Dual-Site Regulation Approach for Improving Photoelectric Performance of Perovskite Solar Cells

Abstract

High power conversion efficiency (PCE) and long-term stability are the keys to the commercialization of perovskite solar cells (PSCs). However, the defects of formamidinium lead tri-halide (FAPbI3) perovskite films limit the PCE of the device to the Shockley Queisser limit. The conventional strategies for enhancing the properties of perovskite films often pivot on the selective interaction between a passivating agent and a solitary constituent within the perovskite matrix. Herein, we present an alternative dual-site regulation approach using 6-fluorobenzamide (6-FB) to modulate the reaction kinetics of Pb and I, resulting in FAPbI3 films with fewer defects and significantly enhanced carrier lifetimes. 6-FB can not only passivate the uncoordinated Pb2+ defects and iodine vacancies. The optimized PSCs achieved a PCE of 25.03% (certified at 24.25%) with an area of 0.0625 cm², and retained 94.1% of their initial PCE after storage in ambient air (~10 relative humidity, RH) for over 800 h. This method expands the scope of chemical interactions possible by leveraging the interaction between 6-FB and the perovskite.

Keywords: perovskite solar cell, 6-fluorobenzamide, Dual-site regulation, Defects.