Theoretical Selection of 2D Perovskite for Constructing Efficient Heterojunction Solar Cells

Two-dimensional (2D) metal halide perovskites can co-construct with the state-of-the-art three-dimensional (3D) perovskite analogs to form 2D/3D perovskite hetero-junction architectures, which enables the photovoltaic devices to deliver higher energy conversion efficiency and near-commercial stability. However, the question remains as to whether any type of 2D perovskite, i.e., RP, DJ, or ACI perovskites, is workable with a 3D analog to outperform the pristine 3D perovskites. Here, we investigate the structural and electronic properties of distinct types of 2D/3D perovskite heterojunctions based on first-principles calculations. We selected a 3D FAPbI3 perovskite combined with representative 2D RP, DJ, and ACI perovskites to construct a series of 2D/3D perovskite heterojunctions and analyzed the carrier transport kinetics and charge recombination of each heterojunction. The results indicate that RP-PbI, DJ-FAI, and ACI-FAI heterojunctions exhibited favorable transport and separation of photogenerated carriers, but the RP-PbI and ACI-FAI heterojunctions appear to possess greater potential for photovoltaic applications than the DJ-FAI heterojunction due to relatively fewer recombination losses. Moreover, based on the direction of photogenerated carrier transport at the heterojunction, we predict that RP-PbI would be superior to DJ-FAI for conventional 2D/3D devices and that the ACI-FAI heterojunction is expected to well function in the inverted 2D/3D devices.

Automated summary

In this study, we investigated the structural and electronic properties of different types of 2D/3D perovskite heterojunctions using first-principles calculations. The RP-PbI and ACI-FAI heterojunctions showed favorable carrier transport and separation, with relatively fewer recombination losses, indicating greater potential for photovoltaic applications. Based on the direction of carrier transport at the heterojunction, we predict that RP-PbI would outperform DJ-FAI in conventional 2D/3D devices, while the ACI-FAI heterojunction is expected to function well in inverted 2D/3D devices.