Variation in luminescence and bandgap of Zn-doped SnO2 nanoparticles with thermal decomposition

Zn doped Tin oxide (SnO2:Zn) nanoparticles have been synthesized by the chemical precipitation route with different thermal decomposition temperatures having emission intensities in visible light and narrowed bandgap. Band gap narrowing and emission intensities can be controlled by doping and calcination. The average particle sizes estimated by TEM agree with those calculated by XRD to be around 18.48 and 21.44 nm and the optical bandgap values found to be 1.30 and 2.52 eV in SnO2:Zn annealed at 400 and 600 A degrees C, respectively. Blue shift in bandgap and decrease in photoluminescence intensity is noticed in (SnO2:Zn) nanoparticles with high annealing temperature, which is due to large grain sizes. As the grain sizes grow so defect density decreases and crystallanity increases. These defects act as luminescent centers and cause decrease in emission intensity and increase in band gap.