What’s so Hot about Electrons in Metal Nanoparticles?

Abstract

Metal nanoparticles are excellent light absorbers. The absorption processes create highly excited electron-hole pairs and recently there has been interest in harnessing these hot charge carriers for photocatalysis and solar energy conversion applications. The goal of this Perspectives article is to describe the dynamics and energy distribution of the charge carriers produced by photon absorption, and the implications for the photocatalysis mechanism. We will also discuss how spectroscopy can be used to provide insight into the coupling between plasmons and molecular resonances. In particular, the analysis shows that the choice of material and shape of the nanocrystal can play a crucial role in hot electron generation and coupling between plasmons and molecular transitions. The detection and even calculation of many-body hot-electron processes in the plasmonic systems with continuous spectra of electrons and short lifetimes are challenging, but at the same time very interesting from the point of view of both potential applications and fundamental physics. We propose that developing an understanding of these processes will provide a pathway for improving the efficiency of plasmon-induced photocatalysis.

Monitoring Simultaneous Electrochemical Reactions with Single Particle Imaging

“…Silver nanoparticles (NPs) have a wide range of applications, such as catalyzing the photodecomposition of environmental contaminants, [1] selectively oxidizing organic species such as benzene and carbon monoxide, [2,3] serving as substrates for surface-enhanced Raman scattering (SERS), [4] acting as plasmonic photo-catalysts through the generation of hot charge carriers, [5,6] and providing antimicrobial activity. [7] However, a major issue with Ag NPs is the formation of an oxide/hydroxide layer on their surface that results in reduced efficiency in all of the above-mentioned applications.…”

The Renaissance of Luminescent Solar Concentrators: The Role of Inorganic Nanomaterials

“…Co-doping the LSC matrix with Au or Ag nanoparticles is typically resulting in an enhancement of the fluorescence intensity of the luminophore, either organic dyes, [121][122][123][124] semiconductor QDs, [125] or lanthanides complexes, [126] but no speculation on the final contribution to the LSC optical efficiency has been reported. [127] Indeed, while this approach has been successfully employed in many fields, ranging from biosensing [128] to photocatalysis, [129] its practical utilization in LSC technology is challenging due to different reasons: (i) the fine control of the 3D structure of the luminophore-metal nanoparticle adduct is essential to achieve a positive sensitization of the luminophore, [130,131] and it is often negatively counterbalanced by (ii) the rise of charge-transfer [132] and (iii) backenergy transfer processes to the metal nanoparticle. [127] Indeed, while this approach has been successfully employed in many fields, ranging from biosensing [128] to photocatalysis, [129] its practical utilization in LSC technology is challenging due to different reasons: (i) the fine control of the 3D structure of the luminophore-metal nanoparticle adduct is essential to achieve a positive sensitization of the luminophore, [130,131] and it is often negatively counterbalanced by (ii) the rise of charge-transfer [132] and (iii) backenergy transfer processes to the metal nanoparticle.…”

Combination Law for Drude–Sommerfeld's Electron Damping in Multilayer Thin Metal Films

“…This work focuses on the effective e − damping in thin multilayer metal films. Damping is the most critical parameter ultimately determining the quality factor in many optics and plasmonics applications . By combining a mean‐field view with the free e − model, the overall behavior fulfills a parallel combination rule of pure materials coefficients, as here it is tested for Cu/Au and Au/Ag.…”

“…Damping is the most critical parameter ultimately determining the quality factor in many optics and plasmonics applications. [25,26] By combining a mean-field view with the free e À model, the overall behavior fulfills a parallel combination rule of pure materials coefficients, as here it is tested for Cu/Au and Au/Ag. Theories linking mesoscopic to microscopic/atomic scales well suit condensed matter investigations such as polarization, dielectric, [27][28][29] flow, [30] and solidstate properties.…”