丁二腈固態電解質搭配紫精應用於有機電致色變元件

Abstract

本論文主要探討丁二腈固態電解質搭配紫精應用在電致色變元件上，藉由不同的元件設計與搭配，討論搭配不同電致色變材料以及操作環境下的影響。首先對電致色變元件的性質與量測方法作一簡短的介紹，並對有機電致色變材料，紫精，以及高分子變色材料聚苯胺的合成方法以及歷史與應用端做一完整的介紹。本論文主要針對有機電致色變材料進行性能提升之研究，因為這些材料相較於無機材料具有較多樣的顏色變化。這些有機材料之中，以氮原子為變色基團之材料通常能夠提供較短波長光波範圍的吸收。而在這些電氮原子為變色基團之材料中，又以紫精屬於最大宗，使得紫精材料成為本論文之主軸。 紫精系列變色分子的研究由來已久，其高光學穿透度對比一直是其特色之一，然該分子在元件操作中一直存在有分子聚集、老化等現象，不利元件的表現。本論文著重在庚基紫精(Heptyl viologen, HV)與苯基紫精 (Phenyl viologen, PV)為基礎之元件表現上做改進，因該分子具有較低的操作電位。本研究首次以丁二腈 (Succinonitrile, SN)搭配一種紫外光可聚合網狀高分子單體，乙氧基化三羟甲基丙烷三丙烯酸酯 (Ethoxylated trimethylolpropane triacrylate,ETPTA)，在受到紫外光照射後相互交聯，可與丁二腈形成一固態電解質並解決丁二腈本身固態電解質之樹枝狀結晶造成的不易去色問題，且進一步提供電子運動的通道，並應用於電致色變元件中。本研究同時開發出一原位光聚合法，亦即在對一液態的電致色變元件施加電位的同時照射紫外光，使電解質內的光聚合分子ETPTA聚合。本論文發現以此方法合成之固態電解質中，光聚合而成的網狀高分子能進一步將操作中的HV分子固定在電極表面上，使得元件穩定性大幅提升。之後，本研究進一步利用此光聚合固態電解質，搭配另一呈現綠色的PV，因而使得元件穩定性的大幅提升並得到能從透明變色至綠色、藍綠色、藍色之多彩電致色變元件。

In this dissertation, succinnitrile (SN) and viologens-based electrochromic devices (ECDs) were studied. Since this material itself demonstrate significant color contrast, favorable electrochromic performance. Even though the viologens were well-known for their high color contrast, their lack of cycling stability resulted from aggregation or aging process remains. We have successfully developed novel all-solid-sate electrolyte based on succinonitrile (SN) and UV-curable polymer network, Eehoxylated trimethylolpropane triacrylate, ETPTA. ETPTA is added to the SN matrix in order to eliminate the crystalline nature of SN. This all-solid-state ECD made with this non-crystalline solid polymer matrix shows a high optical contrast. We employed polyaniline–carbon nanotube (PANI-CNT) and poly (butyl viologen) (PBV) as electrochromic materials, which was obtain through electropolymerization. In addition, we proposed a facile approach to fabricate viologen-immobilized ECD by in-situ photo-polymerization method, enabled good opto-electrochemical characteristics to the ECD. The polymer matrix in the obtained all-solid-state electrolyte immobilize the heptyl viologen (HV) on the electrode surface, giving better cycling stability. Following this, this UV-curing polymer network is found that it can effectively hinder formation of phenyl viologen (PV) agglomeration, resulting in better cycling stability. Therefore, a SN-based solid electrolyte composed of HV, PV, and UV-cured electrolyte was successfully fabricated and applied for the solid-state ECDs through a simple in-situ UV-curing method. The successful fabrication of multicolor ECDs containing two viologen species is demonstrated; the obtained ECDs showed variable colors, including transparent, green, marine, and gray blue, with a fast switching time. In addition, the proof-of-concept of utilizing di-reduced viologen neutral species with good write–erase ability has been demonstrated.