Anti reflective coating for photovoltaic glass panel
View Patent ↗A method of making an anti-reflective film comprises preparing a liquid composition with specific amounts of tetraethyl orthosilicate, polyethylene glycol, HCl, ethanol and at least one alcohol having a higher boiling point than ethanol and miscibility with both ethanol and water; applying the liquid composition onto a surface of a substrate to form a liquid film; evaporating the ethanol and the at least one alcohol from the liquid film to form a solid film; and heating the solid film to form a silica film.
1. A method reducing reflectiveness of a substrate, the method comprising:
(i) preparing a composition comprising a compound comprising Si and O, a polymeric glycol, a strong acid, ethanol, n-butanol, and water;
(ii) applying the composition onto a surface of a substrate in need thereof, thereby forming a film of said composition;
(iii) evaporating the alcohols from the film to solidify the film; and
(iv) heating the solidified film to a temperature of from 500 to 800° C., thereby forming a coating comprising Si on the substrate;
wherein n-butanol is miscible with ethanol and water,
during the preparing, a ratio of a volume % of a solution of 30 g polymeric glycol in 100 ml water to a volume % of the compound comprising Si and O is at least 1, and
the composition comprises from 0.1 to 15 volume % of the compound comprising Si and O, from 0.1 to 80 g of the polymeric glycol per liter of composition, from 0.1 to 20 g of the strong acid per liter of composition, and from 0.1 to 5 volume % of n-butanol.
2. The method according to claim 1 , wherein after heating, the film is between 700 Å and 2000 μm thick.
3. The method according to claim 1 , wherein after heating, the film is porous.
4. The method according to claim 1 , wherein the composition is prepared by mixing together
0.1 to 5 volume % of tetraethyl orthosilicate, present as said compound comprising Si and O,
0.1 to 5 volume % of a solution of 30 g polyethylene glycol in 100 ml water,
0.1 to 2 volume % of a solution of 37 weight % HCl in water,
0.1 to 0.5 volume % of n-butanol, and
a balance of ethanol.
5. The method according to claim 4 , wherein the composition comprises 1 to 3 volume % of tetraethyl orthosilicate.
6. The method according to claim 4 , wherein the composition comprises 4.6 to 6.9 g of polyethylene glycol per liter of the liquid composition.
7. The method according to claim 4 , wherein the composition comprises 1.78 to 2.66 g of HCl per liter of the liquid composition.
8. The method according to claim 1 , wherein the substrate is selected from the group consisting of plastic and glass.
9. The method according to claim 1 , wherein the substrate is photovoltaic glass having at least one smooth or patterned surface.
10. The method according to claim 1 , wherein during the applying the substrate is at room temperature and atmospheric pressure.
11. The method according to claim 1 , wherein during the applying the composition is at room temperature.
12. The method according to claim 1 , wherein during the applying the substrate is at a temperature of 50° C. or above.
13. The method according to claim 1 , wherein during the applying the composition is at a temperature of 50° C. or above.
14. The method according to claim 1 , wherein the applying comprises spraying the composition onto the surface of the substrate.
15. The method according to claim 1 , wherein the film is a silica film and is between 700 Å and 2000 μm thick.
16. The method according to claim 2 , wherein the film is a silica film and is porous.
17. The method according to claim 1 , wherein said compound comprising Si and O comprises at least one member selected from the group consisting of a silicate, a silanol, a siloxane, and a silane.