Core-functionalized dendritic oligothiophenes-novel donor-acceptor systems

Novel core-functionalized dendritic oligothiophenes (DOT) bearing pyridine or methylpyridinium acceptors have been synthesized up to the third generation. A bathochromic shift in the absorption of the functionalized dendritic oligothiophenes and the appearance of new absorption bands were noticed issuing from an intramolecular charge transfer process. These novel donor-acceptor systems are, due to their broad absorption, promising materials for optoelectronic applications such as organic solar cells. By electrochemical measurements HOMO/LUMO energy levels have been determined and two compounds could be identified with almost ideal energy levels for application in bulk heterojunction solar cells (BHJSC) with fullerene PC61BM as acceptor.