Surface Reaction‐Driven Sulfur Vacancy Engineering via Formation Energy Reduction: Revolutionizing Sensing Mechanism of Sulfide‐Based Semiconductors and Unlocking Human Alkyladenine DNA Glycosylase Photoelectrochemical Detection

ABSTRACT The exploration of new photoelectrochemical (PEC) sensing mechanisms based on metal sulfides offers a promising approach to mitigate their inherent drawbacks caused by monotonous PEC sensing mechanisms and their inherent photocorrosion effects, thus advancing the establishment of robust and high‐performance PEC platforms. This study proposes a surface reaction mediated reduction in formation vacancy energy to introduce sulfur vacancies (Sv), establishing an innovative sensing paradigm for sulfide‐based semiconductors. Specifically, dopamine (DA) anchored on CdZnS surfaces effectively reduces the energy barrier for Sv formation, enabling rapid and facile in situ generation of Sv. These Sv introduce new defect energy levels that suppress charge carrier recombination, while simultaneously inducing localized surface polarization electric fields that enhance charge separation efficiency and significantly amplify the photocurrent response. A highly sensitive PEC biosensor for human alkyladenine DNA glycosylase (hAAG) was constructed, exhibiting a dynamic range of 5 × 10 − 4 –1.0 U/mL and a detection limit of 1.7 × 10 − 4 U/mL (S/N = 3). This surface reaction strategy, by lowering Sv formation energy, revolutionizes sulfide‐based PEC sensing mechanism and unlock a breakthrough approach for hAAG detection. Beyond PEC sensing, the Sv engineering strategy holds prospects for enhancing the performance of different devices across verstatile fields such as photocatalysis, PEC catalysis, and solar energy conversion.