Synthesis and Photoluminescence Properties of SnO₂Nanopowder

SnO 2 nanopowder was synthesized by calcining metastannic salt (SnO 2 ·H 2 O) prepared by chemically etching metallic Sn in aqueous HNO 3 solution. The calcined SnO 2 nanopowder was investigated by X-ray diffraction (XRD) measurement and photoluminescence (PL) spectroscopy. The XRD and PL intensities increased with increasing calcining temperature, yielding an activation energy of ∼0.65 eV. The PL spectra of the calcined SnO 2 nanopowder exhibited green (G) and red (R) emission bands with peaks at ∼2.5 and ∼2.0 eV, respectively, that were clearly dependent not only on the excitation light wavelength but also on the sample temperature. The temperature dependence of the PL intensity between 20 and 300 K was explained by the thermal quenching with activation energies of ∼15 meV ( T =20–60 K) and ∼0.12–0.18 eV ( T ≥100 K). The G and R emission states were found to originate from the Jahn–Teller effect of the 5s 2 (Sn 2+ ) ions in the SnO 2 matrix and were similar to those generally observed in many ns 2 -doped alkali halides and SnCl 2 .