Tuning Localized Surface Plasmon Resonance Wavelengths of Silver Nanoparticles by Mechanical Deformation

Abstract

We describe a simple technique to alter the shape of silver nanoparticles (AgNPs) by rolling a glass tube over them to mechanically compress them. The resulting shape change in turn induces a red-shift in the localized surface plasmon resonance (LSPR) scattering spectrum and exposes new surface area. The flattened particles were characterized by optical and electron microscopy, single nanoparticle scattering spectroscopy, and surface enhanced Raman spectroscopy (SERS). AFM and SEM images show that the AgNPs deform into discs; increasing the applied load from 0 to 100 N increases the AgNP diameter and decreases the height. This deformation caused a dramatic red shift in the nanoparticle scattering spectrum and also generated new surface area to which thiolated molecules could attach as evident from SERS measurements. The simple technique employed here requires no lithographic templates and has potential for rapid, reproducible, inexpensive and scalable tuning of nanoparticle shape, surface area, and resonance while preserving particle volume.

Decoupled in-plane Dipole Resonance Modulated Colorimetric Assay-Based Optical Ruler for Ultra-Trace Gold (Au) Detection

“…The extent of plasmon shifting for a nanodisc to that of a nanosphere 56 by applying same optical force has been calculated analytically in the Supporting Information Section where variation of relative stress for discs (with a constant disc thickness) and spheres with their diameter have been estimated (Fig. 3S ).…”

Pulse-Modulated Radio-Frequency Alternating-Current-Driven Atmospheric-Pressure Glow Discharge for Continuous-Flow Synthesis of Silver Nanoparticles and Evaluation of Their Cytotoxicity toward Human Melanoma Cells

“…Flowing liquid electrode solutions containing Ag(I) ions of defined concentrations (with or without pectin) were continuously introduced to the plasma-reaction system and treated by pm-rf-APGD. Plasma-treated solutions containing AgNPs were collected and subjected to analysis by UV/Vis absorption spectrophotometry to acquire the λ max value of the LSPR absorption band, characteristically in the range of 400–750 nm for spherical AgNPs [ 19 , 35 ].…”

Promoting Catalytic Oxygen Activation by Localized Surface Plasmon Resonance: Effect of Visible Light Pre‐treatment and Bimetallic Interactions

“…The LSPR effect relies on the excitation of electrons on the metal surface, which occurs only at a specific frequency corresponding to a specific wavelength that is characteristic of the metal. The versatility of the LSPR effect, especially in terms of the tunability of excitation wavelength (light absorption range), which can be exploited simply by manipulating the nanoparticle size and shape, makes it an interesting and highly valuable property to be brought into catalysis . One of the most commonly studied metals for the LSPR effect is Au, either as monometallic nanoparticles, bimetallic nanoparticles, or metal oxide‐supported metal nanoparticles, owing to its excitation wavelength laying within the visible range.…”

“…The versatility of the LSPR effect, especially in terms of the tunability of excitation wavelength (light absorption range), which can be exploiteds imply by manipulating the nanoparticle size and shape, makes it an interesting and highly valuable property to be brought into catalysis. [18][19][20] One of the most commonly studied metalsf or the LSPR effect is Au, either as monometallic nanoparticles,b imetallic nanoparticles, or metal oxide-supported metal nanoparticles, [12,[15][16][17]21] owing to its excitation wavelength laying within the visible range. An umber of studies have already been reported in the literature on the enhancement by Au LSPR under visible light for photocatalytic reactions.…”