Improvement of the photoluminescent intensity of ZnTa{sub 2}O{sub 6}:Pr{sup 3+} phosphor
Highlights: • The optimal luminescence intensity was obtained for 0.4 mol% Pr{sup 3+} doped ZnTa{sub 2}O{sub 6}. • The ZnTa{sub 2}O{sub 6}:Pr{sup 3+} has a colour index matching an ideal red emission. • The cross relaxation process led to a decrease in red emission at higher Pr{sup 3+} concentrations. • The blue emission continues to increase at higher Pr{sup 3+} concentrations. • The persistent luminescent increases with an increase in Pr{sup 3+} concentration. - Abstract: A red emitting ZnTa{sub 2}O{sub 6}:Pr{sup 3+} 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 ZnTa{sub 2}O{sub 6} was crystallized. A homogeneous distribution of the Pr{sup 3+} 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 Pr{sup 3+} 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 {sup 1}D{sub 2} ⟶ {sup 3}H{sub 4}, {sup 3}P{sub 0} ⟶ {sup 3}H{sub 6} and {sup 3}P{sub 0} ⟶ {sup 3}F{sub 2} transitions of Pr{sup 3+}, respectively. With increasing concentration of Pr{sup 3+}, 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.