Special topic on emerging directions in plasmonics

Cortés, Emiliano; Govorov, Alexander O.; Misawa, Hiroaki; Willets, Katherine A.

doi:10.1063/5.0017914

Cited by 10 publications

(9 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results substantiate a new paradigm for how energy flows from optical fields to hot electrons in metals via the intermediary collective plasmonic response. Our study challenges a diametric consensus that plasmon decay distributes energy evenly (democratically) between electrons and holes according to their densities of states, − ,,,− , and confirms Hopfield’s conjecture that plasmon decay selectively transfers the photon energy to electrons at E F .…”

Section: Plasmonic Photoemissionsupporting

confidence: 83%

“…The collective plasmon-mediated excitations have large cross sections for harvesting optical energy and transferring it to hot electron excitations. Hot electrons are considered to be key intermediates of energy transduction in optically induced chemical and physical processes at metal surfaces, − especially when energized by the plasmonic modes. − We find a preferential transfer of energy from plasmons to electrons at the Fermi level, E F , implying a substantially improved budget than is commonly assumed for energy harvesting in physical, chemical, and engineering processes. ,− …”

mentioning

confidence: 84%

“…How the optical energy is converted into hot electrons in a plasmonic metal is poorly understood, because at ENZ, higher-order terms in the electric field dominate over the linear response, and therefore, the bulk dielectric response is nonperturbative, , while at a surface it is nonlocal in both space and time. , This has been extensively addressed by experiment and theory in linear photoemission spectroscopy for the alkali − and free electron Al, Be, and Mg metals, ,− which could be studied through ENZ by photoemission because their work functions Φ are below their ℏω p . For pure alkali atom films, it has been established that their bulk plasmon decay preferentially excites photoelectrons from the Fermi level − rather than producing a hot electron and hole distribution defined by their joint densities-of-states (DOSs) spanning between − ℏω p and + ℏω p with respect to E F , as is commonly believed in the plasmonics community. − ,,,,− We refer to the decay of plasmons preferentially exciting photoemission from E F as the plasmonic photoemission .…”

Section: Plasmonic Photoemissionmentioning

confidence: 99%

See 2 more Smart Citations

Plasmonic Photoemission from Single-Crystalline Silver

Reutzel

Wang

et al. 2021

ACS Photonics

View full text Add to dashboard Cite

Optical fields interacting with solids excite single particle quantum transitions and elicit collective screening responses that define their penetration, absorption, and reflection. The interplay of these interactions on the attosecond time scale defines how optical energy transforms to electronic, setting the limits of efficiency for processes such as solar energy harvesting or photocatalysis. Our understanding of light–matter interactions is primarily based on specifying the electronic structure of solids and initial particles or fields occupying well-defined states, and the outcome of their interaction culminating in photoelectron or photon emission and analysis, with scant ability to follow the transitional, ultrafast many-body interactions that define it. The optical properties of metals transubstantiate from metallic to dielectric when the real part of their dielectric response function, Re[ε(ω)], passes through zero: at low frequencies, Re[ε(ω)] < 0, and the collective free electron plasmonic response confers high reflectivity; at high frequencies, Re[ε(ω)] > 0, and the fields penetrate as charge-density or longitudinal plasmon waves. How such collective plasmonic responses decay on the femtosecond time scale into single particle excitations is cardinal to plasmonics, but not sufficiently well described by experiment or theory. We examine the spectroscopic signatures of the nonlinear single particle and collective excitations of the low index crystals of silver by nonlinear two-photon photoemission spectroscopy, at frequencies where the bulk dielectric response passes through zero. We find that the transition through zero dielectric region is reflected in the nonlinear photoemission spectra, and in particular, the bulk plasmons decay by giving rise to a non-Einsteinian plasmonic photoemission component. This response, where the energy of photoelectrons is not defined by the incoming photons, occurs when photons excite the longitudinal plasmons, which then decay by exciting photoelectrons selectively from the Fermi level. Such mode of plasmon decay into hot electrons is contrary to the general agreement, but confirms a theoretical prediction by J. J. Hopfield from 1965. Our experiment illuminates a more energy efficient optical-to-electronic energy flow in metals that so far has escaped scrutiny.

show abstract

Section: Plasmonic Photoemissionsupporting

confidence: 83%

mentioning

confidence: 84%

Section: Plasmonic Photoemissionmentioning

confidence: 99%

See 1 more Smart Citation

Plasmonic Photoemission from Single-Crystalline Silver

Reutzel

Wang

et al. 2021

ACS Photonics

View full text Add to dashboard Cite

show abstract

“…[8] However, the relative importance of EM and molecular effects in producing signal enhancement is still a subject of discussion in emerging field of surface plasmonics. [8,39,40] It is pertinent to present mathematical formulations that forms the basis of concurrent EM and CE factors from graphene/metal "hybrid" nanomaterials. The SERS intensity due to localized surface plasmon resonance is described by polarization (or susceptibility) of analyte molecule which is expressed by, P / N:σ SERS :…”

Section: Sers and G-sers Theoretical Formulationmentioning

confidence: 99%

“…[ 8 ] However, the relative importance of EM and molecular effects in producing signal enhancement is still a subject of discussion in emerging field of surface plasmonics. [ 8,39,40 ] It is pertinent to present mathematical formulations that forms the basis of concurrent EM and CE factors from graphene/metal “hybrid” nanomaterials. The SERS intensity due to localized surface plasmon resonance is described by polarization (or susceptibility) of analyte molecule which is expressed by,

P \propto N . σ_{SERS} . \frac{{(||, E_{loc} false(((),, r 0, ω))}^{4}}{{(||, E_{o} ((),, r 0, ω))}^{4}} {|E_{0}|}^{2}

, where, N is the number of Stokes‐active scatterers (or number of molecules within the laser focal volume), σ SERS is the scattering cross‐section (or CE factor), | E 0 | 2 is the incident laser power (= I 0 ( r 0 , ω)), [ 41 ] E loc and E 0 are the amplitudes of the localized electric field and incident electric field, respectively.…”

Section: Introductionmentioning

confidence: 99%

Detection of DNA bases and environmentally relevant biomolecules and monitoring ssDNA hybridization by noble metal nanoparticles decorated graphene nanosheets as ultrasensitive G‐SERS platforms

Gupta

Banaszak

2021

J Raman Spectroscopy

View full text Add to dashboard Cite

Surface‐enhanced Raman scattering (SERS) and graphene‐mediated surface‐enhanced Raman scattering (G‐SERS) are attractive analytical techniques for the detection of chemical and biological molecules at a single‐molecule level registering their chemical fingerprints. Graphene‐based surface enhancement (or G‐SERS) boosted traditional SERS phenomenon producing signal enhancement from both electromagnetic (EM) and chemical enhancement (CE) mechanisms. Thus, graphene oxide (GO) nanosheets coated with silver (Ag [30 nm]) and gold (Au [40 nm]) nanoparticles smart array platforms, for direct detection and differentiation of DNA bases, namely, adenine (A), cytosine (C), guanine (G), thymine (T), and environmental relevant β‐carotene (β‐C) and malachite green (MG) biomolecules, are developed. The size and interparticle gap were controlled via dispersion and loading on GO surface to achieve optimal enhancement factors. The morphology of these substrates was characterized by scanning electron microscopy and atomic force microscopy. The Raman spectra consisted of discrete bands occurring at (A: 732.8 cm−1; C: 792 cm−1; G: 658 cm−1; T: 796 cm−1; β‐C: 1416 cm−1; MG: 1174 cm−1) that are characteristic of molecular modes of vibration and serve as chemical fingerprint of three‐dimensional structure, intramolecular interaction and steady‐state dynamics, of biomolecule ensemble. The GO‐decorated nanoparticles are capable of sensitive biomolecular detection over a broad concentration range 100 nM to 100 μM with limit of detection (LOD) noted at <1 ppm for A, C, G, T, β‐C, and MG. Moreover, the experimental results illustrated five to six orders of magnitude signal enhancement in the following order: GO/Ag30 > GO/Au40 > Ag30 > Au40 > GO. Moreover, ssDNA probe and complementary target C‐ssDNA were monitored simultaneously during hybridization on the same substrates assigned confidently to base, local chemical structure, and global conformation of resulting dsDNA. The experimental findings suggest a strong GO‐nanoparticle coupling leading to interfacial orbital hybridization (charge transfer) and polarization affected by biomolecule orientation, and it will help in designing ultrasensitive platforms covering range of inorganic nanoparticles and nanostructured surfaces for a wealth of biomedicine and environmental applications.

show abstract