Lin, Y.-C.Y.-C.LinHuang, Y.-W.Y.-W.HuangWu, Y.-S.Y.-S.WuLi, J.-S.J.-S.LiYang, Y.-F.Y.-F.YangWEN-CHANG CHENCHU-CHEN CHUEH2021-08-052021-08-05202126376105https://www.scopus.com/inward/record.uri?eid=2-s2.0-85103445695&doi=10.1021%2facsapm.1c00006&partnerID=40&md5=c6ced9d40948199dbe71a87456fb56a0https://scholars.lib.ntu.edu.tw/handle/123456789/576244P3HT, as one of the most important conjugated polymers, has been reported to possess low mobility and poor stretchability. In this study, two polythiophenes are prepared by attaching ester-substituted, biaxially extended conjugated side chains with backbones of 3-(thiophen-2-yl)-6-(thiophen-3-yl)thieno[3,2-b]thiophene-bithiophene (PDCTT2T) and 3-(thiophen-2-yl)-6-(thiophen-3-yl)thieno[3,2-b]thiophene-difluorobithiophene (PDCTT2T-F) and compared with their respective counterparts without the biaxially extended side chains (thieno[3,2-b]thiophene-bithiophene and thieno[3,2-b]thiophene-difluorobithiophene backbones for PDCTT and PDCTT-F). Through investigating mobility-stretchability properties of these four polymers, the synergetic effect of ester-substituted, biaxially extended conjugation and backbone fluorination is demonstrated to improve mobility-stretchability properties of polythiophenes, especially in a highly stretched state. On the one hand, the biaxially extended side chains implant a more amorphous structure and reinforce the intramolecular charge transfer between polymer backbones. On the other hand, the backbone fluorination confers to a rigidified polymer backbone, facilitating effective intrachain charge transport. As a result, PDCTT2T-F delivers superior mobility (0.20 cm2 V-1 s-1) to PDCTT-F (0.054 cm2 V-1 s-1) alongside 11 times higher mobility retention at a 100% strain. In addition, both PDCTT2T and PDCTT2T-F encouragingly retain decent mobility throughout 800 stretching-releasing cycles (at a 60% strain), outperforming their respective parent polymers without side-chain conjugation that show a one-order decrease in mobility. The results shown in this work signify an effective design strategy to fine-tune mobility-stretchability properties of polythiophenes. ? 2021 American Chemical Society.Charge transfer; Esters; Fluorination; Halogenation; Polymeric implants; Thiophene; Amorphous structures; Design strategies; Extended conjugation; Intra-molecular charge transfer; Polymer backbones; Polythiophene derivatives; Superior mobility; Synergetic effect; Conjugated polymersjournal article10.1021/acsapm.1c000062-s2.0-85103445695