Designing Organic Electron Transport Materials for Stable and Efficient Performance of Perovskite Solar Cells: A Theoretical Study.

In this article, electron transporting layer (ETL) materials are designed to enhance the performance and stability of methyl ammonium lead iodide (MAPbI) perovskite solar cells (PSCs). The optical and electronic properties of the designed ETLs are investigated using density functional theory. The designed ETLs show better charge mobility compared to nickel phthalocyanines (NiPcs). The NiPc, a hole transporting layer material, shows ETL-like behavior for PSCs with the substitution of different electron withdrawing groups (X = F, Cl, Br, and I). The stability and electron injection behavior of the designed ETLs are improved. The BrNiPc shows the highest charge mobility. Further, the stability of the designed ETLs is relatively better compared to NiPc. Due to the hydrophobic nature, the designed ETLs act as a passivation layer for perovskites and prevent the absorber materials from degradation in the presence of moisture and provide extra stability to the PSCs. The effect of designed ETLs on the performance of MAPbI solar cells is also investigated. The PSCs designed with BrNiPc as an ETL shows a relatively better (23.23%) power conversion efficiency (PCE) compared to a TiO-based device (21.55%).