Luminescence intensity ratio based wide range contactless temperature sensing properties of Er3+/Yb3+ions co-doped La2Ti2O7 ceramics

Temperature sensing in the range (93-773 K) using luminescence intensity ratio method has been studied in rare earth ion modified La2-x-yErxYbyTi2O7 powders and ceramics. The optimised composition with (x = 0.025, y = 0.05) shows improved upconversion luminescence. For temperature sensing applications the need for excellent phase purity and better densification is emphasized in ceramics. In comparison to phase-impure calcined powders, single phase dense ceramic shows improved upconversion emission and better thermometric performance. The sintered ceramic is found useful for non-contact temperature sensing with a wider operating temperature range (243-1293 K) in comparison to calcined powders (163-863 K). The optimised phosphor in ceramic form exhibits good linearity in the range (173-393 K). Repeatability ex-periments reveal measurement accuracy within the range - 0.5 to + 0.8 K. Repeated heating and cooling cycles from 190 to 455 K show minimal thermal fatigue. The precision of the temperature read-out from the optical sensor by the intensity ratio method is found to be better (0.24%) at higher temperatures (> 373 K) in comparison to the estimated precision of 2.1% at lower temperatures.(c) 2023 Elsevier B.V. All rights reserved.