Hydrovoltaic-Photoelectric Coupling Strategy Triggered a Robust Output Signal for High-Performance Self-Powered Electrochemical Sensing

Hydrovoltaic self-powered electrochemical sensors hold significant potential for constructing wearable, portable, and real-time detection devices, but the low output signal due to the slow phase transition rate of water molecules and the intricate nature of integration limits their applications. In this work, a hydrovoltaic-photovoltaic coupling effect-enhanced self-powered electrochemical sensor was prepared by combining zinc oxide (ZnO) nanowire arrays with cerium-organometallic framework (Ce-MOF) materials, which greatly improved the electrical output of self-powered electrochemical systems and provided a new detection strategy for an efficient self-powered electrochemical sensing system. The heterojunction constructed by ZnO arrays and Ce-MOF could generate a built-in electric field under the action of light irradiation and promote the separation of the photocarriers. Moreover, the number of charged particles in the film further boosted the water evaporation effect. Notably, the optimal ZnO/Ce-MOF-based self-powered electrochemical device by hydrovoltaic-photoelectric coupling strategy displayed an outstanding output signal, which was 11-fold that of a pure hydrovoltaic-based device. As a proof of concept, the self-powered electrochemical sensing platform was explored for sensitive detection of lincomycin via electrostatic adsorption for the binding of an aptamer. The self-powered sensor showed superior performances, including a wide linear range from 1 fM to 1 nM with a detection limit of 0.2 fM, good stability, and satisfactory recoveries for the determination of lincomycin in real samples, holding great promise in environmental monitoring and food analysis. This study provides a promising avenue to boost the energy conversion efficiency with a high output signal for constructing sensitive self-powered biosensors.