請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/21629
標題: | 含蒽醌之新穎不對稱紫精應用於全波段吸收電致色變元件 Electrochromic Devices with Panchromatic Absorption Based on Novel Asymmetric Viologens with Anthraquinone Unit |
作者: | Kuan-I Chen 陳冠逸 |
指導教授: | 何國川(Kuo-Chuan Ho) |
關鍵字: | ??,不對稱紫精,電致色變元件,膠態電解質,全波段吸收,拉曼光譜, Anthraquinone,Asymmetric viologens,Electrochromic devices,Gel electrolytes,Panchromatic absorbance,Raman spectra, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | 近年來,被稱作紫精的1,1'-雙取代-4,4'-雙吡啶鹽,因其顯著且具高度可逆的電致色變性質而受到高度關注。紫精的雙吡啶部份擁有兩個活性氮原子,不同的官能基可以鍵結到它們上並成為它們的取代基。當兩個活性氮原子上的取代基相同時,該紫精稱為對稱紫精,相反地,當兩個活性氮原子上的取代基不同時,該紫精稱為不對稱紫精。本論文的主要想法是將蒽醌單元和芳基鍵結到紫精上,因芳基紫精通常在光波長大約530奈米處缺乏吸光度,而蒽醌恰好可在光波長大約530奈米處提供吸光度。因此,透過將芳基紫精與蒽醌單元的結合,以合成出新穎的不對稱紫精,預期可以創造出全波段吸收。在這種情況下,本文所提出的紫精將可以從其他大多數只能發出藍色或綠色的紫精中脫穎而出。
本文第三章,選擇蒽醌單元以及對氰基苯作為該不對稱紫精的兩個取代基,從循環伏安圖來看,該不對稱紫精擁有三對氧化還原對,有別於只有兩對氧化還原對的一般紫精,表示蒽醌單元在受到施加電位時也會進行氧化還原反應。本論文提出含有不對稱紫精和作為氧化還原對的二茂鐵的電致色變元件。該電致色變元件在−1.3 V 以及 0 V來回操作時可以在光波長530奈米處提供65.0%之初始光學穿透度變化,以及快速的著去色響應時間(3.05秒著色時間及1.89秒去色時間)。同時,將高分子添加到電解質中以增加黏度後,可以得到良好的長期穩定性,達成在一萬圈連續操作後仍保有其最初83.3%之光學穿透度變化。此外,該電致色變元件的表觀質傳系數也透過Cottrell方程式計算出來,並確認元件內部的工作機制。 本文第四章,追求更佳的長期穩定性一直都是研究電致色變元件學者的終極目標,因此,決定更進一步提升第三章所合成之不對稱紫精的長期穩定性。在此選擇了蒽醌單元以及對第三丁基苯作為第四章中不對稱紫精的兩個取代基,從過去文獻中發現當某個紫精的取代基變得更為龐大時可以改善該紫精的長期穩定性,因龐大的取代基可以避免紫精團聚或形成二聚體。在第四章中合成出的不對稱紫精和第三章中所合成之紫精具有相似的電化學性質,只有在達成全波段吸收的能力上稍有衰減,其可能的原因為不同取代基具有不同的誘導效應所導致。在與第三章具有相同的條件下,第四章所提出的電致色變元件最終可以達成在一萬圈連續操作後仍可保持其最初95.0%之光學穿透度變化。最後,拉曼光譜數據提供本文兩章節所合成之紫精的訊號差異,通過此數據得到改變紫精的取代基確實可以影響其團聚或形成二聚體的傾向,進而提供影響其長期穩定性的直接證據。 本文透過結合蒽醌單元與紫精,成功製作出全波段吸收電致色變元件,使得含紫精的電致色變元件的顏色得以多樣化,並探討當蒽醌單元與不同的紫精結合時對電致色變元件的顏色以及長期穩定性的影響,同時,本文也證實結合兩種不同電致色變材料的構想是可以實現的。 Viologens, also referring as 1,1'-disubstituted-4,4'-bipyridiniums salts, are electrochromic (EC) materials that gain much attention for their dramatic and highly reversible EC properties in recent years. Viologens possess two reactive nitrogen atoms on its bipyridine part, different functional groups can graft onto them and become their substituents. They would be regarded as symmetric viologens when the two substituents of them are the same. In contrast, they would be regarded as asymmetric viologens when the two substituents of them are different. The main idea of this thesis is to graft an anthraquinone unit and an aryl group onto viologen. Aryl viologens often lack absorbance at about 530 nm light wavelength, while anthraquinone happens to provide absorbance at about 530 nm light wavelength. Therefore, we would combine aryl viologens and anthraquinone unit and synthesize novel asymmetric viologens, expecting to produce panchromatic absorbance. In this case, the proposed viologens could stand out from most of the other viologens, which could only produce blue or green color. In Chapter 3, we would choose anthraquinone unit and p-cyanophenyl group as the two substituents of the asymmetric viologen. Differ from other viologens, which only have two redox pairs in their cyclic voltammetric curve, our asymmetric viologen have three redox pairs in its cyclic voltammetric curve, indicating anthraquinone unit also involves redox process as we applied voltages. Through combining the asymmetric viologen with a redox mediator, ferrocene, the electrochromic device (ECD) was fabricated. The ECD could give 65.0% transmittance change (ΔT%) initially at 530 nm light wavelength when being switched between −1.3 V and 0 V. Fast response times (3.05 s in coloring and 1.89 s in bleaching) were observed. Meanwhile, good long-term stability can be obtained after adding polymers into electrolyte to increase the viscosity, maintaining 83.3% of its initial ∆T% after 10,000 continuous cycles. In addition, the apparent diffusion coefficient (Dapp) of the ECD was calculated by Cottrell equation, and the working mechanism of the ECD was also determined. In Chapter 4, pursuing a better long-term stability is always an ambitious goal for researchers investigating ECDs. Therefore, we decided to further improve the long-term stability of the viologen in Chapter 3. We chose anthraquinone unit and 4-tert-butylphenyl group as the two substituents of the asymmetric viologen. From the reported literatures, we found out that the long-term stability could be improved as the substituents of viologens get bulkier, bulkier substituents can prevent viologens from aggregation or forming dimers. The electrochemical properties of the proposed viologen in Chapter 4 are nearly the same with the one in Chapter 3, with only a little decay in the ability of reaching panchromatic absorbance. The possible reason may due to the different inductive effect among the functional groups. The proposed ECD in Chapter 4 could finally retain 95.0% of its initial ∆T% after 10,000 continuous cycles under the same condition with the one in Chapter 3. At the end, Raman spectra data was provided to compare the signals between the viologens in Chapter 3 and Chapter 4, this data provide a direct evidence that by changing the substituents of viologens can actually affect their tendency to form aggregates or dimers and thus further affect their long-term stability. In this thesis, we successfully produced ECDs with panchromatic absorption by combining anthraquinone unit and viologens, making the color of viologen-based ECDs diverse, and discussed the influences on the color and long-term stability of ECDs when anthraquinone unit combined with different viologens. In addition, this thesis also proved that the idea of combining two different EC materials is implementable. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/21629 |
DOI: | 10.6342/NTU201901207 |
全文授權: | 未授權 |
顯示於系所單位: | 化學工程學系 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-108-1.pdf 目前未授權公開取用 | 12.65 MB | Adobe PDF |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。