Simple and Tailorable Synthesis of Silver Nanoplates in Gram Quantities

Abstract

Due to plasmonic and catalytic properties, silver nanoplates are of significant interest; therefore, their simple preparation in gram quantities is required. Preferably, the method is seedless, consists of few reagents, enables preparation of silver nanoplates with desired optical properties in high concentration, is scalable, and allows their long-term storage. The developed method is based on silver nitrate, sodium borohydride, polyvinylpyrrolidone, and H 2 O 2 as the main reagents, while antifoam A204 is implemented to achieve better product quality on a larger scale. The effect of each component was evaluated and optimized. Solution volumes from 3 to 450 mL and concentrations of silver nanoplates from 0.88 to 4.8 g/L were tested. Their size was tailored from 25 nm to 8 μm simply by H 2 O 2 addition, covering the entire visible plasmon spectra and beyond. They can be dried and spontaneously dispersed after at least one month of storage in the dark without any change in plasmonic properties. Their potential use in modern art was demonstrated by drying silver colloids on different surfaces in the presence of reagents or purified, resulting in a variety of colors but, more importantly, patterns of varying complexity, from simple multi-coffee-rings structures to dendritic forms and complex multilevel Sierpinśki triangle fractals.

Gram-Scale Continuous Flow Synthesis of Silver-on-Silica Patchy Nanoparticles with Widely Tunable Resonances for Plasmonics Applications

“…This suggests that at low ρ 0, Seed , insufficient gold nanocrystals are present to initiate growth and due to the low reaction temperature of 30 °C, the conditions needed for the kind of heterogeneous nucleation seen on bare silica particles in our earlier work are not present. ,, Besides higher order in-plane resonances in the range 500–700 nm, which shift similarly to the main dipole peak, a further feature in the extinction spectra for the cases of ρ 0, Seed between 10 and 40 can be seen at a constant wavelength value of around 331 nm. This peak was observed in our earlier studies with silver patches and corresponds to the out-of-plane quadrupole resonance, similar to that seen for flat silver nanoprisms. , Since this feature depends almost exclusively on the patch thickness, we can conclude that the value of ρ 0, Seed has rather little influence on that aspect of the patch morphology. It follows that for a lower seeding density, the coverage of patches should increase.…”

“…This peak was observed in our earlier studies with silver patches and corresponds to the out-of-plane quadrupole resonance, similar to that seen for flat silver nanoprisms. 41,55 Since this feature depends almost exclusively on the patch thickness, 47 we can conclude that the value of ρ 0, Seed has rather little influence on that aspect of the patch morphology. It follows that for a lower seeding density, the coverage of patches should increase.…”

“…This results from a major limitation of most liquid phase techniques to produce noble metal nanostructures with non-spherical morphologies: their reliance on surfactants and other additives to promote symmetry breaking 38 as well as the need for a deep awareness of the "variety of synthetic details and nuances" 39 that should be under practical control. While much work has been carried out to improve the more robust synthetic protocols, 37,40,41 there is still a great need for new approaches involving a minimal number of process steps, requiring few reagents, avoiding functional ligands but at the same time enabling localized surface plasmon resonances (LSPR) to be tuned over a wide spectral range. In 2011, we introduced a single step electroless plating process for the formation of thin silver patches on silica spheres.…”

Guar gum assisted synthesis of high‐quality silver nanoplates and their polyimide matrix nanocomposites for electromagnetic interference shielding applications

“…Two‐dimensional (2D) metal nanostructures such as gold, platinum, iron, silver, rhodium, palladium, cobalt, and others, as well as their alloys are of particular interest for their high aspect ratio, quantum effects, high electrical and thermal conductivity, and unique surface chemistry 1 . Among these, silver nanoplates (AgNPls) offer the highest electrical and thermal conductivity, 2,3 enhanced catalytic activity, 4,5 antibacterial activity, 6,7 and tunable optical properties coupled with surface plasmon resonance 8,9 .…”

Large-area arrays of epitaxially aligned silver nanotriangles seeded by gold nanostructures

“…Another reagent of note is acetonitrile which has been included in some protocols for its ability to form complexes with Ag + ions, and in doing so, can slow reaction rates to lessen the number of seeds formed in the nucleation step 30 or inhibit the spontaneous nucleation of Ag nanostructures in seed-mediated growth modes. 23 Altogether, these various colloidal syntheses represent an impressive collection that has led to the establishment of Ag nanotriangles as a renowned nanoscale building block where capabilities in terms of scalability, 23,31 yield, 23,24 and control over nanotriangle dimensions 21,23,32 are all well-documented. When compared to the unmitigated successes associated with the colloidal synthesis of Ag nanotriangles, efforts directed toward synthesizing similar structures directly on substrate surfaces appear somewhat subdued.…”