Control of microstructure in polymer: Fullerene active films by convective self-assembly

It is nowadays accepted that the optoelectronic properties of the donor-acceptor active layers are microstructure dependent and can be manipulated by employing various film deposition techniques. In this work, we show that fully intercalated co-crystalline polymer:fullerene microstructure can be obtained when depositing thin films using convective self-assembly technique. Moreover, this microstructure appears to be dependent, under specific film casting conditions, on the fullerene size. Use of slightly bigger fullerenes is leading to a multi-phase microstructure comprised of neat polymer domains, fullerene aggregates and co-crystalline polymer:fullerene structures.