Bifunctional Template-Induced VO₂@SiO₂ Dual-Shelled Hollow Nanosphere-Based Coatings for Smart Windows

Abstract

Thermochromic vanadium dioxide (VO 2 ) as one of the most promising candidates for smart windows has attracted widespread attention in recent years. Excellent optical performances (luminous transmittance, T lum , and solar modulation efficiency, ΔT sol ) of VO 2 -based coatings are usually pursued as crucial issues. In the current work, we report an ingenious approach for the synthesis of VO 2 @SiO 2 dual-shell hollow nanospheres (DSHNs) and the preparation of DSHNs thermochromic coatings. A sequential bifunctional template-induced mechanism for the formation of DSHNs was proposed. Because of the unique hollow-core and dualshell structure, the as-prepared VO 2 @SiO 2 DSHNs coatings exhibited appealing optical performances with enhanced luminous transmittance of 61.8% and solar modulation efficiency of 12.6%, compared with continuous and dense VO 2 coatings. It has been proved that the improvement of visible transmittance could be ascribed to the effective reduction of refractive index (from 2.6 to 1.6 at 630 nm). In addition, its excellent thermochromic performance has been confirmed by the model cubes measurements, expressing a great potential as energy-efficient smart windows in high-rise buildings. The bifunctional template-induced synthetic strategy may inspire more facile, efficient and inexpensive processes for development of well-defined multishelled hollow nanostructures for varied applications.

VO2@SiO2 Nanoparticle-Based Films with Localized Surface Plasmon Resonance for Smart Windows

“…In addition, the dynamic range first increases with increasing the annealing temperature and then decreases, and the maximal dynamic range is obtained at an annealing temperature of 450 °C, in which the ΔT sol is of 18.9% with T lum of 38%. The thermochromic performance of the VO 2 (M)@SiO 2 NP films in this study is comparable with that reported in the literatures, in which the VO 2 @SiO 2 core− shell structure exhibited a ΔT sol of 12.6% and T lum of 61.8%, 45 while the VO 2 @SnO 2 core−shell NPs exhibited a ΔT NIR of 47.5%, 46 but our preparation of the VO 2 (M)@SiO 2 NPs is relatively simple and can be produced in batches. Our result is also comparable with that of pure VO 2 (M) NP films without an SiO 2 shell, in which the ΔT sol is of 14.9% and T lum is of 48.8% when annealed at 400 °C, 33 but the SiO 2 shell can enhance the durability and antioxidation ability of the VO 2 (M) core.…”

Superhydrophobic VO2 Nanoparticle/PDMS Composite Films as Thermochromic, Anti-icing, and Self-Cleaning Coatings

“…As previously reported by our group and other groups, VO 2 as a typical thermochromic material exhibits the dramatic self-regulating ability of optical transmission/reflection with temperature changes, which has attracted extensive attention for the development of energyefficient strategies and renewable resources. 17,18,20,23,26,28,59 In this work, the large-scale production of the multifunctional thermochromic film was achieved with a 4 in. diameter.…”

Systematic Exploration of the Synthetic Parameters for the Production of Dynamic VO2(M1)

“…Some works, reported by Zhu et al [31] and Zhe at al. [32], describe a functionalization route aimed at coating VO 2 nanoparticles with silica using TEOS as a precursor. In our work, TEM analysis was employed in order to detect the presence of the SiO 2 layer, as reported in Figure 8.…”