title: Refractive index susceptibility of the plasmonic palladium nanoparticle: potential as the third plasmonic sensing material.
abstract: We demonstrate that Pd nanospheres exhibit much higher susceptibility of the localized surface plasmon resonance (LSPR) peak to medium refractive index changes than commonly used plasmonic sensing materials such as Au and Ag. The susceptibility of spherical Au nanoparticle-core/Pd-shell nanospheres (Au/PdNSs, ca. 73 nm in diameter) was found to be 4.9 and 2.5 times higher, respectively, than those of Au (AuNSs) and Ag nanospheres (AgNSs) having similar diameters. The experimental finding was theoretically substantiated using the Mie exact solution. We also showed from a quasi-static (QS) approximation framework that the high susceptibility of Pd LSPR originates from the smaller dispersion of the real part of its dielectric function than those of Au and Ag LSPR around the resonant wavelength. We conclude that the Pd nanoparticle is a promising candidate of "the third plasmonic sensing material" following Au and Ag to be used in ultrahigh-sensitive LSPR sensors.
authors: College of Science and Technology, Nihon University , Chiyoda, Tokyo 101-8308, Japan.
authors: Kosuke
authors: K
authors: Sugawa
authors: Hironobu
authors: H
authors: Tahara
authors: Ayane
authors: A
authors: Yamashita
authors: Joe
authors: J
authors: Otsuki
authors: Takamasa
authors: T
authors: Sagara
authors: Takashi
authors: T
authors: Harumoto
authors: Sayaka
authors: S
authors: Yanagida
mesh_terms: D053768:Metal Nanoparticles; D010165:Palladium / Q000737:chemistry*; D012031:Refractometry; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D010165:Palladium
keywords: core−shell nanoparticles; localized surface plasmon; palladium nanoparticles; refractive index susceptibility; ultraviolet region