Stopper molecules attached to nanozeolite L (NZL) boost the luminescence of confined Eu(3+)-β-diketonate complexes. The mechanism that is responsible was elucidated by comparing two diketonate ligands of different pK(a) and two aromatic imines, and by applying stationary and time resolved spectroscopy. The result is that the presence of the imidazolium based stopper is favorable to the sustainable formation of Eu(3+)-β-diketonate complexes with high coordination by decreasing the proton strength inside the channels of NZL. A consequence is that strongly luminescent transparent films can be prepared using aqueous suspension of the stopper modified composites.
Keywords: luminescence; rare earth elements; supramolecular chemistry; thin films; zeolites.
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