[Paper Review] Hot-electron dynamics in plasmonic nanostructures

Jacob B. Khurgin, Anton Yu. Bykov+1 more|arXiv (Cornell University)|Feb 20, 2023

Gold and Silver Nanoparticles Synthesis and Applications9 citations

TL;DR

A review of hot-electron generation and dynamics in plasmonic nanostructures, covering theory, experimental probes, and applications in ultrafast optics and catalysis.

ABSTRACT

The coherent oscillations of mobile charge carriers near the surface of good conductors-surface plasmons-are been exploited in many applications in information technologies, clean energy, high-density data storage, photovoltaics, chemistry, biology, medicine and security. Light can be coupled to surface plasmons and trapped near the interface between a metal and an adjacent material. This leads to the nanoscale confinement of light, impossible by any other means, and a related electromagnetic field enhancement. Microscopic electron dynamic effects associated with surface plasmons are capable of significantly influencing physical and chemical processes near a conductor surface, not only as a result of the high electric fields, but also via the excitation of energetic charge carriers: holes below Fermi level or electrons above it. When remaining inside plasmonic media, these so-called hot carriers result in nonlinear, Kerr-type, optical effects important for controlling light with light. They can also transfer into the surroundings of the nanostructures, resulting in photocurrent, or they can interact with adjacent molecules and materials, inducing photochemical transformations. Understanding the dynamics of hot carriers and related effects in plasmonic nanostructures is essential for the development of ultrafast detectors and nonlinear optical components, broadband photocatalysis, enhanced nanoscale optoelectronic devices, nanoscale and ultrafast temperature control, and other technologies of tomorrow. This review will discuss the basics of plasmonically-engendered hot electrons, theoretical descriptions and experimental methods to study them, and describe prototypical processes and examples of the most promising applications of hot-electron processes at the metal interfaces.

Motivation & Objective

• Motivate the study of hot carriers generated by surface plasmons and their impact on physical and chemical processes near metal interfaces.
• Summarize the theoretical frameworks describing hot-electron dynamics in plasmonic systems.
• Survey experimental methods used to study hot carriers and illustrate prototypical processes and applications.
• Highlight prospective applications leveraging hot-electron phenomena in devices and technologies.

Proposed method

• Present theoretical descriptions of plasmonically-generated hot electrons and their nonthermal and thermal dynamics.
• Review experimental approaches for probing hot carriers, including ultrafast spectroscopy and related techniques.
• Describe prototypical processes such as nonlinear optical effects and carrier transfer to surrounding materials.
• Discuss applications in ultrafast detectors, nonlinear optics, photocatalysis, and nanoscale optoelectronics.

Experimental results

Research questions

• RQ1 What are the fundamental mechanisms by which surface plasmons generate hot electrons and holes in plasmonic nanostructures?
• RQ2 How do hot carriers influence nonlinear optical effects and near-interface chemistry or device performance?
• RQ3 What experimental methods best characterize hot-electron dynamics and carrier transfer to adjacent materials?
• RQ4 What are the most promising applications that exploit hot-electron processes at metal interfaces?

Key findings

• Hot carriers can drive nonlinear, Kerr-type optical effects within plasmonic media.
• Hot electrons and holes can transfer into surrounding materials and participate in photocurrent generation and photochemical transformations.
• Understanding hot-carrier dynamics is essential for developing ultrafast detectors, broadband photocatalysis, and nanoscale optoelectronic devices.
• Plasmonically-engendered hot-electron processes enable control over light with light and surface-mediated chemical and physical transformations.