Annealing temperature dependence of photovoltaic properties of solar cells containing Cu₂SnS₃ thin films produced by co‐evaporation

The ternary compound Cu 2 SnS 3 (CTS) is composed of elements that are low in cost, non‐toxic, and abundant in the Earth's crust. In addition, CTS is a p‐type semiconductor with a high reported absorption coefficient of more than 10 4 cm −1 and a band gap energy of 0.92–1.77 eV. It is, therefore, considered to be a suitable candidate for the absorber layer in thin film solar cells. In the present study, CTS thin films were produced by first depositing precursor films by co‐evaporation of Cu, Sn, and S, and then annealing them. Solar cells were then fabricated using the CTS films as absorber layers, and the dependence of their photovoltaic properties on the annealing temperature was investigated. The solar cell using the CTS thin film annealed at 570 °C exhibited an open‐circuit voltage of 248 mV, a short‐circuit current density of 33.5 mA/cm 2 , a fill factor of 0.439, and a conversion efficiency of 3.66%.