In this study we used Suzuki cross-coupling to synthesize three new donor/acceptor copolymers - PFTBO, PAFTBO, and PCTBO - featuring soluble alkoxy-modified 2,1,3-benzooxadiazole (BO) moieties as acceptor units and electron-rich building blocks - dialkyl fluorene (F), alkylidene fluorene (AF), and carbazole (C), respectively - as donor units. These polymers, which we characterized using gel permeation chromatography, thermogravimetric analysis, NMR spectroscopy, UV-Vis absorption spectroscopy, and electrochemical cyclic voltammetry, exhibited good solubility, low-lying energy levels for their highest occupied molecular orbitals, excellent thermal stability, and air stability. Using these polymers, we fabricated bulk-heterojunction solar cell devices having the structure indium tin oxide/poly(3,4-ethylenedioxythiophene): polystyrenesulfonate/polymer:[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) (1:1, w/w)/Ca/Al. Under AM 1.5G illumination (100 mW cm-2), the solar cell incorporating PFTBO exhibited a high value of Voc of 1.04 V and that based on PCTBO provided a power conversion efficiency of 4.1% without the need for any post treatment.
- Donor/acceptor conjugated polymers
- Polymer solar cell
- Suzuki coupling