A photovoltaic cell exhibiting an overall conversion efficiency of at
least 9.0% is prepared from a copper-indium-gallium-diselenide thin film.
The thin film is prepared by simultaneously electroplating copper,
indium, gallium, and selenium onto a substrate using a buffered
electro-deposition bath. The electrodeposition is followed by adding
indium to adjust the final stoichiometry of the thin film.