Grafting of a Eu3+-tfac complex on to a Tb3+-metal organic framework for use as a ratiometric thermometer

Microrods of [Tb-2(bpydc) 3(H2O)(3)].nDMF (TbMOF) were employed as a platform for grafting a beta-diketonate complex of Eu3+ for the purpose of obtaining ratiometric luminescence thermometer materials. A straightforward post-synthetic functionalization is employed to obtain the TbMOF@ Eu_ tfac (tfac = trifluoroacetylacetonate) compounds. The emission color of the TbMOF@ Eu compounds can be slightly tuned by varying the percentage of the grafted beta-diketonate complex of Eu-3 (+). Also, as shown, the thermometric properties of the material can be tuned by the percentage of grafted beta-diketonate complex of Eu3(+.) The TbMOF@ 3% Eu_ tfac and TbMOF@ 7.3% Eu_ tfac compounds were investigated in detail for their use as luminescent ratiometric thermometers. For the TbMOF@ 3% Eu_ tfac compound an absolute sensitivity Sa of 0.069 K-1 (225 K) and relative sensitivity Sr of 2.59% K-1 (225 K) were obtained showing its good sensing capability. For the TbMOF@ 7.3% Eu_ tfac compound a Sa of 0.012 K-1 (275 K) and relative sensitivity Sr of 1.33% K-1 (325 K) were obtained showing that the TbMOF@ 3% Eu_ tfac compound is superior for temperature sensor applications. We also show that the emission color of the parent TbMOF material itself can be tuned by varying the excitation wavelength from 250-380 nm. It can be tuned from light-green to blue by simply changing the excitation wavelength.