Structure and Thermal Degradation of CdSe Nanoparticles Capped with Mercaptoacetic Acid

We have prepared different sizes of CdSe nanoparticles with different amounts of capping molecules on their surface. Through Colloidal method, the nanoparticles were prepared using different starting precursors and different ratios of the starting reagents. We have characterized the prepared nanoparticles by Energy dispersive X-ray (EDX), X-ray diffraction (XRD), UV-Vis optical absorption, infrared spectroscopy and thermogravimetric analysis. The EDX analysis showed that the extracted nanoparticles have different ratios of the constituent of the capping molecule relative to CdSe core. X-ray and UV-Vis analysis revealed that there is a graded diffusion of sulfur on the surface of the nanoparticles. The graded diffusion of sulfur decreased for the rich selenium prepared samples. Infrared analysis proved the coordination of thiol and carboxylate groups to the surface of the nanoparticles. On the other hand, thermogravimetric analysis showed that the size of the nanoparticles and amount of capping molecules have a high influence the thermal degradation of the nanoparticles.