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Improved thermochromic properties in bilayer films of VO2 with ZnO, SnO2 and WO3 coatings for energy efficient glazing.
- Source :
- Journal of Materials Chemistry C; 12/14/2018, Vol. 6 Issue 46, p12555-12565, 11p
- Publication Year :
- 2018
-
Abstract
- The thermochromic properties of bilayer films consisting of a nanostructured VO<subscript>2</subscript> under-layer and top-layers of ZnO, SnO<subscript>2</subscript> or WO<subscript>3</subscript> are presented. In each case, the VO<subscript>2</subscript> under-layer was deposited by electric field assisted AACVD on a fluorine doped tin oxide coated glass substrate, with the metal oxide top-layer deposited using sol–gel spin coating. The deposited films were analysed and characterised using scanning electron microscopy, X-ray powder diffraction, variable temperature UV/Vis/NIR spectroscopy, X-ray photoelectron spectroscopy, glow discharge photoelectron emission spectroscopy and contact angle measurements. Compared to bare VO<subscript>2</subscript> films, the bilayer films exhibit superior thermochromic properties, with dramatic increases in the visible light transmittance (T<subscript>vis</subscript>), integrated luminous transmittance (T<subscript>lum</subscript>) and solar modulation (ΔT<subscript>sol</subscript>). The thermochromic efficiency was also improved in some cases, with a reduction in the hysteresis loop width to ca. 10 °C, and a decrease in the transition temperature (T<subscript>c</subscript>), which was as low as 44 °C and 43 °C for VO<subscript>2</subscript>/ZnO and VO<subscript>2</subscript>/SnO<subscript>2</subscript> films, respectively. The best balance of thermochromic, thermal protection and aesthetic properties was achieved for ZnO coated films, with the VO<subscript>2</subscript> under-layer deposited at a field strength of 1500 V m<superscript>−1</superscript> under a negative DC bias (T<subscript>c</subscript> = 47 °C, T<subscript>lum</subscript> = 61.6%, T<subscript>vis</subscript> = 68% and ΔT<subscript>sol</subscript> = 6%). [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 20507526
- Volume :
- 6
- Issue :
- 46
- Database :
- Complementary Index
- Journal :
- Journal of Materials Chemistry C
- Publication Type :
- Academic Journal
- Accession number :
- 133278197
- Full Text :
- https://doi.org/10.1039/c8tc04543g