Anomalous thermal quenching behavior of novel orange-red SrLa1-xNaTeO6:xSm3+ phosphors for optical temperature sensing.

A series of novel orange-red phosphors were synthesized in this study by adding Sm3+ into the double perovskite-structured SrLaNaTeO 6 host lattice using a solid-state reaction technique, and their luminescence properties and thermal stability were studied in detail. X-ray diffraction (XRD) analyses revealed that the obtained SrLa 1-x NaTeO 6 :xSm3+ phosphors are triclinically symmetrical, with a space group of Fm-3m. The optimal Sm3+ doping concentration was determined to be x = 0.05 in the SrLa 1-x NaTeO 6 :xSm3+ phosphor, and excessive dopants will cause concentration quenching due to energy transfer interaction between Sm3+ ions. Under the excitation of near-ultraviolet λ ex = 405 nm, the luminous intensity of SrLa 0·95 NaTeO 6 :0.05Sm3+ phosphor at 573 K remained at 125.8% of its original value at 298 K. And then, the phosphor has excellent quantum yield (49.26%) and negative thermal quenching. Besides, the optimum S A and S R values of SrLa 0·95 NaTeO 6 :0.05Sm3+ phosphor were 0.088% K−1@573 K (S A) and 0.149% K−1@498 K (S R), respectively. The excellent negative thermal quenching and good thermal stability of SrLa 0·95 NaTeO 6 :0.05Sm3+ phosphor indicate that it has a potential for applications as white LEDs and optical temperature sensing. In this research, the effect of temperature on the fluorescence intensity and quantum yield of phosphor SrLa 0·95 NaTeO 6 :0.05 S m3+ has been studied. This phosphor exhibits excellent thermal stability and a strong negative thermal quenching. Meanwhile, SrLa 0·95 NaTeO 6 :0.05 S m3+ phosphor can be used to measure temperature based on negative thermal quenching. [Display omitted] • A series of SrLa 1-x NaTeO 6 :xSm3+ orange-red-emitting phosphor is prepared for the first time. • SrLa 0·95 NaTeO 6 :0.05 S m3+ orange-red-emitting phosphor has remarkable negative thermal quenching. • SrLa 0·95 NaTeO 6 :0.05 S m3+ phosphor demonstrates excellent quantum yield (49.26%) and color purity (98.5%). • The intensity ratios of emission bands of SrLa 0·95 NaTeO 6 :0.05 S m3+ phosphor can be used to measure temperature. [ABSTRACT FROM AUTHOR]