Dy³⁺ and Mn⁴⁺ Ions Co-Doped Stannate Phosphors for Applications in Dual-Mode Optical Thermometry

In order to break through the limitations of the application of traditional temperature measurement technology, non-contact optical temperature sensing material with good sensitivity is one of the current research hotspots. Herein, a series of Dy³⁺ and Mn⁴⁺ co-doping Mg₃Ga₂SnO₈ fluorescent materials were prepared successfully, and the crystal structure, phase purity, and morphology of the synthesized phosphors were comprehensively investigated, as well as their photoluminescence properties, energy transfer, and high-temperature thermal stability. The two pairs of independent thermally coupled energy levels of Dy³⁺ ions and Mn⁴⁺ ions in Mg₃Ga₂SnO₈ are utilized to realize the dual-mode optical temperature detection with excellent performance. On the one hand, based on the different ionic energy level transitions of ⁴F_9/2→⁶H_13/2 and ²E_g→⁴A_2g responding differently to temperature, two emission bands of 577 nm and 668 nm were chosen to construct the fluorescence intensity ratio thermometry, and the maximum sensitivity of 1.82 %K^-1 was achieved at 473 K. On the other hand, based on the strong temperature dependence of the lifetime of Mn⁴⁺ in Mg₃Ga₂SnO₈:0.06Dy³⁺,0.009Mn⁴⁺, fluorescence lifetime thermometry was constructed and a maximum sensitivity of 2.75 %K^-1 was achieved at 473 K. Finally, the Mg₃Ga₂SnO₈: 0.06Dy³⁺,0.009Mn⁴⁺ sample realizes dual-mode optical temperature measurement with high sensitivity and a wide temperature detection range, indicating that the sample has promising applications in optical temperature measurement.