Cadmium free high efficiency Cu2ZnSn(S,Se)4 solar cell with Zn1−xSnxOy buffer layer

Abstract

We have investigated the simulation approach of a one-dimensional online simulator named A Device Emulation Program and Tool (ADEPT2.1) and the device performances of a thin film solar cell based on Cu2ZnSn(S,Se)4 (CZTSSe) absorber have been measured. Initiating with a thin film photovoltaic device structure consisting of n-ZnO:Al/i-ZnO/Zn1-xSnxOy (ZTO)/CZTSSe/Mo/SLG stack, a graded space charge region (SCR) and an inverted surface layer (ISL) were inserted between the buffer and the absorber. The cadmium (Cd) free ZTO buffer, a competitive substitute to the CdS buffer, significantly contributes to improve the open-circuit voltage, Voc without deteriorating the short-circuit current density, Jsc. The optimized solar cell performance parameters including Voc, Jsc, fill factor (FF), and efficiency (η) were calculated from the current density-voltage curve, also known as J–V characteristic curve. The FF was determined as 73.17%, which in turns, yields a higher energy conversion efficiency of 14.09%.

Keywords

• CZTSSe solar cell
• Cd free
• ZTO buffer
• Efficiency
• Conduction band offset