Acta Chim. Sinica ›› 2018, Vol. 76 ›› Issue (9): 691-700.DOI: 10.6023/A18040178 Previous Articles     Next Articles

Article

一种基于聚噻吩-聚硒吩全共轭嵌段共聚物的合成及性质研究

崔惠娜, 邱枫, 彭娟   

  1. 聚合物分子工程国家重点实验室 复旦大学高分子科学系 上海 200433
  • 收稿日期:2018-04-28 出版日期:2018-09-15 发布日期:2018-07-12
  • 通讯作者: 彭娟 E-mail:juanpeng@fudan.edu.cn
  • 基金资助:

    项目受国家自然科学基金(Nos.21674024,21320102005)和科技部(No.2016YFA0203301)资助.

Synthesis and Properties of an All-Conjugated Polythio-phene-Polyselenophene Diblock Copolymer

Cui Huina, Qiu Feng, Peng Juan   

  1. State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433
  • Received:2018-04-28 Online:2018-09-15 Published:2018-07-12
  • Contact: 10.6023/A18040178 E-mail:juanpeng@fudan.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21674024, 21320102005) and Ministry of Science and Technology of China (No. 2016YFA0203301).

All-conjugated rod-rod block copolymers (BCPs) have gained immense interest over the past few years because they combine fascinating self-assembly properties of BCPs with the optical and electronic properties of conjugated polymers. Based on it, an all-conjugated rod-rod BCPs, poly(3-hexylselenophene)-b-poly[3-(6-hydroxyl)hexylthiophene] (P3HS-b-P3HHT) with hydroxyl groups as side substitution groups was synthesized via the Grignard metathesis (GRIM) method. The introduction of side hydroxyl groups was designed to endow different polarity between P3HS and P3HHT blocks and enrich the solution structures of P3HS-b-P3HHT. During thermal annealing, the cross-linking of hydroxyl groups was also utilized to improve the thermal stability of poly(3-hexylthiophene) (P3HT)-based organic field-effect transistors (OFETs) when blended with a certain amount of P3HS-b-P3HHT. On one hand, the use of mixed solvents provided an effective way to control the self-assembly behavior of P3HS-b-P3HHT. Depending on the mixed solvent ratio (i.e., chloroform/pyridine or methanol/pyridine), the rod-rod interaction of the copolymer chains was controlled, yielding a series of nanostructures such as nanoribbons, nanofibers, and nanospheres. Detailed morphologies and the corresponding photophysical behavior of different nanostructures were characterized by transmission electron microscope and UV-vis absorption spectra. The conformations of the P3HS and P3HHT chains in the solutions influenced their photophysical properties greatly. On the other hand, based on the thermal cross-linkable properties of hydroxyl groups, a certain amount of P3HS-b-P3HHT was mixed with P3HT homopolymer to fabricate P3HS-b-P3HHT/P3HT OFETs. For control samples, the charge carrier mobility of pure P3HT-based OFETs was improved with the increased annealed temperatures up to 170℃, then decreased significantly when the temperature further increased to 200℃. While overall, the charge carrier mobilities of P3HS-b-P3HHT/P3HT OFETs were lower than those of pure P3HT-based OFETs, they were improved with the increased temperature to 200℃. It was found the P3HS-b-P3HHT(10%)/P3HT OFETs exhibited the charge carrier mobility of 0.040 cm2·V-1·s-1 after annealing at 200℃ for 1 h, which was higher than P3HT OFETs (0.025 cm2·V-1·s-1) under the same experimental condition. It was due to the cross-linking of hydroxyl groups in P3HS-b-P3HHT retain the crystallization structures of P3HT, thus improved the thermal stability of OFETs. Overall, this work demonstrates a new polythiophene-polyselenophene BCP with controlled nanostructures by solvent blending and promising application in OFETs to improve their thermal stability.

Key words: all-conjugated diblock copolymer, polythiophene, polyselenophene, solution self-assembly, organic field-effect transistors (OFETs)