Growth of Amorphous Passivation Layer Using Phenethylammonium Iodide for High‐Performance Inverted Perovskite Solar Cells

Organic–inorganic lead halide perovskite solar cells have realized a rapid increase of power conversion efficiency (PCE) in the past few years. However, their performance still suffers trap‐assisted decline due to defects at the surface and grain boundaries of the perovskite film. Herein, a phenethylammonium iodide‐lead iodide (PEAI‐PbI 2 ) passivation layer is formed on the CH 3 NH 3 PbI 3 perovskite film. The characterization results indicate that the PEAI covering layer leads to the reduction of surface defects and suppression of nonradiative recombination. By manipulating this surface passivation method, a remarkably improved V OC of 1.16 V and an enhanced PCE of 20.8% are achieved.