Highly Efficient and Stable Perovskite Solar Cell with 1D-3D Mixed Dimensional Perovskite

Abstract

Perovskite solar cells (PSCs) have shown a steep increment in power conversion efficiencies (PCEs) and it is about to be commercialized. However, stability is one of the critical issues that hinders commercialization. Low-dimensional perovskite (0D, 1D, 2D) have been studied widely due to its hydrophobicity compared to 3D perovskite. Not only the enhancement it water stability due to its large organic cation, but the wide bandgap of the low dimensional perovskite can increase open circuit voltage (VOC) by approaching the quasi -fermi level splitting (QFLS) of the perovskite. Although low dimensional perovskite induces higher stability, it has a weakness in the aspect of charge extraction due to its in-plane crystal growth, especially in 2D perovskite. 1D perovskite, on the other hand, grows in out-of-plane direction which rarely hinders charge extraction. In this study, ionic liquid is selected since it can have dual role. Here in, an ionic liquid 1-Ethyl-3-methylimidazolium methane sulfonate (EMIM-MeSO3) is introduced to form 1D-3D mixed dimensional perovskite. 1-Ethyl-3- methylimidazolium cation (EMIM+) forms stable 1D perovskite interacting with PbI2. In addition, methane sulfonate anion (MeSO3-) effectively passivate the defect sites on the perovskite surface, owing to the Lewis base characteristic of oxygen. With both benefits from low dimensional perovskite formed by cation, and passivation ability of anion, EMIMMeSO3 treated PSCs has reached a champion efficiency up to 22.54% and enhance long term stability.