High-performance thermochromic VO2-based coatings with a low transition temperature deposited on glass by a scalable technique

Abstract

We report on high-performance thermochromic ZrO2/V0.982W0.018O2/ZrO2 coatings with a low transition temperature prepared on glass by a low-temperature scalable deposition technique. The V0.982W0.018O2 layers were deposited by a controlled high-power impulse magnetron sputtering of V target, combined with a simultaneous pulsed DC magnetron sputtering of W target to reduce the transition temperature to 20–21 °C, at a low substrate surface temperature of 330 °C in an argon–oxygen gas mixture. ZrO2 antireflection layers both below and above the thermochromic V0.982W0.018O2 layers were deposited at a low substrate temperature (< 100 °C). A coating design utilizing a second-order interference in the ZrO2 layers was applied to increase both the luminous transmittance (Tlum) and the modulation of the solar transmittance (ΔTsol). The ZrO2/V0.982W0.018O2/ZrO2 coatings exhibit Tlum up to 60% at ΔTsol close to 6% for a V0.982W0.018O2 thickness of 45 nm, and Tlum up to 50% at ΔTsol above 10% for a V0.982W0.018O2 thickness of 69 nm.

Pulsed Magnetron Sputtering of Strongly Thermochromic VO2-Based Coatings with a Transition Temperature of 22 °C onto Ultrathin Flexible Glass

“…The coating performance strongly depends on the thickness of the bottom and the top AR layer (hb and ht, respectively). It has been detailed [26] and experimentally justified [25,26] that while the There are data below T tr (full symbols) and above T tr (empty symbols), obtained on the ultrathin FG substrate (triangles up) and SLG substrate (triangles down) using the transmittance (T) and the reflectance (R) presented in Figure 6.…”

“…The coating performance strongly depends on the thickness of the bottom and the top AR layer (h b and h t , respectively). It has been detailed [26] and experimentally justified [25,26] that while the usual thin quarter-wavelength AR layers lead to a maximum T lum at a very low ∆T sol , thicker three quarter-wavelength AR layers lead to maxima of both T lum (due to the second-order interference in the visible) and ∆T sol (due to the first-order interference in the near infrared where most of the energy saving takes place). This leads to an optimum optical path length of ZrO 2 corresponding to, e.g., h b = h t = 180 nm at n 550 = 2.15 (value considered in [26]) and similarly for other n 550 values.…”

“…depositions of individual layers. In addition, the structure, optical properties (not only transmittance as in [25], but also reflectance and absorption) and colors of these thermochromic coatings deposited onto 0.1 mm thick FG and 1 mm thick SLG substrates are presented.…”

Chromogenic Technologies for Energy Saving

“…On the other hand, to increase the luminous transmittance of VO 2 films, antireflection coatings or structures are adopted. For instance, Kolenaty et al reported a three-layer structure, with ZrO 2 antireflective layers acting as a protection layer and structure template [49]. Several works have used SiO 2 , TiO 2 , and ZrO 2 antireflective layers [37].…”

In-Operando Diffraction and Spectroscopic Evaluation of Pure, Zr-, and Ce-Doped Vanadium Dioxide Thermochromic Films Derived via Glycolate Synthesis

“…Doped VO 2 is commonly prepared by hydrothermal synthesis [6], chemical vapour deposition [14], magnetron sputtering [15], sol-gel synthesis [16], etc. Although these methods usually require long-lasting thermal treatment at high temperatures in an inert atmosphere, VO 2 films can be successfully prepared by fairly low temperature magnetron sputtering depositions [17][18][19][20]. Nevertheless, VO 2 can be prepared by means of facile wet-chemistry synthesis through intermediate vanadyl glycolate, VO(OCH 2 CH 2 O), thus enabling short annealing times and avoiding inert atmosphere requirements [21].…”