摘要
Undirected charge transfer and inhibited carrier separation significantly limit the photoelectrochemical (PEC) performance of the sensing element, thereby reducing the sensitivity of the PEC sensor. Herein, a novel self-powered PEC sensor was developed for ultrasensitive detection of microcystin-RR (MC-RR) using an S-scheme pyrene-based hydrogen-bonded organic framework (Py-HOF)/AgIn 5 S 8 heterojunction with dual signal amplification driven by oriented charge transfer and a photothermal self-enhancement effect. The well-aligned energy bands and matched Fermi levels between the two components of Py-HOF and AgIn 5 S 8 facilitated efficient and oriented separation of electron-hole pairs through the built-in electric field. Additionally, the intrinsic photothermal effect of AgIn 5 S 8 generated localized ‘hot islands’, which elevated the local temperature at the reaction interface, further accelerating charge migration and enhancing PEC performance. This synergistic mechanism of oriented charge transfer and the photothermal self-enhancement effect significantly augmented the photocurrent response by 8-fold, enabling ultrasensitive self-powered detection without external bias. Leveraging target-induced signal modulation of MC-RR aptamer, a novel self-powered PEC sensor was fabricated as a proof of concept. Under optimized conditions, the proposed sensor demonstrated a wide linear range (1 × 10 −14 M to 1 × 10 −9 M), an ultralow detection limit (1.5 × 10 −15 M), high specificity, good reproducibility, showing a satisfactory applicability in real water samples. This work demonstrates a synergistic design strategy integrating S-scheme charge transfer and photothermal effects, paving the way for the development of advanced self-powered sensors for monitoring trace-level pollutants in environmental systems.
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