Active Functional Groups and Adjacent Dual-Interaction Strategies Enable Perovskite Solar Cells to Prosper: Including Unique Morphology and Enhanced Optoelectronic Performance

Excellent photoelectric properties entail perovskite solar cells with established position prevailing in the new-generation photovoltaic landscape. However, the traditional solution preparation inevitably yields numerous defects, which eventually bloom ion migration and lead to the gradual collapse of perovskite. Here, phthalic acid (PHA) with adjacent carboxylic acid groups (-COOH) is used to passivate defects and regulate the morphology of perovskite films. Based on density functional theory (DFT) calculations, the two adjacent -COOH of PHA construct a dual interaction with the uncoordinated Pb2+ of perovskite, thus significantly enhancing the passivation effect. Furthermore, the double-bonding interaction brought by PHA induces a unique surface-protruding morphology on perovskite films, which may act as a green channel for charge delivery, ultimately increasing the photo-generated current of perovskite solar cells (PSCs) to some extent. Under full-air preparation conditions, the PHA-optimized champion PSCs showed an efficiency of 20.02% with a boosted short-circuit current of 22.80 mA cm-2, showing one of the best performances in all-air preparation until now. Meanwhile, PHA-PSCs exhibited brilliant stability. In short, this work provides some reliable and flexible guidance for the design of small-molecule additives.