Nanoparticles, while a long-known subset of nanoscience research, have only in recent years begun migrating from the strictly research sector to the public domain. Nanoparticles exhibit a unique energetic phenomenon called Surface Enhanced Raman Scattering (SERS) due to their size. All molecules exhibit some unique Raman scattering signature that is determined by intramolecular vibrations, but the concentration of the molecule needed to read this signature is typically impractical in the field. However, nanoparticles have coulombic attractions at the nanoscale that greatly enhance the electromagnetic fields around them. This means that the Raman signature of a molecule can be read with much lower concentrations and much greater detail, due to SERS. For this SERS enhancement to occur a perpendicular surface to the incident light is necessary to ensure proper interaction and scattering. This means increasing the number of surface defects increases the number of regions for these enhancements to occur on. Since this phenomenon only takes place at the surface, the surface to volume ratios should ideally be maximized. As a result, moving from spherical nanoparticles to anisotropic nanostructures becomes an area of interest within nanoparticle research. The modification of both surface ligands and reaction kinetics allow for syntheses of many different arrangements of nanoparticles.<br/><br/>Electron Microscopy (SEM) and Selected Area Electron Diffraction have thus far shown successful synthesis of undulated gold nanoplates using simple bioreductants extracted from plant materials. Energy Dispersive X-ray Spectroscopy results have confirmed that the undulations are gold and not hydrocarbon deposits. These undulations would provide more SERS enhancement due to the creation of regional hotspots at the intersection of the undulations. Additionally, we have thus far confirmed with SEM the formation of Silver nanoflowers using a dendritic nanoplate template. This dendritic nanoplate template allows us to etch the dendrites into whatever shape desired, and in a one-pot synthesis we are able to systematically shape them from plate dendrites to flower spikes to star tips. In both syntheses, the multi-twin defects and rough, defined features would theoretically lead to very high SERS enhancement relative to just simple spherical nanoparticles or even anisotropic nanoplates, allowing for stronger sensing and SERS options.

Manipulation of the metal crystal lattice to synthesize anisotropic nanoparticles

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.