PBDB-T Accessed via Direct C–H Arylation Polymerization for Organic Photovoltaic Application
Na Chen, Lingjun Yang, Yan Chen, Yu Wu, Xu‐Min Huang, Hui Liu, Hongyan Xie, Lin Hu, Zaifang Li, Shiyong Liu
Abstract
Poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b′] dithio-phene))-alt-(5,5-(1′,3′-di-2-thienyl-5′,7′-bis(2-ethylhexyl)benzo[1′,2′-c:4′,5′-c′]dithiophene-4,8-dione))] (PBDB-T), one of the most important donor polymers in organic photovoltaics (OPVs), is successfully synthesized, for the first time, via atom-economic direct C–H arylation polymerization (DArP). We systematically investigated the effects of reaction parameters on the molecular weights, polydispersity index, optical properties, device performance, and morphologies. Five batches of PBDB-T (P1–P5) with different molecular weights are synthesized under varied DArP conditions. Among them, P5 synthesized with the assistance of tetramethyl-ethylenediamine (TMEDA) co-ligand shows the best performance for OPV device, yielding a 6.52% power conversion efficiency (PCE) in the bulk heterojunction pairing with ITIC. Briefly, an optimal DArP protocol toward PBDB-T has been developed in the current study, which will provide a guideline for the synthesis of high-performance OPV materials in an atom-economic way.