Sulfurization temperature dependences of photovoltaic properties in Cu₂SnS₃-based thin-film solar cells

Abstract

We report on the sulfurization of metal-alloyed precursors in Cu2SnS3 (CTS)-based thin-film solar cells. CTS thin films were prepared through the sulfurization of Cu–Sn alloy precursors at sulfurization temperatures of 500–580 °C for 2 h in a N2 atmosphere with sulfur vapor. The Cu/Sn composition ratios of the sulfurized films were determined by X-ray fluorescence analysis to be in the range of 1.77–1.89. The photovoltaic properties of CTS-based solar cells improved with increasing sulfurization temperature owing to the higher external quantum efficiency at long wavelengths. The solar cell comprising a CTS thin film with a sulfurization temperature of 580 °C exhibited the optimum performance among the cells examined: an open-circuit voltage of 244 mV, a short-circuit current density of 29 mA/cm2, a fill factor of 0.385, and a conversion efficiency of 2.7% were obtained.