Synthesis and photovoltaic performance of a low bandgap fluorinated phenanthrenequnioxaline-based conjugated polymer

摘要

A novel alternating copolymer with benzo[1,2-b:4,5-b']dithiophene as electron-rich unit and fluorinated phenanthrenequinoxaline segment as electron-withdrawing unit was synthesized. The polymer showed a low-lying highest occupied molecular orbit energy level of -5.34 eV with a very low bandgap of 1.53 eV. Solar cell devices were fabricated by using the polymer as donor and [6,6]-phenyl-C71-butyric acid methyl ester as acceptor, respectively. The photovoltaic properties were studied and power conversion efficiency of 1.90% was obtained with an open-circuit voltage of 0.72 V for an optimal donor/acceptor weight ratio of 1:2 with 3% 1,8-diiodooctane. These results demonstrated that fluorine substituted phenanthrenequinoxaline based D-A conjugated polymer might be promising materials for bulk heterojunction photovoltaic cells. (C) 2014 Elsevier B.V. All rights reserved.