Synthesis of BaAl 12O 19:Mn 2+ nanophosphors by a reverse microemulsion method and its photoluminescence properties under VUV excitation

Abstract

BaAl 12O 19:Mn 2+ nanoparticles were successfully synthesized by a reverse microemulsion method. The nanoparticles were characterized by transmission electron microscopy, X-ray diffraction and photoluminescence measurements. The results indicate that BaAl 12O 19:Mn 2+ with spherical morphology can be synthesized at 1200 °C, which is about 300 °C lower than that of solid state reaction with size ranging from 40 to 100 nm. Monitored at 515 nm, the excitation spectra of as-prepared BaAl 12O 19: x Mn 2+ (0.1⩽ x⩽0.5) and bulk BaAl 12O 19:0.1 Mn 2+ are similar. The bands at 130 and 156 nm were observed and assigned to the optical absorption of AlO 4 and AlO 6 groups, respectively. The emission band position of nano-BaAl 12O 19:0.1 Mn 2+ is 6 nm shorter than that of the bulk due to the low symmetry of crystal field near the surface of nano-BaAl 12O 19:Mn 2+. The optimum emission intensity was obtained at x=0.2 of Mn 2+ doping. Furthermore, the decay behaviors of nano-sized and bulk BaAl 12O 19:0.1 Mn 2+ have also been discussed.