Enhanced Planar Perovskite Solar Cell Performance via Contact Passivation of TiO₂/Perovskite Interface with NaCl Doping Approach

Perovskite solar cells (PSCs) have been developed rapidly in recent years due to the excellent photoelectric properties and development potential. In this study, high performance and hysteresis-less planar structured perovskite (MA_1–<i>y</i>FA_<i>y</i>PbI_3–<i>x</i>Cl_<i>x</i>) solar cell was successfully achieved via contact passivation of the compact titanium dioxide (TiO₂)/perovskite interface with NaCl doping method. It was found that the sodium chloride (NaCl) doping treatment on TiO₂ could significantly improve the electrical property of TiO₂ electron transport layer (ETL), and passivate the trap states at TiO₂/perovskite interface. Moreover, the improved interface contact between TiO₂ ETL and perovskite could efficiently enhance the charge transfer and suppress the charge recombination in the device. Hence, the power conversion efficiency (PCE) of PSC device based on NaCl-doped TiO₂ was enhanced to 18.3% compared with the pristine compact TiO₂-based PSCs (15.1%)