Interfacial Hot Carrier Collection Controls Plasmonic Chemistry

TL;DR

This study investigates how interfacial hot carrier collection influences plasmonic photocatalytic efficiency, revealing that optimizing charge transfer at interfaces enhances device performance and guides future design of plasmonic systems.

Contribution

It uncovers the complex interdependence of plasmon excitation, hot carrier transport, and interfacial collection, emphasizing the role of hot hole collection at the metal/electrolyte interface in device efficiency.

Findings

Hot hole collection at the metal/electrolyte interface is crucial for device performance.

High-energy d-band holes in [111] orientation enhance oxidation reactions.

Experimental and ab initio methods reveal orientation-dependent hot carrier dynamics.

Abstract

Harnessing non-equilibrium hot carriers from plasmonic metal nanostructures constitutes a vibrant research field. It promises to enable control of activity and selectivity of photochemical reactions, especially for solar fuel generation. However, a comprehensive understanding of the interplay of plasmonic hot carrier-driven processes in metal/semiconducting heterostructures has remained elusive. In this work, we reveal the complex interdependence between plasmon excitation, hot carrier generation, transport and interfacial collection in plasmonic photocatalytic devices, uniquely determining the charge injection efficiencies at the solid/solid and solid/liquid interfaces. Interestingly, by measuring the internal quantum efficiency of ultrathin (14 to 33 nm) single-crystalline plasmonic gold (Au) nanoantenna arrays on titanium dioxide substrates, we find that the performance of the device is governed by hot hole collection at the metal/electrolyte interface. In particular, by combining a solid- and liquid-state experimental approach with ab initio simulations, we show a more efficient collection of high-energy d-band holes traveling in [111] orientation, resulting in a stronger oxidation reaction at the {111} surfaces of the nanoantenna. These results thus establish new guidelines for the design and optimization of plasmonic photocatalytic systems and optoelectronic devices.