Defect- and Doping-Modulated Nanowires In Situ Grown on Carbonized Silk for Water Evaporation, Electricity Generation, and UV Sensing

Hydrovoltaic technology can harvest electrical energy from water–solid interactions and has emerged as a promising power solution for wearable electronics due to its broad material compatibility and strong environmental adaptability. However, the selection of flexible substrates and the relatively low interfacial charge separation efficiency still restrict its widespread application. In this work, biomass-derived carbonized silk fabric was utilized as a conductive and flexible substrate, and ordered TiO 2 nanowires were grown in situ on the fiber surface to construct an efficient evaporation-driven hydrovoltaic device. Subsequently, reduction–phosphorus doping, asymmetric electrode engineering, and photothermal enhancement were incorporated to regulate surface defect chemistry and establish additional internal fields, thereby promoting charge separation. Impressively, these synergistic optimizations significantly improved the electrical output, ultimately enabling the TiO 2– x -P nanowire-based device to achieve a high open-circuit voltage of 868.5 mV and a short-circuit current of 18.6 μA. Additionally, devices encapsulated with plastic film can generate a sustained ∼962 mV output voltage for over 80 h. Furthermore, the device can also function as a self-powered sensor to detect ultraviolet radiation, demonstrating its multifunctionality for future wearable and sensing applications.