Enhancement of Open‐Circuit Voltage of Perovskite Solar Cells by Interfacial Modification with p‐Aminobenzoic Acid

Abstract Various approaches of interface engineering are shown to be effective in improving the device performance of organic–inorganic hybrid perovskite solar cells (PSCs). The modification of the photoactive layer of PSC, CH 3 NH 3 PbI 3 (MAPbI 3 ), by spin‐coating a layer of p ‐aminobenzoic acid (PABA), which can significantly enhance the open‐circuit voltage ( V OC ), the fill factor (FF), and the power conversion efficiency (PCE) of PSCs, is herein reported. The champion device shows a short‐circuit current ( J SC ) of 22.83 mA cm −2 , V OC of 1.167 V, FF of 0.768, and PCE of 20.47%. The improvement in photovoltaic performance is attributed to the suppression of carrier trap states and the improvement in the morphologies of perovskite films. This work demonstrates a simple and effective protocol to enhance the device performance, and provides an insight into the influence of PABA post‐treatment on the charge carrier dynamics.