Influence of calcining temperature on photoluminescence and triboluminescence of europium-doped strontium aluminate particles prepared by sol-gel process

On the basis of a new modified base-catalyzed sol - gel process and a careful investigation in the structure, this study systematically discussed the effects of the calcining temperature on the microstructure and luminescent properties of europium-doped strontium aluminates (SAO-E). A phase transformation from Sr₃Al₂O₆ to SrAl₂O₄ is found with increasing calcining temperature. The SAO-E sample calcined at 1400 °C for 2 h possesses a SrAl₂O₄ single monoclinic phase (space group P2₁). The light emission transition of SAO-E particles at low calcining temperature originated from both Eu²⁺ and Eu³⁺ ions where the trivalent europium ions were proved to be incorporated in the SrAl₂O₄ phase, which gradually transformed into the divalent ions with increasing calcining temperature. The strong photoluminescence and triboluminescence were obtained without luminance temperature-degradation in this single monoclinic SrAl₂O₄ phase.