Wide‐Bandgap Perovskite Solar Cells With Large Open‐Circuit Voltage of 1653 mV Through Interfacial Engineering

Low‐cost wide‐bandgap solar cells are attractive candidates for potential applications including tandem photovoltaics, solar‐driven electrochemical energetic devices, and photovoltaic solar panels for spacecraft due to their relatively high output voltage and sustainability in critical environment. Recently, solar cells based on the organic–inorganic lead halide perovskites have emerged as a promising avenue toward high power conversion efficiency (PCE). However, the investigations on achieving high operating voltage with sufficient output power remains a missing part for the halide perovskite solar cells. Here the effectiveness of employing both anode and cathode interfacial modification layers to reach high open‐circuit voltage ( V OC ) for the methylammonium lead tribromide (MAPbBr 3 ) perovskite solar cells is demonstrated. Specifically, high work function e‐beam processed MoO x layer with vacuum annealing treatment is used to reengineer the anode interface and an atomic layer deposited ZrO 2 layer is used to modify the cathode interface, respectively. The minimized energy barrier height by MoO x modification and hole‐blocking effect by ZrO 2 synergistically restrain the charge carrier recombination loss and render a consequent larger quasi‐Fermi level separation that endows a higher V OC . The MAPbBr 3 perovskite solar cell with a highest PCE of 10.08% and a new record V OC of 1653 mV under one sun‐illumination are demonstrated.