Method of making an antireflective silica coating, resulting product, and photovoltaic device comprising same

• US 20090101209A1
• Filed: 10/19/2007
• Published: 04/23/2009
• Est. Priority Date: 10/19/2007
• Status: Abandoned Application

• Current Assignee: Guardian Glass LLC (KOCH Industries Incorporated)
• Original Assignee: Guardian Industries Corporation (KOCH Industries Incorporated)
• Inventors: Sharma, Pramod K., Thomsen, Scott V., Varaprasad, Desaraju V., Lu, Yiwei, Mellott, Nathan P.
• Application Number:
  US11/976,079
• Publication Number:
  US 20090101209A1
• Time in Patent Office: Days
• US Class Current: 136/261
• CPC Class Codes: C03C 17/23 Oxides C03C17/02 takes precedence
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 17/3458 comprising a chloride
• CPC Class Codes: C03C 2217/213 SiO2
• CPC Class Codes: C03C 2217/734 comprising an alternation of high and low refractive indexes
• CPC Class Codes: C03C 2218/113 by sol-gel processes
• CPC Class Codes: C03C 2218/365 Coating different sides of a glass substrate
• CPC Class Codes: G02B 1/113 using inorganic layer materials only
• CPC Class Codes: H01L 31/02168 the coatings being antireflective or having enhancing optical properties for the solar cells
• CPC Class Codes: H01L 31/0392 including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate textured substrates H01L31/02366
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y10T 428/31612 As silicone, silane or siloxane

Abstract

A low-index silica coating may be made by forming silica sol including a silane and/or a colloidal silica. The silica precursor may be deposited on a substrate (e.g., glass substrate) to form a coating layer. The coating layer may then be cured and/or fired using temperature(s) of from about 550 to 700° C. A barrier undercoating including a metal oxide, such as, silica, alumina, titania, zirconia, and/or an oxynitride of silica may be deposited between the coating layer and substrate. Preferably, the barrier undercoating does not substantially affect the percent transmission or reflection of the low-index silica coating. The low-index silica based coating may be used as an antireflective (AR) film on a front glass substrate of a photovoltaic device (e.g., solar cell) or any other suitable application in certain example instances.

Claims

1. A method of making a low-index silica based coating, the method comprising:

depositing a barrier undercoating on a glass substrate, wherein the barrier undercoating comprises a metal oxide selected from at least one of silica, alumina, titania, zirconia, and an oxynitride of silica;

forming a silica precursor comprising a silica sol comprising a silane and/or a colloidal silica;

depositing the silica precursor on the barrier undercoating to form a coating layer; and

curing and/or firing the coating layer in an oven at a temperature of at least about 550°

C. for a duration of from about 1 to 10 minutes.

2. The method of claim 1, wherein either step of depositing comprises spin-coating, roller-coating, or spray-coating.

3. The method of claim 1, wherein the barrier undercoating is formed by physical vapour deposition, chemical vapour deposition, or chemical liquid deposition.

4. The method of claim 1, wherein the barrier undercoating has a refractive index less than 1.6.

5. The method of claim 1, wherein the barrier undercoating inhibits corrosion of the glass substrate when aged.

6. A method of making a photovoltaic device comprising a photoelectric transfer film, at least one electrode, and the low-index coating, wherein the method of making the photovoltaic device comprises making the low-index coating according to claim 1, and wherein the low-index coating is provided on a light incident side of a front glass substrate of the photovoltaic device.

7. A method of making a photovoltaic device including a low-index silica based coating used in an antireflective coating, the method comprising:

depositing a barrier undercoating on a glass substrate, wherein the barrier undercoating comprises a metal oxide selected from at least one of silica, alumina, titania, zirconia, and an oxynitride of silica;

forming a silica precursor comprising a silica sol comprising a silane and/or a colloidal silica;

depositing the silica precursor on the barrier undercoating to form a coating layer;

curing and/or firing the coating layer in an oven at a temperature of from about 550 to 700°

C. for a duration of from about 1 to 10 minutes; and

using the glass substrate with the low-index silica based coating thereon as a front glass substrate of the photovoltaic device so that the low-index silica based coating is provided on a light incident side of the glass substrate.

8. The method of claim 7, wherein either step of depositing comprises spin-coating, roller-coating, or spray-coating.

9. The method of claim 7, wherein the barrier undercoating is formed by physical vapour deposition, chemical vapour deposition, or chemical liquid deposition.

10. The method of claim 7, wherein the low-index coating has a percent transmission and/or percent reflection that is not substantially affected by the barrier undercoating.

11. A photovoltaic device comprising:

a photovoltaic film, and at least a glass substrate on a light incident side of the photovoltaic film;

an antireflection coating provided on the glass substrate;

wherein the antireflection coating comprises at least a barrier undercoating layer provided directly on and contacting the glass substrate, the undercoating layer comprising a metal oxide selected from at least one of silica, alumina, titania, zirconia, and an oxynitride of silica; and

a second layer on the barrier undercoating layer, wherein the second layer is produced using a method comprising the steps of;

forming a silica precursor comprising a silica sol comprising a silane and/or a colloidal silica;

depositing the silica precursor on a glass substrate to form a coating layer;

curing and/or firing the coating layer in an oven at a temperature of from about 550 to 700°

C. for a duration of from about 1 to 10 minutes.

12. The photovoltaic device of claim 11, wherein the barrier undercoating layer comprises silica and has a refractive index of less than 1.6.

13. The photovoltaic device of claim 11, wherein the antireflection coating has a percent transmission and/or percent reflection that is not substantially affected by the barrier undercoating.

14. A coated article comprising:

a glass substrate;

an antireflection coating provided on the glass substrate;

wherein the antireflection coating comprises at least a barrier undercoating layer provided directly on and contacting the glass substrate, the undercoating layer comprising a metal oxide selected from at least one of silica, alumina, titania, zirconia, and an oxynitride of silica; and

a second layer on the barrier undercoating layer, wherein the second layer is produced using a method comprising the steps of;

forming a silica precursor comprising a silica sol comprising a silane and/or a colloidal silica;

depositing the silica precursor on a glass substrate to form a coating layer;

curing and/or firing the coating layer in an oven at a temperature of from about 550 to 700°

C. for a duration of from about 1 to 10 minutes.

15. The coated article of claim 14, wherein the barrier undercoating layer comprises silica and has a refractive index of less than 1.6.

16. The coated article of claim 14, wherein the antireflection coating has a percent transmission and/or percent reflection that is not substantially affected by the barrier undercoating.