Intrazeolite nanostructure of Nd(III) complex giving strong near-infrared luminescence

We investigated the variation of the emission properties of tetramethylammonium ion-containing faujasite zeolite treated with bis-(perfluoromethylsulfonyl)amide (PMS) as a function of the Nd(III)-loading level. The emission intensity increased with the Nd(III)-loading level. The emission decays did not follow simple first-order kinetics and the average lifetime became longer with increasing Nd(III)-loading level. It was found that at low Nd(III)-loading levels, Nd(PMS)(3) Complexes formed with coordinating water molecules in the supercage of the zeolite, resulting in rapid emission with a lifetime of less than 40 mus. On the other hand, the components with lifetimes longer than 100 mus observed at high loading levels were attributed to [Nd(PMS)] zeolite complexes without coordinating water molecules. The zeolites with high Nd(III)-loading levels gave more efficient emission due to the large contribution of the complex in the zeolite that emitted more efficiently. The suppression of energy migration among the Nd(III) ions by co-exchanging with La(III) led to more efficient near-IR emission of Nd(III) complexes encaged in the faujasite-type zeolite.