The excellent dual optical thermometry of the Yb3+, Er3+ doped SrLu2O4.

SrLu 2 O 4 : Yb3+, Er3+ samples were achieved successfully via a traditional solid-state method at 1450 °C. As 980-nm laser exciting, the UC spectra include red and green emissions mainly centering on 665 and 552 nm, respectively. The red is dominant, and the green part is a relative weakness. For all co-doped samples, intense red radiation is obtained. Meanwhile, the experimental formulas about pumping power and spectrum intensity helped us comprehend the up-conversion processes further, and the conclusion is a two-photon process in UC. The 4S 3/2 and 2H 11/2 levels ions are thermal coupled energy levels. We also investigated thermometric characteristics of the samples on the fluorescence intensity ration technology. For SrLu 2 O 4 : Er3+/Yb3+, it can be used as a temperature sensor by using its green emission and red emission, and the sensor sensitivity was calculated. The maximum absolute sensitivity and the relative sensitivity is 0.00226 K-1 and 0.0119 K−1 at 513 K for green emission and the maximum absolute sensitivity and the relative sensitivity is 0.00126 K-1 and 0.0026 K−1 at 303 K for red emission. The fluorescence intensity ratio (FIR) values are almost stable and accurate in repeated tests. As a result, the SrLu 2 O 4 : Er3+/Yb3+ samples would useful hopefully to optical engineering and sensors. • Thedual optical non-contact thermometerSrLu 2 O 4 : Er3+/Yb3+ based on FIR was investigated firstly. • The maximal S A and S R is 0.00226 K-1 and 0.0119 K−1 at 513 K for green emission, • 0.00126 K-1 and 0.0026 K−1 at 303K for red emission. • The fluorescence intensity ratio (FIR) values are almost stable and accurate in repeated tests. [ABSTRACT FROM AUTHOR]