Metal nanoclusters consist of a small number of atoms, at most in the tens. These nanoclusters can be composed either of a single or of multiple
elements, and typically measure less than 2
nm.
[1][2] Such nanoclusters exhibit attractive electronic,
optical, and chemical properties compared to their larger counterparts.
[1][2][3][4] Materials can be categorized into three different regimes, namely bulk,
nanoparticles or
nanostructures and atomic clusters. Bulk metals are
electrical conductors and good optical reflectors, while metal
nanoparticles display intense colors due to surface
plasmon resonance.
[3][4] When the size of metal nanoclusters is further reduced, to 1nm or less, in other words to just a few atoms, the
band structure becomes discontinuous and breaks down into discrete
energy levels, somewhat similar to the energy levels of
molecules.
[3][4][5][6][7]