Direct observation of low frequency confined acoustic phonons in silver nanoparticles: Terahertz time domain spectroscopy

TL;DR

This study employs terahertz time domain spectroscopy to directly observe low frequency confined acoustic phonons in silver nanoparticles, revealing specific vibrational modes and demonstrating the technique's effectiveness in nanoparticle characterization.

Contribution

It provides the first direct observation of low frequency confined acoustic phonons in silver nanoparticles using terahertz spectroscopy, complementing Raman methods.

Findings

Identification of spheroidal and toroidal modes at 0.60 THz and 2.12 THz

Demonstration of terahertz spectroscopy as a useful tool for nanoparticle phonon analysis

Confirmation of low frequency phonon modes in silver nanoparticles

Abstract

Terahertz time domain spectroscopy has been used to study low frequency confined acoustic phonons of silver nanoparticles embedded in poly(vinyl alcohol) matrix in the spectral range of 0.1 to 2.5 THz. The real and imaginary parts of the dielectric function show two bands at 0.60 THz and 2.12 THz attributed to the spheroidal and toroidal modes of silver nanoparticles, thus demonstrating the usefulness of terahertz time domain spectroscopy as a complementary technique to Raman spectroscopy in characterizing the nanoparticles.