Ceramic composition having dispersion of nano-particles therein and methods of fabricating same
View Patent ↗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.
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 ).