Chalcogenophene-Sensitive Charge Carrier Transport Properties in A–D–A′′–D Type NBDO-Based Copolymers for Flexible Field-Effect Transistors

• Published in: Macromolecules 2018-11, Vol.51 (21), p.8662-8671
• Main Authors: Shi, Keli, Zhang, Weifeng, Zhou, Yankai, Wei, Congyuan, Huang, Jianyao, Wang, Qiang, Wang, Liping, Yu, Gui
• Format: Article
• Language: English
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/acs.macromol.8b01944

The use of chalcogenophenes runs through the whole history of developing high performance π-conjugated materials toward organic electronics devices. In this work, we report three A–D–A′–D type (3E,7E)-3,7-bis­(2-oxo-1H-pyrrolo­[2,3-b]­pyridin-3­(2H)-ylidene)­benzo­[1,2-b:4,5-b′]­difuran-2,6­(3H,7H)-dione- (NBDO-) based π-conjugated copolymers containing different chalcogenophenes, i.e., 4,7-di­(thiophen-2-yl)­benzo­[c]­[1,2,5]­thiadiazole (TTT), 4,7-di­(selenophen-2-yl)­benzo­[c]­[1,2,5]­thiadiazole (STS), or 4,7-di­(selenophen-2-yl)­benzo­[c]­[1,2,5]­selenadiazole (SSS). The effects of chalcogen atom on their optoelectronic properties were explored by a range of techniques, including thermal, optical, electrochemical, computational, molecular aggregation, and carrier transport properties. Interestingly, both PNBDO-TTT and PNBDO-STS formed highly ordered, crystalline, and lamellar packing thin films with uniform intertwined fibrillar morphologies, whereas PNBDO-SSS only gave random molecular packing thin film with amorphous morphology, despite their similar chemical structures, optical and electrochemical properties. In consequence, PNBDO-TTT and PNBDO-STS-based flexible field-effect transistors on PET substrate exhibited high electron mobilities of 2.41 and 2.68 cm2 V–1 s–1, respectively, whereas PNBDO-SSS-based ones only showed a lowered electron mobility of 0.012 cm2 V–1 s–1.