“Pseudo-TCELs” of Tm3+ induced ultra-highly sensitive fluorescence thermometers with adjacent emission peaks

Abstract

Up to now, fluorescence thermometers based on fluorescence intensity ratio (FIR) technology is difficult to meet high sensitivity and short recording wavelength range simultaneously. In this work, Tm3+/Yb3+ co-doped oxyfluoride glass ceramics (GCs) were synthesized via melting-quenching method and subsequent thermal treatment. Well-crystallized Tm3+/Yb3+ co-doped fluoride nanocrystals (NCs) have formed in the oxide glass matrix. UCL properties of Tm3+/Yb3+ co-doped oxyfluoride GCs under excitation of 976 nm laser at room temperature (RT) were measured and studied, in which an unusual emission at 724 nm originated from 1D2→3F2,3 transition was recorded for the first time. Besides, temperature measurements capable of Tm3+/Yb3+ co-doped oxyfluoride GCs was studied and ultra-high sensitivity and short recording wavelength range were achieved simultaneously based on “pseudo-TCELs” of Tm3+. The maximum Sr and Sa were obtained based on the “pseudo-TCELs” of Tm3+, 3F2,3→3H6 (I680 nm+700 nm)/1D2→3F2,3 (I724 nm), as values of 4.17% K−1 at 288 K and 13.95% K−1 at 498 K, which broke the limitation of ΔE on thermosensitivity and were significantly higher than existing luminescent thermometers. Moreover, the value of Sr based on the “pseudo-TCELs” of Tm3+ maintained larger than 1.12%K−1 in high temperature range of 350–500 K without obvious descending, superior to most previous reports. The “pseudo-TCELs” of Tm3+ provides a new strategy for obtaining high sensitivity based on adjacent emission peaks and short recording wavelength range simultaneously, contributing to significantly improve the quality and efficiency of temperature detection.