From organic powders to geometrically well defined low-dimensional structures: A way for unprecedented optical and chemical properties

Scaling down the size of a bulk material into a quantum size regime grants new optical and electrical properties due to the emergence of discrete electronic energy states according to the quantum size effect. Another way to secure new optical, electrical and chemical properties is to design and grow crystalline low dimensional structures from individual ensemble molecules, which is known as meso size effect. The meso size effect is especially of great interest for highly conjugated molecules. For example, we have recently demonstrated that C70 cubes are directly crystallized from individual C70 molecules in solution phase, and the C70 cubes emit strong photoluminescence (PL) due to the reduced exciton scattering sites by the crystallization. In this presentation, I will introduce new examples that exhibit unprecedented optical and chemical properties upon the crystallization of individual multi-phenyl ring molecules and macrocyclic molecules into 1D wires. The synthetic method, crystal plane-dependent PL activity and crystal structure-dependent intermolecular interaction changes that are primarily induced by the crystallization will be discussed in detail.