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

Abstract

In this article, a series of KBaY(MoO4)3:Yb3+,Er3+ (KBYMO:Yb3+,Er3+) materials with efficient up-conversion (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 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2, 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 Er3+ ions. In order to explore its potential application in optical temperature sensor, the temperature-dependent behavior of a representative KBYMO:0.50 Yb3+,0.02Er3+ was investigated in detail. Based on fluorescent intensity ratio (FIR) technique, the calculated FIR values of I519/I550 in KBYMO:0.50 Yb3+,0.02Er3+ (250–460 K) were utilized as the original data. Therefore, the maximum absolute sensitivity Sa and relative sensitivity Sr 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.