電致色變材料是近年來被大家廣泛研究的一項薄膜光學技術，它可以被應用在汽車和建築物之視窗玻璃上，以製作節省能源、調節光線及控制熱負荷之智慧型窗戶。使用溶膠-凝膠法製備氧化鎢薄膜有前驅物配置容易、可以調整控制所需薄膜的孔隙度及成分，以及可披覆於大面積基材等優點，故以溶膠-凝膠法製備電致色變薄膜已開始被大家探討及應用。
實驗結果發現添加氧化劑的濃度為2 M時之鍍膜，在波長為550 nm時穿透率改變最大，可以達到70%。氧化鎢薄膜在沒有經過熱處理時為非晶質結構，熱處理到400℃時開始有結晶現象產生，並在500℃時完全結晶，結晶後的薄膜較非晶的更為緻密，而導致薄膜的光學穿透性能有降低的趨勢，但是可以提升薄膜的化學穩定度；故實驗最後利用在前驅物中添加多苯乙烯的高分子球，鍍膜後再以熱處理將其去除，以提升薄膜的孔隙度，進而提升薄膜因為熱處理而下降的光學穿透性能，進而製作出穩定且高效能的氧化鎢薄膜。

In recent years, electrochromism has been extensively utilized due to its potential application in smart windows utilized in architecture and those in automobile glazing. These have its repercussions in preventing energy wastage concomitant with modulation of light and solar radiation transmission.In this study, the precursor solutions were synthesized by sol-gel method while conventional low cost spin –coating technique was utilized for deposition of thin films, no need of high vacuum.

Experimental results indicated that the WO3 films comprising of 2M H2O2 concentration exhibited the optimum electrochromic properties. WO3 films were found to retain their amorphous phase up to 300oC. The onset of the crystalline phase occurs at 400oC and it become completely crystalline at 500oC. After annealing the electrochromic properties of WO3 deteriorate, however their chemical stability is better than the amorphous counterparts.
At the last, the polystyrene intermediate layer was used in order to generate porosity in the WO3 layers, eventually enhancing their surface area. This leads to improve its electrochromic properties and retent its chemical stability, which is the prime requisite for applications in smart windows.

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