Uniform Ag Nanocubes Prepared by AgCl Particle–Mediated Heterogeneous Nucleation and Disassembly and Their Mechanism Study by DFT Calculation

Uniform Ag nanocubes are reproducibly synthesized by a AgCl particle‐mediated heterogeneous nucleation and disassembly process in polyol chemistry. By introducing N,N‐dimethylformamide (DMF) in a conventional polyol method with HCl etchant, Ag nanocrystals (NCs) begin to be nucleated on the surface of AgCl‐precipitated particles due to the promoted reduction reaction by DMF. The nucleated Ag NCs on the AgCl particles are grown to Ag nanocubes in shape by consuming Ag sources from the AgCl mother particles. Eventually the grown Ag nanocubes are disassembled from the mother AgCl particles because the AgCl particles are fully digested by the growing Ag nanocubes. Density functional theory calculation confirms that the Ag atoms can be favorably deposited on the (100) facet of AgCl particles and the Ag nuclei on the AgCl particles tend to reveal (100) facet.     

Surface-induced synthesis and self-assembly of metal suprastructures

A systematic study on the synthesis of a series of self-assembled suprastructures, such as cubes, stars, belts, and microspheres, of Ag nanoparticles (AgNPs) in borosilicate glassware heavily cleaned with aqua regia is presented. These self-assembled structures are mostly formed from the crystallographically iso-oriented AgNPs, and exhibit well-defined shapes. In regular washed glassware, only Ag nanowires are synthesized. The formation mechanisms of these self-assembled Ag structures, based on monitoring of their structural evolution in glassware decorated with different molecules, are proposed. This work not only demonstrates that the surface energy of glassware can affect chemical synthesis, but also provides an interesting approach to the shape-controlled synthesis of novel self-assembled suprastructures of AgNPs, which could be potentially used as synthesis templates, drug vessels, and microreactors.     

Freeze the Moment: High Speed Capturing of Weakly Bonded Dynamic Nanoparticle Assemblies in Solution by Ag Ion Soldering

Despite the versatile forms of colloidal aggregates, these spontaneously formed structures are often hard to find a suitable application in nanotechnology and materials science. A determinate reason is the lack of a suitable method to capture the transiently formed and quickly evolving colloidal structures in solution. To address this challenge, a simple but highly efficient strategy is herein reported to capture the dynamic and metastable colloidal assemblies formed in an aqueous or nonaqueous solution. This process takes advantage of a recently developed Ag ion soldering reaction to realize a rapid fixation of as‐formed metastable assemblies. This method works efficiently for both solid (3D) nanoparticle aggregates and weakly bonded fractal nanoparticle chains (1D). In both cases, very high capturing speed and close to 100% efficiency are achieved to fully retain a quickly growing structure. The soldered nanochains further enable a fabrication of discrete, uniform, and functionalizable nanoparticle clusters with enriched linear conformation by mechanical shearing, which would otherwise be difficult to make. The captured products are water dispersible and mechanically robust, favoring an exploration of their properties toward possible applications. The work paves a way to previously untouched aspects of colloidal science and thus would create new chances in nanotechnology.     

Self‐Destruction of Cancer Induced by Ag2S Amorphous Nanodots

Studies on distinctive performances and novel applications of amorphous inorganic nanomaterials are becoming attractive. Herein, Ag₂S amorphous and crystalline nanodots (ANDs and CNDs) are prepared via facile methods. In vitro and in vivo studies indicate that Ag₂S ANDs, rather than CNDs, can induce the self‐destruction of tumors, which can be attributed to their distinctive chemical properties, e.g., the higher electrochemical active surface area and lower redox potential well matching with the redox reaction requirement in the tumor microenvironment. Ag₂S ANDs can be oxidized by intracellular reactive oxygen species (ROS) to release Ag⁺, which further stimulates high generation of intracellular ROS. This mutual stimulation damages the mitochondria, induces apoptosis, and leads to the self‐destruction of the tumor. Moreover, Ag₂S ANDs do not show observable in vitro and in vivo side effects. These findings provide a promising self‐destructive strategy for cancer therapy by utilizing distinctive chemical properties of inorganic nanomaterials, while avoiding complicated external assistance.     

A Deformable and Highly Robust Ethyl Cellulose Transparent Conductor with a Scalable Silver Nanowires Bundle Micromesh

Huge challenges remain regarding the facile fabrication of neat metallic nanowires mesh for high‐quality transparent conductors (TCs). Here, a scalable metallic nanowires bundle micromesh is achieved readily by a spray‐assisted self‐assembly process, resulting in a conducting mesh with controllable ring size (4–45 µm) that can be easily realized on optional polymer substrates, rendering it transferable to various deformable and transparent substrates. The resultant conductors with the embedded nanowires bundle micromesh deliver superior and customizable optoelectronic performances, and can sustain various mechanical deformations, environmental exposure, and severe washing, exhibiting feasibility for large‐scale manufacturing. The silver nanowires bundle micromesh with explicit conductive paths is embedded into an ethyl cellulose (EC) transparent substrate to achieve superior optoelectronic properties endowed by a low amount of incorporated nanowires, which leads to reduced extinction cross‐section as verified by optical simulation. A representative EC conductor with a low sheet resistance of 25 Ω □^?1, ultrahigh transmittance of 97%, and low haze of 2.6% is attained, with extreme deformability (internal bending radius of 5 µm) and waterproofing properties, opening up new possibilities for low‐cost and scalable TCs to replace indium‐tin oxide (ITO) for future flexible electronics, as demonstrated in a capacitive touch panel in this work.     

One‐Pot Hydrothermal Synthesis of FeMoO4 Nanocubes as an Anode Material for Lithium‐Ion Batteries with Excellent Electrochemical Performance

Metal molybdates nanostructures hold great promise as high‐performance electrode materials for next‐generation lithium‐ion batteries. In this work, the facial design and synthesis of monodisperse FeMoO₄ nanocubes with the edge lengths of about 100 nm have been successfully prepared and present as a novel anode material for highly efficient and reversible lithium storage. Well‐defined single‐crystalline FeMoO₄ with high uniformity are first obtained as nanosheets and then self‐aggregated into nanocubes. The morphology of the product is largely controlled by the experimental parameters, such as the reaction temperature and time, the ratio of reactant, the solution viscosity, etc. The molybdate nanostructure would effectively promote the insertion of lithium ions and withstand volume variation upon prolonged charge/discharge cycling. As a result, the FeMoO₄ nanocubes exhibit high reversible capacities of 926 mAh g⁻¹ after 80 cycles at a current density of 100 mA g⁻¹ and remarkable rate performance, which indicate that the FeMoO₄ nanocubes are promising materials for high‐power lithium‐ion battery applications.