Photovoltaic device having multilayer antireflective layer supported by front substrate

• US 20090032098A1
• Filed: 08/03/2007
• Published: 02/05/2009
• Est. Priority Date: 08/03/2007
• Status: Abandoned Application

• Current Assignee: Guardian Glass LLC (KOCH Industries Incorporated)
• Original Assignee: Guardian Industries Corporation (KOCH Industries Incorporated)
• Inventors: Lu, Yiwei
• Application Number:
  US11/882,759
• Publication Number:
  US 20090032098A1
• Time in Patent Office: Days
• US Class Current: 136/257
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2217/734 comprising an alternation of high and low refractive indexes
• CPC Class Codes: G02B 1/115 Multilayers
• 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

Abstract

In certain embodiments of this invention, an improved multilayer anti-reflection (AR) coating is provided on the exterior surface of the front glass substrate of a photovoltaic device. This AR coating functions to reduce reflection of desirable wavelengths from the front glass substrate, thereby allowing more light within the desirable solar spectrum to pass through the incident glass substrate and reach the photovoltaic semiconductor film so that the photovoltaic device can operate more efficiently. Also, the AR coating can reduce the amount of undesirable light (e.g., at least some IR and/or UV radiation) which reaches the semiconductor film of the device. In certain example embodiments, the multilayer AR coating includes a plurality of pairs of alternating high refractive index and low refractive index layers.

Claims

1. A photovoltaic device comprising:

a front glass substrate;

a photovoltaic semiconductor film; and

a multilayer anti-reflection coating provided on a light incident side of the front glass substrate, the anti-reflection coating comprising from the front glass substrate moving outwardly away from the semiconductor film, a first high index layer comprising an oxide of titanium, a first low index layer comprising an oxide of silicon, a second high index layer comprising an oxide of titanium, a second low index layer comprising an oxide of silicon, a third high index layer comprising an oxide of titanium, a third low index layer comprising an oxide of silicon, a fourth high index layer comprising an oxide of titanium, and a fourth low index layer comprising an oxide of silicon.

2. The photovoltaic device of claim 1, wherein the first high index layer is in direct contact with the front glass substrate.

3. The photovoltaic device of claim 1, wherein the first low index layer is substantially thicker than the first high index layer.

4. The photovoltaic device of claim 1, wherein the fourth low index layer is substantially thicker than the fourth high index layer.

5. The photovoltaic device of claim 1, wherein the fourth low index layer is thicker than any of the first, second and third low index layers.

6. The photovoltaic device of claim 1, wherein the semiconductor film comprises silicon.

7. The photovoltaic device of claim 1, wherein the anti-reflection coating on the front glass substrate reflects at least about 10% of incident radiation in the range of from about 1200-2500 nm.

8. The photovoltaic device of claim 1, wherein the anti-reflection coating on the front glass substrate reflects at least about 12% of incident radiation in the range of from about 1200-2500 nm.

9. The photovoltaic device of claim 1, wherein the anti-reflection coating on the front glass substrate reflects at least about 14% of incident radiation in the range of from about 1200-2500 nm.

10. The photovoltaic device of claim 1, wherein the anti-reflection coating has less than about 2% absorption loss in a wavelength range of from about 450 to 1100 nm.

11. The photovoltaic device of claim 1, wherein the anti-reflection coating on the front glass substrate reflects at least about 12% of incident radiation in at least a majority of a range of from about 1500-2500 nm.

12. The photovoltaic device of claim 1, wherein the anti-reflection coating on the front glass substrate reflects at least about 15% of incident radiation in at least a majority of a range of from about 1500-2500 nm.

13. A photovoltaic device comprising:

a front glass substrate;

a photovoltaic semiconductor film; and

a multilayer anti-reflection coating provided on a light incident side of the front glass substrate, the anti-reflection coating comprising from the front glass substrate moving outwardly away from the semiconductor film, a first high index layer, a first low index layer, a second high index layer, a second low index layer, a third high index layer, and a third low index layer.

14. The photovoltaic device of claim 13, wherein the anti-reflection coating further comprises a fourth high index layer and a fourth low index layer.

15. The photovoltaic device of claim 13, wherein one or more of the high index layers comprise an oxide of titanium.

16. The photovoltaic device of claim 13, wherein one or more of the high index layers comprise silicon nitride.

17. The photovoltaic device of claim 13, wherein the high index layers each have a refractive index of at least about 2.0, and the low index layers each have a refractive index of no more than about 1.7.

18. The photovoltaic device of claim 13, wherein the high index layers each have a refractive index of at least about 2.3, and the low index layers each have a refractive index of no more than about 1.6.

19. The photovoltaic device of claim 13, wherein one or more of the low index layers comprises an oxide of silicon.

20. The photovoltaic device of claim 13, wherein the anti-reflection coating on the front glass substrate reflects at least about 10% of incident radiation in the range of from about 1200-2500 nm.

21. The photovoltaic device of claim 13, wherein the anti-reflection coating on the front glass substrate reflects at least about 12% of incident radiation in the range of from about 1200-2500 nm.

22. The photovoltaic device of claim 13, wherein the anti-reflection coating on the front glass substrate reflects at least about 14% of incident radiation in the range of from about 1200-2500 nm.

23. The photovoltaic device of claim 13, wherein the anti-reflection coating has less than about 2% absorption loss in a wavelength range of from about 450 to 1100 nm.

24. The photovoltaic device of claim 13, wherein the anti-reflection coating on the front glass substrate reflects at least about 12% of incident radiation in at least a majority of a range of from about 1500-2500 nm.

25. The photovoltaic device of claim 13, wherein the anti-reflection coating on the front glass substrate reflects at least about 15% of incident radiation in at least a majority of a range of from about 1500-2500 nm.