title: Ag-nanoparticles-decorated NiO-nanoflakes grafted Ni-nanorod arrays stuck out of porous AAO as effective SERS substrates.
abstract: NiO-nanoflakes (NiO-NFs) grafted Ni-nanorod (Ni-NR) arrays stuck out of the porous anodic aluminum oxide (AAO) template are achieved by a combinatorial process of AAO-confined electrodeposition of Ni-NRs, selectively etching part of the AAO template to expose the Ni-NRs, wet-etching the exposed Ni-NRs in ammonia to obtain Ni(OH)2-NFs grafted onto the cone-shaped Ni-NRs, and annealing to transform Ni(OH)2-NFs in situ into NiO-NFs. By top-view sputtering, Ag-nanoparticles (Ag-NPs) are decorated on each NiO-NFs grafted Ni-NR (denoted as NiO-NFs@Ni-NR). The resultant Ag-NPs-decorated NiO-NFs@Ni-NR (denoted as Ag-NPs@NiO-NFs@Ni-NR) arrays exhibit not only strong surface-enhanced Raman scattering (SERS) activity but also reproducible SERS-signals over the whole array. It is demonstrated that the strong SERS-activity is mainly ascribed to the high density of sub-10 nm gaps (hot spots) between the neighboring Ag-NPs, the semiconducting NiO-NFs induced chemical enhancement effect, and the lightning rod effect of the cone-shaped Ni-NRs. The three-level hierarchical nanostructure arrays stuck out of the AAO template can be utilized to probe polychlorinated biphenyls (PCBs, a kind of global environmental hazard) with a concentration as low as 5 × 10(-6) M, showing promising potential in SERS-based rapid detection of organic environmental pollutants.
authors.affiliation: Key Laboratory of Materials Physics, and Anhui Key Laboratory of Nanomaterials and Nanostructures, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China. gwmeng@issp.ac.cn.
authors.forename: Qitao
authors.initials: Q
authors.lastname: Zhou
authors.forename: Guowen
authors.initials: G
authors.lastname: Meng
authors.forename: Qing
authors.initials: Q
authors.lastname: Huang
authors.forename: Chuhong
authors.initials: C
authors.lastname: Zhu
authors.forename: Haibin
authors.initials: H
authors.lastname: Tang
authors.forename: Yiwu
authors.initials: Y
authors.lastname: Qian
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.forename: Bensong
authors.initials: B
authors.lastname: Chen
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D009532:Nickel / Q000737:chemistry*; D011078:Polychlorinated Biphenyls / Q000032:analysis; D016062:Porosity; D012235:Rhodamines / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman
chemical_list: D012235:Rhodamines; C026188:rhodamine 6G; D012834:Silver; D009532:Nickel; C028007:nickel monoxide; D011078:Polychlorinated Biphenyls; D000537:Aluminum Oxide