Transparent Power‐Generating Windows Based on Solar‐Thermal‐Electric Conversion

Abstract Integrating transparent solar‐harvesting systems into windows can provide renewable on‐site energy supply without altering building aesthetics or imposing further design constraints. Transparent photovoltaics have shown great potential, but the increased transparency comes at the expense of reduced power‐conversion efficiency. Here, a new technology that overcomes this limitation by combining solar‐thermal‐electric conversion with a material's wavelength‐selective absorption is presented. A wavelength‐selective film consisting of Cs 0.33 WO 3 and resin facilitates high visible‐light transmittance (up to 88%) and outstanding ultraviolet and infrared absorbance, thereby converting absorbed light into heat without sacrificing transparency. A prototype that couples the film with thermoelectric power generation produces an extraordinary output voltage of ≈4 V within an area of 0.01 m 2 exposed to sunshine. Further optimization design and experimental verification demonstrate high conversion efficiency comparable to state‐of‐the‐art transparent photovoltaics, enriching the library of on‐site energy‐saving and transparent power generation.