Self-assembly of porphyrin and fullerene supramolecular complex into highly ordered nanostructure by simple thermal annealing

The homeotropic alignment of one nanoscale liquid crystalline porphyrin and fullerene supramolecular complex into highly ordered nanostructure by simple thermal annealing, was investigated. The porphyrin was prepared in a facile synthesis, and its chemical structure was identified by H NMR. The porphyrin-fullerene blend was prepared by mixing porphyrin with PCBM in 30:1 molar ratio in Ch₂Cl₂ followed by the removal of solvent under reduced pressure. The absorption spectrum of porphyrin in Ch ₂Cl₂ changed upon the addition of PCBM, and the absorption at the Soret band is decreased whereas the absorptions at about 260 and 327 nm wavelength are increased. Synchrotron XRD obtained from an optically dark homeotropic monodomain in thin film confirms the homeotropically aligned crystal phases of both materials, which their molecules stack into columns forming a hexagonal lattice.