Effect of electron-donating methoxy groups on photovoltaic properties of triphenylamine-substituted quinoxaline-based polymers

Abstract

In this study, two p-type quinoxaline-based donor–acceptor (D–A)-type conjugated polymers were designed and synthesized for use in polymer solar cells. An electron-donating benzodithiophene (BDT) moiety was polymerized with an electron-accepting triphenylamine-substituted quinoxaline unit under Stille coupling conditions to afford the target polymer, PBS-TAQ. To investigate the effect of electron-donating groups on the polymer, methoxy groups were introduced onto the triphenylamine substituents on the 2 and three positions of the quinoxaline acceptor to produce polymer PBS-MDTAQ. After confirming the chemical structures of the two polymers, their optical, electrochemical, and photovoltaic properties were carefully investigated. Notably, the photovoltaic properties of the triphenylamine-substituted quinoxaline-based polymers were significantly reduced by the presence of methoxy groups on the triphenylamine substituents.