An alternating donor-acceptor conjugated polymer based on benzodithiophene and [3,4-c]pyrrole-4,6-dione: Synthesis, characterization, and application in photovoltaic devices

Abstract

The synthesis is described of a new alternating donor-acceptor semiconducting polymer based on an N-octylthieno[3,4-c]pyrrole-4,6-dione building block together with a newly designed 2,3-bis(2-ethylhexyl)thiophenylethynyl substituted benzodithiophene (BDT). The introduction of electron-rich thiophene units to BDT raises the highest occupied molecular orbital (HOMO) level of the conjugated polymer and the concomitant reduction of the bandgap enhances the harvesting of solar radiation. This modification also introduces less sterically demanding triple bonds, thereby potentially enabling more favourable molecular interactions and an extra dimension of conjugation perpendicular to the main polyme..