Controlling Secondary Crystallization with 1‐Butanol for High‐Efficiency Perovskite Solar Cells

Regulating nucleation and crystallization is crucial for achieving high-quality, pinhole-free, and defect-minimized perovskite films for efficient solar devices. This study explores the impact of alcoholic antisolvents as ecofriendly alternatives to the commonly used chlorobenzene (CB) on the optoelectronic properties of perovskite films, including crystallization, film quality, and defect density in perovskite films. The findings show that 1-butanol (BuOH) is the most effective, promoting both primary and secondary crystallization with MACl, reducing defects, and enhancing film quality. Time-dependent studies indicate that shorter BuOH application times improve crystalline growth, albeit with some impact on surface morphology. A champion power conversion efficiency of 25.45% along with an open-circuit voltage (V_OC) of 1.223 V is achieved in perovskite solar cells with a bandgap of 1.59 eV, highlighting the potential of alcoholic antisolvents for enhancing performance and offering a sustainable, scalable solution for high-efficiency device fabrication.