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

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.