Enhancing Photovoltaic Performance through Optimized Antisolvent Strategy for Low-Bandgap Pb–Sn Perovskites

Low-bandgap Pb–Sn mixed perovskite solar cells (PSCs) are emerging as promising contenders for next-generation solar technology due to their broad spectral response and high photocurrent output. To achieve high-quality perovskite films, we propose a mixed antisolvent engineering approach for Pb–Sn mixed perovskites. This technique balances the saturation rate between the precursor and the mixed antisolvent, modulating perovskite nucleation and crystal growth. We discovered that an optimal mixture of chlorobenzene (CB) and ethyl acetate (EA) decelerated the extraction of perovskite precursors, leading to the formation of smoother perovskite films with improved crystallinity and larger grain sizes. Consequently, we observed enhanced charge transport, reduced trap state densities, and an extended near-infrared (NIR) response. These enhancements collectively contributed to the improved performance of low-bandgap Pb–Sn mixed PSCs. Furthermore, the use of EA, an eco-friendly antisolvent, aligns our approach with sustainable manufacturing practices by reducing toxicity during fabrication.