Fluorescent sensing probe based on heterovalent doped Lu 2 W 2.5 Mo 0.5 O 12 :Er 3+ /Yb 3+ phosphor for real-time chip temperature monitoring

The influence of Li + /Zn 2+ heterovalent doping on the structural change and upconversion luminescence properties of Lu 2 W 2.5 Mo 0.5 O 12 :Er 3+ /Yb 3+ phosphors was investigated in details. The gradual substitution of Li + /Zn 2+ ions for Lu 3+ ions result in the evolution from orthorhombic Lu 2 W 2.5 Mo 0.5 O 12 to monoclinic (LiZn) 2 W 2.5 Mo 0.5 O 12, which bring the structural distortion, the reduction of local symmetry and the crystallite growth. The green upconversion intensity of Er 3+ ions at 536 nm and 550 nm were enhanced significantly by a factor of 8000 and 4000. The temperature sensing characteristics of a single (LiZn) 2 W 2.5 Mo 0.5 O 12 :Er 3+ /Yb 3+ particle in all-fiber structure was explored and the unusual thermally-enhanced upconversion luminescence was observed, which is beneficial for achieving high-precision temperature measurement based on the fluorescence intensity ratio technology. The absolute temperature sensitivity reached a maximum of 0.0095 K −1  at 423 K and the temperature deviation was less than 0.6 K. The as-built all-fiber temperature sensor was successfully applied in the on-line monitoring of CPU temperature.