Robust Dipicolinic Acid‐Anchored Self‐Assembled Monolayers for High‐Performance Wide‐Bandgap and Tandem Perovskite Photovoltaics

The anchoring group of self‐assembled monolayer (SAM) hole‐transporting materials dictates both substrate binding and interfacial passivation, serving as a key lever for high‐performance perovskite photovoltaics. Herein, we report a novel SAM molecular material, denoted by XS21 , engineered with a multidentate dipicolinic acid (DPA) anchoring core to address conventional adhesion and degradation limitations. From an experimental perspective, the DPA anchor is found to promote molecular chemisorption onto the substrate, potentially originating from the dual‐action mechanism of pyridine–Ni coordination coupled with dicarboxylate‐metal interaction. Furthermore, XS21 imparts both low acid‐dissociation constants ( K a ) and superior ultraviolet (UV) photostability. Consequently, wide‐bandgap (1.79 eV) perovskite solar cells containing XS21 deliver a champion power conversion efficiency (PCE) of 21.54% with an exceptional open‐circuit voltage of 1.372 V. Crucially, integrating XS21 into monolithic all‐perovskite tandem solar cells yields a remarkable PCE of 29.62%, alongside an outstanding operational stability (retaining >90% of initial efficiency after 900 h of continuous operation). This work establishes multi‐dentate pyridine‐carboxylate anchoring as a vital paradigm for next‐generation efficient and stable perovskite photovoltaics.