Síntese e caracterização de nanopartículas semicondutoras comnanoestruturas tipo núcleolcasca CdS/CdSe obtidas por rota coloidal

Abstract

Quantum Dots (QDs) are semiconductor nanoparticles with quantum confinement properties. The synthesis of these nanocrystals via aqueous route, when compared to other synthesis methods, is reproducible, less toxic and capable of forming biocompatible materials. Poly (vinyl alcohol), PVA, has significant importance in the stabilization and control of nucleation and growth of cadmium sulfide QDs (CdS), as it is a semicrystalline polymer which is soluble in water with good interfacial characteristics. Some aspects have been studied as the influence of temperature and variation of the molar ratio of cadmium and sulfur in the synthesis of CdS QDs core. The morphological characterization was performed by transmission electron microscopy (TEM), the analysis of the size of QDs was made by the program ImageJ. A spectroscopic characterization by ultraviolet visible (UV-Vis) was also carried out to monitor the formation and stability of quantum dots of CdS core and CdS/CdSe setting in core/shell. Finally a spectroscopic characterization by photoluminescence (PL) was performed to monitor the emission spectra of CdS QDs core and CdS/CdSe core/shell. It was then possible to synthesize CdS QDs with average core diameters of 3,4 nm in the QDs and CdS / CdSe core / shell with an average diameter of 3,9 to 4,4 nm, stable colloidal solution.