Photoluminescence analysis of α-Al2O3 powders doped with Eu3+ and Eu2+ ions

Alumina (Al2O3) powders doped with europium trivalent (Eu3+) were prepared by a low-temperature (∼280 °C) combustion synthesis technique. When the powder was heat treated at 1200 °C for 2 h in the presence of flowing ammonia (NH3), α-Al2O3 crystalline ceramic powders was obtained. The analysis of the luminescence showed that Eu3+ was reduced to europium divalent (Eu2+) after the heat-treatment process. Under ultraviolet (UV) lamp excitation (λ=254 nm) these powders containing sub-microcrystalline structures present bright red (Al2O3:Eu3+) and green (Al2O3:Eu2+) luminescence indicating that this material is a potential candidate for applications in phosphor technology.