title: Au-Ag core-shell nanoparticle array by block copolymer lithography for synergistic broadband plasmonic properties.
abstract: Localized surface plasmon resonance of metallic nanostructures receives noticeable attention in photonics, electronics, catalysis, and so on. Core-shell nanostructures are particularly attractive due to the versatile tunability of plasmonic properties along with the independent control of core size, shell thickness, and corresponding chemical composition, but they commonly suffer from difficult synthetic procedures. We present a reliable and controllable route to a highly ordered uniform Au@Ag core-shell nanoparticle array via block copolymer lithography and subsequent seeded-shell growth. Size-tunable monodisperse Au nanodot arrays are generated by block copolymer self-assembly and are used as seed layers to grow Ag shells with variable thickness. The resultant Au@Ag core-shell nanoparticle arrays exhibit widely tunable broadband enhancement of plasmonic resonance, greatly surpassing single-element nanoparticle or homogeneous alloy nanoparticle arrays. Surface-enhanced Raman scattering of the core-shell nanoparticle arrays showed an enhancement factor greater than 270 from Au nanoparticle arrays.
authors.forename: Seung Keun
authors.initials: SK
authors.lastname: Cha
authors.forename: Jeong Ho
authors.initials: JH
authors.lastname: Mun
authors.forename: Taeyong
authors.initials: T
authors.lastname: Chang
authors.forename: Sang Yun
authors.initials: SY
authors.lastname: Kim
authors.forename: Ju Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Hyeong Min
authors.initials: HM
authors.lastname: Jin
authors.forename: Jeong Yong
authors.initials: JY
authors.lastname: Lee
authors.forename: Jonghwa
authors.initials: J
authors.lastname: Shin
authors.forename: Kwang Ho
authors.initials: KH
authors.lastname: Kim
authors.forename: Sang Ouk
authors.initials: SO
authors.lastname: Kim
keywords: bimetal; block copolymer; nanoparticle; plasmon; self-assembly