Edge-modified phosphorene nanoribbons enhance interfacial carrier extraction in perovskite solar cells

The search for cheap, stable and efficient electron and hole transport layers (ETL and HTL) of perovskite solar cells (PVSCs) remains a significant challenge. In this study, we construct a series of edge-modified phosphorene nanoribbons (PNRs) and explore their potentials as either ETL or HTL in PVSCs using PNRs/MAPbI3 heterojunction. The results reveal that the different functional groups have distinct effects on the electronic structures of individual PNRs. When combined with MAPbI3, the electronic structures of PNRs are further regulated due to the strong interaction. Considering the combined influence of both modifying groups and MAPbI3, several PNRs/ MAPbI3 including COH-PNR/MAPbI3, OCN-PNR/MAPbI3 and CN-PNR/MAPbI3 show the tendency for electron transfer from MAPbI3 to PNRs. Conversely, NH2-PNR/MAPbI3 has a possibility for hole transfer. The timedomain noncollinear DFT-based nonadiabatic carrier dynamics simulations for H-PNR/MAPbI3, CN-PNR/ MAPbI3 and NH2-PNR/MAPbI3 validate that the -CN group facilitates interfacial electron transfer, while the -NH2 group promotes hole transfer compared to H-PNR/MAPbI3. The addition of modifying groups increases the number of states of the PNRs in PNRs/MAPbI3 that are capable of accepting electron or hole from MAPbI3, thereby enhancing the carrier extraction capacity. This computational work proposes a design strategy to enhance the efficiency of ETL and HTL in PVSCs.