Plasmonic hot carrier dynamics in solid-state and chemical systems for energy conversion

Abstract

Surface plasmons provide a pathway to efficiently absorb and confine light in metallic nanostructures, thereby bridging photonics to the nano scale. The decay of surface plasmons generates energetic 'hot' carriers, which can drive chemical reactions or be injected into semiconductors for nano-scale photochemical or photovoltaic energy conversion. Novel plasmonic hot carrier devices and architectures continue to be demonstrated, but the complexity of the underlying processes make a complete microscopic understanding of all the mechanisms and design considerations for such devices extremely challenging. Here, we review the theoretical and computational efforts to understand and model plasmonic hot carrier devices. We split the problem into three steps: hot carrier generation, transport and collection, and review theoretical approaches with the appropriate level of detail for each step along with their predictions. We identify the key advances necessary to complete the microscopic mechanistic picture and facilitate the design of the next generation of devices and materials for plasmonic energy conversion.

Hot‐Electron‐Mediated Photochemical Reactions: Principles, Recent Advances, and Challenges

“…The recent theoretical studies on hot carrier dynamics are described in an excellent review by Narang et al [25] Briefly, the excited surface plasmons decay by either emitting a photon (radiatively) or generating an electron-hole pair (nonradiatively) through Landau damping. The electron-hole pairs have a much larger energy than the carriers near the Fermi energy, and are called "hot" carriers.…”

“…The slower equilibration of the electron and lattice temperatures originates from the smaller energy exchange per electron-phonon scattering compared to interelectron scattering, despite their comparable mean free time. [25] The complete description of hot carrier dynamics, including electron-electron and electron-phonon scattering, is extremely challenging. It spans multiple time (a few femtoseconds to several picoseconds) and space (a few angstroms to tens of nanometers) scales, as well as different hot carrier energies.…”

“…The result shown in Figure 3e displays the energy and momentum distribution as a function of transport distance L for an initial excitation at 2.6 eV. [25] At the initial point (L = 0), high-energy holes and low-energy electrons are generated with clear directionality that originates from the band structure. High-energy holes are severely scattered and are almost lost at L = 3 nm.…”

Harvesting the loss: surface plasmon-based hot electron photodetection

“…Lastly, the momentum distribution of hot carriers can be modified by engineering the modes of the plasmonic structures. Therefore, surface plasmons provide a powerful tool for efficient hot electron generation and extraction [54]. …”

“…In this case, carriers excited with photon energies lower than the semiconductor bandgap can be captured, circumventing bandgap limitations and opening pathways for additional energy harvesting. This review focuses on the recent development of hot electron-based photodetection, and we point the reader to other review articles that cover chemical catalysis and photovoltaic applications [27,34,54]. In this article, we will first cover the basic principles underlying hot carrier generation and extraction.…”