A dual-mode self-referenced optical thermometry with high sensitivity based on Er3+-Yb3+ co-doped Sr2YTaO6 thermochromic phosphor

Up conversion luminescent materials Sr2YTaO6: Er3+, Yb3+ phosphors were prepared by high temperature calcination. In view of the formation, temperature characteristics, and photoluminescence features of the sample, X-ray diffraction and photoluminescence were used. Under the excitation at 980 nm, the series of samples is significantly stimulated by Er3+ up-conversion luminescence and Yb3+ sensitization at 524, 550 and 659 nm. According to the diversity of temperature sensing performance from these three highest peaks, a dual-mode temperature sensor on account of fluorescence intensity ratio (thermally coupled level between H-2(11/2) and S-4(3/2), and nonthermally coupled energy levels between H-2(11/2) and F-4(9/2)) is achieved by using a single luminescent center. Moreover, the phosphor has strong thermal stability, which is helpful to improve the accuracy of temperature measurement. Under the temperature measurement of a dual-mode temperature sensor, it is calculated that the optimal absolute sensitivity Sa of thermally coupled energy level is 0.78 x 10(-3) K-1 (473 K) and relative sensitivity Sr is 1.32 %K-1 (293 K), and the maximum optimal absolute sensitivity Sa of non-thermally coupled energy level is 1.02 x 10(-4) K-1 (473 K) and relative sensitivity Sr is 0.58 %K-1 (293 K). All results imply that Sr2YTaO6: Er3+, Yb3+ phosphors are promising materials for self-referenced optical temperature measurement.

Automated summary

Up conversion luminescent material Sr2YTaO6: Er3+, Yb3+ phosphors are prepared by high temperature calcination. X-ray diffraction and photoluminescence are used to study the formation, temperature characteristics, and photoluminescence features of the sample. The samples show significant stimulated Er3+ up-conversion luminescence and Yb3+ sensitization at specific wavelengths. By utilizing the fluorescence intensity ratio, a dual-mode temperature sensor is achieved using a single luminescent center. The phosphor exhibits strong thermal stability, improving the accuracy of temperature measurement. The optimal sensitivities for both thermally and nonthermally coupled energy levels are calculated, indicating the potential of Sr2YTaO6: Er3+, Yb3+ phosphors in self-referenced optical temperature measurement.