Hydrothermal synthesis, characterization and luminescence properties of orange–red-emitting phosphors SnO₂:Eu

Abstract

Orange–red-emitting phosphors SnO₂:Eu nanoparticles were synthesized by hydrothermal method followed by calcination process. The phase structure, morphology, optical absorption and luminescence properties of the obtained samples were characterized by X-ray powder diffraction, scanning electron microscopy, UV–Vis optical absorption spectra and photoluminescence spectra. The results indicated that the as-synthesized SnO₂:Eu was all tetragonal phase with space group P42/mnm when pH = 1. The particles were nearly spherical in shape, and the average size was about 100 nm. The excitation spectrum was composed of a broad band ascribed to the direct optical transition from the valence band to the conduction band of SnO₂. The emission spectrum was consisted of a strong peak and several weak peaks, and the main peak was at 589 nm, corresponding to the ⁵D₀ → ⁷F₁ magnetic dipole transition of Eu³⁺. The SnO₂:xEu phosphors presented excellent orange–red-emitting properties when the concentration (x) of Eu³⁺ was 0.09, pH = 1, calcination temperature and time were 900 °C and 3 h, respectively.