Hydrovoltaic–Photoelectric\nCoupling Strategy\nTriggered a Robust Output Signal for High-Performance Self-Powered\nElectrochemical Sensing

Hydrovoltaic self-powered electrochemical sensors hold\nsignificant\npotential for constructing wearable, portable, and real-time detection\ndevices, but the low output signal due to the slow phase transition\nrate of water molecules and the intricate nature of integration limits\ntheir applications. In this work, a hydrovoltaic–photovoltaic\ncoupling effect-enhanced self-powered electrochemical sensor was prepared\nby combining zinc oxide (ZnO) nanowire arrays with cerium-organometallic\nframework (Ce-MOF) materials, which greatly improved the electrical\noutput of self-powered electrochemical systems and provided a new\ndetection strategy for an efficient self-powered electrochemical sensing\nsystem. The heterojunction constructed by ZnO arrays and Ce-MOF could\ngenerate a built-in electric field under the action of light irradiation\nand promote the separation of the photocarriers. Moreover, the number\nof charged particles in the film further boosted the water evaporation\neffect. Notably, the optimal ZnO/Ce-MOF-based self-powered electrochemical\ndevice by hydrovoltaic–photoelectric coupling strategy displayed\nan outstanding output signal, which was 11-fold that of a pure hydrovoltaic-based\ndevice. As a proof of concept, the self-powered electrochemical sensing\nplatform was explored for sensitive detection of lincomycin via electrostatic\nadsorption for the binding of an aptamer. The self-powered sensor\nshowed superior performances, including a wide linear range from 1\nfM to 1 nM with a detection limit of 0.2 fM, good stability, and satisfactory\nrecoveries for the determination of lincomycin in real samples, holding\ngreat promise in environmental monitoring and food analysis. This\nstudy provides a promising avenue to boost the energy conversion efficiency\nwith a high output signal for constructing sensitive self-powered\nbiosensors.