Ratiometric optical thermometry based on temperature-induced shift of V-O charge transfer band edge

Ratiometric optical thermometry was designed using temperature-induced shift of V-O charge transfer band (CTB) edge combined with temperature-induced variation of Tb 3+ emission in YV 1-x P x O 4 . P was introduced into YVO 4 lattice to form YV 1-x P x O 4 solid solution successfully, with the purpose of enhancing Tb 3+ emission. Under 352 nm excitation which locates in the tail of the V-O CTB, emission spectra of YV 0.3 P 0.7 O 4 :Tb 3+ , Eu 3+ /Sm 3+ were recorded at a series of temperatures ranging from 300 to 440 K. It is demonstrated that Tb 3+ and Eu 3+ /Sm 3+ emissions exhibit opposite temperature dependences. The mechanisms for such opposite variations have been interpreted in detail. Based on the varied fluorescence intensity ratio of Eu 3+ /Sm 3+ o Tb 3+ with temperature, high relative sensitivity was obtained with a maximal value of 2.85% K -1 around 365 K. Our results imply that the proposed strategy is a promising candidate for high-sensitive optical temperature sensing.