Nanoscale Charge Transport in Au@PANI Assemblies: Bulk-like Films and Linear Assemblies

Abstract

Hybrid nanostructures from metal nanoparticles equipped with conducting polymer shells are of great interest for use as functional materials in sensing and optoelectronics, as well as for ink-deposited conductors. Here, we investigate the charge transport mechanism of nanostructures composed of gold nanoparticles coated with a polyaniline shell (Au@PANI). In particular, we focus on how geometry influences the charge transport behavior. Highly ordered linear assemblies of Au@PANI nanoparticles were fabricated using template-assisted assembly, while bulk-like films were obtained via drop-casting. Temperature-dependent transport measurements were analyzed using established conductance models. Linear assemblies exhibit more localized transport, characterized by variable-range hopping (VRH) and thermally assisted tunneling (TAT), whereas bulk-like films show more delocalized transport, dominated by Arrhenius-type and thermionic conduction. These findings highlight the critical role of geometry, also due to its effect on electrical field strength in determining charge transport mechanisms in nanoparticle-based hybrid systems.