Down/Upconversion Luminescence Behaviors and Temperature-Sensing Properties of Highly Transparent (Er1-xYbx)2O3 Ceramics

Cubic binary transparent (Er1-xYbx)(2)O-3 (x = 0.005 and 0.01) ceramics with a high transmittance of similar to 78.1% at 600 nm (similar to 95.6% of the theoretical transmittance of the Er2O3 single crystal) were successfully fabricated by vacuum sintering. Upon 980 nm laser pumping, the (Er1-xYbx)(2)O-3 ceramics emit characteristic near-infrared downconversion radiation at 1450-1600 nm arising from the I-4(13/2) -> I-4(15/2) transition of Er3+. The upconversion spectra of (Er,Yb)(2)O-3 ceramics present typical red emission at 650-670 nm and green emission at 520-555 nm corresponding to F-4(9/2) -> I-4(15/2) and H-2(11/2)/S-4(3/2) -> I-4(15/2) transitions of Er3+, respectively. A 0.5 at. % Yb3+ dopant dramatically improves the upconversion luminescence intensity by similar to 13 times relative to the pure Er2O3 counterpart. The luminescence intensity gradually increases with the rising laser output power, and the upconversion mechanism ascribes to two-phonon processes. The fluorescence lifetimes of the (Er0.995Yb0.005)(2)O-3 ceramic are determined to be similar to 19.26 mu s for the 540 nm green emission and similar to 26.60 mu s for the 668 nm red emission. The noncontact optical thermometric ability of the (Er0.995Yb0.005)(2)O-3 ceramic in the temperature range of 298-473 K is assessed using the thermoresponsive fluorescence intensity ratio technique, and the maximum absolute sensitivity is similar to 0.0045 K-1.