Luminescence Boosting after adding Quaternary ammonium/Phosphine Cations to Europium (III) Laponite Clay

Abstract

Quaternary ammonium/phosphine cations added to the platelets of Laponite clay can lead to the remarkable enhancement of luminescence efficiency of the europium (III) β-diketonate complex. The mechanism for the luminescence boosting by the organic cations was elucidated by comparing two diketonate ligands with different pKa and the pH value of the selected organic salts based on the stationery and time resolved spectroscopy. It can be concluded as that the presence of the quaternary ammonium or quaternary phosphine cations helps to form Eu³⁺-β-diketonate complexes with high coordination numbers by decreasing the acidic sites on the platelet surface of laponite clay. Our work further strengthens the simplicity and generalization of obtaining highly luminescent materials and provides a unique insight into the function of the quaternary ammonium/quaternary phosphine cations in boosting the luminescence of lanthanide-based organic-inorganic hybrid materials.