Studies on Optical Properties of CdS/ZnO Quantum Dots Prepared by Sol-Gel Method

Abstract

CdS/ZnO quantum dots (QDs) were prepared at a temperature of 293 K by the sol-gel method with Triethanolamine (TEA) as a capping agent. The effect of CdS/ZnO mixture ratio of 1:9, 1:1 and 9:1 on the optical absorption and fluorescence spectra were investigated by UV-Vis and Fluorescence spectroscopy. By increasing ZnO composition, a blue-shift of absorption edge and emission spectra were observed. The band gap for 1:9, 1:1 and 9:1 were found to be 4.13, 3.93 and 3.11 eV, respectively. The morphology of the CdS/ZnO QDs for each mixing ratio was obtained by transmission electron microscope (TEM). The size of the QDs was found to be in the range of 5-10 nm with some agglomerated particles.