Dual-mode temperature sensing properties and systematic applications of Ce/Cr co-doped Y3Al5O12 phosphors

The fluorescence intensity ratio (FIR) technique has emerged as a pivotal approach in non-contact optical thermometry, offering substantial application potential. In this study, Y 3 Al 5 O 12 (YAG) phosphors co-activated with Ce 3+ and Cr 3+ ions were successfully synthesized through a high-temperature solid-state reaction method. Spectroscopic analysis revealed efficient energy transfer between the dopant ions, manifesting as distinct luminescence intensity variations compared to their single-doped counterparts. Under 450 nm excitation, the system demonstrates prominently yellow-green emission from Ce 3+ ions and well-resolved red emission from Cr 3+ ions, ensuring excellent spectral discrimination. Capitalizing on the differential thermal response between the two luminescent centers, the developed system achieves remarkable temperature sensing performance. The FIR method yields a maximum relative sensitivity of 0.845 % K −1 , maintaining sensitivity above 0.6 % K −1 throughout the 340–580 K range, coupled with exceptional temperature resolution below 0.03 K. Furthermore, we have engineered a novel FIR thermometry system incorporating 3D-printed spectral modules and fiber-optic phosphor encapsulation. The integrated system demonstrates superior sensing capabilities, reaching sensitivity values of 1.23 % K −1 in Cr 3+ lifetime mode and 4.64 % K −1 in FIR mode. These results indicate that Ce/Cr co-doped YAG has exceptional potential in multimodal optical thermometry applications.