Lanthanide ions doped nonhygroscopic La2Mo3O12 microcrystals based on multimode luminescence for optical thermometry

The non-contact thermometry based on fluorescence intensity ratio of phosphors has been extensively investigated owing to its high sensitivity and fast response. However, most of them only use a single mode of upconversion or downconversion emission for temperature sensing and ignore the affection of the humidity. In this work, the Yb/Er ions doped La2Mo3O12 microcrystals with nonhygroscopic property and multimode luminescence have been developed for temperature sensing. The optical thermometer could be based on not only luminescent intensity ratio of upconversion and downconversion, but also average fluorescence decay lifetime. The maximal absolute sensitivity can reach up to 6.2% K−1 and the maximal relative sensitivity is 1.63% K−1. Moreover, the fluorescence emission intensity of the doped La2Mo3O12 microcrystals will not be affected by the humidity compared to some doped molybdate and tungstate. These excellent performances suggest that the La2Mo3O12:Yb/Er microcrystals possess great potential for practical applications in temperature sensing.