Hydrogel‐Based Droplet Electricity Generators: Intrinsically Stretchable and Transparent for Seamless Integration in Diverse Environments

Abstract

Droplet‐based electricity generators (DEGs) have emerged as innovative devices capable of transducing the kinetic energy of falling water droplets into electrical power, thereby presenting a promising solution for ambient energy harvesting. For effective application, DEGs must exhibit transparency and flexibility to facilitate aesthetic integration and optical/mechanical adaptability for utilization on natural objects and wearable devices. In this study, a hydrogel‐based DEG (Hy‐DEG) designed is proposed to be seamlessly integrated into everyday environments without compromising design or functionality. With the intrinsic characteristics of hydrogel, the Hy‐DEG exhibits superior optical transmittance (≈99%) and stretchability (≈70% of its original length), generating the electrical output performance of ≈45 V of voltage, 15 µA of current, and 42 µW of maximum peak power, with single droplet impact. This capability of the Hy‐DEG can operate electronic devices for environmental monitoring while maintaining seamless integration with commonly encountered surfaces. In this context, this study elucidates the characteristics of hydrogel bestowing novel functionalities upon the DEG, expanding the potential for energy harvesting in residential and commercial contexts. The implications of this research extend beyond conventional energy generation, fostering the development of self‐powered, transparent, and flexible devices.