Combinatorial effects of solvent type, thermal annealing and al electrode on the morphology of P3HT: PCBM layer

Abstract

Poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM) films were spin-cast using either pure chlorobenzene as the solvent or a chlorobenzene:dichlorobenzene solvent mixture. Compared to films fabricated using pure chlorobenzene, those prepared using the mixed solvent showed better crystallinity of the P3HT domains and a higher initial tensile strain. Thermal annealing relieved the tensile strain and increasing the domain crystallinity. The films spin-cast using the solvent mixture exhibited minimal Al atom diffusion into the P3HT:PCBM layer during thermal annealing. The presence of an Al layer enhanced the grazing incidence small angle X-ray scattering contrast between the P3HT and PCBM domains at the Al layer interface.