A dye encapsulated terbium-based metal–organic framework for ratiometric temperature sensing

A terbium-based metal-organic framework (MOF) TbTATAB (H3TATAB = 4,4',4''-s-triazine-1,3,5-triyltri-p-aminobenzoic acid) with a 1D channel has been synthesized and structurally characterized. Then, the luminescent dye 7-diethylamino-4-methylcoumarin (C460) was encapsulated into the channel of TbTATAB by an exchange strategy to yield the dual-emitting MOF⊃dye composite TbTATAB⊃C460. Luminescence explorations demonstrated that the composite can be applied as a ratiometric thermometer over a wide temperature range from 100 to 300 K. The unique energy transfer between C460 molecules and Tb3+ enables the TbTATAB⊃C460 thermometer to be highly temperature-sensitive with a maximum relative sensitivity of 4.484% K-1 at 300 K. The composite luminescent thermometer is self-calibrated, colorimetric, reusable and much more thermosensitive than most of the other explored sensors.