Ambient- and Calcination- Temperature Induced Color-Tunable Upconversion Luminescence in Yb3+/Er3+ Co-Doped Y2(MoO4)3 Phosphors for Optical Thermometer

Trivalent lanthanides (Ln3+)-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, Y2Mo3O12:Yb3+/Er3+ phosphor synthesized by the modified sol-gel method is explored in selectively enhanced green emission (Er3+: 2H11/2/4S3/2 -> 4I15/2) due to the formation of Yb-MoO4 dimer at high ambient-temperature. The 54-fold selectively enhancement of green emission is obtained from 298 K to 523 K. In addition, the in-fluences 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 2H11/2/2F9/2 and 4S3/ 2/2F9/2 as well as (2H11/2 + 4S3/2)/2F9/2, the optimal relative sensitivity of temperature sensing in the Y2Mo3O12: Yb3+/Er3+ sample could reach 0.14 K-1 at 298 K. All these indicate that this Y2Mo3O12:Yb3+/Er3+ material is a promising candidate for high-sensitivity optical temperature sensing.