Thermochromic smart window utilizing passive radiative cooling for Self-Adaptive thermoregulation

Abstract

Being a major impediment, the development of advanced smart windows with exceptional thermoregulation in both the visible-near infrared (Vis-NIR) and the long-wave infrared remains a significant aspiration to scholars. Herein, an innovative strategy was implemented to achieve self-adaptive smart window that seamlessly integrates the thermochromic and radiative cooling technologies (TRSW), and holds great potential in effectively addressing the intricate thermal radiation requirements arising from unpredictable climatic conditions. The TRSW demonstrated an impressive capacity to regulate solar energy through automatic modulation of emissivity (ε) at both high (εLWIR-H = 0.68) and low (εLWIR-L = 0.35) temperatures, while effectively maintaining Vis-NIR regulation (20.12%). Moreover, the results of TRSW’s outdoor performance exhibited its efficiency in implementing dual solar energy transmission modes, effectively inhibiting the Vis-NIR transmission to mitigate solar overheating in high-temperature conditions, while diminishing heat dissipation and promoting radiative cooling in low-temperature situations. Compared to conventional cooling materials, the dynamic emissivity modulation of TRSW provided an effective approach to prevent overcooling at lower temperatures. Consequently, TRSW fostered an efficient synergy between the solar transmittance modulation (ΔTsol) and Δε, which led to heightened modulation of the entire spectrum and facilitated exceptional thermal management. This work paves an intriguing prospect of developing advanced smart windows with remarkable thermoregulation and promises a wide range of thermal regulation applications, such as windows, roofs, walls, and advanced textiles.