Effect of Alkyl Substituents on 2D and 1D Self-assembly and Photovoltaic Properties of Hydrogen-bonded Oligothiophene Rosettes

Abstract : Hydrogen-bonding oligothiophene bearing octyl chains self-assembles into extended nanorods via the formation of cyclic hexamer. The nanorods can function as an electron-donating materials for electron-accepting PC71BM in bulk-heterojunction solar cells. We report the impact of longer alkyl chains on 2D and 1D assembly. Compared to the previously reported hexylated derivative, newly synthesized octylated derivative showed a lower degree of ordering in 2D assembly on a solid–liquid interface, but higher capability in 1D self-assembly into nanorods upon solution-casting.