Combustion synthesis and optimization of Tb³⁺-doped AZr₂(PO₄)₃(A⁺= Li, Na, K) phosphors for mercury-free lamp and plasma display panels application

Abstract

Tb doped AZr 2 (PO 4 ) 3 (AZP) green phosphors were synthesized by novel solution combustion method and the excitation spectra of pure compound in the vacuum ultraviolet (VUV) regions are investigated. The VUV characteristic was optimized by Tb 3+ concentration and by alkali metals A + (Li, Na, K) contents. The concentration quenching was observed when the concentration of Tb 3+ was 2.0 at % of Zr 2 . The band ranging from 130 to 160 nm in excitation spectra is due to the absorption band of host lattice or PO 4 groups; the band at 160-200 nm is related to the charge transfer (CT) transition of O-Zr. The strong band at 225 nm and the weak band at 261 nm in the excitation spectra are assumed to the spin-allowed and spin-forbidden f-d transitions (4f 8 → 4f 7 5d 1 ) of Tb 3+ .The excitation and emission spectra indicate that the phosphors can be effectively excited by 147 nm and 172 nm and demonstrated a satisfactory green light performance. The high luminescent intensity, excellent color purity and chemical stability of AZr 2 (PO 4 ) 3 :Tb 3+ make it an attractive green emitting phosphors for mercury free luminescent lamp and plasma display panel. The prepared phosphor sample was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Vacuum ultraviolet spectra were studied.