The colloidal synthesis of QDs is well suited for the fabrication of engineered heterostructure nanoparticles such as CdSe/CdS (core/shell). By changing the shell thickness and core size, the emission of type-I QDs can be tuned easily and within a widerange. This paper describes the synthesis of coreshell CdSe/CdS quantum dots (QDs) in non aqueous solution by new sol gel route. CdSe sol was prepared by cadmium acetate and selenium dioxide precursor at a Cd:Se concentration ratio of 1:1.complexing with Triethlioamine and heating the sol for up to 3 h at 70°C. The sol is continuously stirred to transform it into the gel. Solution become orange in colour but gel is appeared after around 24 hours. For core shell preparation. Thiourea (0.05 mg) as a sulfur source was added separately to the asprepared CdSe QDs (50 mL) to maintain a constant S:Se molar ratio of 1. Upon increasing the temperature (80°C), the size of the CdSe/CdS QDs increases. Colour Tunability is observed with increasing temperature. In this paper we describe the details of preparation techniques and its optical characterization.
Nanoparticles, semiconductor, CdSe/CdS, Quantum dots
