Surface Defect Passivation of Pb–Sn-Alloyed Perovskite Film by 1,3-Propanediammonium Iodide toward High-Performance Photovoltaic Devices

摘要

The power conversion efficiency (PCE) of narrow-bandgap Pb–Sn-alloyed perovskite solar cells (PVSCs) is seriously impeded by the large open-circuit voltage (V_(OC)) deficit. Finding an effective approach to passivate defects in the perovskite film is critical to reduce the V_(OC) deficit. Herein, a linear organic cation 1,3-propanediammonium iodide (PDAI_2) is used to passivate the surface defects of perovskite film, thus restraining the nonradiative recombination. After treating with PDAI_2, the defect density of perovskite film is decreased to half and the carrier lifetime is prolonged more than 1.5 times. As a result, the champion Pb–Sn-alloyed PVSC based on PDAI_2 treatment exhibits a small V_(OC) deficit of 0.39 V, and a high PCE of 20.2%.