Plasmon resonances of graphene-assisted core-bishell nanoparticles

Abstract

We study the Localized Surface Plasmon Resonance (LSPR) in graphene-assisted core-bishell nanoparticles which consist of a graphene layer (outer shell) wrapped around a metal shell and either a dielectric or a metal core. Small nanoparticles with a size much smaller than the wavelength of incident light are assumed, and the quasi-static approximation is applied to develop analytic equations to describe the absorption, scattering, and extinction efficiencies in the core-bishell nanoparticles. The proposed nanostructures exhibit two LSPRs; one is in the visible range and corresponds to a plasmon mode of the core-inner shell composite, while the second lies in the near infrared (NIR) and is induced by the graphene plasmons excited at the outer shell. Interestingly, the LSPR of graphene has an ultra-narrow bandwidth and can be tuned in the NIR by altering the physical parameters of graphene, such as the Fermi energy and the number of graphene layers. Therefore, the LSPR peak of graphene is promising for medical applications. In addition, the LSPR of graphene can be tuned to the visible range near the position of the first LSPR, resulting in two narrow linewidth peaks. These resonance peaks could be beneficial for highly sensitive LSPR-based sensors.

Bandwidth of quantized surface plasmons: competition between radiative and nonradiative damping effects

“…Þ =o r as given by eqn ( 5) and ( 6), respectively. In eqn (32), the relaxation rate is given by g = g rad + g sca where 2 ] and g rad = 2mo r 3 R 3 /c 3 as given by eqn (31). The dielectric constant of the aqueous medium is assumed to be E m ¼ 1:78, unless otherwise specified.…”

“…As mentioned above, g = g rad + g sca , where 2 ] as indicated by eqn (6) and G D = G bulk + Av F /a. With the help of eqn ( 23) and ( 30), g rad takes the form of…”

“…Localized Surface Plasmon Resonance (LSPR) is a phenomenon that occurs when light interacts with metallic nanoparticles (NPs) resulting in a resonating collective oscillation of free electrons on the surface of these NPs. [1][2][3] This resonance can be tuned to specific wavelengths by controlling the size, shape, and composition of NPs and their surrounding dielectric environment. [4][5][6][7][8][9][10] LSPR has found numerous applications in diverse fields, including photonics, chemistry, medicine, and energy harvesting.…”

Defects detection in dentistry: designing a graphene multi-layered based plasmonic sensor

“…= 1.8745), Calcium Fluoride (CaF 2 ) (r.i. = 1.4329), Au and Porcelain fillings (r.i. = 1.511), Glass Ionomer (r.i.= 4.3) are considered now-a-days as they are found to be bio-compatible with the noble metals. N-Graphene layers with r.i. = 3 + 1.49106i and thickness (N × 0.34 nm [(N denotes single graphene layer)] are also introduced into the configuration for enhancing the absorption property [29][30][31][32][33]. The outer-most surface of human teeth i.e., Enamel (r.i. = 1.631), Dentin (r.i. = 1.540) and Cementum (r.i. = 1.582) are then examined in order to check for any plaque formation or requirement for treatment of cavity.…”

Plasmon resonances of GZO core–Ag shell nanospheres, nanorods, and nanodisks for biosensing and biomedical applications in near-infrared biological windows I and II

“…The plasmon resonance wavelength's tunability can be feasibly attained by changing the shell thickness, in addition to the material and geometry of NPs. [16][17][18][19] The configuration of hollow metal nanoshells receives remarkable interest for sensing applications. 20,21 Anisotropic shapes of the nanoshell structure, such as nanorod and nanodisk, allow additional degrees of freedom to enhance the optical features of the induced LSPR.…”