Numerical investigation of the Pb-free titanium-based double-perovskite solar cell.

Lead-free potassium titanium halide (K2TiI6) perovskite is considered a substantial alternative for highly efficient perovskite solar cells. This research consists of a computational study of Pb-free K2TiI6-based perovskite solar cell using SCAPS 1D. Primarily, the TiO2 and PEDOT:PSS are considered as ETL and HTL exhibit a device efficiency of 5.70%. Further, the impact of various ETL and HTL is explored. The optimization is mainly focused on considering its built-in potential relation with the open circuit voltage and its device efficiency. It is obtained from the numerical simulation, that to circumvent the VOC loss, the CB minimum of the PVSK(CBmin_PVSK) layer should be higher than the CB minimum of the ETL (CBmin_ETL), and the CB minimum of the ETL (CBmin_ETL) should either align or lie above than the FTO contact. In order to have proper hole transport from the perovskite, the VB maximum of the perovskite (PVSK) layer should be lower than the VB maximum of HTL and should either align or lie below the back contact. It is obtained from the simulation that the optimized ETL and HTLs are found as PCBM and Sr2Cu2O2 improve the device efficiency. Further, the impact of perovskite thickness is also investigated, which enhances the device efficiency up to 23.75%. The proposed structure shows remarkable PV parameters VOC = 1.32 V, JSC = 22.30 mA/cm2, FF = 81.07%, and ƞ = 24.01% which indicates that the K2TiI6-based perovskite solar cell is considered a remarkable candidate for Pb-free perovskite solar cell development. [ABSTRACT FROM AUTHOR]