Polypropylene Glycol‐Modified Anode Interface for High‐Performance Perovskite Solar Cells^†

Comprehensive SummaryThe surface properties and chemical interactions are critical for perovskite solar cells (PVSCs). In this work, we show that the polypropylene glycol (PPG) can simultaneously passivate the NiOx surface and grain boundaries of perovskite films, allowing more efficient charge transfer at the anode interface and reducing the recombination of PVSCs. As a result, the open‐circuit voltage (Voc) of MAPbI3 based inverted PVSCs increases from 1.087 V to 1.127 V, and the short‐circuit current density (Jsc) is increased from 20.87 mA·cm–2 to 22.32 mA·cm–2, thereby realizing the improvement of the device power conversion efficiency (PCE) from 18.34% to 20.12%. Moreover, the steady‐state output of the PVSCs is remarkably improved by incorporating PPG. Further analysis of surface properties suggests that part of the PPG at the interface can permeate into the precursor solution with the help of DMF solvent and remain in the perovskite layer to form a concentration gradient. The ether bond of PPG and the uncoordinated Pb2+ in the perovskite are coordinated to achieve passivation effects and improve device performance. Our work provides a rational strategy for the preparation of high‐performance PVSCs.