High-sensitivity and wide-temperature-range dual-mode optical thermometry under dual-wavelength excitation in a novel double perovskite tellurate oxide

Abstract

Novel double perovskite SrLaLiTeO₆ (abbreviated as SLLT):Mn⁴⁺,Dy³⁺ phosphors synthesized using a solid-state reaction strategy exhibit distinct dual-emission of Mn⁴⁺ and Dy³⁺. High-sensitivity and wide-temperature-range dual-mode optical thermometry was exploited taking advantage of the diverse thermal quenching between Mn⁴⁺ and Dy³⁺ and the decay lifetime of Mn⁴⁺. The thermometric properties in the range of 298–673 K were investigated by utilizing the fluorescence intensity ratio (FIR) of Dy³⁺ (⁴F_9/2 → ⁶H_13/2)/Mn⁴⁺ (²E_g → ⁴A_2g) and the Mn⁴⁺ (²E_g → ⁴A_2g) lifetime under 351 nm and 453 nm excitation, respectively. The maximum relative sensitivities (S_R) of the resultant SLLT:1.2%Mn⁴⁺,7%Dy³⁺ phosphor under 351 nm and 453 nm excitation employing the FIR technology were determined to be 1.60% K⁻¹ at 673 K and 1.44% K⁻¹ at 673 K, respectively. Additionally, the maximum S_R values based on the lifetime-mode were 1.59% K⁻¹ at 673 K and 2.18% K⁻¹ at 673 K, respectively. It is noteworthy that the S_R values can be manipulated by different excitation wavelengths and multi-modal optical thermometry. These results suggest that the SLLT:Mn⁴⁺,Dy³⁺ phosphor has prospective potential in optical thermometry and provide conducive guidance for designing high-sensitivity multi-modal optical thermometers.