Stable and highly luminescent US nanocrystals (NCs) have been synthesized by means of decomposition of suitable precursors (CdO and elemental sulphur) in octadecene (ODE) and oleic acid at high temperature. Absorption and steady state photoluminescence (PL) measurements have been carried out to study the intrinsic properties of nanocrystals and the effect of ligand and solvent on emission properties. Ageing of nanocrystals has been investigated, and an efficient mechanism of emission recovery has been identified, showing the active role of non coordinating solvent and oleic acid in modifying the surface states. (C) 2003 Elsevier Science B.V All rights reserved.