Thermochromic performance improvement based on W-VO₂@AA core-shell structure nanoparticles

Vanadium dioxide (VO₂) is a promising candidate for thermochromic smart windows for its thermally induced metal-to-insulator phase transition properties. Tungsten doping can reduce the phase transition temperature of VO₂ (W-VO₂) to near room temperature but deteriorates the thermochromic performance. A W-VO₂@AA core-shell structure was proposed to improve the thermochromic performance by enhancing the luminous transmittance and solar modulation, simultaneously. The W-VO₂@AA core-shell structure was prepared by the hydrothermal method based on the surface molecular coordination effect, and the shell thickness of AA was modulated by glacial acetic acid. The phase transition temperature of W-VO₂@AA is 34.53 °C. The solar modulation of the W-VO₂@AA/PVP composite film-based smart windows is increased by 80.2 % (from 5.65 % to 10.18 %) compared with W-VO₂/PVP, and the luminous transmittance is maintained satisfactorily at 70.52 %. This enhancement is primarily attributed to the injection of electrons from AA into the W-VO₂ lattice, which enhances the localized surface plasmon resonance absorption performance. Moreover, the refractive index of AA is between PVP and W-VO₂, which decreases the reflectance. This work provides a new strategy to overcome the trade-off relationship between the two thermochromic properties of W-VO₂. © 2025 Elsevier B.V.