Up-conversion luminescence and optical temperature sensing properties in novel KBaY(MoO4)3:Yb3+,Er3+ materials for temperature sensors

In this article, a series of KBaY(MoO4)(3):Yb3+,Er3+ (KBYMO:Yb3+,Er3+) materials with efficient upconversion (UC) luminescence properties, were synthesized using a high-temperature solid-state reaction method. Upon 975 nm NIR laser excitation, characteristic Er3+ green emission bands around 529 and 550 nm and a feeble red band around 670 nm in KBYMO:Yb3+,Er3+ were observed, which corresponded to the Er3+ transitions H-2(11/2) -> I-4(15/2), S-4(3/2) -> I-4(15/2) and F-4(9/2) -> I-4(15/2), respectively. The UC luminescence mechanism in this kind of materials was analyzed to be a two-photon process and simultaneous energy transfer from Yb3+ to Er(3+ )ions. In order to explore its potential application in optical temperature sensor, the temperature-dependent behavior of a representative KBYMO:0.50 Yb3+,0.02Er(3+) was investigated in detail. Based on fluorescent intensity ratio (FIR) technique, the calculated FIR values of I-519/I-550 in KBYMO:0.50 Yb 3 +,0.02Er 3 + (250-460 K) were utilized as the original data. Therefore, the maximum absolute sensitivity S-a and relative sensitivity S-r were determined to be 0.01306 K-1 (420 K) and 1.80% K-1 (250 K), which can be comparable with reported optical thermometric materials before, respectively. The results suggest that as-prepared KBYMO:Yb3+,Er3+ can be promising candidates applied in optical temperature sensors with good sensitivities. (C) 2019 Elsevier B.V. All rights reserved.