Dynamics of Bulk vs. Nanoscale WS_2: Local Strain and Charging Effects

TL;DR

This study compares the vibrational properties of bulk and nanoparticle WS$_2$, revealing how local strain and curvature influence their structure and charge distribution, which could affect their lubrication performance.

Contribution

It provides new insights into how nanoscale curvature and strain alter the vibrational and charge properties of WS$_2$, a novel understanding of structure-property relations.

Findings

Nanoparticles exhibit a 1.5:1 intralayer charge difference compared to bulk.

Local strain and curvature modify vibrational modes and charge environment.

Charge differences may influence lubrication properties of WS$_2$ nanoparticles.

Abstract

We measured the infrared vibrational properties of bulk and nanoparticle WS$_2$ in order to investigate the structure-property relations in these novel materials. In addition to the symmetry-breaking effects of local strain, nanoparticle curvature modifies the local charging environment of the bulk material. Performing a charge analysis on the \emph{xy}-polarized E$_{1u}$ vibrational mode, we find an approximate 1.5:1 intralayer charge difference between the layered 2H material and inorganic fullerene-like (IF) nanoparticles. This effective charge difference may impact the solid-state lubrication properties of nanoscale metal dichalcogenides.