Superhalogen modulation: an effective approach for minimizing light-induced halide segregation in MAPb(I0.7Br0.3)3

We identify an efficient method to suppress halide segregation by adding BF 4 − as a modulator into MAPbI 2.1 Br 0.9 . Improved device performance indicate BF 4 − -incorporation is beneficial for the mitigation of defect trapping and halide ion hopping.