Multi-mode optical thermometer of luminescence intensity ratio and lifetime based on Ca2LaNbO6:Yb3+, Er3+ phosphors

Rare-earth ions Yb 3+ /Er 3+ co-doped Ca 2 LaNbO 6 have been synthesized successfully. • Photoluminescence of Ca 2 LaNbO 6 :Yb 3+ /Er 3+ under 980 nm excitation was investigated. • Temperature dependence of LIR of I 524 nm / I 565 nm and I 1569 nm / I 1543 nm were studied. • Temperature-dependent decay lifetimes at 524 nm and 565 nm were analyzed. • This work enables multi-mode, anti-interference optical thermometry. Optical thermometry based on the intrinsic luminescent properties of rare-earth ions offers effective immunity to environmental interference. To enable multi-mode thermometry – that is, simultaneous acquisition of the luminescence intensity ratio ( LIR ) and lifetime - Ca 2 LaNbO 6 co-doped with Yb 3+ and Er 3+ was synthesized via a high-temperature solid-state reaction. The phase structure, morphological information, and photoluminescence properties were systematically investigated. Under 980 nm excitation, the optimal luminescence intensity is attained when the concentrations of Yb 3+ and Er 3+ are 12 mol% and 6 mol%, respectively. The two-photon process gives rise to emission mechanisms within the visible range (524 nm: 2 H 11/2  →  4 I 15/2 ; 565 nm: 4 S 3/2  →  4 I 15/2 ; 664 nm: 4 F 9/2  →  4 I 15/2 ); the single-photon process leads to emission in the near-infrared region (1544 nm: 4 I 13/2  →  4 I 15/2 ). The LIRs for visible up-conversion emissions ( I 524 nm / I 565 nm ) and near-infrared down-conversion emissions ( I 1569 nm / I 1543 nm ), along with the lifetimes of the 524 nm and 565 nm emissions, all exhibit pronounced temperature dependence that can be effectively fitted by exponential functions. Overall, this study demonstrates potential for multi-mode, non-contact optical thermometry with anti-interference capabilities. Download: Download high-res image (84KB) Download: Download full-size image