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

Abstract

Ratiometric optical thermometry was designed using temperature-induced shift of V-O charge transfer band (CTB) edge combined with temperature-induced variation of Tb3+ emission in YV1-xPxO4. P was introduced into YVO4 lattice to form YV1-xPxO4 solid solution successfully, with the purpose of enhancing Tb3+ emission. Under 352 nm excitation which locates in the tail of the V-O CTB, emission spectra of YV0.3P0.7O4:Tb3+, Eu3+/Sm3+ were recorded at a series of temperatures ranging from 300 to 440 K. It is demonstrated that Tb3+ and Eu3+/Sm3+ emissions exhibit opposite temperature dependences. The mechanisms for such opposite variations have been interpreted in detail. Based on the varied fluorescence intensity ratio of Eu3+/Sm3+ to Tb3+ 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.