Significant improvement of the performance of ZrO2/V1-W O2/ZrO2 thermochromic coatings by utilizing a second-order interference

Houška, Jiří; Kolenatý, David; Vlček, Jaroslav; Bárta, Tomáš; Rezek, J.; Čerstvý, R.

doi:10.1016/j.solmat.2018.12.004

Cited by 50 publications

(40 citation statements)

References 39 publications

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“…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.…”

Section: Coating Designmentioning

confidence: 97%

“…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.…”

Section: Coating Designmentioning

confidence: 99%

“…The measurements were performed in the wavelength (λ) range 300-2000 nm (below we present properties at λ = 550 nm, n 550 and k 550 ) at the angles of incidence of 55 • , 60 • and 65 • in reflection. The optical model [26] consisted of the FG or SLG substrate, a bottom ZrO 2 layer, a bottom intermix layer, a V 0.984 W 0.016 O 2 layer, a top intermix layer, a top ZrO 2 layer and a surface roughness layer. The intermix layers and half of the surface roughness layer are included in the presented thickness values.…”

Section: Coating Characterizationmentioning

confidence: 99%

See 2 more Smart Citations

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

et al. 2020

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The reversible semiconductor-to-metal transition of vanadium dioxide (VO2) makes VO2-based coatings a promising candidate for thermochromic smart windows, reducing the energy consumption of buildings. This paper deals with maximizing the application potential of these coatings in terms of their performance, an industry-friendly preparation technique, and an industrially relevant substrate. We present a scalable sputter deposition technique for the preparation of strongly thermochromic ZrO2/V0.984W0.016O2/ZrO2 coatings on ultrathin flexible glass and standard glass at a relatively low substrate surface temperature (330 °C) and without any substrate bias voltage. The V0.984W0.016O2 layers were deposited by a controlled high-power impulse magnetron sputtering of a V target, combined with a simultaneous pulsed dc magnetron sputtering of a W target. We explain the fundamental principles of this technique using the discharge characteristics measured for both discharges. We characterize the coating structure (X-ray diffraction) and a wide range of optical properties (spectrophotometry and spectroscopic ellipsometry). We find that the coatings combine a transition temperature of 22 °C, a luminous transmittance approaching 50%, a modulation of the solar energy transmittance over 10% and a temperature-independent color. The results in general, and the successful transfer from a standard glass to the ultrathin flexible glass in particular, are crucial for future applications of the coatings on smart windows.

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“…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.…”

Section: Coating Designmentioning

confidence: 97%

“…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.…”

Section: Coating Designmentioning

confidence: 99%

Section: Coating Characterizationmentioning

confidence: 99%

See 1 more Smart Citation

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

et al. 2020

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“…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].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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Pure and doped vanadia (VO2, V0.98Zr0.02O2, V0.98Ce0.02O2) samples were prepared by wet chemistry synthesis from vanadyl glycolate intermediate phase and tape casted into films. Combining in-operando grazing incidence synchrotron X-ray diffraction and Raman spectroscopy, we studied the structural evolution of the films under isothermal conditions. The setup allowed assessment of the thermochromic functionality with continuous monitoring of the monoclinic to tetragonal transition in pure and doped vanadia phases, responsible for the transmission and reflection of light in the infrared part of the solar spectrum. The materials characterisation by X-ray diffraction beamline (MCX) goniometer demonstrated ideal performance, combining flexible geometry, high resolution, and the potential to accommodate the multi-channel equipment for in-operando characterisation. This method proved viable for evaluating the relevant structural and physical, and thereof functional properties of these systems. We revealed that dopants reduce the transition temperature by 5 °C on average. The synthetic route of the films was held responsible for the observed phase separation. The more favourable behaviour of cerium-doped sample was attributed to cerium alkoxide behaviour. In addition, structural, microstructural, thermal, and spectroscopic characterisation on powder samples was performed to gain more insight into the development of the phases that are responsible for thermochromic features in a broader range of doping ratios. The influence of the dopants on the extent of the thermochromic transition (transmission to reflection hysteresis) was also evaluated using (micro) structural, thermal and spectroscopic methods of powder samples. Characterisations showed that zirconium doping in 2, 4, and 6 mol% significantly influenced the phase composition and morphology of the precursor. Vanadium oxides other than VO2 can easily crystallise; however, a thermal treatment regime that allowed crystallisation of VO2 as a single phase was established.

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“…Although the hybridizing process offers both a larger visible and IR modulating ability, the high critical temperature of VO 2 in the polymer matrix still restricts its application in smart windows. Doping by tungsten can significantly reduce the critical temperature of VO 2 and solve the above problem [17]. Much effort has been made to investigate the effect of W doping on the phase transition temperature of VO 2 .…”

Section: Introductionmentioning

confidence: 99%

Tungsten-Doped VO2/Starch Derivative Hybrid Nanothermochromic Hydrogel for Smart Window

et al. 2019

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Highly efficient energy-saving windows with high solar modulation properties (ΔTsol) are the everlasting pursuit of research for industrial applications in the smart window field. Hybridization is an effective means of improving both ΔTsol and luminous transmittance (Tlum). In this paper, hybrid thermochromic films were synthesized using tungsten-doped VO2 nanoparticles (NPs) and starch derivatives. Thermoresponsive 2-hydroxy-3-butoxypropyl starch (HBPS) was prepared with a low critical solution temperature (LCST) varying from 32 to 21 °C by the substitution of reactive groups. The hybrid film was obtained by dispersing W-doped VO2 NPs in HBPS hydrogels, which exhibiting remarkable solar modulation property (ΔTsol = 34.3%) with a high average luminous transmittance (Tlum, average = 53.9%).

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Significant improvement of the performance of ZrO2/V1-W O2/ZrO2 thermochromic coatings by utilizing a second-order interference

Cited by 50 publications

References 39 publications

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

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

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

Tungsten-Doped VO2/Starch Derivative Hybrid Nanothermochromic Hydrogel for Smart Window

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