Numerical Simulation of CZTS Solar Cell with ZnSe Buffer Layer

CZTS (Copper Zinc Tin Sulfide) solar cell is a low cost, eco-friendly, highly efficient and most significantly, non-toxic solar cell. In addition, CZTS has a high absorption coefficient and an optimal direct band gap, making it ideal for photovoltaic applications. Therefore, CZTS solar cell has piqued the interest of many researchers. In this research paper, the evaluation on performance of CZTS based solar cell where CZTS performs the act as the active absorber and ZnSe acts as the dedicated buffer layer, is numerically researched through SCAPS-1D simulation software as tool. We varied the absorber layer thickness (500nm-3000nm) and doping concentration (1×10¹⁴cm^-3-1×10 ¹⁹cm^-3), as well as the buffer layer thickness (30nm-70nm), to achieve optimized cell performance. Furthermore, the impact of back contact and impact of various operating temperature on cell performance was thoroughly checked. It has been observed that, the researched CZTS based solar cell structure (Al:ZnO|i-ZnO|ZnSe|CZTS|Se) attained maximum photo conversion efficiency 25.30%, with an absorber layer thickness of 2000nm and buffer layer thickness of 50nm with Open Circuit voltage VOC=1.1066V, short-circuit current density, JSC =25.84mA/cm², Fill Factor=88.47%. Simulation showed promising results, indicating that a highly efficient CZTS solar cell is feasible.