Synthesis and characterization of brightly photoluminescent CdTe nanocrystals

A new synthesis procedure for the preparation of spherical shaped CdTe nanocrystals (NCs) is presented, exhibiting bright luminescence with exceptionally high quantum efficiency (up to 85%). The growth of these NCs occurs in a non-coordinating solvent, octadecene, with the addition of oleic acid/tri-octylphosphine stabilizers, CdO as a precursor for the Cd monomers and additional Cd metal particles as a supplementary Cd reservoir source. The dependence of the crystalline quality and the optical properties of the CdTe NCs, on the initial Cd:Te precursors' molar ratio, and the reaction duration were investigated. It was demonstrated that the NCs' properties improved significantly as the initial Cd:Te molar ratios are increased. The obtained NCs' properties were correlated with measurements of the Cd0 concentration in Cd metal particles, CdTe NCs and in Cd monomer solutions.