Polymer-regulated epitaxial crystallization of methanofullerene on mica.

This work focuses on both the structure manipulation and the crystallizing mechanism investigation of the well-known methanofullerene, [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM). PCBM crystals with two novel structures, i.e., five-fold twinned and cubic crystals are obtained by the introduction of the mica substrate and the polymer blenders (P3HT and PS) into PCBM thin films under thermal annealing. The morphology and nanostructure of these crystals have been well investigated with AFM, TEM and XRD techniques. The roles of the mica substrate and the polymer blenders have been studied by varying the annealing temperature, the substrate, the polymer benders and the blending ratio. It has been proved that both the PCBM intermolecular and PCBM-mica interactions influence the PCBM crystallization process. The mica substrate has been proved to have the epitaxial effect on PCBM crystallization. The polymer blenders have been suggested to weaken the PCBM intermolecular interaction and limit PCBM molecular diffusion.