Abstract
Temporal evolution of surface chemistry during oxidation of silicon quantum dot (Si-QD) surfaces were probed using surface-enhanced Raman scattering (SERS). A monolayer of hydrogen and chlorine terminated plasma-synthesized Si-QDs were spin-coated on silver oxide thin films. A clearly enhanced signal of surface modes, including Si-Clx and Si-Hx modes were observed from as-synthesized Si-QDs as a result of the plasmonic enhancement of the Raman signal at Si-QD/silver oxide interface. Upon oxidation, a gradual decrease of Si-Clx and Si-Hx modes, and an emergence of Si-Ox and Si-O-Hx modes have been observed. In addition, first, second and third transverse optical modes of Si-QDs were also observed in the SERS spectra, revealing information on the crystalline morphology of Si-QDs. An absence of any of the abovementioned spectral features, but only the first transverse optical mode of Si-QDs from thick Si-QD films validated that the spectral features observed from Si-QDs on silver oxide thin films are originated from the SERS effect. These results indicate that real-time SERS is a powerful diagnostic tool and a novel approach to probe the dynamic surface/interface chemistry of quantum dots, especially when they involve in oxidative, catalytic, and electrochemical surface/interface reactions.
Highlights
Is that to approach or adsorb a molecule on a surface-enhanced Raman scattering (SERS)-active nanostructured, or roughened surface, and detect the Raman-shifted enhancement signal from the adsorbate
Weak C-C stretching modes were observed from rhodamine 6 G (R6G) at 1140, 1450 and at 1680 cm−1 33,40, which proves the improved enhancement of Ag/Ag2O thin films with respect to Ag thin films
As a function of film thickness, we found that the highest enhancement was observed from 10 nm Ag/Ag2O films
Summary
Is that to approach or adsorb a molecule on a SERS-active nanostructured, or roughened surface, and detect the Raman-shifted enhancement signal from the adsorbate. The feasibility of employing a SERS-active substrate to monitor the chemical state of other nanomaterials surfaces/interfaces has not been exploited, the ability of extreme surface sensitivity offers a great potential on establishing SERS as a surface/interface chemistry analysis technique. Realization of such a surface analysis method with extreme sensitivity will obviously have a significant impact to nanotechnology-driven research due to the critically important surface properties, and surface-chemical dynamics of nanomaterials. These findings imply that, real-time SERS is a powerful diagnostic tool to probe the surface chemistry of Si-QDs during their interaction with the surrounding medium
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.
