title: Ag@Au core-shell dendrites: a stable, reusable and sensitive surface enhanced Raman scattering substrate.
abstract: Surface enhanced Raman scattering (SERS) substrate based on fabricated Ag@Au core-shell dendrite was achieved. Ag dendrites were grown on Si wafer by the hydrothermal corrosion method and Au nanofilm on the surface of Ag dendritic nanostructure was then fabricated by chemical reduction. With the help of sodium borohydride in water, Au surface absorbates such as thiophene, adenine, rhodamine, small anions (Br(-) and I(-)), and a polymer (PVP, poly(N-vinylpyrrolidone)) can be completely and rapidly removed. After four repeatable experiments, the substrate SERS function did not decrease at all, indicating that the Ag@Au dendrite should be of great significance to SERS application because it can save much resource. Six-month-duration stability tests showed that the Ag@Au core-shell dendrite substrate is much more stable than the Ag dendrite substrates. We have also experimented on fast detection of Cd(2+) at 10(-8) M concentration by decorating single-stranded DNA containing adenine and guanine bases on the surface of this Ag@Au dendrite. Finite-difference time-domain simulations were carried out to investigate the influence of Au nanolayer on Ag dendrites, which showed that the local electric fields and enhancement factor are hardly affected when a 4 nm Au nanolayer is coated on Ag dendrite surface.
authors.affiliation: Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, 100029, China.
authors.forename: Hong Jun
authors.initials: HJ
authors.lastname: Yin
authors.affiliation: Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, 100029, China.
authors.forename: Zhao Yang
authors.initials: ZY
authors.lastname: Chen
authors.affiliation: Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China.
authors.forename: Yong Mei
authors.initials: YM
authors.lastname: Zhao
authors.affiliation: Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, 100029, China.
authors.forename: Ming Yang
authors.initials: MY
authors.lastname: Lv
authors.affiliation: Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, 100029, China.
authors.forename: Chun An
authors.initials: CA
authors.lastname: Shi
authors.affiliation: Analytical and Testing Center, Beijing Normal University, Beijing 100875, China.
authors.forename: Zheng Long
authors.initials: ZL
authors.lastname: Wu
authors.affiliation: Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, 100029, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, 100029, China.
authors.forename: Luo
authors.initials: L
authors.lastname: Liu
authors.affiliation: College of Sciences, Yanshan University, Qinhuangdao, 066004, China.
authors.forename: Ming Li
authors.initials: ML
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, 100029, China.
authors.forename: Hai Jun
authors.initials: HJ
authors.lastname: Xu