Surface modification in FAPbI₃ perovskites using methyl-substituted benzene derivatives: impact of functional groups and methyl position

Abstract Perovskite materials are promising candidates for solar cells and other electronic devices due to their exceptional optoelectronic properties. However, the stability and performance of these materials can be significantly influenced by surface modifications. In this study, we investigate the surface modification of FAPbI 3 Perovskites using methyl-substituted benzene derivatives. Specifically, we examine the impact of the functional groups and methyl position in these derivatives on the structure, electronic and optical properties of the FAPbI 3 Perovskite. The study shows that 3,4,5-trimethylbenzene (TMB) derivatives with Pyridine-N, −NH 2 , −COOH and −OCH groups increase FAPbI 3 Perovskite stability due to low adsorption energy. However, the doping with these molecules change the electronic properties of FAPbI 3 Perovskite solar cell. There are remarkable change in work function shift (WFS) of Perovskite surface have been happened, initially ascribable to the effect of interfacial charge transfer and inherent dipole moment of molecules. Moreover, Pyridine-N, −NH 2 , −COOH and −OCH functionalities directly contribute to the band-edge alignment of the FAPbI 3 Perovskite. Optical properties show that these exhibit significant absorption properties, with an absorption strength of up to 23.79%, surpassing that of the pristine FAPbI 3 Perovskite. Furthermore, the strategic placement of methyl groups at the 1, 3, and 5 positions on the benzene ring was analyzed for its impact on the properties of FAPbI 3 . While a significant variation in structural and electronic characteristics was observed, the optical properties, in contrast, showed minimal variation.