Advances in poly (vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] designed for bending-energy harvesters and real-time rainfall monitoring

Polyvinylidene fluoride (PVDF) and its copolymer-based piezoelectric composites are widely used in piezoelectric sensors to facilitate efficient energy conversion due to their flexibility and high electromechanical coupling properties. In this study, we introduce a piezoelectric nanogenerator (PENG) that utilizes BaTiO 3 –Nb 2 O 5 @PDA@MWCNTs/P(VDF-TrFE) composite films (BNP-MCP) for detecting environmental mechanical stimuli and enabling wireless monitoring. Notably, adding 5 wt% BaTiO 3 –Nb 2 O 5 @PDA@MWCNTs increases the dielectric constant (εᵣ)of BNP-MCP to 21.8 from the 14.8 of pristine P(VDF-TrFE) at 100 Hz, thereby enhancing the PENG's output performance by improving the charge density. By optimizing the BaTiO 3 –Nb 2 O 5 @PDA content in the P(VDF-TrFE) matrix, the fabricated PENG is characterized by an output voltage of 7.5 V and a maximum power density of 4.52 μW cm −2 . This optimized PENG maintains stable performance after 4500 bending-releasing cycles and exhibits high sensitivity in detecting diverse mechanical stimuli, spanning from subtle perturbations (e.g., leaf fall and insect crawling) to intense impacts (e.g., water flow and human jumping). Additionally, an autonomous all-weather rainfall monitoring system leverages wirelessly received piezoelectric signals to trigger real-time precipitation alerts with three-tier warning thresholds: light rain, moderate rain, and heavy rain. This study establishes a sustainable monitoring framework for agricultural and environmental applications, advancing next-generation self-powered sensing technologies.