Anti-thermal quenching of luminescence in Y₂W₃O₁₂:Yb³⁺/RE³⁺ (RE = Er/Ho/Tm) and its temperature sensing application

Abstract

Herein, a series of Y₂W₃O₁₂:10%Yb³⁺/<i>x</i>%RE³⁺ (RE = Er/Ho/Tm) phosphors is prepared <i>via</i> a solid-state reaction. The upconversion and downshift luminescence properties of the phosphors were investigated under an excitation of 980 nm. The bright blue light emission from Tm³⁺ ion and the green and red light emissions from Ho³⁺(Er³⁺) ions were observed. The near-infrared light intensity of NIR-I (Tm³⁺, ∼850 nm), NIR-II (Er³⁺: ∼1550 nm; Tm³⁺: ∼1783 nm) and NIR-III (Ho³⁺: ∼2050 nm) were analyzed. In particular, the dramatic thermal enhancement phenomenon in visible and NIR regions was exhibited by the Y₂W₃O₁₂:10%Yb³⁺/<i>x</i>%RE³⁺ (RE = Er/Ho/Tm) phosphors. Among them, the green light intensity of Er³⁺ ions increased 26.77 times, from 303 to 573 K. The NIR-II emission band (∼1783 nm) intensity of Tm³⁺ ions at 533 K increased 168.7 times compared to that at 313 K. The possible thermal enhancement mechanism is illustrated by the negative thermal expansion (NTE) and Frenkel defect of the Y₂W₃O₁₂ host. Finally, the optical temperature sensing performances of Y₂W₃O₁₂:10%Yb³⁺/<i>x</i>%RE³⁺ (RE = Er/Ho/Tm) samples are investigated according to the luminescence intensity dependence relationship on temperature. The maximum value of <i>S</i>_R reached 4.24% K^-1 at 353 K for Y₂W₃O₁₂:10%Yb³⁺/0.6%Ho³⁺ phosphor. The results indicate that the Y₂W₃O₁₂:10%Yb³⁺/<i>x</i>%RE³⁺ (RE = Er/Ho/Tm) phosphors possess anti-thermal quenching properties and are suitable for developing optical temperature sensors.