Method of making a photovoltaic device or front substrate for use in same with scratch-resistant coating and resulting product
View Patent ↗A method of making an anti-reflection coating using a sol-gel process, for use in a photovoltaic device or the like. The method may include the following steps in certain example embodiments: forming a polymeric component of silica by mixing silane(s) with one or more of a first solvent, a catalyst, and water; forming a silica sol gel by mixing the polymeric component with a colloidal silica, and optionally a second solvent; forming a combined sol by mixing siloxane(s) with the silica sol; casting the mixture by spin coating or the like to form a silica and siloxane containing layer on a substrate; and curing and/or heat treating the layer. This layer may make up all or only part of an anti-reflection coating which may be used in a photovoltaic device or the like.
1. A method of making a photovoltaic device including an antireflective coating, the method comprising:
forming a polymeric component comprising silica by mixing at least one silane with one or more of a first solvent, a first catalyst, and/or water;
forming a silica sol by mixing the polymeric component with colloidal silica and/or a second solvent;
forming a combined sol gel by mixing the silica sol with at least one siloxane, wherein the siloxane comprises from about 0.1 to 10% by weight of the combined sol gel;
casting the combined sol gel to form a first layer on a glass substrate;
curing and heat treating the first layer, wherein said heat treating takes place at a temperature of from about 600° C. to about 700° C., and forming a second layer comprising silicon oxide over the first layer, in making the photovoltaic device, and wherein a critical scratch load of the antireflective coating is from about 20 to 50 mN, in making the photovoltaic device.
2. The method of claim 1 , wherein the siloxane comprises from about 2 to 5% by weight of the combined sol gel, and wherein a critical scratch load of the antireflective coating is from about 25 to 50 mN.
3. The method of claim 2 , wherein the critical scratch load of the antireflective coating is from about 30 to 50 mN.
4. A method of making a photovoltaic device including an antireflective coating, the method comprising:
forming a polymeric component comprising silica by mixing at least at least one silane with at least a first solvent, a first catalyst, and water;
forming a silica sol by mixing the polymeric component with at least colloidal silica and optionally with a second solvent;
forming a combined sol gel by mixing the silica sol with at least one siloxane, wherein the siloxane comprises from about 2-5% by weight of the combined sol gel;
casting the combined sol gel to form a layer on a glass substrate;
curing and heat treating the layer, wherein said heat treating takes place at a temperature of from about 600° C. to about 750° C., and wherein a critical scratch load of the antireflective coating is from about 20 to 50 mN, in making the photovoltaic device.
5. The method of claim 4 , wherein the curing is performed and occurs at a temperature between 100 and 150° C. and has a duration of no more than about 2 minutes.
6. The method of claim 4 , wherein the heat treating occurs and is at a temperature between 600 and 750° C. and has a duration of no greater than about 5 minutes.
7. The method of claim 4 , wherein the at least one silane comprises glycydoxylpropyltrimethoxysilane (glymo).
8. The method of claim 4 , wherein (a) one or more of the first solvent and the second solvent comprise n-propanol, and/or (b) the casting comprises spin coating.
9. The method of claim 4 , wherein the first catalyst and/or second catalyst comprise an acid.
10. The method of claim 8 , wherein the acid comprises hydrochloric acid.
11. The method of claim 4 , wherein the colloidal silica comprises methyl ethyl ketone.
12. The method of claim 4 , wherein the at least one siloxane is chosen from the group consisting of: 3,5 bis(3-carboxy propyl)tetramethyl disiloxane; 4,3,5-bis(chloromethyl)octamethyl tetrasiloxane; 1,3 bis(3-methylacryloxy)tetramethyl disiloxane; hexamethyl disiloxane; octamethyl trisiloxane; decamethyl trisiloxane; hydrogen silsesquioxane; hexaethylcyclotrisiloxane; hexaethyl disiloxane; 1,1,3,3,5,5-hexamethyltrisiloxane; hexamethylcyclotrisiloxane; hexavinyldisiloxane; hexaphenyldisiloxane; octaphenylcyclotetrasiloxane; hexachlorodisiloxane; dichlorooctamethyltetrasiloxane; 2-methoxy(polyethyleneoxy)propyl) heptamethyl trisiloxane; 3 acryloxypropyl tris trimethyl siloxysilane; methylacryloxypropyl heptacyclopentyl-T8silsesquioxane; octakis(dimethylsiloxy)octaprismosilsesquioxane; and octavinyl-T8-silsesquioxane.
13. The method of claim 4 , wherein the at least one siloxane is chosen from the group consisting of: 3,5 bis(3-carboxy propyl)tetramethyl disiloxane; 4,3,5-bis(chloromethyl)octamethyl tetrasiloxane; 1,3 bis(3-methylacryloxy)tetramethyl disiloxane; hexamethyl disiloxane; octamethyl trisiloxane; decamethyl trisiloxane; and hydrogen silsesquioxane.
14. The method of claim 4 , wherein the at least one siloxane comprises about 5% wt of the combined sol gel.
15. The method of claim 4 , wherein the at least one siloxane comprises about 2% wt of the combined sol gel.
16. The method of claim 4 , wherein the step of forming a combined sol gel further comprises mixing an organic additive or a metal oxide with the silica sol and siloxane.
17. The method of claim 4 , wherein the critical scratch load of the antireflective coating is from about 25 to 50 mN.
18. The method of claim 4 , wherein the critical scratch load of the antireflective coating is from about 30 to 50 mN.