SYNTHESIS OF CdS QUANTUM DOTS USING WET CHEMICAL CO-PRECIPITATION METHOD

Size tunable Cadmium sulphide (CdS) quantum dots have been synthesized through wet chemical co-precipitation method, at three different temperatures 35C, 50C and 65C for varying pH values of 9 and 10.5 respectively. The solution was prepared using Cadmium chloride and thiourea as material precursors, ammonium hydroxide as precipitating agent and mercaptoethanol as surfactant. Thin films of these nanoparticles were deposited by dip coating technique on glass substrate. The formation of CdS quantum dots was confirmed through their structural characterization using X-Ray diffraction (XRD) technique. Photoluminescence (PL) spectroscopy was used to investigate the optical behaviour of as synthesized CdS quantum dots. XRD analysis reveals that these quantum structures have single phase hexagonalcubic structure. It has also been found that the particle size depends on both temperature and pH. The PL spectra shows the large stoke shift for CdS bulk as compared to CdS nano particle which implies reduction of particle size.