KCS

Fullerene is a representative highly conjugated molecular system of which electronic configuration is well defined to behave as a semiconductor and superconductor when properly doped. To extend its vulnerability, geometrically well-defined structures are highly demanded not just for handling them easily during fabrication into electrical devices, but more importantly for modulation of their electrical or optical properties by defining how their neighborhood molecules are positioned. Self-crystallization is a powerful process that allows high definition single crystalline fullerene structures with high specificity in 1D, 2D, and 3D geometries. In this presentation, I will introduce two self-crystallization processes in vapor and solution phases that have successfully resulted in hexagonal C60 disks and wires, as well as C70 cubes. For the hexagonal C60 disks, a simple vaporization-condensation-recrystallization (VCR) process has been employed, and similar C60 disks and wires have been selectively obtained by choosing appropriate solvents in drop-drying process. In the case of C70 molecules, they are spontaneously self-crystallized into very homogeneous cube crystals by a simple precipitation process employing good solvent microcavities in poor solvent media. Together with the detail story of synthesis and structure characterizations, dramatic enhancement of photoluminescence property of C70 cubes will be also introduced.