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

Abstract

As an ideal thermochromic material for smart windows, vanadium dioxide (VO2(M)) has been receiving wide research interest in recent years. Enhancing the optical switching ability before and after phase transformation of the VO2(M) (i.e., enhancing the solar regulation efficiency ΔT sol while maintaining a great luminous transmittance T lum) is the target for its application in smart windows. However, the recrystallized growth in the annealing process ruins the thermochromic performance of VO2(M) nanoparticles (NPs). Here, we report the preparation and thermochromic performance of VO2(M)@SiO2 NPs. It was found that the SiO2 shell can effectively protect VO2(M) NPs from growth in the annealing process, and the VO2(M)@SiO2 NP film exhibits an excellent thermochromic performance with ΔT sol of 18.9% and T lum of 38% after annealing at 450 °C, because of the outstanding contribution of the enhancement and blue-shifting of the localized surface plasmon resonance. Our results provide an efficient way to synthesize VO2(M) NPs with excellent thermochromic performance for smart windows.

Kirkendall effect induced ultrafine VOOH nanoparticles and their transformation into VO2(M) for energy-efficient smart windows

“…In addition, the blue-shifted LSPR peak of S3 makes its absorption peak match better with the peak of the solar irradiance spectrum, which will further enhance the thermochromic performance of VO 2 film. 36 It was reported that coating VO 2 with a metal oxide widens the optical band gap, but the optical band gap of S3 determined from the Tauc plot was similar to that of uncoated VO 2 (Fig. 4i).…”

“…38,39 For the two-step hydrothermal method, the hydrothermal temperature could be lower than 240 1C but needs to be at least 200 1C. 36,40,41 It is obvious the hydrothermal conditions of our work were mild and effective. Moreover, as for the thermochromic performance, the prepared VO 2 @SiO 2 /PVP film achieved a good balance between DT sol (18.30%) and T lum (50.69%), which is desirable for the application of VO 2 -based films as smart windows.…”

Microwave Hydrothermal Preparation of VO2

“…[6] This phase transition brings about great changes in the optical, electrical, magnetic, and blood properties of VO 2 [7][8][9] . By taking advantage of this change, we can apply VO 2 to vanadium dioxide, mainly in various aspects such as smart windows, [10,11] electrical switches, [12] microsolid engines, [13] and room temperature gas sensors. [14,15] At present, the main way of vanadium dioxide powder preparation includes combustion, [16,17] pyrolysis, [18][19][20] and hydrothermal method.…”

Photocatalytic CO2 reduction enhanced by the thermochromic effect of modified VO2

“…38,39 A thermochromic material could automatically modulate the transmittance by utilizing its metal-semiconductor phase transition at a "critical" temperature T c , about 68 °C. 40 In other words, when the temperature is above the T c , it exhibits metallic properties, which makes it minimize the surface recombination and Shockley-Read-Hall-recombination in the semiconductors. 41 On the basis of this, VO 2 -based materials would probably be an ideal co-catalyst above the T c .…”