A Transparent Droplet-Based Electricity Generator Utilizing Patterned Wetting Surfaces.

Developing efficient technologies to convert renewable energy into electricity is crucial for the advancement of sustainable solutions. As a promising innovation, droplet-based electricity generators with transistor-inspired architectures have demonstrated remarkable potential in the harvesting of energy from water. However, the widespread adoption of conventional devices is hindered by critical limitations, including poor mechanical stability due to electrode peeling and restricted transparency of opaque electrodes, which compromise flexibility and long-term performance. To address these challenges, we propose a droplet-based electricity generator with a water electrode (WE-DEG) that integrates hydrophilic electrode regions directly constructed on a polytetrafluoroethylene (PTFE) substrate. By leveraging the contrasting patterned wettability of the PTFE surface, water droplets are selectively captured at the hydrophilic area to form a stable, transparent "water drain electrode", eliminating the need for conventional solid electrodes. The proposed WE-DEG exhibits exceptional transparency, achieving a visible light transmittance of over 75%, while maintaining robust structural integrity even under high-frequency water jet impacts with substantial flow rates. Its nonuniform wetting surface facilitates directional droplet shedding from hydrophobic to hydrophilic areas, enabling dual functionalities: not only does the WE-DEG achieve stable energy generation, but it also serves as a propulsion mechanism to drive swimmers at a high speed across water surface. Remarkably, this simple yet durable design combines optical clarity with mechanical resilience, positioning WE-DEG as a groundbreaking candidate for next-generation energy harvesting systems. We envision its wide-ranging applications in scenarios demanding transparent, environmentally adaptive energy solutions.