Photonic Contributions to the Apparent Seebeck Coefficient of Plasmonic Metals

TL;DR

This study demonstrates that photonically engineered plasmonic nanostructures can modify the local Seebeck coefficient through photothermal effects, influencing charge transport in metal nanostructures for sensing and energy applications.

Contribution

It reveals that local photonic environments alter the intrinsic Seebeck coefficient via a thermally driven photothermoelectric mechanism, advancing understanding of photon-electron interactions in plasmonic systems.

Findings

Photonic structures create localized photovoltage variations.

Photothermoelectric mechanism dominates charge transport.

Photonic engineering can optimize thermoelectric effects.

Abstract

Photo-induced charge transport in plasmonic metal nanostructures has garnered significant interest for applications in sensing and power conversion, yet the underlying mechanisms remain debated. Here, we report spatially correlated photovoltage generation in photonically engineered Au nanowires illuminated by focused, milliwatt-level laser excitation. Plasmonic nanodisk antennas placed adjacent to the nanowires created local variations in the photonic environment, resulting in clearly defined regions of enhanced photovoltage. Experimental results and simulations strongly support a thermally driven photothermoelectric (PTE) mechanism, where the local photonic structure modifies the intrinsic Seebeck coefficient of the metal, independent of other electronic structural factors. Our findings highlight photon-electron interactions as critical to the observed transport phenomena, suggesting photonic engineering as a viable strategy to systematically control and optimize thermoelectric performance.