Enhanced Droplet Triboelectric Nanogenerator via Interfacial Engineering for Raindrop Energy Harvesting and pH Monitoring

Droplet triboelectric nanogenerators (D-TENGs) hold significant promise for ambient energy harvesting, yet their insufficient output limits practical application. This study proposes an interfacial engineering strategy employing fluorosilane-modified SiO₂ (F-SiO₂) to enhance the performance of conventional D-TENG based on polytetrafluoroethylene. The constructed F-SiO₂-coated droplet TENG (FSD-TENG) exhibits superior hydrophobicity compared to conventional D-TENG, achieving a contact angle of 152.3°. The FSD-TENG achieves an open-circuit voltage of 201.7 V, which is 5.8 times higher than that of untreated devices, and delivers an output power of 2.1 mW, representing a 7-fold improvement over conventional D-TENG. Its practical potential is demonstrated by illuminating 300 LEDs upon a single droplet impact. Furthermore, the FSD-TENG's output characteristics exhibit a strong correlation with droplet pH. Leveraging multi-feature fusion of voltage and current signals, we developed a raindrop pH monitoring system. This system accurately identifies raindrop pH via FSD-TENG's output, with a neural network achieving 95% identification accuracy within pH 3-7 after 20 training epochs. Consequently, the FSD-TENG-based monitoring system not only provides novel data support for digital twin technology but also pioneers innovative pathways for environmental monitoring, showcasing a complete technological chain from fundamental research to practical implementation.