Improved thermochromic properties in bilayer films of VO 2 with ZnO, SnO 2 and WO 3 coatings for energy efficient glazing
| Autor: | Isaac Abrahams, Işıl Top, Marcin Holdynski, Sofia Gaiaschi, Russell Binions, Christian Sol, Ioannis Papakonstantinou |
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| Rok vydání: | 2018 |
| Předmět: |
Spin coating
Materials science Scanning electron microscope Bilayer Analytical chemistry 02 engineering and technology General Chemistry Substrate (electronics) 010402 general chemistry 021001 nanoscience & nanotechnology Tin oxide 01 natural sciences 0104 chemical sciences Contact angle X-ray photoelectron spectroscopy Materials Chemistry Transmittance 0210 nano-technology |
| Zdroj: | Journal of Materials Chemistry C |
| ISSN: | 2050-7534 |
| DOI: | 10.1039/c8tc04543g |
| Popis: | The thermochromic properties of bilayer films consisting of a nanostructured VO2 under-layer and top-layers of ZnO, SnO2 or WO3 are presented. In each case, the VO2 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 VO2 films, the bilayer films exhibit superior thermochromic properties, with dramatic increases in the visible light transmittance (Tvis), integrated luminous transmittance (Tlum) and solar modulation (ΔTsol). 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 (Tc), which was as low as 44 °C and 43 °C for VO2/ZnO and VO2/SnO2 films, respectively. The best balance of thermochromic, thermal protection and aesthetic properties was achieved for ZnO coated films, with the VO2 under-layer deposited at a field strength of 1500 V m−1 under a negative DC bias (Tc = 47 °C, Tlum = 61.6%, Tvis = 68% and ΔTsol = 6%). |
| Databáze: | OpenAIRE |
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