Measurement of Interlayer Screening Length of Layered Graphene by Plasmonic Nanostructure Resonances

Abstract

The variation in localized surface plasmon resonances of single Au nanodisks (diameter 100 nm and height 25 nm) on 0−13 graphene layers is investigated using dark-field scattering spectroscopy to obtain the graphene electric field screening length. For nanodisks (NDs) with and without underlying graphene layers on a SiO 2 (300 nm)/Si substrate, the plasmon resonance red shifts from 604 to 620 nm with increasing graphene layers. The spectra of the plasmonic nanostructures obey an exponential saturation function versus increasing number of layers of graphene from 0 to 13. As a conducting film, the graphene layers screen the electric field generated by the plasmonic resonance of the Au NDs in the vicinity of the interface, and the red shifts of the resonance wavelength are explained in the framework of the electromagnetic field coupling between in-plane antiparallel image dipoles in the graphene layers and the ND dipole. A screening length of 1.2 ± 0.2 nm, equivalent to 3−4 graphene layers, is experimentally obtained, in good agreement with the measurement by field-effect transistors and theoretical calculation in doped graphene. The resonance shift of plasmonic nanostructures on a layered graphene system provides an alternative and convenient method for screening length measurement of graphene films.

Tailored nanoantennas for directional Raman studies of individual carbon nanotubes

“…Such a top-down approach to SERS is at present an emerging field [15][16][17][18]. First investigations employ patterned antenna structures to enhance the Raman signal of graphene [16].…”

Enhanced Electron Penetration through an Ultrathin Graphene Layer for Highly Efficient Catalysis of the Hydrogen Evolution Reaction

“…[23] This strategy represents a new concept for maintaining the high activity and stability of non-precious metals in acidic medium and has recently been further applied in a variety of catalytic systems, for example, for the oxygen reduction reaction (ORR), [23][24][25][26] the HER under acidic conditions, [27,28] the triiodide reduction reaction in dye-sensitized solar cells (DSSCs), [29] and the heterogeneously catalyzed oxidation and reduction reactions. [32,33] Therefore, the synthesis of carbon-encapsulated 3d TM catalysts with a controllable number of graphene layers, especially of catalysts with less than three layers of graphene, will be important for the development of 3d TM catalysts with superior HER activity. [32,33] Therefore, the synthesis of carbon-encapsulated 3d TM catalysts with a controllable number of graphene layers, especially of catalysts with less than three layers of graphene, will be important for the development of 3d TM catalysts with superior HER activity.…”

“…[30,31] However, the carbon shells previously used for these catalysts are too thick and usually consist of multilayer graphitic carbon or composites thereof, which may significantly reduce the catalytic activity as the electronic structure of the outermost carbon layer is only modulated by the electron transferred from the encapsulated metal core when the shell consist of no more than three to four carbon layers. [32,33] Therefore, the synthesis of carbon-encapsulated 3d TM catalysts with a controllable number of graphene layers, especially of catalysts with less than three layers of graphene, will be important for the development of 3d TM catalysts with superior HER activity. Herein, we report a bottom-up method for the preparation of ultrathin graphene spheres with only one to three graphene layers that encapsulate CoNi nanoalloy (CoNi@NC) electrocatalysts by using Co 2+ , Ni 2+ , and ethylenediaminetetraacetate anions (EDTA 4À ) as precursors (see the Supporting Information, Figure S1 for details).Scanning electron microscopy (SEM; Figure 1 b, Figure S3) and transmission electron microscopy (TEM; Figure 1 c, Figure S4) images show that the CoNi@NC samples consist of uniform nanospheres, forming lamellar superstructures on the micrometer scale (Figure 1 a).…”

The Discovery of Plasmon Resonance in Germanide Nanowires Grown on Cu Foil

“…Various nanostructures have been created attempting to achieve different peak position and distinct scattering spectra [29]. One of the prospective ways to obtain strong LSPR of nanoparticles and nanorods is to fabri-cate the structures by exquisite techniques [7], [30]. Compared with these examples, the LSPR spectrum of our Cu 3 Ge NW is broad.…”

“…The LSPR spectrum is associated with the geometry design and environment composition of the surrounding dielectrics [7]. In the vicinity of the surface on these nanostructures, characteristic optical scattering properties can be observed with the LSPR peaks, which are due to the strongly enhanced electromagnetic field.…”