Ratiometric fluorescence temperature sensing based on single- and dual-lanthanide metal-organic frameworks

The ever increasing demand for fast, noninvasive, and accurate determination of temperature at the submicrometer spatial regime, particularly in microelectronic diagnostics, is driving the development of ratiometric temperature probes. In this work, we present two types of self-calibrating metal-organic framework (MOF) thermometers with both the organic chromophore and lanthanide emissions, which proposed an elegant avenue to address these concerns. By employing the symmetric tetracarboxylate ligand [1,1':4',1 ''-Terphenyl]-3,3 '',5,5 '' tetracarboxylic acid, we synthesized and investigated single- and dual-lanthanide MOFs, TbTPTC and GdxEu1-xTPTC, in terms of their temperature dependent luminescence. Based on the energy-back transfer of lanthanide ion to ligand, the intensity ratio between the ligand and lanthanide of both the single- and dual-lanthanide MOF systems exhibits distinctly exponential response to temperatures in the range of 313-473 K. Given their good relative sensitivities, accurate temperature resolution, and excellent repeatability, as well as sensitivity to color change, the proposed dual-emitting MOF materials can be useful for thermal mapping and hot-spot monitoring of microelectronic devices.