Synthesis of Quinoxaline-Based Donor−Acceptor Narrow-Band-Gap Polymers and Their Cyclized Derivatives for Bulk-Heterojunction Polymer Solar Cell Applications
thiophene-substituted quinoxaline monomer 5,8-bis(5-bromothiophen-2-yl)-2,3-bis(5-octylthiophen-2-yl)quinoxaline (TTQx) or its cyclized phenazine derivative monomer 8,11-bis(5-bromothiophen-2-yl)-2,5-dioctyldithieno[2,3-a:3′,2′-c]phenazine (TTPz) as acceptors, were synthesized via Suzuki coupling reaction. It was found that the copolymers based on thiophene-substituted quinoxaline TTQx exhibit obviously