Anti-thermal quenching of luminescence in Y 2 W 3 O 12 :Yb 3+ /RE 3+ (RE = Er/Ho/Tm) and its temperature sensing application.

Herein, a series of Y 2 W 3 O 12 :10%Yb 3+ / x %RE 3+ (RE = Er/Ho/Tm) phosphors is prepared via 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 Tm 3+ ion and the green and red light emissions from Ho 3+ (Er 3+ ) ions were observed. The near-infrared light intensity of NIR-I (Tm 3+ , ∼850 nm), NIR-II (Er 3+ : ∼1550 nm; Tm 3+ : ∼1783 nm) and NIR-III (Ho 3+ : ∼2050 nm) were analyzed. In particular, the dramatic thermal enhancement phenomenon in visible and NIR regions was exhibited by the Y 2 W 3 O 12 :10%Yb 3+ / x %RE 3+ (RE = Er/Ho/Tm) phosphors. Among them, the green light intensity of Er 3+ ions increased 26.77 times, from 303 to 573 K. The NIR-II emission band (∼1783 nm) intensity of Tm 3+ 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 Y 2 W 3 O 12 host. Finally, the optical temperature sensing performances of Y 2 W 3 O 12 :10%Yb 3+ / x %RE 3+ (RE = Er/Ho/Tm) samples are investigated according to the luminescence intensity dependence relationship on temperature. The maximum value of S R reached 4.24% K -1 at 353 K for Y 2 W 3 O 12 :10%Yb 3+ /0.6%Ho 3+ phosphor. The results indicate that the Y 2 W 3 O 12 :10%Yb 3+ / x %RE 3+ (RE = Er/Ho/Tm) phosphors possess anti-thermal quenching properties and are suitable for developing optical temperature sensors.