Combustion synthesis of long-persistent luminescent MAl2O4: Eu2+, R3+ (M=Sr, Ba, Ca, R=Dy, Nd and La) nanoparticles and luminescence mechanism research

Abstract Eu 2+ , R 3+ co-doped alkaline earth aluminates MAl 2 O 4 : Eu 2+ , R 3+ (M = Sr, Ba and Ca; R = Dy, Nd and La) nanoparticles with high brightness and long afterglow have been prepared by solution-combustion synthesis at 600 °C without a post-annealing process for the first time. The morphologies and the phase structures of the products have been characterized by transmission electron microscopy and X-ray diffraction. The excitation and emission spectra of the products have been measured by an Edinburgh FLS920 spectrometer at room temperature. The characteristic luminescence of the as-prepared sample has been evaluated, and the reason why the wavelength changed from yellow-green to blue-green and then to blue-purple in visible range when the composition changed from SrAl 2 O 4 : Eu 2+ , Dy 3+ to BaAl 2 O 4 : Eu 2+ , Nd 3+ and then to CaAl 2 O 4 : Eu 2+ , La 3+ has been explained. Furthermore, a new persistent luminescence mechanism was proposed in this article.