Surface Passivation of Sn-Based Wide Band Gap Perovskite Solar Cells Using Functional Molecules

Surface passivation with multifunctional molecules is a powerful approach to enhancing the performance and stability of perovskite solar cells (PSCs). This study reports the fabrication of wide-bandgap tin-based perovskite solar cells (WB-Sn-PSCs) with a bandgap of 1.68 eV, achieving a power conversion efficiency of 11.14%. Molecular surface passivation using 4-Fluorobenzohydrazide (F-BHZ) significantly improves device performance and stability by engineering both the surface and bulk properties of the WB-Sn-HP film. F-BHZ treatment strengthens electrostatic potential and molecular interactions with functional groups, mitigating surface defects and suppressing Sn<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>⁺ oxidation, as confirmed by theoretical calculations. This work highlights the potential of advanced chemical engineering strategies to optimize non-toxic, lead-free perovskite solar cells, advancing their competitiveness as environmentally friendly photovoltaic solutions.