Ln3+ (Er3+, Tm3+ and Ho3+)-doped NaYb(MoO4)2 upconversion phosphors as wide range temperature sensors with high sensitivity

[摘要] )Well-crystallized NaYb(MoO4)(2) doped with lanthanide ions (Ln(3+) Er3+ Tm(3+)and Ho3+ are successfully synthesized by hydrothermal method with further calcination. And the samples with different morphologies are obtained by changing the pH values and the molar ratio of Ln(NO3)(3)/Na2MoO4 of the resultant solutions. The upconversion (UC) luminescence spectra of NaYb(MoO4)(2): Ln(3+) between 323 K and 573 K under 980 nm excitation exhibit temperature-dependent property. The fluorescence intensity ratio (FIR) techniques with thermally coupled states (TCS) (Er3+: H-2(11/2), S-4(3/2) -> H-4(5/2), Tm3+: (1)G(4(1),(2)) -> H-3(6), Ho3+: F-5(5(1),(2)) -> I-5(8)) have high sensitivity (S) values (Er3+: 0.0122 K-1 at 548 K, Tm3+: 0.0025 K-1 at 323 K and Ho3+: 0.00035 K-1 at 323 K). The non-TCS (Ho3+: F-5(5), (S2/5F4)-S-5 -> I-5(8)) is used to extend the range of S, and the slope of FIR (non-TCS)-T is the S value as high as 0.02455 K-1 in the wide temperature range from 323 K to 573 K. (C) 2017 Elsevier B.V. All rights reserved.

[发布日期] 2017-12-25

[关键词] Hydrothermal method;Fluorescence intensity ratio;Temperature sensor