A novel K3(Y0.88Yb0.10Er0.02)Si2O7 silicate phosphor for multi-mode thermometry of high sensitivity through up-conversion luminescence

Non-contract optical thermometry shows great advantages for temperature measurement in harsh environments, and it is highly desired to develop novel and high-performance systems. In this work, a novel K 3 (Y 0.88 Yb 0.10 Er 0.02 )Si 2 O 7 phosphor was synthesized via solid-state reaction, and its up-conversion luminescence and optical thermometric performance were systematically investigated. Under 980 nm excitation, the K 3 (Y 0.88 Yb 0.10 Er 0.02 )Si 2 O 7 phosphor showed a strong green UC emission through a three photon process. The phosphor was found well capable of sensing temperature via the multi-modes of fluorescence intensity ratio (FIR) of thermally/non-thermally coupled energy levels and fluorescence lifetime (FL). The maximum absolute (S A ) and relative (S R ) sensitivities are S A  = 156 × 10 −4  K −1 (I 531 /I 555 , 298 K) and S R  = 1.80% K −1 (I 519 /I 555 , 298 K) via the FIR mode, and are S A  = 661 × 10 −4  K −1 (548 K) and S R  = 9.77% K −1 (298 K) via the FL mode, which are higher than those of most previous studies.