title: Surface-enhanced Raman spectroscopic study of p-aminothiophenol.
abstract: p-aminothiophenol (PATP) is an important molecule for surface-enhanced Raman spectroscopy (SERS). It can strongly interact with metallic SERS substrates and produce very strong SERS signals. It is a molecule that has often been used for mechanistic studies of the SERS mechanism as the photon-driven charge transfer (CT) mechanism is believed to be present for this molecule. Recently, a hot debate over the SERS behavior of PATP was triggered by our finding that PATP can be oxidatively transformed into 4,4'-dimercaptoazobenzene (DMAB), which gives a SERS spectra of so-called "b2 modes". In this perspective, we will give a general overview of the SERS mechanism and the current status of SERS studies on PATP. We will then demonstrate with our experimental and theoretical evidence that it is DMAB which contributes to the characteristic SERS behavior in the SERS spectra of PATP and analyze some important experimental phenomena in the framework of the surface reaction instead of the contribution "b2 modes". We will then point out the existing challenges of the present system. A clear understanding of the reaction mechanism for nitrobenzene or aromatic benzene will be important to not only understand the SERS mechanism but to also provide an economic way of producing azo dyes with a very high selectivity and conversion rate.
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China. bren@xmu.edu.cn.
authors.forename: Yi-Fan
authors.initials: YF
authors.lastname: Huang
authors.forename: De-Yin
authors.initials: DY
authors.lastname: Wu
authors.forename: Hong-Ping
authors.initials: HP
authors.lastname: Zhu
authors.forename: Liu-Bin
authors.initials: LB
authors.lastname: Zhao
authors.forename: Guo-Kun
authors.initials: GK
authors.lastname: Liu
authors.forename: Bin
authors.initials: B
authors.lastname: Ren
authors.forename: Zhong-Qun
authors.initials: ZQ
authors.lastname: Tian
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D004579:Electron Transport; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D014732:Vibration
chemical_list: D000814:Aniline Compounds; D013438:Sulfhydryl Compounds; C064316:4-aminothiophenol