Spontaneous Self-Assembly of Silver Nanoparticles into Lamellar Structured Silver Nanoleaves

Abstract

Uniform lamellar silver nanoleaves (AgNLs) were spontaneously assembled from 4 nm silver nanoparticles (AgNPs) with p-aminothiophenol (PATP) as mediator under mild shaking at room temperature. The compositions of the AgNLs were verified to be ∼1 nm Ag25 nanoclusters and PATP molecules in quinonoid model. The underlying assembly mechanism was systematically investigated and a two-step reaction process was proposed. First, the 4 nm AgNPs were quickly etched to ∼1 nm Ag25 nanoclusters by PATP in the form of [Ag25(PATP)n]n+ (n<12), which were then further electrostatically or covalently interconnected by PATP to form the repeated unit cells of [Ag25(PATP)n-1](n-1)+-PATP-[Ag25(PATP)n-1](n-1)+ (abbreviated as Ag25-PATP-Ag25). Second, these Ag25-PATP-Ag25 complexes were employed as building blocks to construct lamellar AgNLs under the directions of the strong dipole-dipole interaction and the π-π stacking force between the neighboring benzene rings of PATP. Different reaction parameters including the types and concentrations of ligands, solvents, reaction temperature, ionic strength, and pH, etc., were carefully studied to confirm this mechanism. Finally, the preliminary investigations of the applications for AgNLs as "molecular junctions" and SERS properties were demonstrated. We expect that this convenient and simple method can be in principle extended to other systems, or even mixture system with different types of NPs, and will provide an important avenue for designing metamaterials and exploring their physicochemical properties.

In situ synthesis and electronic transport of the carbon-coated Ag@C/MWCNT nanocomposite

“…The peaks in Fig. 3(b) conrm pure Ag with zero valances through the binding energies of Ag 3d electrons (368.0 eV for 3d 5/2 , 374.0 eV for 3d 3/2 electrons), 25 without any silver oxides, which indicates that the pure Ag has been protected by the carbonaceous species. The feature peak of O 1s electrons at a binding energy of 532.26 eV is attributed to the adsorbed -OH/O 2 species in air (Fig.…”

Facile self-assembly and stabilization of metal oxide nanoparticles

“…single vs. multi-layered [18], or compact vs. porous structures [19]. One approach to control the architecture of nanostructured materials is to self-assemble the nanoparticles into the desired configuration which has led to many reports for metallic nanoparticles such as gold or silver [20]. However, the self-assembly of metal oxide particles has been much less studied.…”

“…This may also reflect the need to apply post-assembly, high temperature heat treatments to promote interparticle bonding and substrate adhesion whilst also evaporating/combusting the colloidal matrix used to process the nanoparticles [21]. For example, mesoporous TiO 2 coatings used as photoanodes for photovoltaic devices or photocatalytic water treatment [19][20][21][22] are printed onto glass from suspensions containing solvent and rheology modifiers both of which are removed using heat treatment typically at 450°C [23]. This can be a problem because the very high surface:volume ratio of nanoparticles can accelerate surface energy driven phenomena over bulk transformations.…”

Synthesis of palladium and palladium sulfide nanocrystals via thermolysis of a Pd–thiolate cluster

“…These metal-thiolate clusters exhibit intriguing properties and potential applications in the fields of catalysis [20,21], optics [22,23] and magnetism [24,25]. Recently, self-assemblies of these individual metal-thiolate clusters into specific nano-architectures have also gained extensive concern [26][27][28][29][30]. Wu et al [26,27] reported the synthesis of gold nanosheets and copper nanoribbons through the controlled self-assembly of Au 15 and Cu 12 clusters.…”