Non-contact thermometry with dual-activator luminescence of Bi3+/Sm3+: YNbO4 phosphor

Based on the luminescence of Bi 3+ , novel temperature sensing materials YNbO 4 :Bi 3+ and YNbO 4 :Bi 3+ /Sm 3+ were successfully synthesized by solid state reaction. The XRD patterns show that the synthesized materials have a pure phase of YNbO 4 . With the excitation of 314 nm, the YNbO 4 :Bi 3+ material shows intense temperature-dependent luminescence in the range of 303 K–463 K. Based on the temperature-dependent luminescence of Bi 3+ in YNbO 4 , the maximum relative sensitivity can be obtained at 434 K (1.72% K −1 ). Under the excitation of 406 nm, the YNbO 4 :Sm 3+ material shows the characteristic emission peaks of Sm 3+ . In YNbO 4 :Bi 3+ /Sm 3+ phosphor, the large overlap between the emission spectra of Bi 3+ and the excitation spectra of Sm 3+ leads to a significant energy transfer from Bi 3+ to Sm 3+ . With the excitation of 314 nm, the emission spectra of YNbO 4 :Bi 3+ /Sm 3+ material shows the characteristic peaks of Bi 3+ and Sm 3+ . The luminescence intensity ratio of Sm 3+ and Bi 3+ shows a strong temperature dependence. Based on the luminescence intensity ratio, a large relative sensitivity is obtained at 455 K (1.57% K −1 ).