Structural and optical characterization of Zn doped TiO2 nanoparticles prepared by sol-gel method

Undoped and zinc-doped TiO2 nanoparticles (Ti1-xZnxO2 where x = 0.00-0.10) were synthesized by a sol-gel method. The synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and UV-VIS spectrometer. XRD pattern confirmed the tetragonal structure of synthesized samples. Average grain size was determined from X-ray line broadening using the Debye-Scherrer relation. The crystallite size was varied from 10 to 40 nm as the calcination temperature was increased from 350 to 800 degrees C. The incorporation of 3-5 mol% Zn2+ in place of the Ti4+ provoked a slight decrease in the size of nanocrystals as compared to undoped TiO2. The SEM and TEM micrographs revealed the agglomerated spherical-like morphology with a diameter of about 10-30 nm and length of several nanometers, which is in agreement with XRD results. Optical absorption measurements indicated a blue shift in the absorption band edge upon 3-5 mol% zinc doping. Direct allowed band gap of undoped and Zn-doped TiO2 nanoparticles measured by UV-VIS spectrometer were 2.95 and 3.00 eV at 550 degrees C, respectively.