Targeted synergistic chemical bonding strategy for Efficient and stable CsPbI3-based perovskite solar cells

Regulating the crystallization process of perovskite film and suppressing iodine-related defects hold significant importance in improving the efficiency and stability of CsPbI3-based perovskite solar cells (PSCs), thereby endowing their more potential for commercial applications. Herein, we introduced 2-Aminoethyl methylsulfone hydrochloride (AMS) into the perovskite precursor solution to establish targeted synergistic chemical bonding involving Lewis acid-base interactions and hydrogen bonds with CsPbI3 perovskite. We emphasize the importance of the DMAPbI3 intermediate phase for the crystal quality of CsPbI3 perovskite, and reveal that diminishing the size of Pb-I framework colloids in precursor solution can facilitate the formation of DMAPbI3 and optimize the crystallization process of CsPbI3 perovskite. Simultaneously, we demonstrate the generation of high valence iodine defects due to the photoinduction, and prove that constructing N-H center dot center dot center dot I hydrogen bond can effectively passivate the iodine-related defects. Consequently, the CsPbI3-based PSCs display an impressive power conversion efficiency of 19.59% along with markedly improved stability. Our finding presents a feasible strategy for managing perovskite crystallization and mitigating the defects-induced perovskite degradation, thus promoting the commercialization of CsPbI3-based PSCs.