ELECTRONICS OF COLLOIDAL NANOMETER PARTICLES

Small colloidal particles) and clusters*) of semiconductors and metal s exhibit unusual properties and may be considered as a new physico-ch emical dimension between the molecules and the bulk materials. The sur face to volume ratio is extremely large; small-particle research there fore constitutes a combination of solid state and surface science. The electronic properties of the particles (light absorption, colour, flu orescence, catalytic and photocatalytic activity, electrochemistry etc .) depend on particle size. Chemical surface modification affects thes e properties and allows one to prepare new nano-structures in solution , in layers, and in the crystalline state. No attempt is made in the p resent article to review the whole field, but to describe this new bra nch of colloid chemistry by focussing on a few selected topics.