P-type semiconducting dendrimers bearing thiophenyl peripheral moieties: Effect of alkyl chains on molecular packing geometry

First generation thiophene-labeled conjugated dendrimers have been synthesized through the Heck coupling reaction between the 5-vinyl-[2,2'] bithiophenyl derivative and 1,2,4,5-tetrabromo-benzene as a core. One dendrimer has hexyl groups at the periphery and the other does not have it. They display a considerably better solubility than the linear conjugated oligothiophene. We observe drastic spectral change in a film state of dendrimer due to crystallization and a high extent of intermolecular interaction. Effect of peripheral alkyl groups on the intermolecular interaction and lamella orderness was investigated using two dendrimers.