A study on defect, doping, and performance of ETLs (ZnO, TiO2, and IGZO) for the lead-free CsSnCl3 perovskite solar cell by SCAPS-1D framework

The potential of lead-free perovskite materials using cesium as an organic cation has been explored as a replacement for lead-based perovskite absorbers to minimize toxicity. These materials exhibit high stability, a tunable bandgap, and superior optoelectronic properties compared to lead-based materials. Extensive studies have investigated Sn-based cesium tin chloride (CsSnCl3) in the literature, focusing on multiple hole transporting layers (HTLs) and electron transporting layers (ETLs). A numerical study has been conducted to study the effects of thickness, series, and shunt resistance, as well as favorable band alignment with the absorber, HTL, and ETL layers. According to the literature, ETLs such as TiO2, ZnO, and IGZO, in combination with CBTS as the HTL, have emerged as the most promising candidates for achieving optimal fabrication of CsSbCl3 devices. However, several investigations have yet to be covered in the reports. These include analyzing the effects of absorber and interface defects on the ETLs/HTLs layers, determining the optimal metal back contact electrode, and optimizing the doping concentration of the absorber or ETLs/HTLs to achieve device optimization and the desired operating temperature. Through the optimization process, the study identified the optimum numerical values necessary to achieve higher device performance. It specifically found that ZnO performs the best as an ETL candidate, and the configuration combination of ITO/ZnO/(CsSnCI3)/CBTS/Se emerged as the most favorable compared to the values reported in the literature.