γ-Fe2O3 as a novel Electron Transporting Material for Planar Heterojunction Perovskite Solar Cells by simple Room-Temperature Solution method

Abstract

α-Fe2O3 has been demonstrated to be a promising electron transporting material (ETL) for fabricating efficient perovskite solar cells (PSCs) with good stability under ultraviolet light compared to the commonly used TiO2. However, α-Fe2O3 films need to be processed over 500 °C, which is a serious impediment to fabricate devices on the flexible substrates. Herein, γ-Fe2O3, which could be deposited onto the substrates under room temperature, would be an alternative magnetic ETL with a reasonable performance. We report that pure and fine nano-sized γ-Fe2O3 particles can be synthesized below 200 °C and the corresponding compact layers have been fabricated by a simple room-temperature solution process. The methylammonium lead iodide (MAPbI3) PSCs based on γ-Fe2O3 show a power conversion efficiency of 12.86% with a short circuit current (Jsc) of 21.79 mA/cm2, an open circuit photovoltage (Voc) of 0.93 V and a fill factor (FF) of 63.3%. These results indicate a possible direction for preparing flexible perovskite solar cells.