Study on Electronic Properties of Composite Clusters toward Nanoscale Functional Advanced Materials

Clusters consisting of 10-1000 atoms size-dependently exhibit novel electronic and geometric properties. In particular, composite clusters composed of several elements and/or components provide a promising way for a bottom-up approach for designing functional advanced materials, because the functionality of the composite clusters can be optimized not only by the cluster size but also by their compositions. This account surveys recent investigations of composite clusters focusing on the efforts to create a new functional composite cluster by a fine doping or hybridization based on their size-specific electronic properties. Organometallic clusters and caged clusters are demonstrated as a representative example of designing the functionality of magnetism and electronic state structures. In order to create functional nanomaterials, furthermore, a fine controlling methodology of the soft-landing technique has been developed to fix the composite clusters onto a surface decorated with a self-assembled monolayer. The embedded isolation mechanism on the substrate is discussed form the viewpoint of self-assembly phenomena with the molecular ordering of a sigma-sigma interaction, and also the electronic structures characterized by molecular ordering of pi-pi interaction is intrinsically revealed by molecular clusters of pi-conjugate polyacenes as a model for self-assembled aggregates.