Synthesis and Characterization of SrAl₂O₄:Eu²⁺, Dy³⁺ Nanocrystalline Phosphorescent Pigments

Abstract

In this research, the Eu²⁺ and Dy³⁺ co-doped strontium aluminate (SrAl₂O₄) nanocrystalline phosphorescent pigments with high brightness and long afterglow was successfully synthesized by urea-nitrate solution combustion method (SCS) at 600°C, followed by heating the resultant combustion ash at 1200°C in an atmosphere which was weak reducing (5%H₂ + 95%N₂). The pure SrAl₂O₄ monoclinic phase as host structure could be formed by combustion method in which the temperature is very much lower than solid-state method. A broad-band UV-excited luminescence of the SrAl₂O₄:Eu²⁺, Dy³⁺ phosphorescent pigments was observed at λ_max = 517 nm due to transitions from 4f⁶5d¹ to 4f⁷ configuration of the emission center (Eu²⁺ ions). The excitation spectra showed two main peaks at 240 and 256 nm. Eventually, the average grain size of the combustion ash powder and SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor particles were obtained as 40 and 62 nm, respectively via Scherrer’s formula and these particles were in thin flake form.

Keywords:

• Combustion synthesis
• Pigment
• Nanocrystalline
• Phosphor
• Emission