エレクトロクロミズム材料ビルディングブロック

セレノフェンはチオフェンよりも低い酸化電位と電子供与性を有し，共役ポリセレノフェンポリマーが新しい機能性材料として注目されています。Toppareらは，セレノフェンを原料に用いた共役セレノフェンモノマーの合成について報告しています。またこのモノマーから電解重合により作成したエレクトロクロミック素子は，電圧0.0 Vで薔薇色，1.3 Vで青色，応答速度0.5-0.6秒の良好なエレクトロクロミズムを示し，2000サイクルの電圧印加の後もその特性を保持します。

“A bis-selenophene substituted alkoxy benzene derivative as a highly stable novel electrochromic polymer”

Y. A. Udum, S. Tarkuc, L. Toppare, Synth. Met. 2009, 159, 361. DOI: 10.1016/j.synthmet.2008.08.012

Up to date there are few studies reporting the use of selenophene derivatives as electrochromic polymers. This report highlights the synthesis of a selenophene containing multi-ring aromatic polymer which possesses reasonable optical contrasts at both visible and near-IR regions. Electrochemical synthesis of a conducting polymer from a multi-ring aromatic monomer, 2-(2,5-bis(hexyloxy)-4-(selenophen-2-yl)phenyl)selenophene (BSB(OC₆H₁₃)₂), was achieved at a lower potential than its corresponding parent, selenophene. The strong absorption band for the undoped polymer was 474 nm and the onset energy for the π–π^* transition (Eg) was 1.9 eV (645 nm).

A novel dual-polymer electrochromic device was constructed in sandwich configuration where poly(BSB(OC₆H₁₃)₂) was used as the anodically coloring material. It is the first electrochromic device where a selenophene-containing polymer was used as an active layer. The device switches between a rose-colored state and a blue-colored state with a fast response time (less than 1 s).