Numerical Study of 25.459% Alloyed Inorganic Lead-Free Perovskite CsSnGeI3-Based Solar Cell by Device Simulation

The toxic lead component as well as the expensive and less stable spiro-OMeTAD in perovskite solar cells (PSCs) pose a great deal of hindrance to their commercial viability. Herein, a computational approach towards modeling and simulation of all inorganic cesium tin-germanium triiodide (CsSnGeI3) based perovskite solar cell was proposed and implemented using solar cell capacitance simulator (SCAPS–1D) tool. Aluminium doped zinc oxide (ZnO:Al) and Copper Iodide (CuI) were used as electron and hole transport layers (ETL and HTL) respectively. The initial device without any optimization gave a power conversion efficiency (PCE) of 24.826%, fill factor (FF) of 86.336%, short circuit current density (Jsc) of 26.174 mA/cm2 and open circuit voltage (Voc) of 1.099 V. On varying the aforementioned parameters individually while keeping others constant, the optimal values are 1000 nm for absorber thickness, 1014 cm-3 for absorber layer defect density, 50 nm for ETL thickness, 1017 cm-3 for ETL doping concentration and 260 K for temperature. Simulating with these optimized values results to PCE of 25.459%, Voc of 1.145 V, Jsc of 25.241 mA/cm2, and a FF of 88.060%. These results indicate that the CsSnGeI3 is a viable alternative absorbing layer for usage in the design of a high PCE perovskite solar cell device.