Sol-Gel Synthesis and Optical Temperature Sensing Behavior of Double-Perovskite Gd2ZnTiO6:Yb3+/Er3+ Phosphors

The Gd2ZnTiO6:Yb3+/Er3+ phosphors (abbreviated as GZT:Yb3+/Er3+) have been successfully prepared by means of the sol-gel method. The GZT:Yb3+/Er3+ phosphor exhibits intense green upconversion (UC) emission bands near 525/547 nm (H-2(11/2)/S-4(3/2)-> I-4(15/2)) and weak red UC emission band near 663 nm (F-4(9/2)-> I-4(15/2)) upon the 980 nm laser excitation. Furthermore, the sample simultaneously emits near-infrared centered at 1527 nm associated with I-4(13/2)-> I-4(15/2) transition of Er3+ ions. The high thermal activation energy (0.34 eV) of the GZT:Yb3+/Er3+ phosphor is determined via the temperature dependent luminescence spectra upon the 980 nm laser excitation (low power density: 0.8W/cm(2)). Two thermally coupled levels (H-2(11/2)/S-4(3/2)) for Er3+ using the fluorescence intensity ratio (FIR) technology were studied in detail. The maximum absolute sensitivity (90.11 x 10(-4) K-1 at 539 K) of the targeted phosphor is determined from the experimental results. All results demonstrate a potential of application of as-prepared GZT:Yb3+/Er3+ phosphors in optical thermometry. (c) 2019 The Electrochemical Society.