Codoping Pr3+ and Er3+ into NaLaTi2O6 to realize dual-mode FIR temperature sensing properties.

Dual-mode FIR temperature sensing properties in NaLaTi 2 O 6 :Pr3+, Er3+ phosphors were investigated in this work. [Display omitted] • A series of Pr3+/Er3+ codoped NaLaTi 2 O 6 phosphors were first synthesized. • Codoping Pr3+/Er3+ into NaLaTi 2 O 6 to realize UC and DS luminescence. • Maximal S a and S r reach 0.0831 K at 294 K and 1.826 % K−1 at 294 K, respectively. In this report, a Pr3+/Er3+ doped NaLaTi 2 O 6 phosphor was prepared as self-reference optical thermometer via a typical solid-state sintering method. The phase component, crystal structure and luminescence properties were elaborated in detail. A broad IVCT band along with several narrow 4f–4f excitation bands were readily found when monitored at 608 nm in Pr3+ singly doped NaLaTi 2 O 6 material. In addition, the material showed typical 4f–4f transitions with two dominant bands around 495 nm and 609 nm originating from 3P 0 → 3H 4 and 1D 2 → 3H 4 , respectively, upon ICVT or Pr3+ unique 4f–4f excitation. In Pr3+, Er3+ co-doped samples, the up-conversion (UC) emission bands around 522 nm, 548 nm and 661 nm, originating from characteristic transitions 2H 11/2 → 4I 15/2 , 4S 3/2 → 4I 15/2 and 4F 9/2 → 4I 15/2 of Er3+ ion was found, respectively, upon 980 nm radiation. Besides, the four main bands around 495 nm, 522 nm, 543 nm, 609 nm assigned to Pr3+ 3P 0 → 3H 4 , Er3+ 2H 11/2 → 4I 15/2 , Er3+ 4S 3/2 → 4I 15/2 , Pr3+ 1D 2 → 3H 4 , respectively, can be observed upon 379 nm co-excitation. By monitoring thermal responses emission intensities of versatile transitions under UC and down-shift (DS) excitation modes, good temperature sensitivity and signal discriminability based on FIR technique have been achieved in phosphor NaLaTi 2 O 6 :Pr3+, Er3+. Additionally, the maximal absolute temperature sensitivity S a and relative temperature sensitivity S r reach 0.0831 K−1 at 294 K and 1.15 % K−1 at 294 K under 980 nm excitation mode, and 0.01742 K−1 at 453 K and 1.826 % K−1 at 294 K under 379 nm excitation mode, respectively, indicating the prepared material in this work can be considered as a latent candidate for optical thermometry. More inspired, this work sets up a new pathway of codoping Pr3+ and Er3+ into suitable matrices to devise excellent FIR optical thermometry. [ABSTRACT FROM AUTHOR]