Kinetically Controlled, High-Yield Synthesis of Au_(25) Clusters

摘要

Noble metal nanoparticles (e.g., Au, Ag) have become one of the most important types of nanomaterials that are being extensively explored in nanoscience and nanotechnology research. Between metal atoms and bulk metals, there are two distinct size regimes of particular interest, that is, the clu ster state and the nanocrystal state. state. Metal nanoclusters (M_n~0, n = the number of metal atoms in the core) are ideally composed of an exact number of metal atoms (n ranging from several to hundreds of atoms), and their size typically ranges from subnanometer to approximately 2 nm (core diameter). Because of the strong quantum confinement of electrons in this extremely small size regime, electron energy quantization occurs, and such an effect drastically alters the physical and chemical properties of metal clusters, for example, plasmon excitation, which is characteristic of metal nanocrystals, no longer exists in the cluster state.