Luminescence Enhancement after Adding Stoppers to Europium(III) Nanozeolite L

Abstract

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.

Enhanced NIR Luminescence of Nanozeolite L Loading Lanthanide β‐Diketonate Complexes

“…Herein we represent a simple way of achieving the remarkably enhanced NIR luminescence of Ln 3+ -diketonate complexes (Ln＝Nd and Er) hosted in the channels of nanosized zeolite L (NZL) by attaching stopper molecules (an imidazolium salt) to the channel entrances of NZL in aqueous solution, resulting in an obvious enhancement of luminescence intensity, which is similar with the report containing Eu 3+ -β-diketonate complexes. [7] The reaction mechanism, which is same with our previous report, [7] is that the decreasing of the proton strength in the zeolite channels promotes the formation of Ln 3+ -β-diketonate complexes with high coordination numbers. This provides an important basis for the development of NIR luminescence materials which have great potential applications in optical fiber and telecommunications.…”

“…The imidazolium salt X (X＝1 or 2) as stopper molecule, has a large head (Si(OEt) 3 ) and positively charged long tail, to modify Ln 3+ (TTA n )@NZL. [7] The large head of the stopper molecule X is too large to enter into the channels of zeolite L, which can react with -OH groups present at the channel entrance, and the positively charged long tail can insert into the negatively charged channels by cation exchange (Figure 2). [7] The X modified nanocomposites were donoted as Ln 3+ (TTA n ) @NZL-X, where Ln＝Nd or Er.…”

“…[7] The large head of the stopper molecule X is too large to enter into the channels of zeolite L, which can react with -OH groups present at the channel entrance, and the positively charged long tail can insert into the negatively charged channels by cation exchange (Figure 2). [7] The X modified nanocomposites were donoted as Ln 3+ (TTA n ) @NZL-X, where Ln＝Nd or Er. In Figures 3a and 3b, we compared the excitation and emission spectra of Nd 3+ (TTA n )@NZL-1 and Nd 3+ (TTA n )@NZL-2 with Nd 3+ (TTA n )@NZL.…”

“…In the previous report, [7] we attached stopper molecules (imidazole salt) to nanozeolite L (NZL), the channels of which contained Eu 3+ -β-diketonate complexes, which resulted in an obvious enhancement of luminescence intensity. Herein we represent a simple way of achieving the remarkably enhanced NIR luminescence of Ln 3+ -diketonate complexes (Ln＝Nd and Er) hosted in the channels of nanosized zeolite L (NZL) by attaching stopper molecules (an imidazolium salt) to the channel entrances of NZL in aqueous solution, resulting in an obvious enhancement of luminescence intensity, which is similar with the report containing Eu 3+ -β-diketonate complexes.…”

Close-Packed Dye Molecules in Zeolite Channels Self-Assemble into Supramolecular Nanoladders

“…Since the nanometric diameter channels of zeolites may induce an anisotropic arrangement of photoactive molecules, the resulting host-guest materials show outstanding energy transfer capabilities, mimicking the functionalities of the antenna systems of living plants. 17,18,19,20,21 This is a key requirement for the fabrication of increasingly sophisticated optical devices which might open novel pathways in areas such as solar energy harvesting, information processing and nanodiagnostics. 22,23,24 Zeolite L (ZL) is a very appealing host matrix for the realization of one dimensional photoactive domains.…”