Bromide Substituted 2D Additive for Stable and Efficient Perovskite Photovoltaics

In this article, a bromide substituted 2D layered perovskite having a repeated vertical orientation and coexisting with a bulk of 3D perovskite is reported for the first time. This novel structure is obtained through controlled compositional management of the perovskite precursor solution. The photovoltaic performance of this novel 2D/3D perovskite was higher than 3D MAPbI3 and a maximum photoconversion efficiency PCE of 17.4% was achieved. The devices fabricated using this perovskite heterostructure were stable and retained their initial PCE up to 20 days when kept open in a laboratory environment with 40% relative humidity.