Effect of Annealing Temperatures on Structural and Luminescence Properties of SnO2 Nanoparticles

This study aims to understand the structural and photoluminescence properties of SnO2 synthesized via the facile sol–gel method by systematically varying annealing temperatures. X-ray diffraction (XRD) analysis reveals that all samples possess a polycrystalline single-phase tetragonal rutile structure with no detectable impurity phases. Both the crystallite size and crystalline quality of the samples increase with rising annealing temperatures. Raman spectroscopy demonstrates the presence of forbidden Raman and IR-active modes in SnO2 nanoparticles. The positions and intensities of the Raman peaks are significantly influenced by the annealing temperature, which correlates with variations in crystallite size and crystalline quality of the synthesized materials. Additionally, photoluminescence (PL) spectra exhibit peaks in both the ultraviolet (UV) and visible regions. The UV emission peaks arise from electron recombination near the band gap, while the visible emission peaks are attributed to oxygen vacancies () and tin interstitials. This research provides valuable foundational knowledge that will support future studies on SnO2.