Upconversion luminescence color modulation and temperature sensing of Na0.5Bi2.5Nb2−xTaxO9:Er3+/Yb3+ phosphors. Issue 11 (1st July 2022)

• Record Type: Journal Article
• Authors: Li, Lei; Cao, Yongze; Cui, Hongqiang; Zhang, Yuhang; Li, Guojian; Wang, Yichao; Li, Xiangping; Xu, Sai; Chen, Baojiu
• Is Part Of: Journal of the American Ceramic Society. Volume 105:Issue 11(2022)
• Page Start: 6640
• Page End: 6651
• Publication Date: 2022-07-01
• Subjects: Na0.5Bi2.5Nb2O9 -- Na0.5Bi2.5Ta2O9 -- phosphors -- temperature sensing -- upconversion luminescence; Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.18627
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract: A series of Na0.5 Bi2.5 Nb2− x Ta x O9 (NBN2− x T x ):Er 3+ /Yb 3+ upconversion luminescence (UL) phosphors were prepared by a solid‐state sintering method, and the lattice structure of the prepared samples was studied by X‐ray diffraction. Under 980‐nm laser excitation, the UL properties were investigated by a spectrophotometer from room temperature to 723 K, and the optimal concentration of co‐doping Er 3+ /Yb 3+ is 0.14 and 0.26 by replacing Bi 3+ sites in NBN2− x T x host, respectively. With the increase of Ta 5+ concentration, the color of UL gradually changes from green to yellow corresponding color coordinates from (0.301, 0.682) to (0.441, 0.549) under 980‐nm laser excitation. This color change is attributed to the decrease of lattice unit volume leading to the increase of cross relaxation of Er 3+ to Er 3+ and energy back transfer from Er 3+ to Yb 3+ . Using the luminescence intensity ratio technique, the maximum absolute sensitivities ( S A ) are obtained as 0.00674 K −1 at 538 K and 0.00603 K −1 at 573 K, and relative sensitivities ( S R ) are obtained as 0.01174 K −1 at 303 K and 0.01244 K −1 at 303 K based on 2 H11/2 → 4 I15/2 and 4 S3/2 → 4 I15/2 energy level transitions of Er 3+ in NBN2 :0.14Er 3+ /0.26Yb 3+ phosphors under 980‐ and 1550‐nm laser excitations, respectively. The results suggest that the NBN2− x T x :Er 3+ /Yb 3+ phosphors are promising candidates for temperature sensing with different UL colors.