Thin film solar cell

摘要

An improved efficiency thin film solar cell is disclosed. Nanoscale indentations or protrusions are formed on the cross sectional surface of a carrier layer, onto which a thin metal film is deposited. Additional layers, including semiconductor absorber and collector layers and a window layer, are disposed on the metal film, thereby completing the solar cell. The nanostructure underlying the metal film serves to reduce the work function of the metal and thereby assists in the absorption of holes created by solar photons. This leads to more efficient electricity generation in the solar cell. In a further embodiment of the present invention the cross sectional surface of the semiconductor absorber layer is also modified by nanoscale indentations or protrusions. These indentations or protrusions have the effect of altering the size of the semiconductor band gap, thereby optimizing the radiation absorption properties of the solar cell.

主权项

1. A thin film solar cell characterized by improved efficiency of electricity generation from solar photons comprising:
a. a carrier layer comprising a polymer, wherein a surface of said carrier layer comprises periodically repeating indents and protrusions, each said indent having a depth of 5 nm and a width of less than approximately 100 nm; b. a metal back contact layer deposited on the periodically repeating indents and protrusions on said carrier layer surface, wherein a surface of said metal contact back layer in contact with said carrier layer surface comprises periodically repeating indents and protrusions located and sized to correspond to said periodically repeating indents and protrusions on said carrier surface layer, said periodically repeating indents and protrusions being configured to reduce work function; c. a p-type semiconductor absorber layer comprising Copper Indium Gallium Diselenide disposed on a surface of said metal back contact layer opposite said metal back contact layer surface with indents, wherein said p-type semiconductor absorber layer includes a band gap; d. an n-type semiconductor collector layer disposed on a surface of said p-type semiconductor absorber layer not in contact with said metal back contact layer to form a p-n junction with a voltage differential; e. a window layer comprising zinc oxide (ZnO) disposed on a surface of said n-type semiconductor collector layer opposite said p-n junction; and f. an electrical contact comprising an aluminum grid positioned on a surface of aid window layer to receive electrons from said n-type semiconductor collector layer.