The effect of changes in π-conjugated terthienyl systems using thienyl and ethylenedioxybenzene functionalized thieno[3,4-b]pyrazine precursors: Multicolored low band gap polymers

详细信息    查看全文

• 作者：Simge Tarkuc ; Elif Kose Unver ; Yasemin Arslan Udum ; Cihangir Tanyeli ; Levent Toppare
• 关键词：Electrochemical polymerization ; Conducting polymer ; Low band gap polymer ; Electrochromism ; Thienopyrazine
• 刊名：Electrochimica Acta
• 出版年：2010
• 出版时间：1 October 2010
• 年：2010
• 卷：55
• 期：24
• 页码：7254-7258
• 全文大小：422 K

文摘

New classes of thieno[3,4-b]pyrazines containing thienyl and ethylenedioxy phenyl units on electron-withdrawing moieties of π-conjugated terthienyl were synthesized. The effect of structural differences on electrochemical and optoelectronic properties of the resulting polymers was investigated. Changes in the electronic nature of the functional groups enable to tune the electrochemical properties of the π-conjugated terthienyl monomers by lowering oxidation potential from 0.62 V (DTTP) to 0.56 V (DBTP). Spectroelectrochemical analyses revealed that the neutral polymer (PDBTP) is dark green in its neutral state revealing π–π* transitions in two well-separated bands at 410 and 751 nm. The electronic band gap of polymer, defined as the onset of the π–π* transition, is found to be 1.0 eV. Using the thienyl unit instead of ethylenedioxy phenyl, a red shift in the band gap (0.95 eV) is observed. The polymer, PDTTP, exhibits multicolor electrochromism and can be switched between a dark yellow neutral state, a green intermediate state, and a brown oxidized state. PDBTP also shows a multicolored electrochromic behavior with three distinct states: dark green at the neutral state, a brown intermediate state, and a brown-violet oxidized state.