A Capillary Structured Droplet-Based Triboelectric Nanogenerator for High-Accuracy Rainfall Monitoring

Accurate rainfall monitoring carries significant importance across meteorological and hydrological domains. However, the existing sensors face numerous challenges, including issues related to accuracy, stability, and limited measurement range, particularly during heavy rain events. Here, an innovative droplet-based triboelectric nanogenerator (D-TENG) rain gauge is proposed to overcome the above challenges. It incorporates a saddle-shaped rainfall bearing plate designed to channel rainwater for regular dripping onto the D-TENG, thereby generating electrical signals for droplet enumeration. The feasibility of the D-TENG rain gauge is substantiated through the analyses of the stability of the electrical signal (short-circuit current) and droplet weight. Experimental results illustrate the effective measurement range of the D-TENG rain gauge as 0–243.1 mm/h, with the relative error in calculated rainfall intensity within ±4%, satisfying the Chinese standard for precipitation observation instruments. Furthermore, the resolution of the D-TENG rain gauge is $3.96\times 10^{-{6}}$ mm, five orders of magnitude smaller than the resolution of widely-used tipping bucket rain gauge (TBR). Thus, our proposed D-TENG rain gauge provides a feasible solution for high-accuracy and high-resolution rainfall monitoring across a wide effective measurement range.