CdS quantum dots : Aqueous synthesis, spectroscopic and microscopic investigation

School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur-492 010, Chattisgargh, India

E-mail : manmohanchem@gmail.com

Department of Chemsitry, Govt. Madhav P.G. Science College, Ujjain-456 010, Madhya Pradesh, India

Manuscript received online 15 December 2014, revised 25 January 2015, accepted 06 February 2015

The spherical shape CdS quantum dots with cubic zinc blend phase were synthesized through aqueous route using cadmium chloride and thiourea as cadmium and sulfur source and thioglycolic acid as a stabilizing agent. The size regime of the CdS quantum dots is in between 1.5 to 4.1 ± 0.9 nm. The effect of concentration of cadmium and TGA has been investigated to explain the growth kinetics and stabilization of CdS quantum dots. Structural and morphological studies carried out by X-ray diffraction (XRD), Transmission electron microscopy (TEM), and Scanning electron microscopy (SEM). Optical properties have been studied by UV-Visible spectroscopy, Fluorescence measurements, and FTIR analysis. FTIR study suggested the thiolated interaction between CdS and thioglycolic acid. The electronic band gap was found to increase up to 3.93 eV from bulk 2.42 eV. The effect of cationic and anionic surfactants on stabilization of TGA capped CdS quantum dots have been studied. The first order growth kinetic was observed and k_obs 5.78 × 10^–4 s^–1 was obtained in optimized condition.