Color-tunable hypersensitive temperature sensor based on metal organic framework doped with Eu3+ and Dy3+ via phonon-assisted energy transfer

In this work,catena-[(μ-benzene-1,3,5-tricarboxylato)-(1,10-phenanthroline)-(N,N-dimethylfo rmamide)-gadolinium(ⅲ)-N,N-dimethylformamide solvate](denoted as Gd-MOF) co-doped with Eu3+and Dy3+was successfully synthesized.The entire X-ray diffraction peaks of the sample match well with the GdMOF phase.A detailed characterization by inductively coupled plasma mass spectrometry(ICP-MS)shows that the actual concentration is basically consistent with the design concentration.The temperature sensing properties of Gd-MOF:Eu3+,Dy3+were analyzed by temperature-dependent fluorescence spectra from 213 to 453 K.As temperature rises,the emission color of Gd-MOF:Eu3+,Dy3+changes from yellow to red.The relative sensitivity reaches a maximum of 5.8 7%/K at 383 K in the Gd-MOF:1%Eu3+,30%Dy3+sample.The high relative sensitivity of this MOF is due to the phonon-assisted energy transfer from Dy3+to Eu3+,which is proved via fluorescence decay curves and fluoresce nce spectra.The major route of this energy transfer is4F9/2(Dy3+)→5D1(Eu3+).