Binary Microcrystal Additives Enabled Antisolvent-Free Perovskite Solar Cells with High Efficiency and Stability

Developing a facile method to prepare high-quality perovskite films without using the antisolvent technique is critical for upscaling production of perovskite solar cells (PVSCs). However, the as-prepared formamidinium (FA)-based perovskite films often exhibit poor film quality with high density of defects if antisolvent is not used, limiting the photovoltaic performance and long-term stability of derived PVSCs. Herein, this work adopts pre-synthesized 3D methylammonium lead chloride (MAPbCl₃) and 1D 2-aminobenzothiazole lead iodide (ABTPbI₃) microcrystals into self-drying perovskite precursors, which serve as seed crystals to promote nucleation and growth of FAPbI₃-based perovskites without requiring antisolvent extraction. The combined binary microcrystals facilitate the formation of a dense and pinhole-free perovskite film with a stable perovskite lattice and defect-healed grain boundaries, enabling efficient charge carrier transfer and reduced non-radiative recombination loss. As a result, the best-performing inverted architecture device exhibits a champion power conversion efficiency of 23.27% for small-area devices (0.09 cm²) and 21.52% for large-area devices (1.0 cm²). These values are among the highest efficiencies reported for antisolvent-free PVSCs. Additionally, the unencapsulated device shows enhanced moisture, thermal, and operational stabilities, and maintains 92% of its initial efficiency after being held at the maximum power point for 1000 h.