Enhancing performance of organic-inorganic perovskite solar cells using super halogen additive

Abstract

Compositional engineering in perovskite solar cells usually uses mixed cations and halide anions to optimize the growth of perovskite films, reduce film defects and inhibit carrier recombination to achieve high-performance devices. The most commonly used anion component of perovskite is the iodine ion. However, the ionic behavior of iodine greatly affects the stability of perovskite solar cell devices. Here, NaBF 4 was first used to partially replace iodine in perovskite CS 0.05 (FA 0.92 MA 0.08 ) 0.95 Pb(I 0.92 Br 0.08 ) 3 . After doping NaBF 4 , perovskite films show a longer PL lifetime and greater recombination resistance. It is found that the Stokes shift of the PL peak of the target film is reduced, indicating that doping NaBF 4 significantly inhibits the non-radiative recombination in the perovskite film. Doping NaBF 4 in perovskite passivates its defects, significantly improves the open-circuit voltage, filling factor and the power conversion efficiency of the device from 18.31% of the original device to 20.63%. After being stored in a nitrogen environment for 2400 hours, the device efficiency remains unchanged. • A super halogen BF 4 − anion is used to partially replace iodine ion to fine tune the perovskite components. • The efficiency of perovskite solar cell is increased from 18.31% to 20.63%. • After being stored in a nitrogen environment for 2400 hours, the device efficiency remains unchanged.