Synthesis and characterization of polythiophene containing side chain electron acceptor for OPV

Abstract

The two new semiconducting polymers, poly((sexithiophene-5,5'''''-diyl)bis(tridecan-1-one))(PSTTO) and poly((sexithiophene-5,5'''''-diyl)bis(tridecan-1-one)bithiophene) (PSTTOBT), are synthesized and characterized. PSTTO and PSTTOBT have backbone donor and side chain acceptor structure. Compare to poly(3-hexylthiophene), both polymers had deep HOMO levels of 5.15 and 5.14 eV, respectively, due to intramolecular repulsing between the main chain and side chain as well as the introduction of electron withdrawing side chains. In addition, the introduction of bithiophene into the repeating unit of PSTTOBT showed increased long wave absorption and better intermolecular interaction. PSTTO and PSTTOBT based cell showed power conversion efficiencies of 1.1% and 1.6%, respectively.