Cyano substituted (Z)-(thienylmethylene)-2-indolone as a new building block for near-IR absorbing polymers
Dong Zhao, Jiawei Zheng, Jianxin Tang, Qing Zhang
Index: 10.1016/j.dyepig.2018.02.042
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Abstract
A new electron withdrawing monomer, cyano substituted (Z)-(thienylmethylene)-2-indolone (TEI(CN)) has been synthesized and polymerized with different donors to give three alternating donor/acceptor conjugated polymers. The cyano substituted polymers showed significantly reduced LUMO energy levels and small optical bandgaps compared with un-substituted polymer. The optical absorptions of new polymers mainly appeared in NIR region range, peaked at 700–800 nm. With strong electron donor EDOT, the polymer, PTEI(CN)-EDOT showed most of its absorption in NIR region (>700 nm). The inverted bulk hetero-junction polymer solar cells based on two of the new polymers were fabricated and tested.