Microstructure and luminescence properties of Co-doped SnO2 nanoparticles synthesized by hydrothermal method

Co-doped SnO2 nanoparticles were synthesized by a simple hydrothermal method, and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectra (DRS) and Photoluminescence spectroscopy (PL). It is found that the SnO2 crystallites with the tetragonal rutile structure formed directly during the hydrothermal process without calcination. The Co-doped SnO2 nanoparticles were spheric and well-dispersed with narrow size distribution. The crystalline size of SnO2 decreased from 5.98 to 2.22 nm when the Co content increased from 0% to 20%. A considerable red shift in the absorbing band edge was observed with increasing of Co dopant.