Enhanced visible and tunable infrared transmittance of W-doped VO2/SiO2/PVP composite films for smart windows

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Original languageEnglish
Article number111485
Journal / PublicationOptical Materials
Online published20 Aug 2021
Publication statusPublished - Nov 2021


As a thermochromic material, vanadium dioxide (VO2) has great application potential in smart windows. It has always been the focus of research to improve the visible light transmittance (Tlum) and solar modulation ability (ΔTsol) while reducing the phase transition temperature (Tc) of VO2. To achieve this goal, tungsten-doped VO2 nanoparticles (W-VO2 NPs) with a Tc of 34 °C were used to form composite films with polyvinylpyrrolidone (PVP) by a simple method. High ΔTsol of 14.2% was obtained at the optimized volumetric concentration of W-VO2 and film thickness. The W-VO2/SiO2/PVP composite films were proposed to further improve Tlum and ΔTsol. Compared with the W-VO2/PVP composite film with the same thickness and volumetric concentration of W-VO2, Tlum of the film is increased by 19.3% (from 54.5% to 65%) with the introduction of SiO2 microspheres, while the ΔTsol is maintained satisfactorily at 12.6%. This is mainly due to the monolayer dispersed SiO2 microspheres providing optical pathways in the film, which greatly improves Tlum with a slight sacrifice of ΔTsol. Indoor temperature of a scale-model room with W-VO2/SiO2/PVP film-coated glass was 9.1 °C lower than that with blank glass due to the isolation effect of metallic W-VO2 on near-infrared radiation. This work provides a new strategy for promoting the development of VO2 thermochromic smart windows.

Research Area(s)

  • Localized surface plasmon resonance, Optical pathways, Smart windows, W-VO2/SiO2/PVP composite film