Photoluminescence and thermoluminescence properties of rare earth Tm3+, Dy3+ co-doped Y2MgTiO6 double perovskite phosphors

Abstract

Currently, the double perovskite A₂BB'O₆ can be used as an ideal matrix material for the study of rare earth-doped phosphor research because of its flexible chemical composition range and stable crystal structure. In this study, Y₂MgTiO₆:Tm³⁺,Dy³⁺ (YMT:Tm³⁺,Dy³⁺) series phosphors were synthesized via the high-temperature solid-state method. SEM illustrated that the sample consisted of irregular micron particles with some agglomeration. XRD confirmed that the prepared Y₂MgTiO₆ phosphors were in a single pure phase and that Dy³⁺ and Tm³⁺ replaced the Y³⁺ in the crystal lattice. The photoluminescence (PL) spectra revealed three distinct emission peaks (458 nm, 484 nm and 579 nm) of the YMT:Tm³⁺,Dy³⁺ phosphors under UV excitation at 353 nm, which confirmed the existence of the energy transfer from Tm³⁺ to Dy³⁺. The thermoluminescence (TL) curves revealed that the YMT:0.05Tm³⁺,0.2Dy³⁺ sample had the strongest TL response, with four TL glow peaks at 363 K, 413 K, 463 K and 551 K. Both T_m−T_stop method and the computerized glow curve deconvolution (CGCD) method revealed that the TL curve consisted of six overlapping peaks, with trap depths ranging from 0.6 to 1.52 eV. Peak Ⅰ and Peak Ⅳ moved towards high and low temperatures, respectively, with increasing dose; and the main Peak Ⅳ (510∼640 K) of the TL curve had been saturated. The dose-response curves of each overlapping peak were further analysed via the CGCD method, and it was found that Peak 1, Peak 3 and Peak 4 tended to saturate and all other peaks increased linearly. And due to the charge hopping between the traps, it resulted that Peak 2 has not reached saturation yet. In addition, the sample has good repeatability and stability. These experimental results indicate that this rare-earth doped double perovskite phosphor has some potential for TL dosimetry applications.