Highly-sensitive optical temperature sensing and color-tunable upconversion emission based on dual luminescence centers of LuNbO4:Yb3+, Er3+, Tm3+

Abstract

Lanthanide ions doped upconversion system with dual luminescence centers has attracted much interest in fields of display and temperature sensing. Herein, XNbO₄:Yb³⁺,Er³⁺ (X = Lu, Gd, Y) are synthesized by solid state method. LuNbO₄:Yb³⁺,Er³⁺ exhibits optimal upconversion luminescence under the same excitation conditions. Meanwhile, the appropriate combination of dual luminescence centers for Er³⁺ and Tm³⁺ can easily achieve color-tunable emission including white emission by adjusting the content of doped ions upon 980 nm excitation. The improving proportion of red emission with increasing Tm³⁺ is assigned to the effective energy transfer between Er³⁺ and Tm³⁺. Furthermore, UC luminescence thermometric performances are systematically investigated. Using non-thermally coupled levels of ⁴F_9/2 (Er³⁺) and ³F_2,3 (Tm³⁺) based on dual luminescence centers can obtain higher sensitivity performance (maximum absolute and relative sensitivity of 69.1 × 10⁻³ K⁻¹ and 4.0 % K⁻¹) compared to thermally coupled levels of ²H_11/2 and ⁴S_3/2. The above results indicate that LuNbO₄:Yb³⁺,Er³⁺,Tm³⁺ is a promising upconversion luminescence material for solid-state displays and optical thermometry.