsequent to applying the mixture of quantum dots and discrete ceramic precursor molecules to the surface of the LED, forming, from the mixture, a ceramic matrix on the surface of the LED, the ceramic matrix comprising a dispersion of the quantum dots therein, wherein forming the ceramic matrix comprises forming a silica-rich or silicate matrix via heating or UV-light exposure.

2. The method of claim 1, 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.

3. The method of claim 1, 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.

4. The method of claim 1, 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.

5. The method of claim 1, 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.

6. The method of claim 1, wherein the mixture of quantum dots and discrete 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.

7. The method of claim 1, wherein forming the ceramic matrix comprises forming a silica-rich matrix.

8. The method of claim 1, wherein forming the ceramic matrix comprises forming a silicate matrix.

9. The method of claim 1, wherein forming the ceramic matrix comprises forming the forming silica-rich or silicate matrix via heating.

10. The method of claim 1, wherein forming the ceramic matrix comprises forming the forming silica-rich or silicate matrix via UV-light exposure.

11. The method of claim 1, wherein the outer insulator coating comprises a layer of silica (SiO_x).

12. The method of claim 1, wherein the outer insulator coating comprises a layer of titanium oxide (TiO_x).

13. The method of claim 1, wherein the outer insulator coating comprises a layer of zirconium oxide (ZrO_x).

14. The method of claim 1, wherein the outer insulator coating comprises a layer of alumina (AlO_x).

15. The method of claim 1, wherein the outer insulator coating comprises a layer of hafnia (HfO_x).