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 Cd2+ 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.
Highlights
Ag nanostructures possess high Surface enhanced Raman scattering (SERS) properties in SERS applications, they have poor time-stability since their surface is highly sensitive to oxidation
The X-ray photoelectron spectroscopy (XPS) peaks at 368.18 and 374.54 eV correspond to the 3d5/2 and 3d3/2 peaks, respectively, of metallic Ag, and the XPS peaks at 84.12 and 87.40 eV correspond to the 4f7/2 and 4f5/2 peaks, respectively, of metallic Au. These results demonstrate that in this case the Au and Ag are only in the zero-valent state
Ag dendritic nanostructures were successfully grown on a Si wafer by using the method of hydrothermal corrosion and Au nanolayer shell on the surface of the Ag dendrites was formed by chemical reduction method
Summary
Ag nanostructures possess high SERS properties in SERS applications, they have poor time-stability since their surface is highly sensitive to oxidation. Scott et al reported that the thiolate in monolayer-protected Au clusters can be desorbed with a large excess of NaBH4 in tetrahydrofuran[19] Both these results are consistent with the fact that borohydride can readily, rapidly and completely remove all the molecular adsorbates tested on the Au surfaces. A durable, reusable, highly stable and sensitive Ag@Au core-shell dendrite as active SERS substrate was prepared and used for quantitatively detecting Cd2+ through the chelation between the Cd2+ and thiolated single-stranded DNA (ssDNA)[21,22]. We use the Ag@Au core-shell dendrite SERS substrate to detect Cd2+ of concentration around [10−8] M with the help of ssDNA
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
