Synthesis, characterization, and luminescence thermometry investigation of LiSrGd(WO4)3:Pr3+ phosphors.

Identifier:  imarina:9450037

Handle: https://hdl.handle.net/20.500.11797/imarina9450037

Authors:  Tahri R; Fhoula M; Ayachi F; Koubaa T; Dammak M; Carvajal JJ; Pujol MC

Abstract:
In this study, LiSrGd(WO4)3 (LSGW) phosphors doped with different concentrations of Pr3+ were synthesized via the traditional solid-solid method to explore their suitability for luminescence thermometry applications. Structural and morphological analyses using X-ray powder diffraction and scanning electron microscopy offered comprehensive insights. The energy gap value of LSGW, calculated at E g = 3.69 eV for x = 5 at% Pr3+, suggested minimal alteration in the bandgap energy upon incorporation of Pr3+ ions into the LSGW host. The empirical energy levels for the free ion Pr3+ were derived from absorption and emission data are gathered from LSGW:Pr3+. The theoretical energy diagram and corresponding eigenstates for Pr3+ were calculated using block diagonalization of the Hamiltonian's matrix in the basis set of coupled states 〈4f2〉〈4f2τSLJ〉, considering intermediate coupling. Thermometric parameters were calculated using the luminescence intensity ratio strategy based on Pr3+ emission spectra for thermal coupled levels. Our findings revealed that the LIR1 (I 531/I 557) exhibited maximum absolute and relative sensitivities of 31.5 10-4 K-1 and 0.65% K-1, respectively, at 300 K, accompanied by remarkably low-temperature uncertainty (δT) values ranging from 0.031 to 0.037 K in the 300-440 K temperature range. These results show the importance of LiSrGd(WO4)3:Pr3+ phosphors for optical applications.