Luminescence Behavior of Tm3+ Activated GdAlO3 Phosphors Synthesized Using Solid-Reaction Method

Trivalent thulium ions (Tm3+) doped GdAlO3 (Gd1-xTmxAlO3) phosphors which show a blue luminescence of high color purity have been synthesized by using solid-state reaction method starting from nano-sized powders. X-ray diffraction (XRD) measurements were used to analyze the phase transformations that take place during the preparation of the phosphors. The morphologies of the powders calcined at different temperatures were studied by using scanning electron microscopy (SEM). The luminescence properties of the compounds were investigated. Pure phase of orthorhombic type GdAlO3 (GAP) was yielded by calcining the phosphors at 1200 degrees C for 8 h. The PL spectra showed representative Tm3+ emission. The strong band centered at similar to 488 nm and the weak one centered at 697 nm were attributed to the D-1(2)-F-3(4) and (1)G(4)-F-3(4) transitions of Tm3+, respectively. The quenching concentration of Tm3+ was estimated to be similar to 0.75at.% (x=0.0075), for which can be ascribed to the exchange interactions. The decay curve was fitted to be a single exponent and the estimated fluorescent lifetime of the GdAlO3:Tm3+ phosphor was 1.73 +/- 0.08 ms.