Ambient- and calcination- temperature induced color-tunable upconversion luminescence in Yb3+/Er3+ co-doped Y2(MoO4)3 phosphors for optical thermometer

Abstract

Trivalent lanthanides (Ln 3+ )-doped upconversion luminescent (UCL) materials with negative thermal expansion (NTE) property are endowed an exciting thermal enhancement performance. Hitherto, selectively thermal enhancement for the multi-narrow-band emissions of phosphor with NTE property is not implemented. Herein, Y 2 Mo 3 O 12 :Yb 3+ /Er 3+ phosphor synthesized by the modified sol-gel method is explored in selectively enhanced green emission (Er 3+ : 2 H 11/2 / 4 S 3/2 → 4 I 15/2 ) due to the formation of Yb-MoO 4 dimer at high ambient-temperature. The 54-fold selectively enhancement of green emission is obtained from 298 K to 523 K. In addition, the influences of dopant-concentration and calcination-temperature on UCL properties are analyzed. Accordingly, based on the fluorescence intensity ratio (FIR) of non-thermally coupled levels (NTCLs) for 2 H 11/2 / 2 F 9/2 and 4 S 3/2 / 2 F 9/2 as well as ( 2 H 11/2 + 4 S 3/2 )/ 2 F 9/2 , the optimal relative sensitivity of temperature sensing in the Y 2 Mo 3 O 12 :Yb 3+ /Er 3+ sample could reach 0.14 K −1 at 298 K. All these indicate that this Y 2 Mo 3 O 12 :Yb 3+ /Er 3+ material is a promising candidate for high-sensitivity optical temperature sensing.