| Solar energy is clean and renewable energy. With fast consumption ofnon-renewable energy worldwide, the increasing pressure brought by environmentalpollution has greatly boosted the development of solar utilization technology.In solar utilization technology, selective solar absorption film plays a key role for itdirectly converts solar radiation into heat energy. The performance of the filmdefinitively determines the efficiency of solar-thermal conversion.Based on the principle of selective solar absorption films，this paper firstlyintroduces the film absorbing mechanism, the way of film materials selection, and thepreparation methods of the film, reviews the development of the selective solarabsorption films all around the world, then a new high selective solarabsorption film solution is presented.Metal and dielectric materials with suitable properties are selected to design ahigh selective solar absorption film with Ti-Si3N4-Ti-Si3N4structure. Based on theadmittance diagram of optical thin film design theory, the thickness of the dielectricfilm is calculated by1/4law for dielectric film, and the thickness of the translucentmetal absorption layer by MATLAB programming, thus the thickness of each layer ofthe stack can be determined. Essential Macleod software is used to simulate the opticalproperties of the designed stack, and the results show that the average reflectivity of thestack is between4%~5%in near-infrared wavelength range, while the absorption rate isbetween95%~96%, fully satisfy the design requirements.The designed Ti (100nm)-Si3N4(60~70nm)-Ti (10~20nm)-Si3N4(60~70nm) stackon glass substrates is fabricated by JGP560magnetron sputtering machine and itsoptical properties are tested. The results show that the average reflectivity of the film isbetween5%~7%in near-infrared wavelength range, and its absorption rate is between93%~95%, which well agrees with the calculation.In the end of this paper, the conclusion is given and some suggestions about thefuture research are put forward. |
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