A three-mode self-referenced optical thermometry based on up-conversion luminescence of Ca2MgWO6:Er3+,Yb3+ phosphors

To develop new up-conversion luminescent materials for optical thermometry, a sequence of Ca2MgWO6:xEr3+,yYb3+ phosphor samples were synthesized via high temperature solid-state reaction method. Their structure, morphology and luminescent performances were completely explored via X-ray diffraction, scanning electron microscopy and photoluminescence. Excited by 980 nm laser, all phosphor samples emit intense up-conversion luminescence of Er3+ at 531, 549 and 661 nm. Besides, these emissions were greatly enhanced with addition of Yb3+ ions. Benefiting from the different temperature dependence of three emission peaks, a dual-mode temperature sensor based on fluorescence intensity ratio (2H11/2/4S3/2 and 2H11/2/4F9/2) is realized by using single luminescent center. Meanwhile, the fluorescence lifetime of 4S3/2 state of Er3+ ions was used as the third temperature detection signal. More importantly, the phosphors exhibit superior thermal stability that will be helpful to obtain high precision temperature measurement. All results show that Ca2MgWO6:Er3+, Yb3+ samples could have potential applications for self-referenced optical thermometry.