Interface engineering with halide anion ionic liquids: A strategy to enhance the efficiency and stability of carbon-based all-inorganic CsPbBr3 perovskite solar cells

Abstract

Carbon-based all-inorganic CsPbBr₃ perovskite solar cells (PSCs) have garnered significant interest owing to their cost-effective production processes and exceptional thermal stability. Nonetheless, defects within CsPbBr₃ films and inefficient charge extraction in PSCs result in pronounced charge recombination, thereby reducing the overall device efficiency. Herein, the Pb²⁺ and Cs⁺ defects are simultaneously passivated by introducing halide anion ionic liquids at the interface between CsPbBr₃ and carbon, significantly improving film quality and crystallinity and prolong the average carrier lifetime. Moreover, the non-radiative recombination is efficiently inhibited in the film with reduced defects and enhanced light absorption capability, resulting in an enhancement of both open-circuit voltage (V_OC) and fill factor (FF). Finally, all-inorganic CsPbBr₃ PSCs passivated by BMIZ-Br ionic liquid achieved a superior efficiency of 9.34 % with a high V_OC of 1.587 V. This work provides scientific insights into interface engineering to enhance the efficiency and long-term stability of CsPbBr₃-based PSCs, thereby promoting the advancement of perovskite-based optoelectronic technologies.