Mechanochemical synthesis of pure phase mixed-cation/anion (FAPbI(3))(x)(MAPbBr(3))(1−x) hybrid perovskite materials: compositional engineering and photovoltaic performance

Organic–inorganic hybrid perovskites have emerged as promising light harvesting materials for many optoelectronic devices. Here, we present a facile mechanochemical synthesis (MCS) route for the preparation of a series of pure phase mixed-cation/anion (FAPbI(3))(x)(MAPbBr(3))(1−x) (0 ≤ x ≤ 1) hybrid perovskite materials for high-efficiency thin-film perovskite solar cells (PSCs). The use of (α-FAPbI(3))(0.95)(MAPbBr(3))(0.05) perovskite prepared by MCS for the thin-film PSCs achieves a maximum PCE of 15.9% from a current–voltage (J–V) scan, which stabilises at 15.4% after 120 s of the maximum power point output. Furthermore, PSCs based on (KPbI(3))(0.05)(FAPbI(3))(0.9)(MAPbBr(3))(0.05) perovskite prepared by MCS exhibit higher photovoltaic performance and lower hysteresis compared with (α-FAPbI(3))(0.95)(MAPbBr(3))(0.05), with a maximum PCE of 16.7%. These results indicate that the use of mechanochemically synthesised perovskites provides a promising strategy for high performance PSCs and superior control in optoelectronic properties, leading to improved control in fabrication approaches and facilitating the development of efficient and stable PSCs in the future.