Transparent cover for solar cells and modules

1. A method for fabricating a solar cell, comprising:

depositing a back contact, an absorber, a buffer, and a front contact over a substrate to form a photovoltaic substructure;

forming a transparent cover separate from said photovoltaic substructure by:

depositing a metallic layer by physical deposition, chemical vapor deposition (CVD) or atomic layer deposition (ALD) on a bottom surface of a transparent layer,

depositing an anti-reflective coating on a top surface of the transparent layer, and

annealing said metallic layer, anti-reflective coating, and transparent layer to form said transparent cover with a plasmonic nanostructured layer on said bottom surface of said transparent cover; and

adhering said transparent cover on top of said photovoltaic substructure, wherein said plasmonic nanostructured layer on said bottom surface of said transparent cover is in direct contact with said front contact of said photovoltaic structure, so as to be sandwiched between said bottom surface of said transparent cover and said front contact of said photovoltaic structure.

2. The method as in claim 1 , wherein said metallic layer and transparent layer are annealed at a temperature ranging from about 200° to about 500° C.

3. The method as in claim 1 , wherein said depositing, forming and adhering steps are performed in-line.

4. The method as in claim 1 , wherein said plasmonic nanostructured layer comprises metal nanoparticles.

5. The method as in claim 1 , wherein said metallic layer comprises metals selected from Au, Ag, Pt, Al, Cu, or combinations thereof.

6. The method as in claim 1 , wherein said plasmonic nanostructured layer comprises metal nanoparticles with a size ranging from about 5 nm to about 300 nm.

7. The method as in claim 1 , wherein said plasmonic nanostructured layer comprises nanoparticles with a size ranging from about 30 nm to about 300 nm.

8. The method as in claim 1 , wherein said metallic layer has a thickness ranging from about 1 nm to about 30 nm.

9. The method as in claim 1 , wherein depositing said metallic layer is performed by sputtering.

10. A method for fabricating a solar cell, comprising:

depositing a back contact, a chalcopyrite absorber, a buffer, and a front contact over a substrate to form a photovoltaic substructure;

forming a transparent cover separate from said photovoltaic substructure comprising:

providing a transparent layer,

depositing an anti-reflective coating on a top surface of said transparent layer,

depositing metal nanoparticles on a bottom surface of said transparent layer by physical deposition, chemical vapor deposition (CVD) or atomic layer deposition (ALD); and

annealing said metal nanoparticles and transparent layer to form a plasmonic nanostructured layer; and then

adhering said transparent cover on top of said photovoltaic substructure, wherein said plasmonic nanostructured layer on said bottom surface of said transparent cover is in direct contact with said front contact of said photovoltaic structure, so as to be sandwiched between said bottom surface of said transparent cover and said front contact of said photovoltaic structure.

11. The method as in claim 10 , wherein said transparent cover has a transmittance of about 95% or greater.

12. The method as in claim 10 , wherein said plasmonic nanostructructured layer comprises plasmonic metal oxides.

13. The method as in claim 10 , wherein said plasmonic nanostructured layer comprises nanoparticles with various shapes.

14. A method for fabricating a solar module, comprising:

connecting a plurality of photovoltaic substructures each comprising a back contact, absorber, a buffer, and a front contact over a substrate to form a module;

forming a transparent cover separate from said photovoltaic substructures by:

depositing a metallic layer by physical deposition, chemical vapor deposition (CVD) or atomic layer deposition (ALD) on a bottom surface of a transparent layer,

annealing said metallic layer and transparent layer to form a plasmonic nanostructured layer

depositing an anti-reflective coating on a top surface of said transparent layer; and

adhering said transparent cover on top of said module, so as to sandwich said plasmonic nanostructured layer between said bottom surface of said transparent cover and said front contact of said module; wherein said plasmonic nanostructured layer is in direct contact with said front contact of said module.

15. The method as in claim 14 , wherein:

said metallic layer comprises metals nanoparticles selected from Au, Ag, Pt, Al, Cu, or combinations thereof on said transparent layer; and

said annealing step is performed at a temperature of about 200° C. or greater.

16. The method as in claim 14 , wherein said annealing metallic layer is performed under inert gas atmosphere.