Synthesis, crystal structure and photoluminescence properties of new blue-green Ba1−x(PO3)2:Eux2+ (0 < x ≤ 0.040) phosphors for near ultraviolet based white light-emitting diodes

Abstract

A series of new blue-green Ba_1−x(PO₃)₂:Eu_x²⁺ (x = 0.005, 0.010, 0.020, 0.030, 0.035, 0.040) phosphors were synthesized by a solid-state reaction. The phase purities and crystal structures of the series were characterized by X-ray diffraction (XRD) and Rietveld refinements. Their photoluminescence properties were investigated by means of excitation, emission spectra and Commission International de L'Eclairage (CIE) chromaticity coordinates. The concentration quenching mechanism of Eu²⁺ emission in Ba(PO₃)₂ hosts was studied. Thermal stability was evaluated by temperature-dependent luminescence of Ba_0.970(PO₃)₂:Eu_0.030²⁺ phosphor. Moreover, the activation energy (E_a) for thermal quenching was calculated. The photoluminescence of Ba_0.970(PO₃)₂:Eu_0.030²⁺ phosphor shows higher thermal stability than that of the commercial blue phosphor BaMgAl₁₀O₁₇:Eu²⁺ (BAM). All the results show that Ba(PO₃)₂:Eu²⁺ phosphor is a potential blue-green phosphor for near ultraviolet-based white light-emitting diodes (WLED).