Efficient wide band gap double cation – double halide perovskite solar cells

Abstract

We study the properties of the series of compounds Cs_0.15FA_0.85Pb(Br_xI_1−x)3, aiming to develop an efficient complementary absorber for MAPbI₃ in all-perovskite tandems. A bromide content of 0.7 leads to a band gap of 2 eV and a maximum PCE of 11.5% in solar cells, among the highest reported for band gaps wider than 1.8 eV.