Material interface study of transition metal chalcogenides for charge transport in perovskite solar cells

Heterojunctions are expected to show an intrinsic electric field gen-eration at their material interface/s that influences the exciton separa-tion and transport in solar cell devices. Since Perovskite Solar cells (PSCs) having multi material junction interfaces in their configura-tions, their performance is inevitably influenced by this feature. The differences in the crystallization process at the confluences of the materials with respect to the process of manufacturing might lead to variations in the charge distribution between the materials and affect the electric field generation. In this work an Ab initio Density Func-tional Theory (DFT) study is used to investigate the electronic charge re-distribution between the MAPbX3 (X=Cl, Br, or I) and two-dimensional (2D) material interfaces. These 2D materials have been assessed for potential electron or hole transporting layers (ETL and HTL) application in PSCs. The results were compared between three possible MAPbX3 materials to figure out the perfor-mance variation among these PSCs. This study reveals the effect of this interface charge re-distribution on efficiency of PSCs. The materials considered are the layered crystal structures of inorganic, transition metal chalcogenides (TMCs i.e., TcS2, TcSe2). Quantita-tive inter layer charge redistribution and internal electric field analy-sis between perovskite and these TMCs is conducted and compared using Bader charge analysis. The strain induced due to lattice mis-match vary the band edges and thus the inferences made based on pure band edge positions would not be enough to prove the feasi-bility of charge transport