Improvement of the photoluminescent intensity of ZnTa2O6:Pr3+ phosphor

• The optimal luminescence intensity was obtained for 0.4 mol% Pr3+ doped ZnTa2O6.
• The ZnTa2O6:Pr3+ has a colour index matching an ideal red emission.
• The cross relaxation process led to a decrease in red emission at higher Pr3+ concentrations.
• The blue emission continues to increase at higher Pr3+ concentrations.
• The persistent luminescent increases with an increase in Pr3+ concentration.

A red emitting ZnTa2O6:Pr3+ phosphor with Commission Internationale de l‘Eclairage coordinates that match those of an ideal red emission was prepared by solid state chemical reaction. X-ray diffraction confirmed that a pure orthorhombic phase of ZnTa2O6 was crystallized. A homogeneous distribution of the Pr3+ ions was confirmed from the analysis of the time of flight secondary ion mass spectroscopy overlay images. In addition to the reflectance at 259 nm associated with band-to-band absorption, minor reflectance peaks associated with f-f transitions of Pr3+ were observed at 420–500 nm. The main red emission peak was split into minor peaks located at 608, 619 and 639 nm that were assigned to 1D2 ⟶ 3H4, 3P0 ⟶ 3H6 and 3P0 ⟶ 3F2 transitions of Pr3+, respectively. With increasing concentration of Pr3+, a relatively weak blue emission was observed at 488 nm and this phenomenon maybe attributed to virtual charge transfer or/and inter cross relaxation effects. The decay characteristics of the persistent emission were also calculated.

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