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

Identifier:  imarina:9452325

Handle: https://hdl.handle.net/20.500.11797/imarina9452325

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 Eg = 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 >< 4f2 tau SLJ >, 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 (I531/I557) 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 (delta T) 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.