Interfacial engineering of quasi-2-D formamidinium lead iodide nanosheets for perovskite solar cell by mechanochemical approach

Solvent-free synthetic protocols for the formation of nanoarchitectures continues to attract a great attention amoung the wide class of synthetic chemists in order to overcome the harsh reaction conditions. In the current work we demonstrate, for the first time, solvent-free synthesis of dodecylammonium formamidinium lead iodide (DDA)₂ [FAPbI₃]_n−1PbI₄, a quasi-two-dimensional (2D) red-light-emitting perovskite nanosheet, where DDA is dodecylammonium, a long chain ammonium cation, and FA is a formamidinium cation. By varying the amount of DDA, we controlled the dual emission of quasi-2D perovskite comprising of both 2D and three-dimensional perovskite layers. The optical properties have manifested the effect of DDA on the structure of perovskite nanosheets. As a proof-of-concept demonstration the material has been explored in perovskite solar cell. The compound containing least amount of DDA exhibited open-circuit voltage (V_OC) of 0.961 V, short-circuit current density (J_SC) of 23.41 mA cm⁻², and PCE of 15.23% under one-sun illumination conditions.