Hollow flower-like TiO2@CsxWO3 hybrid for effective thermal management using a UV/NIR light absorbing shield strategy

Abstract

Transparent materials accompanying ultraviolet and near-infrared (UV/NIR) shielding play a crucial role in sunlight management and are desirable for reducing energy consumption in buildings. Herein, a hollow flower-like core–shell hybrid, in which hollow TiO₂ spherical cores are bonded with a Cs_xWO₃ hierarchical nanosheet shell (h-TiO₂@Cs_xWO₃ hybrid), is prepared for high-efficiency absorption of UV/NIR light and corresponding transparent membrane-based UV/NIR light shielding for thermal management. Impressively, while maintaining high visible light transmission, the h-TiO₂@Cs_xWO₃ flower-like hybrids display the almost complete absorption of UV and NIR light caused by the multilevel synergistic scattering and absorption of incident light between the components. Next, to expand the application of building energy conservation engineering, the h-TiO₂@Cs_xWO₃ flower-like hybrids are spray-coated onto the surface of a PET film to serve as the membrane material, showing nearly 80% visible light transmission and complete shielding from UV and NIR light. As a proof of concept, based on the UV/NIR light absorbing shield strategy for thermal management, by transferring the as-prepared h-TiO₂@Cs_xWO₃/PET functional membrane as “window glass” on a home-made house model, a temperature reduction of ∼16.4 °C could be achieved relative to a blank house under 1 sun irradiation. Further, outdoor testing (Hefei, China) with simulated room temperatures below ∼25 °C throughout a full day's test cycle achieved a sub-ambient cooling temperature of ∼11.5 °C. Thus, both the solar radiation shielding capability and the combined outdoor service performance significantly advance the UV/NIR shielding strategy for real-world solar/thermal-management applications.