Abstract
Semiconducting oxide nanoparticles have proven to be excellent in detecting extremely low-concentrations of molecules through surface-enhanced Raman scattering (SERS) effects. While the enhancement of the Raman activities arises from a large increase in polarizability due to charge transfer from the molecule to the semiconducting nanoparticle, little is known about how the oxide composition, nanoparticle size, solvent, or pH affects the observed Raman activities. In the current study, we examine these effects by carrying out extensive computational investigations of semiconducting TiO2, SnO2 and Fe2O3 nanoparticles and their complexes with both catechol and dopamine. An increase in the size of the oxide cluster or a decrease in the pH of the system under observation leads to enhanced Raman activities; the variation of the activities in different solvents is very much dependent on the nature of the vibrational modes. The marked increase in the Raman activities of molecules adsorbed on SnO2 or Fe2O3 over that of molecules adsorbed on TiO2 seems to indicate that these oxide nanoparticles would be useful substrates for SERS sensors. Our results also indicate that the Raman activities of some of the TiO2 modes are magnified upon adsorption of molecules, which concurs with some very recent experimental observations. All these results are consistent with a recently proposed theoretical model of SERS on semiconducting substrates. Further, this work has implications on the development of molecular sensing, dye-sensitized solar cells, and photocatalysis.
| Original language | English |
|---|---|
| Pages (from-to) | 8994-9004 |
| Number of pages | 11 |
| Journal | Journal of Physical Chemistry C |
| Volume | 115 |
| Issue number | 18 |
| DOIs | |
| Publication status | Published - May 12 2011 |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Energy(all)
Cite this
Surface-enhanced Raman scattering on semiconducting oxide nanoparticles : Oxide nature, size, solvent, and pH effects. / Tarakeshwar, Pilarisetty; Finkelstein-Shapiro, Daniel; Hurst, Sarah J.; Rajh, Tijana; Mujica, Vladimiro.
In: Journal of Physical Chemistry C, Vol. 115, No. 18, 12.05.2011, p. 8994-9004.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Surface-enhanced Raman scattering on semiconducting oxide nanoparticles
T2 - Oxide nature, size, solvent, and pH effects
AU - Tarakeshwar, Pilarisetty
AU - Finkelstein-Shapiro, Daniel
AU - Hurst, Sarah J.
AU - Rajh, Tijana
AU - Mujica, Vladimiro
PY - 2011/5/12
Y1 - 2011/5/12
N2 - Semiconducting oxide nanoparticles have proven to be excellent in detecting extremely low-concentrations of molecules through surface-enhanced Raman scattering (SERS) effects. While the enhancement of the Raman activities arises from a large increase in polarizability due to charge transfer from the molecule to the semiconducting nanoparticle, little is known about how the oxide composition, nanoparticle size, solvent, or pH affects the observed Raman activities. In the current study, we examine these effects by carrying out extensive computational investigations of semiconducting TiO2, SnO2 and Fe2O3 nanoparticles and their complexes with both catechol and dopamine. An increase in the size of the oxide cluster or a decrease in the pH of the system under observation leads to enhanced Raman activities; the variation of the activities in different solvents is very much dependent on the nature of the vibrational modes. The marked increase in the Raman activities of molecules adsorbed on SnO2 or Fe2O3 over that of molecules adsorbed on TiO2 seems to indicate that these oxide nanoparticles would be useful substrates for SERS sensors. Our results also indicate that the Raman activities of some of the TiO2 modes are magnified upon adsorption of molecules, which concurs with some very recent experimental observations. All these results are consistent with a recently proposed theoretical model of SERS on semiconducting substrates. Further, this work has implications on the development of molecular sensing, dye-sensitized solar cells, and photocatalysis.
AB - Semiconducting oxide nanoparticles have proven to be excellent in detecting extremely low-concentrations of molecules through surface-enhanced Raman scattering (SERS) effects. While the enhancement of the Raman activities arises from a large increase in polarizability due to charge transfer from the molecule to the semiconducting nanoparticle, little is known about how the oxide composition, nanoparticle size, solvent, or pH affects the observed Raman activities. In the current study, we examine these effects by carrying out extensive computational investigations of semiconducting TiO2, SnO2 and Fe2O3 nanoparticles and their complexes with both catechol and dopamine. An increase in the size of the oxide cluster or a decrease in the pH of the system under observation leads to enhanced Raman activities; the variation of the activities in different solvents is very much dependent on the nature of the vibrational modes. The marked increase in the Raman activities of molecules adsorbed on SnO2 or Fe2O3 over that of molecules adsorbed on TiO2 seems to indicate that these oxide nanoparticles would be useful substrates for SERS sensors. Our results also indicate that the Raman activities of some of the TiO2 modes are magnified upon adsorption of molecules, which concurs with some very recent experimental observations. All these results are consistent with a recently proposed theoretical model of SERS on semiconducting substrates. Further, this work has implications on the development of molecular sensing, dye-sensitized solar cells, and photocatalysis.
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U2 - 10.1021/jp202590e
DO - 10.1021/jp202590e
M3 - Article
VL - 115
SP - 8994
EP - 9004
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 18
ER -