Tunable Cathodoluminescence Properties of Tb[sup 3+]-Doped La[sub 2]O[sub 3] Nanocrystalline Phosphors

Abstract

Nanocrystalline Tb3+ -doped La2 O3 phosphors were prepared through a Pechini-type sol-gel process. X-ray diffraction (XRD), field-emission-scanning electron microscopy (FESEM), photoluminescence, cathodoluminescence (CL) spectra, and lifetimes were utilized to characterize the synthesized phosphors. The XRD results revealed that a pure La2 O3 phase can be obtained at 700°C. FESEM images indicated that the La2 O3: Tb3+ phosphors are composed of aggregated spherical particles with sizes ranging from 60 to 100 nm. Under the excitation of UV light and low voltage electron beams (0.5-3 kV), the La2 O3: Tb3+ phosphors showed the characteristic emissions of Tb3+ (D5 3,4 - F7 6,5,4,3 transitions). The CL colors of La2 O3: Tb3+ phosphors was tuned from blue to green by changing the doping concentration of Tb3+ to some extent. The optimum blue CL of La2 O3: Tb3+ phosphors had better Commission International l'Eclairage (CIE) coordinates and higher emission intensity than those of the commercial product Y2 SiO5: Ce3+ (blue, product no. 1047, Nichia Kagaku Kogyo Kabushiki, Japan). © 2009 The Electrochemical Society.