New materials used as optical window in thin film solar cells

The purpose of this work is to investigate new materials which present good properties to be used as optical window and buffer layer in thin film solar cells based on CdTe and CuInSe2. As potential candidates for optical windows, two different bilayer systems were studied: ZnO/InxSey and ZnO/ZnSe. They are planned to be used later in the fabrication of solar cells with structures CuInSe2/InxSey/ZnO and ZnO/ZnSe/CdTe. The methods used to prepare the different window materials, as well as the technological stages of the solar cell fabrication, will be described. Additionally, the optical and morphological properties of the window systems will be studied through transmittance and atomic force microscopy (AFM) measurements. Preliminary results obtained with Cu(In,Ga)Se-2 solar cells, fabricated using ZnO/InxSey as optical window, will be reported. They will be compared with those obtained using ZnO/CdS as optical window, which is regularly used in this type of cells.