Localization of Au Nanoclusters on Layered Double Hydroxides Nanosheets: Confinement‐Induced Emission Enhancement and Temperature‐Responsive Luminescence

Abstract

Gold nanoclusters (Au NCs) stand for a new type of fl uorescent nanomaterials with outstanding optical properties due to their discrete electronic energy and direct electron transition. However, relative low quantum yield (QY) of Au NCs in aqueous or solid state has limited their photofunctional applications. To improve the fl uorescent performances of Au NCs and fi nd an effective approach for the fabrication of Au NCs-based fi lms, in this work, Au NCs are localized onto 2D layered double hydroxides (LDHs) nanosheets via a layer-by-layer assembly process; the as-fabricated (Au NCs/LDH) n ultrathin fi lms (UTFs) show an ordered and dense immobilization of Au NCs. The localization and confi nement effects imposed by LDH nanosheets induce signifi cantly increased emissive Au(I) units as confi rmed by X-ray photoelectron spectroscopy and periodic density functional theoretical simulation, which further results in promoted QY (from 2.69% to 14.11%) and prolonged fl uorescence lifetime (from 1.84 μs to 14.67 μs). Moreover, the ordered (Au NCs/LDH) n UTFs exhibit well-defi ned temperature-dependent photoluminescence (PL) and electrochemiluminescence (ECL) responses. Therefore, this work supplies a facile strategy to achieve the immobilization of Au NCs and obtain Au NCs-based thin fi lms with high luminescent properties, which have potential applications in PL and ECL temperature sensors.

Fabrication of Au25(SG)18–ZIF‐8 Nanocomposites: A Facile Strategy to Position Au25(SG)18 Nanoclusters Inside and Outside ZIF‐8

“…Au 25 (SG) 18 clusters are protected by glutathione (GSH) with good water solubility, where most of the carboxyl groups of the GS ligands tend to be dissociated as the acid dissociation constants of the two carboxyl groups of free GSH are 2.56 and 3.50. [10a] It had been reported that the coordinative interaction between carboxylate groups and metal ions contributed to the formation of HKUST-1, [11] MOF-5 film, [12] Au@HKUST-1, [13] or polystyrene@ZIF-8. [14] The other coordinative interaction between Zn 2+ and the imidazole molecules in ZnN 4 tetrahedron of ZIF-8 was also referred in previous work.…”

Recent Advances Based on Nanomaterials as Electrochemiluminescence Probes for the Fabrication of Sensors

“…Chen's group and Zhu's group demonstrated the anodic and cathodic ECL behavior of BSA‐capped Au 25 in aqueous solution with TEA and S 2 O 8 2− as co‐reactants, respectively. Alternatively, Tian and coworkers found that when localized Au NCs onto confined 2D layered double hydroxides (LDHs) via a layer‐by‐layer assembly process; promoted PL and ECL performances can be achieved. Recently, Wang's group proposed a novel mechanism to enhance the ECL of Au CNs by covalent attachment of co‐reactant N,N‐diethylethylenediamine (DEDA) onto lipoic acid stabilized Au NCs (LA−Au NCs) with matching redox activities (Figure A).…”

Synthesizing a nano-composite of BSA-capped Au nanoclusters/graphitic carbon nitride nanosheets as a new fluorescent probe for dopamine detection

“…2D). The enhanced lifetime of g-C 3 N 4 NSs-AuNCs can be ascribed to the inhibited nonradiative transition after AuNCs were loaded in the interlayer of g-C 3 N 4 NSs and the relevant hosteguest interaction [38]. Moreover, the percentage of the charge carriers of the short lifetime was decreased from 79.25% for g-C 3 N 4 NSs to 73.25% for g-C 3 N 4 NSs-AuNCs at a small cost of shortening the lifetime only by 0.13 ns (3.4 Â 79.25% e 3.5 Â 73.25%), and the value of long-lived charge carriers increased from 20.75% to 26.75% at a small cost of prolonging the lifetime only by 0.94 ns (8.8 Â 26.75% e 6.8 Â 20.75%), which revealed that the increased lifetimes of charge carriers could improve the probability of the electron transport and/or electronic band structure changes induced by quantum confinement effect in the g-C 3 N 4 NSs-AuNCs [39].…”