title: Ultrasensitive SERS performance in 3D "sunflower-like" nanoarrays decorated with Ag nanoparticles.
abstract: Low-cost, stabilized and ultrasensitive three-dimensional (3D) hierarchical surface-enhanced Raman scattering substrates ("sunflower-like" nanoarrays decorated with Ag nanoparticles, denoted as SLNAs-Ag) have been obtained by fabricating binary colloidal crystals and then decorating with Ag nanoparticles. In order to provide a larger density of hot spots within the laser-illumination area, the silica sphere arrays were chosen as the island-type platform for the polystyrene (PS) nanosphere deposition, and the distances between the PS nanospheres were tuned by etching for different durations. Compared with conventional 2D planar systems, the as-fabricated 3D SLNAs-Ag exhibited extremely high SERS sensitivity ascribed to the larger SERS active regions. Quantitative detection of molecules with an extremely low incident laser power was achieved on the "sunflower-like" nanoarrays in which the PS nanospheres were etched for 5 minutes and decorated with Ag nanoparticles, and the corresponding analytical enhancement factor is calculated to be 2 × 1014with the concentration of rhodamine 6G down to 10-15M. Based on the achieved SERS substrates, we have further demonstrated the highly sensitive detection of molecules such as melamine for food safety inspection.
authors.affiliation: Department of Physics and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan 430072, P. R. China. xxh@whu.edu.cn daizhigao@whu.edu.cn.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Physics and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan 430072, P. R. China. xxh@whu.edu.cn daizhigao@whu.edu.cn and Su Zhou Institute of Wuhan University, Suzhou 215123, P. R. China.
authors.forename: Xiangheng
authors.identifier: http://orcid.org/0000-0001-9111-1619
authors.initials: X
authors.lastname: Xiao
authors.affiliation: Department of Physics and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan 430072, P. R. China. xxh@whu.edu.cn daizhigao@whu.edu.cn.
authors.forename: Zhigao
authors.initials: Z
authors.lastname: Dai
authors.affiliation: Laboratory of Printable Functional Nanomaterials and Printed Electronics, School of Printing and Packaging, Wuhan University, Wuhan 430072, P. R. China.
authors.forename: Wei
authors.identifier: http://orcid.org/0000-0002-7672-7965
authors.initials: W
authors.lastname: Wu
authors.affiliation: Department of Physics and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan 430072, P. R. China. xxh@whu.edu.cn daizhigao@whu.edu.cn.
authors.forename: Xingang
authors.initials: X
authors.lastname: Zhang
authors.affiliation: College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072, P. R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Fu
authors.affiliation: Department of Physics and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan 430072, P. R. China. xxh@whu.edu.cn daizhigao@whu.edu.cn.
authors.forename: Changzhong
authors.initials: C
authors.lastname: Jiang