Photovoltaic conversion device

• US 5,421,909 A
• Filed: 03/01/1993
• Issued: 06/06/1995
• Est. Priority Date: 03/03/1992
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kawakami, Soichiro, Saito, Keishi, Ishikawa, Nobuyuki, Okada, Naoto, Kariya, Toshimitsu, Matsuyama, Jinsho, Kouda, Yuzo
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US08/024,252
• Time in Patent Office: 827 Days
• Field of Search: 136/256, 136/258 PC, 136/258 AM, 136/259-260, 257/436
• US Class Current: 136/256
• CPC Class Codes: H01L 31/02167 for solar cells
• CPC Class Codes: H01L 31/022466 made of transparent conductive layers, e.g. TCO, ITO layers
• CPC Class Codes: H01L 31/022475 composed of indium tin oxide [ITO]
• CPC Class Codes: H01L 31/022483 composed of zinc oxide [ZnO]
• CPC Class Codes: H01L 31/0236 Special surface textures
• CPC Class Codes: H01L 31/0543 comprising light concentrating means of the refractive type, e.g. lenses
• CPC Class Codes: H01L 31/0547 comprising light concentrating means of the reflecting type, e.g. parabolic mirrors, concentrators using total internal reflection
• CPC Class Codes: H01L 31/056 the light-reflecting means being of the back surface reflector [BSR] type
• CPC Class Codes: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y02E 10/543 Solar cells from Group II-VI materials
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells

Abstract

A photovoltaic device having a semiconductor layer; front and back electrodes; and a surface protection layer adjacent to the light incident side, wherein granules of a material different from that of the surface protection layer are disposed in the surface protection layer.

Claims

1. A photovoltaic device comprising:

at least one semiconductor layer;

front and back electrodes on opposite sides of said at least one semiconductor layer; and

at least one surface protection layer adjacent to the front electrode light incident side of the device, wherein granules of a material different from that of said surface protection layer are disposed in said at least one surface protection layer, wherein said granules are distributed at a lower density at the light incident surface side and at a higher density at the opposite side in the thickness direction.

2. A photovoltaic device according to claim 1, wherein said granules are disposed to form a layer in said at least one surface protection layer.

3. A photovoltaic device according to claim 2, wherein said granules are disposed to form a plurality of layers in said at least one surface protection layer.

4. A photovoltaic device according to claim 1, wherein two or more types of granules are used.

5. A photovoltaic device according to claim 1, wherein the difference between the refractive index of the material of said granules and that of the material of said at least one surface protection layer is 0.1 or more.

6. A photovoltaic device according to claim 1, wherein a light reflection layer is formed opposite the surface of said at least one semiconductor layer on which light is incidents said light reflection layer having a structure for scattering light.

7. A photovoltaic device according to claim 1, wherein the surface density S of said granules in said at least one surface protection layer is from 0.2 to 0.9.

8. A photovoltaic device according to claim 1, wherein the density per unit volume of said granules in said at least one surface protection layer is from 0.001 to 0.5.

9. A photovoltaic device according to claim 1, wherein said at least one semiconductor layer is an amorphous semiconductor.

10. A photovoltaic device according to claim 1, wherein said granules have an average transmittance of not less than 80% for light of a wavelength of 400 nm to 1,000 nm.

11. A photovoltaic device according to claim 1, wherein said granules have a refractive index of about 1.0 to 3.0.

12. A photovoltaic device according to claim 1, wherein said at least one surface protection layer is at least one selected from silicone resin, polyvinylbutyral resin, acrylic resin, acrylic silicone resin, fluoro resin, and an inorganic glass coating.

13. A photovoltaic device according to claim 1, wherein said at least one surface protection layer has a thickness of at least 0.5 μ

m.

14. A photovoltaic device according to claim 1, wherein said at least one surface protection layer has a thickness not greater than 400 μ

m.

15. A photovoltaic device according to claim 1, wherein said granules in said at least one surface protection layer have an average grain size 0.001-20 μ

m.

16. A photovoltaic device according to claim 1, wherein said granules comprise at least one selected from ZnS, TiO₂, Ta₂ O₅, CeO₂, ZrO₂, Sb₂ O₃, Nd₂ O₃, In₂ O₃, SiC, Si₃ N₄, SiO, La₂ O₃, SnO₂, ZnO, CdO, Cd₂ SnO₄, ThO₂, MgO, Al₂ O₃, CaO, BaO, Y₂ O₃, Eu₂ O₃, Pr₂ O₃, Gd₂ O₃, Tb₂ O₃, Pr₆ O₁₁, Dy₂ O₃, Yb₂ O₃, Er₂ O₃, Ho₂ O₃, CeF₃, PbF₂, NdF₃, LaF₂, MgF₂, LiF, Na₃ AlF₆, NaF, and CaF₂.

17. A photovoltaic device according to claim 1, wherein said granules are in crystalline or clustered crystalline form.

18. A photovoltaic device according to claim 1, wherein said at least one surface protection layer contains at least one of an ultra violet radiation absorbing material and a primer.

19. A photovoltaic device comprising:

at least one semiconductor layer;

front and back electrodes on opposite sides of said at least one semiconductor layer; and

at least one surface protection layer adjacent to the front electrode light incident side of the device, wherein granules of a material different from that of said at least one surface protection layer are disposed in said surface protection layer, wherein said granules are distributed at a higher density at the light incident surface side and at a lower density at the opposite side in the thickness direction.

20. A photovoltaic device according to claim 19, wherein said granules are disposed to form a layer in said at least one surface protection layer.

21. A photovoltaic device according to claim 20, wherein said granules are disposed to form a plurality of layers in said at least one surface protection layer.

22. A photovoltaic device according to claim 19, wherein two or more types of granules are used.

23. A photovoltaic device according to claim 19, wherein the difference between the refractive index of the material of said granules and that of the material of said at least one surface protection layer is 0.1 or more.

24. A photovoltaic device according to claim 19, wherein a light reflection layer is formed opposite the surface of said at least one semiconductor layer on which light is incident, said light reflection layer having a structure for scattering light.

25. A photovoltaic device according to claim 19, wherein the surface density S of said granules in said at least one surface protection layer is from 0.2 to 0.9.

26. A photovoltaic device according to claim 19, wherein the density per unit volume of said granules in said at least one surface protection layer is from 0.001 to 0.5.

27. A photovoltaic device according to claim 19, wherein said at least one semiconductor layer is an amorphous semiconductor.

28. A photovoltaic device according to claim 19, wherein said granules have an average transmittance of not less than 80% for light of a wavelength of 400 nm to 1,000 nm.

29. A photovoltaic device according to claim 19, wherein said granules have a refractive index of about 1.0 to 3.0.

30. A photovoltaic device according to claim 19, wherein said at least one surface protection layer is at least one selected from silicone resin, acrylic resin, acrylic silicone resin, polyvinylbutyral resin, fluoro resin, and an inorganic glass coating.

31. A photovoltaic device according to claim 19, wherein said at least one surface protection layer has a thickness of at least 0.5 μ

m.

32. A photovoltaic device according to claim 19, wherein said at least one surface protection layer has a thickness not greater than 400 μ

m.

33. A photovoltaic device according to claim 19, wherein said granules in said at least one surface protection layer have an average grain size 0.001-20 μ

m.

34. A photovoltaic device accordingly to claim 19, wherein said granules comprise at least one selected from ZnS, TiO₂, Ta₂ O₅, CeO₂, ZrO₂, Sb₂ O₃, Nd₂ O₃, In₂ O₃, SiC, Si₃ N₄, SiO, La₂ O₃, SnO₂, ZnO, CdO, Cd₂ SnO₄, ThO₂, MgO, Al₂ O₃, CaO, BaO, Y₂ O₃, Eu₂ O₃, Pr₂ O₃, Gd₂ O₃, Tb₂ O₃, Pr₆ O₁₁, Dy₂ O₃, Yb₂ O₃, Er₂ O₃, Ho₂ O₃, CeF₃, PbF₂, NdF₃, LaF₂, MgF₂, LiF, Na₃ AlF₆, NaF, and CaF₂.

35. A photovoltaic device according to claim 19, wherein said granules are in crystalline or clustered crystalline form.

36. A photovoltaic device according to claim 19, wherein said at least one surface protection layer contains at least one of an ultra violet radiation absorbing material and a primer.