Double perovskite matrix materials have recently attracted considerable interest due to their structural flexibility, ease of doping, and excellent thermal stability. While photoluminescence (PL) studies of rare-earth-doped double perovskites are common, research on their thermoluminescence (TL) properties is less extensive. This study synthesized a series of \(\hbox {Y}_{2-x}\hbox {Sm}_{x}\hbox {MgTiO}_{6}\) ( \(0\le x \le 0.1\) ) samples using a high-temperature solid-state method. X-ray diffraction (XRD) analysis confirmed a monoclinic crystal structure (space group \(P2_{1}/n\) ), with \(\hbox {Sm}^{3+}\) ions substituting for \(\hbox {Y}^{3+}\) ions in \(\hbox {Y}_{2}\hbox {MgTiO}_{6}\) . The PL results indicated that the optimal doping concentration was \(\hbox {Y}_{1.95}\hbox {Sm}_{0.05}\hbox {MgTiO}_{6}\) , exhibiting emission peaks at 568, 605, 652, and 715 nm under 409 nm blue light excitation. The TL measurements for different doping concentrations showed that the \(\hbox {Y}_{1.98}\hbox {Sm}_{0.02}\hbox {MgTiO}_{6}\) phosphors exhibited the strongest TL signals. The TL peaks observed at 530 and 610 K correspond to defects in the matrix and \(\hbox {Sm}^{3+}\) dopants, respectively. The \(T_\text{m}-T_\text {stop}\) analysis revealed that the TL curve of \(\hbox {Y}_{1.98}\hbox {Sm}_{0.02}\hbox {MgTiO}_{6}\) phosphors was a superposition of seven peaks. Computerized glow curve deconvolution (CGCD) was performed on the TL of the sample according to the results of three-dimensional thermoluminescence spectra (3D-TL) and \(T_\text{m}-T_\text {stop}\) , and the trap depths in the sample were estimated to range from 0.69 to 1.49 eV. Additionally, the lifetimes of each overlapping peak were calculated using the fitting parameters. Furthermore, the dose–response test showed that the saturation dose of the sample was high (9956 Gy). Therefore, this material can serve as a thermoluminescent dosimeter for high-dose measurements. The saturation dose for the lowest-temperature overlapping peak was 102 Gy, which correlated with its specific energy-level lifetime, whereas the other overlapping peaks also exhibited favorable linear relationships.
