The preparation of a plasmonically resonant VO₂thermochromic pigment

Abstract

Vanadium dioxide (VO(2)) undergoes a reversible metal-insulator transition, normally at approximately 68 degrees C. While the properties of continuous semi-transparent coatings of VO(2) are well known, there is far less information available concerning the potential use of discrete VO(2) nanoparticles as a thermochromic pigment in opaque coatings. Individual VO(2) nanoparticles undergo a localized plasmon resonance with near-infrared light at about 1100 nm and this resonance can be switched on and off by simply varying the temperature of the system. Therefore, incorporation of VO(2) nanoparticles into a coating system imbues the coating with the ability to self-adaptively modulate its own absorptive efficiency in the near-infrared. Here we examine the magnitude and control of this phenomenon. Prototype coatings are described, made using VO(2) powder produced by an improved process. The materials are characterized using calorimetry, x-ray diffraction, high-resolution scanning electron microscopy, transmission electron microscopy, and by measurement of optical properties.

Nanothermochromics: Calculations for VO2 nanoparticles in dielectric hosts show much improved luminous transmittance and solar energy transmittance modulation

“…22,23 VO 2 -based nanoparticles of various types have received much interest in recent work, as discussed at length below, and there are a number of demonstrations that clear-cut thermochromic effects can be observed; data have been obtained for nanostructures made by ion implantation followed by annealing, [27][28][29] ion beam lithography and pulsed laser deposition, 30,31 ultrasonic spray and laser pyrolysis, 32 molten salt synthesis, 33 and aqueous chemistry. 34 Our present study demonstrates that nanoparticles dispersed in a dielectric host have advantages over what a thin solid film can offer. Specifically, calculations have shown that the thermochromic nanoparticles can give superior luminous transmittance and solar energy transmittance modulation.…”

Thermochromic Oxide-Based Thin Films and Nanoparticle Composites for Energy-Efficient Glazings

“…Figure 1). A plasmonic character of the near-infrared absorption has been observed and discussed several times in prior work [95][96][97][98]. Figure 12 gives clear evidence for nanothermochromism in a film comprised of VO2-SiO2 and was recorded on the sample illustrated in Figure 7.…”

Switchable glazing technology for eco-efficient construction

“…Still better properties can be obtained with VO 2 hollow nanoshells (Li et al, 2011a). In terms of the underlying physics, the infrared optical absorption of the VO 2 -based nanoparticles is governed by a plasmon resonance that is present in the metallic state at τ > τ c but absent in the insulating state at τ < τ c (Bai et al, 2009;Li et al, 2010).…”