High efficiency thin film cadmium telluride solar cells

Cadmium sulfide (CdS), grown from an aqueous solution, and zinc oxide (ZnO), cadmium zinc sulfide (Cd_1−xZn_xS), and zinc selenide (ZnSe), deposited by metalorganic chemical vapor deposition (MOCVD), have been used as the window for thin film cadmium telluride (CdTe) solar cells. Thin film solar cells were prepared by the successive deposition of the window and p‐CdTe (by MOCVD and close‐spaced sublimation, CSS) on SnO₂:F/glass substrates. CdS/CdTe(CSS) solar cells show considerably better characteristics than CdS/CdTe(MOCVD) solar cells because of the better microstructure of CSS CdTe films. Total area conversion efficiency of 14.6%, verified by the National Renewable Energy Laboratory, has been achieved for solar cells of about 1 cm² area. Solar cell prepared by using ZnO, ZnSe, or Cd_1−xZn_xS as window have significantly lower photovoltage than CdS/CdTe solar cells.