Fully Discrete VO2 Particulate Film with Ultra‐High Transmittance and Excellent Thermochromic Performance

Abstract Vanadium dioxide (VO 2 ) has attracted widespread attention due to its extraordinary thermochromic properties. Visually transparent VO 2 films hold great promise for applying in smart windows, smart radiative coolers, solar cells, and microwave absorbing windows. However, it remains a huge challenge to simultaneously achieve ultra‐high luminous transmittance ( T lum ) and excellent thermochromic performance due to their contradictory relationship. Here, a fully discrete VO 2 particulate (FDVP) film is developed. It shows an ultra‐high T lum of 92.7% due to the reflectance being significantly reduced. Below the phase transition temperature ( T c , 69.1 °C), it is highly transparent to near‐infrared (NIR) light, while above T c , it blocks NIR light through the strong localized surface plasmon resonance (LSPR) effect, resulting in an excellent solar energy modulation (Δ T sol ) of 10.5% for smart windows. In addition, a 3.5 at.%W‐doped FDVP film exhibits a desired T c of 25.8 °C, an extremely narrow hysteresis width (Δ T ) of 4.6 °C, and good optical properties ( T lum = 92.0%, Δ T sol = 8.2%). The performance represents a new milestone for thermochromic VO 2 films. This work will shed light on the structural design for high‐performance VO 2 films.