Feng‐Zao Chen, Lin Zhang, Yuan Gao, Lu Hou, Shu Xu, Bing Sun, Deman Han
Organic photoelectrochemical transistors (OPECTs) represent an emerging bioelectronic platform synergizing photoelectrochemical processes with organic electrochemical transistors for amplified transduction of light-matter-bio interactions. However, OPECT performance remains fundamentally constrained by inefficient carrier dynamics at the photogate. To address this, we develop a novel transition metal dichalcogenide (TMD)-based heterojunction photogate by integrating FeSe 2 with ZnIn 2 S 4, leveraging band alignment engineering to optimize interfacial charge separation. This work pioneers a H 2 O 2 -triggered dynamic band modulation strategy within a TMD heterojunction for OPECT biosensing. Surface oxidation of FeSe 2 by H 2 O 2 disrupts the original band alignment, forming a new charge migration pathway and enhancing the photovoltage of the gate. Such a change restructures the control behavior of the transistor and ultimately amplifies the channel current response. Linking a prostate-specific antigen (PSA)-targeted proteolytic peptide system and the biological generation of H 2 O 2, such a phenomenon was correlated to PSA concentration with good performance in terms of selectivity and sensitivity. This study not only demonstrates the first TMD heterojunction-engineered OPECT for biosensing but also establishes a versatile framework for advancing next-generation bioelectronics through target-responsive interfacial band engineering.