Hydrogen bonding in bulk heterojunction solar cells: A case study

Small molecules with dithieno[3,2-b;2',3'-d]thiophene as central building block and octyl cyanoacetate and octyl cyanoacetamide as different terminal building blocks have been designed and synthesized. The amide containing small molecule can form intermolecular hydrogen bonding between N-H center dot center dot center dot O = C of the amide group. The photovoltaic properties and active layer morphologies of the two molecules in bulk heterojunction solar cells are compared to study the influence of hydrogen bonding on the active layer morphology. New methanofullerene compound containing amide group has also been synthesized and compared with conventional fullerene electron acceptors.