Effects of Gd3+ substitution on the structure, photoluminescence, scintillation, and thermometric features of Pr3+:Lu2Zr2O7 phosphors

In this study, it is shown how the photoluminescence, scintillation, and optical thermometric properties are managed via the introduction of Gd3+ ions into Pr3+:Lu2Zr2O7. Raman spectra validate that partial replacement of Lu3+ with Gd3+ can promote the phase transition of Lu2Zr2O7 host from the defective fluorite structure to the ordered pyrochlore one. Upon 289 nm excitation, all the samples emit the 483 (P-3(0) & RARR; H-3(4)), 581 (D-1(2) & RARR; H-3(4)), 611 (P-3(0) & RARR; H-3(6)), 636 (P-3(0) & RARR; F-3(2)), and 714 nm (P-3(0) & RARR; F-3(4)) emissions from Pr3+ ions, which are enhanced with the addition of Gd3+ ions due to the modification of crystal structure. Dissimilarly, the X-ray excited luminescence spectra consist of a strong emission located at 314 nm from Gd3+ ions (P-6(7/2) & RARR; S-8(7/2)), together with the typical emissions from Pr3+ ions, which exhibit different dependences on the Gd3+ concentration. When the luminescence intensity ratio between the P-3(0) & RARR; H-3(6) (611 nm) and D-1(2) & RARR; H-3(4) (581 nm) transitions is selected for temperature sensing, Pr3+:(Lu0.75Gd0.25)(2)Zr2O7 shows the optimal relative sensing sensitivity of 0.78% K-1 at 303 K, which is higher than that of the Gd3+-free sample. Therefore, the developed Pr3+:(Lu, Gd)(2)Zr2O7 phosphors have the applicative potential for optical thermometry, X-ray detection, and photodynamic therapy.