Lin Kaiwen, Li Caiting, Tao Wang, Huang Jilong, Wu Qinghua, Liu Zijin, Zhang Yangfan, Wang Da, Liu Xi
Department of Materials and Food, Zhongshan Institute, University of Electronic Science and Technology of China, Zhongshan, China.
School of Textile Materials and Engineering, Wuyi University, Jiangmen, China.
Front Chem. 2020 Sep 8;8:819. doi: 10.3389/fchem.2020.00819. eCollection 2020.
A total of six conjugated polymers, namely PDBT-Th, PDBT-Th:Th, PDBT-2Th, PDBT-Th:2Th, PDBT-2Th:Th, and PDBT-2Th:2Th, consisting of dibenzothiophene, thiophene, and bithiophene were electrochemically synthesized. Their electrochemical and electrochromic properties were investigated in relation to the conjugation chain lengths of the thiophene units in the conjugated backbones. Density functional theory (DFT) calculations showed that longer conjugation lengths resulted in decreased HOMO-LUMO gaps in the polymers. The optical band gaps ( ) and electrochemical band gaps ( ) were decreased from PDBT-Th to PDBT-Th:Th, however, PDBT-Th:2Th, PDBT-2Th, PDBT-2Th:Th and PDBT-2Th:2Th displayed the similar band gaps. The conjugation length increments significantly improved the electrochemical stability of the conjugated polymers and exhibited reversible color changes due to the formation of polarons and bipolarons. The results suggest that the conjugated polymers prepared herein are promising candidates for fabricating flexible organic electrochromic devices.
总共六种由二苯并噻吩、噻吩和联噻吩组成的共轭聚合物，即PDBT-Th、PDBT-Th:Th、PDBT-2Th、PDBT-Th:2Th、PDBT-2Th:Th和PDBT-2Th:2Th，通过电化学方法合成。研究了它们的电化学和电致变色性质与共轭主链中噻吩单元共轭链长度的关系。密度泛函理论（DFT）计算表明，共轭长度增加导致聚合物中HOMO-LUMO能隙减小。从PDBT-Th到PDBT-Th:Th，光学带隙（ ）和电化学带隙（ ）减小，然而，PDBT-Th:2Th、PDBT-2Th、PDBT-2Th:Th和PDBT-2Th:2Th显示出相似的带隙。共轭长度的增加显著提高了共轭聚合物的电化学稳定性，并由于极化子和双极化子的形成而呈现可逆的颜色变化。结果表明，本文制备的共轭聚合物是制造柔性有机电致变色器件的有前途的候选材料。
