Study on preparation and characterization of MOF based lanthanide doped luminescent coordination polymers

Coordination polymers (metal–organic frameworks or MOFs) offer the opportunity for fine-tuning the luminescence behavior because of the possibility to entrap in the network pores molecules that can influence the lanthanide (Ln) emission. In this study, Zn (II) and polycarboxylate based MOFs were first pre-formed by solvothermal method, then considered as host-matrix for in situ doping of low-input concentration of Eu³⁺ and Tb³⁺ (two most commonly used lanthanides in life science assays), and afterwards lanthanide doped luminescent materials were synthesized. Different characterizations (X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive Spectroscopy (EDS)) were carried out to confirm accordingly MOF's crystallinity, the structure and chemical composition. The study on luminescent properties of the material has revealed an efficient energy transfer from the ligand excited states to the Eu³⁺ and Tb³⁺ f-excited states. With quite low input concentrations (8–15%) of doped rare earth ions, these complexes displayed intense emissions at room temperature and proved to be good candidates for red and green emitter luminescent materials. Generally, this design concept can be extended for the preparation of other rare earth coordination polymers.