SYNTHESIS OF CdTe QUANTUM DOTS IN AQUEOUS PHASE USING MERCAPTOSUCCINIC ACID

Abstract

Highly luminescent CdTe quantum dots (QDs) are the most widely used nanoparticles for making fluorescent biosensors and optoelectronic devices. In this paper, we present the successful synthesis of CdTe QDs in the aqueous phase using mercaptosuccinic acid (MSA) as a capping ligand. The CdTe QDs were formed by the reaction of the Te precursor (in TeO2) with Cd2+/MSA in solution at 80 oC for 30 min, then annealing in an autoclave at different temperatures (110 - 150 oC) and time intervals (60 - 180 min). The synthesis of QDs in water has many advantages such as the simplicity, environmental friendliness, and using cheap chemical agents, and particularly make the CdTe QDs suitabble for bioapplications because of the biocompatibility. The high quality of the synthesized CdTe QDs was confirmed by X-ray diffraction (XRD) and their optical properties. The XRD pattern shows the cubic zinc blende structure of the synthesized CdTe QDs. Additionally, the influences of the synthesis parameters, namely the annealed temperature, time to the optical properties of the obtained QDs were systematically investigated with regard to the growth rate and particle size. As a result, CdTe QDs become bigger causing the red-shifted of peaks in their absorption and photoluminescence spectra with increasing annealed temperature and time. This provides evidence for the quantum confinement effect.