Synthesis of a side chain conjugated polythiophene copolymer and its photovoltaic property

A new soluble polythiophene copolymer with phenylene–vinylene conjugated side chain (PEHOPVTh-Th) was synthesized. Polymer photovoltaic solar cells using PEHOPVTh-Th as donor and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) as acceptor was demonstrated. The absorption spectrum of the PEHOPVTh-Th showed strong absorption in the visible region and a 55 nm red-shift in comparison with that of its homopolymer (PEHOPVTh). By adjusting the ratio of PEHOPVTh-Th to PC61BM, the polymer solar cells based on PEHOPVTh-Th showed a power conversion efficiency of 0.37% under 100 mW/cm2 AM 1.5G simulated sunlight when the weight ratio of the polymer to PC61BM equals to 1:3.