A method of preparing a polymeric composition with photovoltaic properties comprises a step of blending, in a solvent, at least one electron donor type semiconductor polymeric material essentially in the form of nanofibrils and at least one electron acceptor type material in the solvent, said nanofibrils representing at least 10% by weight of the electron donor type semiconductor polymeric material, to polymeric compositions with photovoltaic properties, and to photovoltaic cells incorporating such polymeric compositions.