A novel copolymer from benzodithiophene and alkylsulfanyl-bithiophene: Synthesis, characterization and application in polymer solar cells

摘要

We present the synthesis and characterization of a novel copolymer from benzodithiophene and alkylsulfanyl-bithiophene units, poly[4,8-bis(2- ethylhexyloxy)benzo[1,2-b:4,5-b′]dithiophene-alt-4,4′- bis(octylsulfanyl)-2,2′-bithiophene] (PolyS). The structural, electrochemical and photophysical properties of PolyS were investigated by gel permeation chromatography (GPC), thermogravimetric analysis (TGA), NMR, UV-vis, photoluminescence (PL) spectroscopy and cyclic voltammetry (CV). PolyS was used to fabricate bulk-heterojunction polymer solar cells (PSCs) in combination with the [60]PCBM and [70]PCBM (electron acceptors). The device realized using [70]PCBM shows a better current output due to the increased absorption of the blend film compared to the PolyS:[60]PCBM one. The power conversion efficiency of the best PSC realized is 2.3% under 100 mW/cm ~2AM 1.5 G illumination.