Linear response fluorescent temperature-sensing properties based on Stark sublevels of Er3+-doped Pb(Mg1/3Nb2/3)O3-PbTiO3-Pb(Yb1/2Nb1/2)O3 ceramics

The Er3+ doped 0.84(PMN-PT)−0.14PYN ceramics were employed as a temperature-sensing material. The obtained compounds exhibit strong visible upconversion (UC) fluorescence under a 980-nm diode laser excitation. On account of the Stark split effect, the 2H11/2, 4S3/2, and 4F9/2 levels of Er3+ split into two Stark sublevels, respectively. The fluorescence intensity ratios (FIR) between these sublevels were calculated in a temperature range of 133-573 K, and a linear FIR vs. temperature relation has been found. FIR of A/B shows a wide temperature sensing range with a relatively low sensitivity of 0.003 K−1. Meanwhile E/C illustrates the highest sensitivity of 0.0134 K−1 but in the smallest temperature range 453-573 K. FIR technique provides us a optical thermometric method with constant sensitivity in a wide temperature range.