Fluorescent Sensing Probe Based on Heterovalent Doped Lu2W2.5Mo0.5O12:Er3+/Yb3+ Phosphor for Real-Time Chip Temperature Monitoring

The influence of Li+/Zn2+ heterovalent doping on the structural change and upconversion luminescence properties of Lu2W2.5Mo0.5O12:Er3+/Yb3+ phosphors was investigated in details. The gradual substitution of Li+/Zn2+ ions for Lu3+ ions result in the evolution from orthorhombic Lu2W2.5Mo0.5O12 to monoclinic (LiZn)2W2.5Mo0.5O12 , which bring the structural distortion, the reduction of local symmetry and the crystallite growth. The green upconversion intensity of Er3+ 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)2W2.5Mo0.5O12:Er3+/Yb3+ 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.