Synthesis of conjugated structural copolymer poly(3-hexylthiophene-random-benzoyl dithieno[3,2-b:2’,3’-d]pyrrole) by electrochemical method

Abstract

Electrochemical copolymer synthesis of benzoyl dithieno[3,2-b:2’,3’-d]pyrrole and 3-hexylthiophene (3HT) promises to create new polymer with suitable improved HOMO and LUMO with the energy level of acceptor compounds such as Fullerene (C60) or the novel accepted organic compound in the heterojunction in organic solar cell. Electrochemical synthesis of copolymer (3-hexylthiophene-random benzoylbdithieno[ 3,2-b:2’,3’-d]pyrrole by linear potential scanning method was studied and applied for synthesis of conjugated copolymer where three electrodes have been used for polymerisation including the working electrode of Indium Tin Oxide (ITO) substrate, the reference electrode of Ag/AgCl in saturated KCl and the counter electrode of platinum wire. The synthesised copolymer was characterised and evaluated through an electrochemical process, Fourier- transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and ultraviolet-visible spectroscopy (UV-Vis) measurements. The synthesised copolymer has a bandgap of 2.09 eV, HOMO and LUMO energy levels of -5.21 and -3.12 eV, respectively. The HOMO-LUMO of the synthesised conjugated copolymer is closed with the HOMO-LUMO of Fullerene; therefore, the conjugated copolymer is a potential material for the fabrication of organic solar cell.