Metal–Organic Gels from Silver Nanoclusters with Aggregation‐Induced Emission and Fluorescence‐to‐Phosphorescence Switching

Abstract

Luminescent metal nanoclusters (NCs) are emerging as a new class of functional materials that have rich physicochemical properties and wide potential applications. In recent years, it has been found that some metal NCs undergo aggregation‐induced emission (AIE) and an interesting fluorescence‐to‐phosphorescence (F‐P) switching in solutions. However, insights of both the AIE and the F‐P switching remain largely unknown. Now, gelation of water soluble, atomically precise Ag9 NCs is achieved by the addition of antisolvent. Self‐assembly of Ag9 NCs into entangled fibers was confirmed, during which AIE was observed together with an F‐P switching occurring within a narrow time scale. Structural evaluation indicates the fibers are highly ordered. The self‐assembly of Ag9 NCs and their photoluminescent property are thermally reversible, making the metal–organic gels good candidates for luminescent ratiometric thermometers.

Self‐Assembly of Precision Noble Metal Nanoclusters: Hierarchical Structural Complexity, Colloidal Superstructures, and Applications

“…More recently, Xie et al. [ 223 ] and Sun et al. [ 224 ] investigated the significance of the position ( ortho or para ) of COOH group on the bound ligands during the self‐assembly of NCs via hydrogen bonding.…”

Progress in aggregation‐induced emission‐active fluorescent polymeric hydrogels

“…One elegant example was very recently reported by Xie et al. [ 62 ] As illustrated in Figure 13, the water‐soluble coordinated Ag NCs were prepared in alkali aqueous solutions of AgNO 3 and thiosalicylic acid. Upon the addition of antisolvent such as ethanol, aqueous solutions of Ag NCs tended to self‐assemble into highly ordered fibers, which simultaneously gelated to give crosslinked network with aggregation‐enhanced photoluminescence.…”

“…(C) Time‐dependent optical properties of the gel after addition of EtOH and Emission curves recorded at different times. Reproduced with permission: 2020, Wiley‐VCH [ 62 ]…”

Multiscale Assembly of [AgS4] Tetrahedrons into Hierarchical Ag–S Networks for Robust Photonic Water

“…[ 8–12 ] In addition to the latest developments in atomically precise ultrasmall particles (mainly limited to below 3 nm), there is also a need to realize their programmable structure (or self‐assembly) into functional materials with a high level of hierarchy, complexity, and accuracy, up to the micro‐ or even macroscale. [ 13–20 ] This multiscale assembly of atomically precise ultrasmall particles provides a reliable platform for the bottom‐up construction of artificial functional materials across all scales, which is an intrinsic requirement for manifesting universal functionality in nature and life. [ 21–23 ] In addition, it also enables the assembly to have imposed stability, collective (and often synergistic) functionality, and expected processability, thereby increasing their acceptance in various fields of practical applications.…”