November 4th (Thu) Graduate Seminar / Prof. Junpei Kuwabara

Facile Synthetic Method of Conjugated Polymers

Conjugated polymers are promising materials for organic optoelectronic devices such as organic photovoltaics (OPVs), organic field effect transistors (OFETs), and organic light emitting diodes (OLEDs). For wide applications of these devices, efficient synthetic methods of conjugated polymer materials are required because conventional methods do not satisfy requirements in cost and environmental considerations. The conventional methods require metal-containing monomers such as organotin compounds causing cost and environmental issues because of their multi-step synthesis and toxicity. For overcoming these issues, polycondensation via direct C-H arylation (C-H/C-X coupling) has been developed to avoid the use of metal-containing monomers [1]. The optimization of reaction conditions enabled to afford conjugated polymers with high molecular weight and high purity, which are regarded as important factors improving OPV performances. For example, the obtained polymer showed better power conversion efficiency (4%) in OPV than the same polymer prepared by a conventional method (0.5%) [2]. Further development of this methodology resulted in synthesis of a donor-acceptor polymer showing higher performance in OPVs (6.8 %) [3]. Recently, polycondensation using cross dehydrogenative coupling (C-H/C-H coupling) has been developed as a 2nd generation method [4].

Scheme 1: Synthetic methods of conjugated polymers.

References 

1. J. Kuwabara, T. Kanbara, Bull. Chem. Soc. Jpn., 2019, 92, 152-161. (Review)

2. J. Kuwabara, T. Yasuda, S. J. Choi, W. Lu, K. Yamazaki, S. Kagaya, L. Han, T. Kanbara, Adv. Funct. Mater., 2014, 24, 3226-3233.

3. J. Kuwabara, Y. Fujie, K. Maruyama, T. Yasuda, T. Kanbara, Macromolecules, 2016, 49, 9388–9395.

4. H. Aoki, H. Saito, Y. Shimoyama, J. Kuwabara, T. Yasuda, T. Kanbara, ACS Macro Lett., 2018, 7, 90-94.