A Highly‐Flexible and Breathable Photo‐Thermo‐Electric Membrane for Energy Harvesting

Abstract Photo‐thermo‐electric (PTE) technology is a simple but sustainable method that directly converts solar energy into electricity. However, the manufacturing of flexible and breathable PTE generators for practical applications, such as intelligent wearable and self‐powered sensors, poses significant challenges due to the rigid thermoelectric materials and unbreathable substrates. Here, a highly‐flexible and breathable photo‐thermal‐electric membrane (FB‐PTEM) is developed by magnetron sputtering (MS) on a photo‐thermal nanofiber membrane. A single unit of FB‐PTEM produced an open‐circuit voltage of 0.52 V under 1 sun (100 mW cm −2 ) and 0.2 V under LED illumination, making it suitable for all‐weather use. The photo‐thermal nanofiber membrane exhibited high photo‐thermal conversion capacity of reaching 70 °C within 50 s under 1 sun irradiation. The FB‐PTEM with a thickness of 0.35 mm achieved a self‐temperature difference of 20.6 °C under 1 sun with the low thermal conductivity of the nanofiber membrane. Furthermore, it has a vapor permeability of 14.6 kg m −2 d −1 due to the inherent high porosity of the nanofiber membranes. The FB‐PTEM demonstrates great potential for the development of highly flexible thermoelectric materials, as it encompasses various advantageous features such as self‐temperature difference, lightweight design, high breathability, and all‐weather suitability.