石墨烯/氧化鎢奈米複合型材料 於電致變色元件之應用研究

Abstract

近年來，奈米結構材料應用於電致變色元件上已被廣泛的研究，其中具備有高比表面積的一維奈米結構氧化鎢最受到矚目。同樣的，石墨烯為一種高比表面積的奈米結構。且因其電阻率極小，擁有快速的電子遷移速率，所以被大量應用於電子元件上，在本論文中我們也用於複合氧化鎢奈米結構至電致變色元件上的應用。 本論文實驗過程中，初始先以水熱法完成石墨烯/氧化鎢奈米束狀結構製備，後續搭配旋鍍法將水熱合成完之石墨烯/氧化鎢複合結構沉積於可撓式基板上。製程中調整石墨烯含量、水熱前驅液濃度及反應時間等實驗參數，進而找出最佳化製備條件，將氧化鎢奈米束狀結構應用於可撓式電致變色元件研究。 實驗結果顯示，在石墨烯/鎢離子前驅液濃度10mM、水熱反應時間6h及溫度180oC之水熱條件下，所合成之石墨烯/氧化鎢複合奈米束狀結構具備有多孔隙外形和八面體結晶性，將其應用於可撓式電致變色元件，可呈現出較佳著/褪色穿透率變化(40.1%)、最短著/褪色切換響應時間(著色6.5秒和褪色4秒)、優異的著色效率變化(250.1cm2 C-1)和化學穩定性。在最後，我們將其作成元件，並量測其的電致變色特性。

In recent years, nano-structured materials for electrochromic device have being widely explored. Among them, WO3 and graphene 1D nano-structured have attracted great attention due to their large specific surface area. Their fast electron mobility results in low resistivity is suitable for electronic component and application.

In this thesis, the combination of those two materials as graphene-WO3 composite that have unique characteristic in electrochromic application was comprehensively studied. The production of GRA (graphene)/WO3 nanobundles structure was synthesized by hydrothermal method. Spin coating technique was used to deposit hydrothermally synthesized GRA/WO3product on flexible substrate. We are able to find optimum condition by adjusting graphene contents, precursor solution concentration, and hydrothermal time.

Highly porous morphology and octahedral crystal structure of GRA/WO3nanobundles was successfully hydrothermal-synthesized by using 2 mg graphene and 10mM tungsten ion precursor for 6 hours at 180oC. In addition to this flexible electrochromic device, transmittance can be increased up to 43.7% with shortest switching response time (6.5 and 4 sec for colored and bleached, respectively), excellent color efficiency (250.1 cm2 C-1), and chemically stable. Besides, production of GRA/WO3 compound by reflux method was also studied in this work.