A Density Functional Theory Study of two-dimensional post-transition metal chalcogenides and halides for interfacial charge transport in Perovskite Solar Cells

This computational study focuses on charge transport using two-dimensional materials as the interfacial materials in Perovskite Solar Cells (PSCs). Layered structures of post-transition metal chalcogenides (InS, InSe, PbI2) and tin and lead monoxides (SnO and PbO) are studied using Density Functional Theory (DFT). A hybrid exchange-correlation functional based assessment was conducted for variation in the electronic properties with an increase of numbers of 2D layers of these materials. Their band edge positions are then compared with that of MAPbI3 perovskite (as an archetypal PSC material) and assessed for their use as either for electron or hole transport materials (ETM or HTM). Further analysis of charge density distribution, planar potential variation, and Bader charge analysis was conducted for PbO (as an HTM) and InSe (as an ETM) monolayers and compared with MAPbI3. Mono-layered lead monoxide (PbO) and double-layered tin monoxide (SnO) were useful for transporting holes, while hexagonal phases of InS and InSe are suitable for electron transport in PSCs.