Charge-Selective Surface-Enhanced Raman Scattering Using Silver and Gold Nanoparticles Deposited on Silicon-Carbon Core-Shell Nanowires
- Authors
- Baik, Sun Young; Cho, Yong Jae; Lim, Young Rok; Im, Hyung Soon; Jang, Dong Myung; Myung, Yoon; Park, Jeunghee; Kang, Hong Seok
- Issue Date
- Mar-2012
- Publisher
- AMER CHEMICAL SOC
- Keywords
- surface-enhanced Raman scattering; charge selectivity; N-doped graphitic layers; silicon nanowires; silver nanoparticles; first principles calculations; electron transfer
- Citation
- ACS NANO, v.6, no.3, pp.2459 - 2470
- Indexed
- SCIE
SCOPUS
- Journal Title
- ACS NANO
- Volume
- 6
- Number
- 3
- Start Page
- 2459
- End Page
- 2470
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/105348
- DOI
- 10.1021/nn204797b
- ISSN
- 1936-0851
- Abstract
- The deposition of silver (Ag) or gold (Au) nanoparticles (NPs) on vertically aligned silicon-carbon (Si-C) core-shell nanowires (NWs) produces sensitive substrates for surface-enhanced Raman spectroscopy (SERS). The undoped and 30% nitrogen (N)-doped graphitic layers of the C shell (avg thickness of 20 nm) induce a higher sensitivity toward negatively (-) and positively (+) charged dye molecules, respectively, showing remarkable charge selectivity. The Ag NPs exhibit higher charge selectivity than the Au NPs, The Ag NPs deposited on p- and n-type Si NWs also exhibit (-) and (+) charge selectivity, respectively, which is higher than that of the Au NPs. The X-ray photoelectron spectroscopy analysis indicates that the N-doped graphitic layers donate more electrons to the metal NPs than the undoped ones. More distinct electron transfer occurs to the Ag NPs than to the Au NPs. First principles calculations of the graphene-metal adducts suggest that the large electron transfer capacity of the N-doped graphitic layers is due to the formation of a N -> Ag coordinate bond involving the lone pair electrons of the N atoms. We propose that the more (-) charged NPs on the N-doped graphitic layers prefer the adsorption of (+) charged dyes, enhancing the SERS intensity. The charge selectivity of the Si NW substrates can also be rationalized by the greater electron transfer from the n-type Si to the metal NPs.
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Collections - Graduate School > Department of Advanced Materials Chemistry > 1. Journal Articles
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