Fundamental analysis of lead-free CsGeI3 perovskite solar cell

The perovskite solar cells have shown notable improvement in efficiency and stability among all solar cells. Research on perovskite solar cells began in 2009 and has focused on understanding and improving their conversion efficiency made over the past 6 years. In 2014, they showed efficiencies of around 15.9%. Most recently, they showed an efficiency of 25%. However, there are lot of problems with lead-based perovskite solar cells. Being toxic to the environment, there should be an alternative like germanium, which has excellent optical properties but practically it has low efficiency as well as poor stability compared to lead-based perovskite solar cells. Therefore, it becomes essential to invent alternatives that offer comparable efficiency and stability like Pb-based solar cells. The completely Pb-free cesium germanium triiodide (CsGeI3) heterostructure perovskite solar cell was simulated and conversion efficiency of 12.2% was achieved with significantly improved device parameters. To optimize lead-free components, the influence of the defect density and doping concentration of absorber layer are investigated. The solar cell capacitance simulator (SCAPS) simulation results succeed in achieving the highest power conversion efficiency in an all-inorganic non-toxic CsGeI3 based solar cell. The obtained performance metric values are PCE = 12.2%, FF = 70.6%, Jsc = 20.6 mA / cm2 and Voc = 0.84 V.