| Abstract: | 本研究以金屬鎢粉和雙氧水為起始物，添加聚乙二醇 (polyethylene glycol, PEG, MW = 20,000) 並以無水乙醇和二氯甲烷為共溶劑製備前驅物，利用溶膠/凝膠法搭配旋轉塗佈法，於 FTO 導電基材上製備三氧化鎢 (WO3) 薄膜。藉由改變 PEG 與鎢粉之重量比 (PEG / W)，修飾所得 WO3 薄膜之微結構。利用穿透式電子顯微鏡和掃描式電子顯微鏡對薄膜進行表面成分、微結構分析，利用恆電位/恆電流儀和紫外光/可見光光譜儀同步量測進行定性與定量分析，量測薄膜之電化學行為、著/去色應答時間、著/去色吸收光譜、穿透度調幅以及著色效率。PEG 在系統中可抑制三氧化鎢晶型的生成。XRD 實驗結果顯示，當 PEG / W = 1/2 (w / w)時，薄膜為無晶型 (amorphous) 相態，但在高解析度穿透式電子顯微鏡觀察下可發現晶格線的存在，所以推測其為無晶型結構包覆著結晶型態的 WO3 薄膜。薄膜結構中觀察到大小約 5 ~ 8 nm 之微小孔洞分佈，推測為使去色時間較未修飾 WO3 薄膜快速的原因。W-P33 薄膜擁有最佳穿透度調幅 (ΔT = 93.95 % @ 700 nm)，於 700 nm 波長之著色/去色應答時間為19.09 s / 3.82 s，著色效率為50.56 cm2/C。
修飾過之三氧化鎢薄膜中添加四丁氧基鈦 (Titanium(IV) n-butoxide, TTNB)作為光電子提供者，形成具光電致色變性質之薄膜。以上述薄膜為工作電極，濺鍍白金於 ITO 導電基材上為對電極，0.5 M 錪化鋰溶在碳酸丙烯酯為電解質溶液，形成三明治結構之光電致色變元件，並對元件進行照光性質分析。在無外加電場及開路電路狀態之下，將光電致色變元件放置紫外光曝光機下進行著色 (365 nm, 18 mW/cm2)。光電致色變實驗結果顯示，W90 (W / Ti = 90 / 10 (mol / mol)) 薄膜有較佳之光學性能，ΔT = 23.18 % (92.68 % ~ 69.50 %)；電致色變顯示結果，W90 薄膜於 700 nm 波長下之穿透度調幅為 86.86 % (7.98 % ~ 94.84 %)，著色/去色應答時間為 18.86 s / 3.17 s，著色效率為 43.79 cm2/C。
In this study, using the metal tungsten powder and hydrogen peroxide as starting materials, and adding polyethylene glycol (PEG, MW = 20,000) to prepare precursor. Dried anhydrous ethanol and dichloromethane as the solvent of the precursor prepared PEG-template WO3 thin film by sol / gel and spin coating method. Adding PEG to WO3 precursor to modify WO3 thin films microstructure by changing the ratio of PEG / W. The thin film surface component, microstructure analysis obtained from SEM and TEM respectively. In situ potentiostat / galvanostat and UV / Vis study of measuring quantitative and qualitative analysis (electrochemical performance, colored / bleaches state, modulation transmittance and coloration efficiency). Diffusion coefficient of Li ion in the thin film obtained from EIS. As PEG / W = 1 / 2 (w / w), WO3 thin film is amorphous phase by XRD. HR-TEM image reveals that the PEG-template WO3 thin film have line lattice with 5 ~ 8 nm. Combining the XRD, SEM and HT-TEM results, we conclude that the PEG-template WO3 thin film has porous nanostructure of nanocrysrtalline WO3 embedded in an amorphous WO3 matrix. W-P33 thin film has the much better electro-optical performance (ΔT = 93.95% @ 700 nm, tc / tb = 19.09 s / 3.82 s, C.E. = 50.56 cm2/C).
Adding TTNB, photoelectron provider, to be modified WO3 thin film to form photoelectrochromic devices. The above thin film was working electrode and sputtering Pt on the ITO was counter electrode. The electrolyte solution was 0.5 M LiI /PC. On open circuit state, PECD was placed under UV exposure machine (365 nm, 18 mW/cm2) for coloring. W90 (W / Ti = 90 / 10 (mol/mol)) thin film has much better optic properties (ΔT = 23.18 %, 92.68 % ~ 69.50 %). For electrochromic prpperties, it also has great performance (ΔT = 86.86 %, 7.98 % ~ 94.84 % @700 nm, tc / tb = 18.86 s / 3.17 s, C.E. = 43.79 cm2/C). |
