隨著經濟的蓬勃發展，民生用品需求之增加，各種製造業之興起，工業污染亦隨之増加，人們生活環境的品質受到嚴重的水及空氣的污染，偵測污染源提出預警變得愈來愈重要。為了改善傳統氣體感測器之昂貴、笨重與偵測耗時的缺點，近年來已有許多的研究專注於薄膜氣體感測器之研發。本研究利用 block copolymer 作為界面活性劑，WCl6 為原料，以溶膠凝膠法製備介孔WO3薄膜，浸鍍於鍍有白金電極之 Al2O3 基板作為氣體感測器。經 X-ray，SEM，TEM，BET 分析元件材料微結構，並量測不同溫度下之電阻值變化，研究介孔結構之 WO3 對 NOx 氣體感測性質之影響。
實驗結果顯示，本實驗所用之介孔 WO3 薄膜，當其製造時使用界面活性劑 F127 (Pluronic EO100PO64EO100) 經 250 ℃ 煆燒後，可獲得扭曲之 monoclinic 結構，由 XRD 圖形計算其晶粒大小約為 3.8 nm。對 NO2 氣體之感測於 100 ℃ 操作時有最大之靈敏度，偵測 3 ppm 之 NO2 之靈敏度約為 226。如改以界面活性劑 F68 製作，於操作溫度 120 ℃，通入 100 ppm NO 時，介孔氧化鎢感測器之靈敏度達最高值 160。
此外，WO3 的高著色效率亦使其成為一種重要的變色材料。本研究同樣利用溶膠凝膠法製作介孔 WO3，並利用紫外-可見光光譜儀測定介孔 WO3 的能隙及探討其變色行為。研究結果顯示 ; 介孔 WO3 經 250 ℃ 煆燒後求出其能隙值為 3.5 eV。當介孔氧化鎢以紫外光照射時，由無色變為深藍色，照射前後之改變量幾乎可以完全回復。

Our environment has suffered damage as the economic expands. In order to improve the drawbacks of expensive, heavy and time-consuming in traditional gas sensors, many studies have focused on thin film gas sensor recently.
Mesoporous WO3 thin films were deposited on Al2O3 substrate as gas sensor by sol-gel process in this study. The effects of calcining temperatures on the structure of mesoporous WO3 were investigated by X-ray diffraction, SEM, TEM and BET analyses. Sensor properties for NO2 were also investigated.
Mesoporous WO3 thin film obtained is characterized with distorted monoclinic structure. The grain size of 3.8 nm calculated from XRD result was obtained after calcining at 250℃for 5 hrs. The sensitivity for NO2 depends on the operation temperature, which has a maximum value of 226 for 3 ppm NO2 at 100℃ with good reproductivity and stability.
For the optical properties, the optical band gap value of mesoporous WO3 is found to be 3.5 eV. The mesoporous WO3 exhibits the photochromic effect upon exposure to the UV-light. The optical change during the exposure and removal of the UV-light is almost reversible.

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