Moisture‐Light Harvesting Enhanced Hydrovoltaic Electric Generation

Moisture-voltaic power generation using hygroscopic materials harnesses atmospheric water to produce clean, sustainable energy. Yet environmental complexity means single mode moisture to electricity conversion suffers from efficiency limits and poor adaptability, making the development of flexible, multimodal clean‑energy harvesters essential. Here, a strategy is presents that combines hygroscopic polyelectrolyte material with light-responsive BiOBr nanosheets to create a moisture-light harvesting electric generator (MLEG). We utilized the PSS/AMPS-Na/PVA/BiOBr (PAPBO) composite as the flexible active layer, achieving highly efficient hydrovoltaic power output. Additionally due to the incorporation of BiOBr, long-lived holes are generated through light harvesting, which further enhances the output performance through water oxidation. When exposed to an environment with 75% relative humidity, a single MLEG delivers a substantial open-circuit voltage of 0.77 V and a short-circuit current of 18.73 µA. After the MLEG harvests light energy, the consumption of holes by water molecules generates additional hydrogen ions, resulting in a 60.98% increase in output power density (from 72.75 to 117.11 µW cm^-2). The device can also function as a humidity sensor, responding to humidity levels from 10% to 100%. This work provides a novel approach to harvesting and converting multiple natural energy sources, boosting the hydrovoltaic effect and opening a new path for sustainable power generation.