SYNTHESIS OF CDS QUANTUM DOTS BY MECHANOCHEMICAL REACTION

The synthesis of ultrafine cadmium sulphide quantum dots by mechanoche mical reaction has been studied using X-ray diffraction, transmission electron microscopy and UV-VIS absorption spectroscopy. The solid-stat e displacement reaction of CdCl2 + Na2S --> CdS + 2NaCl induced by mec hanical milling resulted in the formation of CdS particles with an ave rage diameter of < 8 nm. The average particle size was controlled with in the range of 4 to 8 nm by varying the size of the grinding media. T he onset energy of optical absorption showed a blue shift with decreas ing particle size.