Multilayer passive radiative selective cooling coating based on Al/SiO2/SiNx/SiO2/TiO2/SiO2 prepared by dc magnetron sputtering
| Autor: | A. AL-Rjoub, N.F. Cunha, L. G. Vieira, Senentxu Lanceros-Méndez, L. Rebouta |
|---|---|
| Přispěvatelé: | Universidade do Minho |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Selective coating
Materials science Silicon Ciências Naturais::Ciências Físicas Ciências Físicas [Ciências Naturais] chemistry.chemical_element Infrared spectroscopy 02 engineering and technology 7. Clean energy 01 natural sciences 0103 physical sciences Materials Chemistry Transmittance Optical constants Spectroscopy 010302 applied physics Science & Technology business.industry Metals and Alloys Surfaces and Interfaces Sputter deposition Molar absorptivity 021001 nanoscience & nanotechnology Surfaces Coatings and Films Electronic Optical and Magnetic Materials Amorphous solid chemistry Passive cooling Optoelectronics 0210 nano-technology business Refractive index |
| Zdroj: | Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP |
| Popis: | A multilayer passive radiative selective cooling coating based on Al/SiO2/SiNx/SiO2/TiO2/SiO2 prepared by dc magnetron sputtering is presented. The design was first theoretically optimized using the optical constants, refractive index and extinction coefficient, of thin single layers. The spectral optical constants in the wavelength range from 0.3 to 27 µm were calculated from the transmittance and reflectance data of thin single layers deposited on silicon and glass substrates. The samples were characterized by Scanning Electron Microscopy, X-ray diffraction, Fourier-transform Infrared Spectroscopy and UV–VIS–NIR spectroscopy. It is shown that the TiO2 layer presents a partially rutile phase polycrystalline structure and a higher refractive index than amorphous SiO2 and SiNx layers in the spectral range from 0.3 to 2.5 μm. The cooling device was deposited on copper substrates and a thin low-density polyethylene foil with high transmittance in the 8 to 13 µm spectral range was used as convection cover material. The device is characterized by both low reflectance (high emittance) in the sky atmospheric window (wavelength range from 8 to 13 µm) and high hemispherical reflectance elsewhere, allowing for temperature drops of average 7.4 °C at night-time in winter, which corresponds to a net cooling power of ~43 W m−2. Further, a temperature drop of 2.5 °C was obtained during winter daytime. FCT in the framework of the Strategic Funding UID/FIS/04650/2013 and the financial support of FCT, POCI and PORL operational programs through the project POCI-01-0145-FEDER-016907 (PTDC/CTM-ENE/2892/2014), co-financed by European community fund FEDER |
| Databáze: | OpenAIRE |
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