Quantum mechanical study of the coupling of plasmon excitations to atomic-scale electron transport

Abstract

The coupling of optical excitation and electron transport through a sodium atom in a plasmonic dimer junction is investigated using time-dependent density functional theory. The optical absorption and dynamic conductance is determined as a function of gap size. Surface plasmons are found to couple to atomic-scale transport through several different channels including dipolar, multipolar, and charge transfer plasmon modes. These findings provide insight into subnanoscale couplings of plasmons and atoms, a subject of general interest in plasmonics and molecular electronics.

A classical treatment of optical tunneling in plasmonic gaps: extending the quantum corrected model to practical situations

“…The resulting Localized Surface Plasmon Polaritons (LSPPs) allow the manipulation of light at the To be able to capture these effects, one possibility is to perform rigorous quantum mechanical calculations of the optical response using the Time Dependent Density Functional Theory (TDDFT). 34,[57][58][59][60][61] In contrast to classical calculations, quantum results for very narrow gaps show pronounced effects of electron tunneling such as a strong reduction of the eld enhancement, a continuous transition of modes between the non-touching and contact regimes and the appearance of a Charge Transfer Plasmon (CTP) mode before the nanoparticles touch. 33,62 These effects are outlined by dotted green lines in Fig.…”

Controllable Cobalt Oxide/Au Hierarchically Nanostructured Electrode for Nonenzymatic Glucose Sensing

“…This multiplexing assay showed great sensitivity in detecting both markers in blood serum with the LOD for CEA being 5 ng/ml and that of AFP being 20 ng/ml [326]. The enhanced LOD is due to the presence of surface pinholes generating hot spots and plasmon coupling between both the inner and outer cavity and EM coupling between neighboring particles in the near field [297,298,302]. …”

“…In general, aggregation intensifies the second harmonic generation of HGNs in contact with one another, effectively combining their collective energy to generate new photons with twice the frequency and half the wavelength [292][293][294][295]. HGN aggregates are also known to exhibit both hybridized plasmon modes, which are the result of surface plasmon interactions with cavity plasmon modes, and collective charge transfer resonances [296][297][298]. However, even when not in direct contact with one another there is an intensification of the dipole charge at the interparticle gap of nanoparticle aggregates in near field proximity [8,[299][300][301].…”

“…A novel tracer, glucose oxidase (GOD)-functionalized HGNs encapsulating GOD (Au shell @GOD) has been reported by Song et al [298]. This tracer was designed to label the ferrocenmonocarboxylic-grafted secondary antibodies (Ab 2 @Fc) of tumor markers using carboxyl group functionalized multi-wall carbon nanotubes (MWCN) as a platform.…”

“…This tracer was designed to label the ferrocenmonocarboxylic-grafted secondary antibodies (Ab 2 @Fc) of tumor markers using carboxyl group functionalized multi-wall carbon nanotubes (MWCN) as a platform. The electrocatalytic activity of the GOD-Au shell @GOD-Ab 2 @Fc bioconjugated was tested against three sets of bio-recognition using chronoamperometry and was found to show the greatest current shift [298]. The ferrocene mediated electron transfer between GOD and the electrode surface along with high concentrations of GOD particles associated with the surface and cavity of the HGNs lead to enhanced signal amplification and enhanced detection along with the increased charge transport ability of the multi-walled carbon nanotubes (MWCN) [298].…”