title: Ag-decorated TiO₂ nanograss for 3D SERS-active substrate with visible light self-cleaning and reactivation.
abstract: The production of SERS-active substrates which are uniform, sensitive, reproducibile and durable still remains an important issue. Here, we report a strategy for the fabrication of a large-area Ag-decorated TiO₂ nanograss SERS-active substrate by a simple solvothermal approach combined with Ag evaporation. The nanograss consists of dense rutile TiO₂ nanorods of about 5 nm in diameter and the decorated Ag nanoparticles are an average of 8 nm in diameter. The Ag protrusions and gaps between them contribute to three dimensional SERS "hot spots" which can be modulated by simply controlling the Ag evaporating parameters. The Ag-decorated TiO₂ substrate is highly efficient in detecting rhodamine 6G (R6G) and 4-aminothiophenol (4-ATP) molecules and has good homogeneity. An obvious red shift and even high enhancement of b₂ vibration mode were observed in detecting 4-ATP due to the effective charge transfer from the Ag atoms to sulfur atoms. The Ag-decorated TiO₂ substrate can be easily self-cleaned and reactivated by visible light irradiation without obvious degeneration of SERS signals. Our results demonstrate that the Ag-decorated TiO₂ substrate with high and homogeneous SERS activity has potential feasibility as a sensitive SERS probe.
authors.affiliation: Key Laboratory of Materials Physics, Anhui Key Lab of Nanomaterials and Nanostructure, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, PR China. scxu@issp.ac.cn
authors.forename: S C
authors.initials: SC
authors.lastname: Xu
authors.forename: Y X
authors.initials: YX
authors.lastname: Zhang
authors.forename: Y Y
authors.initials: YY
authors.lastname: Luo
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.forename: H L
authors.initials: HL
authors.lastname: Ding
authors.forename: J M
authors.initials: JM
authors.lastname: Xu
authors.forename: G H
authors.initials: GH
authors.lastname: Li