Effect of chemical surface modification on dendritic gold in surface‐enhanced Raman scattering‐active substrates

We fabricate crystalline dendritic gold (Au‐D) via a simple electrochemical method and characterize it using several techniques. Chemical modification by self‐assembled thiol molecules on the Au‐D is used to adjust the chemical environment of the substrate surface and to improve surface‐enhanced Raman scattering (SERS) performance. First, the Au‐D modified with different length chains of n‐alkyl thiols cause an enhancement of SERS, which follows a relationship of normalized intensity, IIo, versus (1 + dr) with a slope of −10 according to the electromagnetic mechanism. Subsequently, phenyl thiols with various end‐functional groups are attached to study the effect of chemical modification on SERS enhancement. The results indicate that the 4‐methylthiophenol‐ and thiophenol‐modified substrates do not exhibit significant SERS enhancement, resulting in intensity being dependent on distance. It is worth noting that the 4‐mercaptophenol‐ and 4‐aminothiophenol‐modified surfaces have an effective electric field effect and strong interaction with polarity probe molecules, and they produce a more intense signal than do bare Au‐D particles. We fabricate crystalline dendritic gold via a simple electrochemical method and characterize it using several techniques. Chemical modification by self‐assembled thiol molecules on the Au‐D is used to adjust the chemical environment of the substrate surface and to improve surface‐enhanced Raman scattering performance. The phenyl thiol‐modified surface provided a chemical environment that causes various terminal functional groups to be used for enhanced Raman signal.