以PEDOT及PMeT構成之全塞吩電致色變元件之光電性質及最適化

The Electro-optical Properties and Optimization of a PEDOT-PMeT All-thiophene Electrochromic Device

黃詩雯(Shih-Wen Huang)

指導教授 ： 何國川

國立臺灣大學/工學院/化學工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.10076

摘要

本研究論文首次提出以PEDOT搭配PMeT之全塞吩有機電致色變元件，在顏色變化上可由亮紅色轉為深藍色。對於單極薄膜性質，除了針對PEDOT及PMeT之電致色變性質及操作穩定性加以分析，更以EQCM分析離子進出薄膜之現象，在過氯酸鋰鹽之有機電解質溶液中，於不同操作電位下以循環伏安法及階梯電位法皆獲相同結論，即在p-type摻雜及去摻雜的過程中，陽離子(Li+)及陰離子(ClO4-)皆參與摻程過程，此數據亦可進一步改善元件表現與長期穩定性質。基於對單極薄膜的了解，此全塞吩PEDOT-PMeT 構成之元件首先對兩極電量比作最適化研究，再以不同之著、去色電位做長期穩定性之最適化實驗，以0.5 V為去色電位及-1.3 V為著色電位，於655 nm波長下具有40 % 之穿透度變化，且在30,000圈之連續階梯電位操作後仍具有22 %。對於電致色變元件來說，以往的研究不具有良好的可信度且無法得知元件操作時之單極電位分布，而本研究進一步改進文獻中之實驗裝置，以雙電流電位儀之方式，量測到單極薄膜於元件內之著、去色電位分布。得到單極薄膜之電位分布後，對於整體元件之操作衰退可有更可靠的數據支持元件操作時，單極薄膜是否操作於理想電位，有助了解電位偏離之情形。除此之外本研究亦以不同電量比之元件，得到單極薄膜電位分布之趨勢與理論的預測吻合。在本研究的最後階段，以PVDF-HFP高分子基質加入電解質液中形成之膠態電解質可減少元件漏液情形並提高安全性，適用之膠態電解質具有良好的導離度，且對於元件表現及長期穩定性的表現並無明顯不良影響。

關鍵字

電致色變元件 ； EQCM ； poly(3,4-ethylenedioxythiophenes)(PEDOT) ； 聚三甲基塞吩 ； 電位分布

並列摘要

A novel all-thiophene ECD with a color change from light red to deep blue was presented. For PEDOT and PMeT thin film properties, not only the basic electrochromic performances and stabilities but also the ion transfer phenomena cycled in lithium perchlorate organic electrolyte were studied upon different of cyclic voltammetric and potential step methods. Based on the understandings of PEDOT and PMeT thin films, the optimization of the PEDOT-PMeT ECD was searched by varying the charge capacity ratio at first, and then by exploring the long-term stabilities with different bleaching and darkening potentials. Finally, the optimized potentials were obtained: 0.5 V for bleaching and -1.3 V for darkening. The transmittance change was 40 % at 655 nm, and after 30,000 potential step cycles, the transmittance change still remained 22 %. In literature, studies were either rare about the potential distributions on each electrode within an ECD or the reported data were not reliable. In this thesis, a method reversibly measure the potential distributions of PEDOT and PMeT within the ECD by a bipotentiostat was established, and it can help us to observe the real state of each thin film, thus to improve the performances of the ECD. The potential distributions of PEDOT and PMeT within the ECDs with different charge capacity ratios were recorded by this method and the operating windows of each thin film within the ECDs were obtained, which was in good agreement with the theoretical prediction. Finally, in order to improve the liquid electrolytes’ leakage problem and for safety concern, the PVDF-HFP was added to the ordinary liquid electrolyte as a polymer matrix.

並列關鍵字

Electrochromic device (ECD) ； EQCM ； poly(3,4-ethylenedioxythiophenes) (PEDOT) ； poly(3-methylthiophene) (PMeT) ； potential distribution

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