Graphene-coupled nanowire hybrid plasmonic gap mode–driven catalytic reaction revealed by surface-enhanced Raman scattering

The single-layer graphene (SLG)-coupled nanowire (NW) hybrid plasmonic gap mode (PGM)-driven molecular catalytic reaction was investigated experimentally and theoretically. First, an SLG-coupled NW was constructed, then the surface-enhanced Raman scattering (SERS) effect of graphene in the hybrid plasmonic gap was studied via the normal and oblique incidence of excitation light. The SERS peaks of the D and G of graphene are more intensely enhanced by oblique incidence than by normal incidence. Furthermore, the catalytic reaction of the dimerization of the 4-nitrobenzenethiol molecule to p,p′-dimercaptoazobenzene molecule driven by PGM was carried out by SERS. It was demonstrated that the efficiency of the PGM-driven catalytic reaction is much higher for oblique incidence than that for normal incidence. The mechanism of the PGM-driven catalytic reaction was studied by a finite-difference time-domain numerical simulation. When the PGM is excited by oblique incidence with θ = 30°, the coupling between the NW and SLG/SiO2 substrate increases to the maximum value. This is clearly evidenced by the excitation of a vertical bonding dipolar plasmon mode under the dipole approximation. The theoretical and experimental results were consistent with each other. This research may open up a pathway toward controlling PGM-driven catalytic reactions through polarization changes in excitation laser incidence on single anisotropic nanostructures

Nanowire dimer optical antenna brightens the surface defects of silicon

Plasmonic hot spots located between metallic dimer nanostructures have been utilized comprehensively to achieve efficient light emission. However, different from the enhancement occurred in the plasmonic hot spot, the investigation of light emission off the hot spot on submicron scale remains challenge. In this work, we have constructed a plasmonic nanowire dimer (NWD) system to brighten the light emission of the surface defects of silicon off the hot spot on the submicron scale. The NWD can trap light through plasmonic gap, then, the excited emitter on the submicron scale can radiate light efficiently by coupling with the dipole gap plasmonic mode. Furthermore, the coupling of dipole plasmonic mode with the emitters can be tuned by changing the gap size, and then photoluminescence emission was drastically enhanced up to 126 folds. Theoretical simulations reveal the photoluminescence enhancement arises from the combination of the NWD’s high radiation efficiency, Purcell enhancement, efficient redirection of the emitted photoluminescence and the excitation enhancement. In this study, the photoluminescence signal can be effectively enhanced by placing nano-antenna patch on the detected low-quantum-efficiency emitters, which may open up a pathway toward controlling plasmonic gap mode enhanced light emission off the hot spot on submicron scale

Strong Coupling of Plasmonic Nanorods with a MoSe₂ Monolayer in the Near-Infrared Shortwave Region

Strong room-temperature light–matter coupling between quantum emitters and plasmonic nanoparticles is a central issue in nanophotonics. However, few studies have reported on the coherent states in the near-infrared shortwave region (NIR-I). In this study, a hybrid system composed of a single gold nanorod (Au NR) and a MoSe2 monolayer was constructed. By tuning the length-to-diameter ratio of the single-anisotropy Au NR to match the exciton energy of MoSe2 at 1.57 eV (791 nm), Rabi splitting of up to 75 meV was obtained via the dark-field scattering spectrum. Moreover, theoretical calculations using the finite-difference time-domain method were obtained and found to correspond with the experimental spectral results. This is attributed to the mode volume reduction and localized electric field distribution at the NIR-I resonance peak. These results facilitate obtaining and manipulating strong room-temperature light–matter couplings in the NIR-I region

Developing the measurement of 60Fe with AMS at CIAE

The long lived radioactive nuclide 60Fe is interesting in many research fields such as astrophysics and nuclear physics. Taking the advantage of the high energy of HI-13 tandem AMS system and the high performance of a Q3D magnetic spectrometry at CIAE, the measurement method of 60Fe is being developed. As first step, 58Fe and 58Ni are used for simulating 60Fe and 60Ni for optimizing the measurement conditions and checking the ability of isobar suppression. The results shown that an overall suppression factor of more than 1011 can be obtained by using the ΔE-Q3D technique in combination with a four-anodes gas ionization chamber. Based on the findings a detection sensitivity of 60Fe/Fe ∼ 10−15 can be anticipated

Supplementary document for Biexcitons-plasmon coupling of Ag@AuAg@Au Hollow Nanocube/MoS2MoS_{2} Heterostructures based on Scattering Spectra - 6854113.pdf

Supplemental Material

Supplementary document for Biexcitons-plasmon coupling of Ag@AuAg@Au Hollow Nanocube/MoS2MoS_{2} Heterostructures based on Scattering Spectra - 6857074.pdf

supplemental material

Supplementary document for Biexcitons-plasmon coupling of Ag@AuAg@Au Hollow Nanocube/MoS2MoS_{2} Heterostructures based on Scattering Spectra - 6785739.pdf

supplimental material

Supplementary document for Biexcitons-plasmon coupling of Ag@AuAg@Au Hollow Nanocube/MoS2MoS_{2} Heterostructures based on Scattering Spectra - 6845284.pdf

supplemental material