Effects of thickness of absorption layer and buffer layer on the performance of Cu₃BiS₃ solar cell

Ternary chalcogenide semiconductor Cu₃BiS₃ has been perceived as a potential candidate of solar absorber materials in recent years, due to the low-toxic and earth-abundant component elements, and excellent optoelectronic properties. Nonetheless, sporadic investigations on Cu₃BiS₃ solar cell devices have been reported. There are lots of key scientific problems in structure design and manufacture process of photovoltaic device urgently need to be solved. In this paper, we adjusted the thickness of absorption layer and buffer layer through the spin-coating cycle and deposition time of chemical bath, respectively. Then, the effects of thickness of absorption and buffer layer on the performance of Cu₃BiS₃ solar cell were systematically analyzed. The results show that, increasing the thickness of absorption layer will enhance the light absorption and short-circuit current density (J_SC), consequently improve the conversion efficiency. However, too thick film will cause the decline of device efficiency. Increasing the thickness of buffer layer is beneficial to the open-circuit voltage (V_OC). Similarly, too thick film will bring about the decrease of J_SC and device efficiency. The best device efficiency of 0.288% was obtained in our experiments. The corresponding V_OC, J_SC and fill factor (FF) values are 215 mV, 2.292 mA/cm² and 48.049%, respectively.