3D Ordered Macroporous VO₂ Thin Films with an Efficient Thermochromic Modulation Capability for Advanced Smart Windows

Abstract Thermochromic smart windows can provide innovative energy savings via intelligently modulating the transmittance of indoor solar radiation to reduce the energy consumption of air conditioning in buildings. Vanadium dioxide (VO₂) has desirable thermochromic properties and great prospects in smart windows. Herein, 3D ordered macroporous (3DOM) VO₂ films are prepared via a sacrificial colloid template method. The as‐fabricated 3DOM VO₂ films exhibit a pure monoclinic phase with a uniform layout, controllable thickness and domain sizes, and excellent optical properties. Compared to a nontemplated film, the 3DOM structured VO₂ exhibits improved thermochromic performance with a high solar modulation ability (ΔT_sol) of 10.8% and an ultrahigh visible transmittance (T_vis) of 71.1%. In the near‐infrared region, a large contrast transmittance of 59.5% at 2500 nm is obtained for the 3DOM VO₂ film. Such excellent optical properties arising from the 3DOM structure are also demonstrated by finite element analysis. This work offers a promising way to manipulate the optical properties of a VO₂ thermochromic film via structural engineering for the deployment of smart windows.