在聚光型太陽熱能發電系統(concentrating solar power system, CSP)中，太陽能選擇性吸收膜是提升光熱轉換效率的關鍵，本實驗利用導納軌跡法的概念設計金屬-介電質堆疊的結構，形成在太陽能波段有廣波域的吸收以及紅外線波段低發射率的高效率的吸收膜。材料使用Nb2O5、SiO2、Mo，並搭配橢圓儀、穿透光譜對材料的光學常數進行分析。 膜層結構:Substrate/ Mo / Nb2O5/ Mo/ Nb2O5/ SiO2，設計在太陽能波段400~1200nm的吸收率有98%以上，在溫度300K~600K的發射率可以在10%以下。實際製作的結果在400~1200nm波段的吸收率也可達97%以上，在溫度300K~600K的發射率在8%~12%。在後續的熱穩定性測試中，膜層經過500℃的烘烤後吸收率提升0.24%。 ;In concentrating solar power system, Solar selective absorber is the key of enhancing photo-thermal conversion efficiency. In this research, we design metal-dielectric stack structure base on optical admittance loci, and the structure has broadband absorption in solar energy region and low emissivity in infrared region. The metal layer is Mo, and the dielectric layers are Nb2O5 and SiO2. Also, we use ellipsometer and transmittance spectrum to analyze the optical constant of materials. The structure Substrate/ Mo / Nb2O5/ Mo/ Nb2O5/ SiO2 is designed to have absorption higher than 98% in solar energy spectrum of 400~1200nm and emissivity lower than 10% in infrared region at the temperature of 300K~600K. The fabrication result also has absorption higher than 97% and emissivity about 8%~12%. Then, the solar selective absorber has also shown a good thermal stability up to the temperature of 500℃ and the absorption has risen 0.24%.
