Coated article comprising colloidal silica inclusive anti-reflective coating, and method of making the same

• US 20110108101A1
• Filed: 11/12/2009
• Published: 05/12/2011
• Est. Priority Date: 11/12/2009
• Status: Active Grant

• Current Assignee: Guardian Glass LLC (KOCH Industries Incorporated)
• Original Assignee: Guardian Industries Corporation (KOCH Industries Incorporated)
• Inventors: Lewis, Mark A., Sharma, Pramod K.
• Granted Patent: US 8,617,641 B2
• Time in Patent Office: Days
• US Class Current: 136/256
• CPC Class Codes: B32B 15/082 comprising vinyl resins; comprising acrylic resins
• CPC Class Codes: B32B 17/10018 comprising only one glass sheet
• CPC Class Codes: B32B 17/10788 containing ethylene vinylacetate
• CPC Class Codes: C03C 17/25 by deposition from the liquid phase
• CPC Class Codes: C03C 17/36 at least one coating being a metal
• CPC Class Codes: C03C 17/3678 specially adapted for use in solar cells
• CPC Class Codes: C03C 2217/213 SiO2
• CPC Class Codes: C03C 2217/732 made of a single layer
• CPC Class Codes: C03C 2218/113 by sol-gel processes
• CPC Class Codes: C03C 2218/116 by spin-coating, centrifugation
• CPC Class Codes: C03C 2218/365 Coating different sides of a glass substrate
• CPC Class Codes: H01L 31/02168 the coatings being antireflective or having enhancing optical properties for the solar cells
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y10T 428/259 Silicic material

Abstract

Certain example embodiments of this invention relate to coated articles that include anti-reflective (AR) coatings produced from colloidal silica with variable size particles in formulation, and/or methods of making the same. In certain example embodiments, the AR coatings advantageously exhibit high transmission, high transmission gain with respect to uncoated articles, and high b* values, before and/or after heat treatment. The AR coatings of certain example embodiments may be temperable or otherwise heat treatable (e.g., at temperatures of 500 degrees C. or greater) together with their supporting substrates. In certain example embodiments, the particle size for the colloidal silica is 10-110 nm, and the b* values are at least about 0.8. Certain example embodiments may be used in connection with photovoltaic devices and/or the like.

Claims

1. A method of making a coated article, the method comprising:

providing a glass substrate;

preparing a sol, the sol comprising colloidal silica having a particle size of 10-110 nm;

spin coating the sol, directly or indirectly, onto the glass substrate;

curing the sol to form a silica-inclusive anti-reflective (AR) coating; and

heat treating the glass substrate together with the AR coating at a temperature of at least about 500 degrees C.,

wherein, post heat treatment, the AR coating has a b* value of 0.8 or greater.

2. The method of claim 1, wherein post heat treatment, the AR coating provides a visible transmission gain of at least about 2.5% relative to the glass substrate alone.

3. The method of claim 1, wherein the particle size is 20-100 nm.

4. The method of claim 3, wherein post heat treatment, the AR coating has a b* value of 0.9 or greater.

5. The method of claim 3, wherein post heat treatment, the AR coating has a b* value of 1 or greater.

6. The method of claim 1, wherein the curing comprises exposing the substrate together with the sol spin coated thereon to first and second elevated temperatures, the second elevated temperature being higher than the first elevated temperature.

7. The method of claim 6, wherein the substrate together with the sol spin coated thereon is exposed to a temperature of about 150 degrees C. for 2 minutes, followed by a temperature of about 220 degrees for 2.5 minutes.

8. The method of claim 1, wherein the preparing of the silica sol comprises:

preparing a polymeric component, the polymeric component comprising n-propanol, Glycydoxylpropyltrimethoxysilane (Glymo), water, and hydrochloric acid;

mixing the polymeric component;

forming a coating solution by combining the polymeric solution with the colloidal silica in methyl ethyl ketone; and

stirring the coating solution to form the silica sol.

9. The method of claim 1, further comprising building the glass substrate together with the AR coating into a photovoltaic device.

10. A method of making a solar cell, the method comprising:

providing a glass substrate;

spin coating a sol comprising colloidal silica having a particle size of 10-110 nm, directly or indirectly, onto the glass substrate;

curing the sol to form a silica-inclusive anti-reflective (AR) coating; and

heat treating the glass substrate together with the AR coating at a temperature of at least about 500 degrees C.,

wherein, post heat treatment, the AR coating has a b* value of 0.8 or greater and the AR coating provides a visible transmission gain of at least about 2.5% relative to the glass substrate alone.

11. The method of claim 10, wherein the curing comprises exposing the substrate together with the sol spin coated thereon to first and second elevated temperatures, the second elevated temperature being higher than the first elevated temperature.

12. The method of claim 10, wherein the particle size is 20-100 nm.

13. The method of claim 12, wherein post heat treatment, the AR coating has a b* value of 0.9 or greater.

14. The method of claim 12, wherein post heat treatment, the AR coating has a b* value of 1 or greater.

15. The method of claim 12, wherein the heat treatment comprises thermally tempering in a tempering furnace at a temperature of at least 580 degrees C.

16. A coated article, comprising:

a heat treated glass substrate;

an AR coating spin coated from a sol comprising colloidal silica having a particle size of 10-110 nm, directly or indirectly, onto the substrate;

wherein the AR coating has a b* value of 0.8 or greater, and

wherein the AR coating provides a visible transmission gain of at least about 2.5% relative to the glass substrate alone.

17. The coated article of claim 16, wherein the particle size is 20-100 nm.

18. The coated article of claim 17, wherein post heat treatment, the AR coating has a b* value of 0.9 or greater.

19. The coated article of claim 17, wherein post heat treatment, the AR coating has a b* value of 1 or greater.

20. An electronic device comprising the coated article of claim 16.