Comparative study on Cu2ZnSn(S,Se)4 based thin film solar cell performances by adding various back surface field (BSF) layers

In this research work, SCAPS-1D (Solar Cell Capacitance Simulator in one Dimension) is used to simulate the CZTSSe (Cu2ZnSn(S,Se)4) solar cell with Al/ZnO:Al/ZnO(i)/CdS/CZTSSe/Mo structure. The simulation results have been compared and validated with real experimental results. After that, an effective receipt is proposed with the aim of improving the efficiency of the CZTSSe solar cell, in which a BSF layer is inserted using various materials (SnS, CZTSSe and CZTSe). The obtained results show that the efficiencies of CZTSSe solar cells are increased from 12.3% to 15.7%, 15.3% and 15% by the insertion of SnS, CZTSSe and CZTSe materials as BSF layers, respectively. This enhancement corresponds with a BSF layer thickness of 30 nm and doping concentration of 1E18 cm(-3). Next, an optimization of BSF layers thickness has been conducted. The optimum value of thickness is considered at 40 nm with an enhancement ratio in efficiency of 36.70%, 26.21% and 21.53% for SnS, CZTSSe and CZTSe, respectively. Better performances have been noted for SnS material. The optimized CZTSSe solar cell with SnS as a BSF layer achieves an efficiency of 16.95% with J(SC) = 36.34 mA/cm(2), V-OC = 0.69 V, and FF = 67% under Standard Test Conditions (AM1.5 G and cell temperature of 25 degrees C).