Effect of [6,6]-phenyl-C 61-butyric acid methyl ester on the morphology of poly(3-hexylthiophene) film

Abstract

The change of morphology of poly(3-hexylthiophene) (P3HT) film as a result of blending with [6,6]-phenyl-C 61-butyric acid methyl ester (PCBM) was studied using a freeze-dry method. A porous structure was observed as the P3HT/PCBM solution was freeze-dried. The pore size decreased as the proportion of PCBM increased in the P3HT/PCBM blended film. Additionally, the freeze-dried P3HT/PCBM film was more resistant to the formation of PCBM crystals than that prepared by a spin-coating method during the thermal annealing process. Homogeneous distribution of PCBM in the freeze-dried P3HT/PCBM film was the main reason for the reduction of large PCBM crystal formation. Addition of [6,6]-phenyl-C 61-butyric acid methyl ester (PCBM) to poly(3-hexylthiophene) (P3HT) solution induced local aggregation of P3HT and resulted in a pore structure with smaller pore size than that without PCBM. © 2011 Society of Chemical Industry.