초록 |
The general mechanisms for the nucleation and growth of colloidal cadmium chalcogenides, CdE (E = S, Se, Te), quantum dots/rods are studied in order to control the size and shape of nanocrystals. Quantum-sized CdE nanocrystals were synthesized by the reaction of CdCl2 as a Cd-precursor and elemental S powder, TOPSe and TOPTe as a chalcogenide precursor respectively in an oleylamine solution. CdE quantum dots and rods with various sizes and aspect ratios were obtained under relatively low reaction temperature (120~160℃). As-prepared CdE nanocrystals obtained without further size-sorting process were nearly monodisperse and highly crystalline and were found to have quantum sized diameters below 10nm. The effect of process variables including monomer concentration, reaction time and initial precursor ratio on nucleation and growth of nanocrystals were examined. By controlling these factors, novel sized and shaped nanocrystals can be reproducibly obtained. |