Dye-functionalized head-to-tail coupled oligo(3-hexylthiophenes)—perylene–oligothiophene dyads for photovoltaic applications

Abstract

A series of novel donor–acceptor systems, consisting of head-to-tail coupled oligo(3-hexylthiophene)s covalently linked to perylenemonoimide, is described. These hybrid molecules, which differ by the length of the oligothiophene units from a monothiophene up to an octathiophene, were created via effective palladium-catalyzed Negishi and Suzuki cross-coupling reactions in good to excellent yields. The optical and electrochemical properties of these compounds were determined and based on this series structure–property relationships have been established which give vital information for the fabrication of photovoltaic devices. Because the synthesized perylenyl–oligothiophenes distinguish themselves by a high absorption between 300 and 550 nm and an almost complete fluorescence quenching of the perylene acceptor, they meet the requirements for organic solar cells.