Low-temperature processing of a solution-deposited CuInSSe thin-film solar cell

A low-temperature (~ 350 °C) solution-processed CuInSSe photovoltaic cell is reported. The CuInSSe film was solution-deposited via spin-coating from a precursor solution consisting of metal chalcogenides (Cu2S and In2Se3) dissolved in hydrazine (N2H4). X-ray diffraction data indicated a full conversion from the hydrazine precursor to CuInSxSe2−x structure at 350 °C with an average crystallite size of approximately 45 nm. Bandgap tuning of the CuInSxSe2−x was achieved by varying the excess amount of sulfur in the precursor solution. Based on the (220) reflection of the XRD pattern, the bandgap of CuInSxSe2−x ranged from 1.00 to 1.14 eV. Standard testing conditions at 1-sun intensity resulted in a power conversion efficiency of 7.43%.