A method for the production of a robust, chemically stable, crystalline, passivated
nanoparticle and composition containing the same, that emit light with high efficiencies
and size-tunable and excitation energy tunable color. The methods include the thermal
degradation of a precursor molecule in the presence of a capping agent at high
temperature and elevated pressure. A particular composition prepared by the methods
is a passivated silicon nanoparticle composition displaying discrete optical transitions.
