Photo-sensitive hydrovoltaic energy harvester with fire-sensing functionality

Artikel i vetenskaplig tidskrift, 2025

Hydrovoltaic (HV) mechanisms have recently gained attention as a cost-efficient method for electricity generation, though their integration with sensor technologies remains underexplored. In this study, we developed a 3D-structured HV device for dual applications: power generation and fire detection. Waste cotton was recycled as the HV system substrate, coated with Triton-X and Polypyrrole (PPy) to enhance electricity generation and fire sensing application. Triton-X, a negatively charged hydrophilic agent, improved proton absorption and water flow through the PPy-coated cotton. Additionally, the light-absorbing property of PPy provided photo-to-thermal conversion, boosting electricity generation under various light conditions. The optimized device achieved an open-circuit voltage of approximately 0.42 V and a short-circuit current of about 20 µA with an excellent power density of 56.6 μW/g. The strong adhesion of PPy to the cotton surface ensured long-term stability, with no significant performance degradation after 28 days of continuous tests and ten cycles of repeated power generation tests. The excellent responsive nature of the device under light conditions enabled the device to function as a fire detector, with a fast fire-sensing response time of approximately 10 s. This study demonstrates the potential of integrating Triton-X and PPy for high-performance HV systems, as well as their applications in self-powered fire detection systems.