High performance tungsten-doped VO₂ polycrystalline films for advanced dynamic radiant thermal management

The utilization of W-doped VO₂ (W_xV_1-xO₂) for dynamic radiative thermal management (DRTM) is a breakthrough in refrigeration technology, gaining attention for its energy efficiency and environmental benefits. The W_xV_1-xO₂-based DRTM holds great promise for passive thermal regulation, but the challenge of synthesizing high-quality crystalline W_xV_1-xO₂ films has hindered its widespread application. Herein, we utilize high-power impulse magnetron sputtering (HiPIMS) to deposit highly polycrystalline W_xV_1-xO₂ films with enhanced phase-transition properties. Through thermal excitation, the manipulation of electrons from the d_// bonding state to the π^* anti-bonding state in W_xV_1-xO₂ film is observed to modify the dynamic infrared radiation, potentially disrupting V-V dimers via the collapse of molecular orbitals. The resulting polycrystalline W_xV_1-xO₂ film enables the achievement of a DRTM reflector with a considerable dynamic range of thermal emissivity tunability, spanning from 0.25 to 0.87 within the 7-13 µm. Comprehensive energy calculations demonstrate that, by using high-emissivity radiative cooling material as the baseline, our passive temperature-responsive DRTM roof can reduce heating, ventilation, and air conditioning energy consumption in buildings by over 8% across five global climate zones. This work not only advances the fabrication of high-performance W_xV_1-xO₂ films but also paves the way for sustainable energy solutions in the face of global climate challenges.