| 1. |
- Dong, Bin, et al.
(författare)
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Local and Remote Charge-Transfer-Enhanced Raman Scattering on One-Dimensional Transition-Metal Oxides
- 2010
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Ingår i: Chemistry - An Asian Journal. - : Wiley. - 1861-4728. ; 5:8, s. 1824-1829
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Tidskriftsartikel (refereegranskat)abstract
- The one-dimensional (1D) transition-metal oxide MoO3 belt is synthesized and characterized with Xray diffraction, scanning electron microscopy, and Raman spectroscopy. Charge-transfer-(CT) enhanced Raman scattering of 4-mercaptobenzoic acid (4-MBA) on a 1D MoO3 belt was investigated experimentally and theoretically. The chemical enhancement of surface-enhanced Raman scattering (SERS) of 4-MBA on the MoO3 belt by CT is in the order of 10(3). The SERS of 4-MBA was investigated theoretically by using a quantum chemical method. The remote SERS of 4-MBA along the 1D MoO3 belt (the light excitation to one side of the MoO3 belt, and the SERS spectrum is collected on the other side of the MoO3 belt) is also shown experimentally, which provides potential applications of SERS. The incident polarization dependence of remote SERS spectra has also been investigated experimentally.
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| 2. |
- Fang, Yurui, et al.
(författare)
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Ascertaining p,p '-Dimercaptoazobenzene Produced from p-Aminothiophenol by Selective Catalytic Coupling Reaction on Silver Nanoparticles
- 2010
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 26:11, s. 7737-7746
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Tidskriftsartikel (refereegranskat)abstract
- Combining experiment and theory, evidence from surface-enhanced Raman scattering (SERS) were obtained for p,p'-dimercaptoazobenzene (DMAB) produced from p-aminothiophenol (PATP) by selective catalytic coupling reaction on silver nanoparticles. The time-dependent SERS spectra of PATE are consistent with the calculated SERS spectra of DMAB), which is the direct evidence or the production of DMAB from PATE by selective catalytic coupling reaction on silver nanoparticles. The so-called "b(2) modes" of PATP is the -N=N- related vibrational modes of DMAB. The silver nanoparticles could be assembled together to form different size of aggregates with different concentration of PATE solution. When the concentration of Ag nanoparticle (the radius 40 nm) in colloid is 35 pM, the time-dependent SERS of DMA B reveals that the better experimental conditions for observing SERS signals of DMA B are (1) concentration of PATE is around 5 x 0(-6) M in which condition the aggregates consist with about 3-5 silver nanoparticles. which are not too big and suitable for SERS measurement, and (2) the Raman signal will be strongest at the thne delay about 27 min for this concentration. By analyzing the symmetry of strong enhanced vibrational modes, it is derived that all ask strong vibrational modes are mostly enhanced by surface plasmons (electromagnetic field). The SERS enhancement calculated with finite-difference time-domain method is on the order of |M|(4) = 9.0 x 10(8) in junctions of AgNPs at 632.8 nm, where |M|(4) = E-loc/E-in and E-loc and E-in are local and incident electric fields, respectively. The total chemical enhancements, including static chemical and resonant enhancements, are on the order of 10(3).
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| 3. |
- Li, Yuanzuo, et al.
(författare)
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Theoretical Characterization of the PC60BM:PDDTT Model for an Organic Solar Cell
- 2011
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 115:44, s. 21865-21873
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Tidskriftsartikel (refereegranskat)abstract
- We use time-dependent density functional theory together with a set of extensive multidimensional visualization techniques to characterize band gap, optical absorption properties, intramolecular and intern-wreaths charge transfer, exciton binding energy, charge transfer integral, and the rate of charge transfer and recombination in the PC60BM:PDDTT Model of an organic,solar cell. These theoretical methods and calculation techniques only promote deeper understanding of the connection between chemical structures and the optical and electronic properties Of the donor-acceptor system but also can be used to rational design novel donor-acceptor system.
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| 4. |
- Song, Peng, et al.
(författare)
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External Electric Field-Dependent Photoinduced Charge Transfer in a Donor-Acceptor System for an Organic Solar Cell
- 2013
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:31, s. 15879-15889
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Tidskriftsartikel (refereegranskat)abstract
- External electric field is incorporated into the generalized Mulliken-Hush model and Marcus theory. With this new development, we have investigated the field-dependent electronic structure and rate of photoinduced charge transfer in organic donor-acceptor dyad using time-dependent density functional theory and extensive multidimensional visualization techniques. The model is used to evaluate the influence of the external electric field on the electronic coupling between donor and acceptor. The reorganization energy and the free energy change of the electron transfer were calculated. It was found that the major effects in the external electric field dependent rate of the charge transfer originate from changes in the electronic coupling. The new theoretical approach not only promotes a deeper understanding of the connection between the external electric field, chemical structure, and optical and electronic properties of the donor-acceptor system, but also can be used for rational design of novel donor-acceptor system for organic solar cells.
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| 5. |
- Sun, Mengtao, et al.
(författare)
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Remote Excitation Polarization-Dependent Surface Photochemical Reaction by Plasmonic Waveguide
- 2011
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Ingår i: Plasmonics. - : Springer Science and Business Media LLC. - 1557-1963 .- 1557-1955. ; 6:4, s. 681-687
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Tidskriftsartikel (refereegranskat)abstract
- For the first time, we report remote excitation polarization-dependent surface photochemical reaction by plasmonic waveguide. Remote excitation polarization-dependent surface-enhanced Raman scattering (SERS) spectra indicate a surface photochemical reaction that p-aminothiophenol is converted to p,p'-dimercaptoazobenzene (DMAB) induced by the plasmonic waveguide. Surface plasmon polaritons generated at the end of a silver nanowire can propagate efficiently along the nanowire, and be coupled by nanoparticles near the nanowire as a nanoantenna. Massive electromagnetic enhancement is generated in the nanogap between the nanowire and the nanoparticles. The remote excitation polarization-dependent SERS spectra can be obtained experimentally in the nanogaps; furthermore, the remote excitation polarization-dependent SERS spectra of DMAB reveal the occurrence of this surface catalytic reaction. Theoretical simulations using finite-difference time-domain methods strongly support our experimental results.
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| 6. |
- Xia, Lixin, et al.
(författare)
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Selective reduction of nitroaromatic compounds on silver nanoparticles by visible light
- 2012
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Ingår i: Journal of Raman Spectroscopy. - : Wiley. - 1097-4555 .- 0377-0486. ; 43:8, s. 1024-1028
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Tidskriftsartikel (refereegranskat)abstract
- For the first time, we report experimentally and theoretically that nitroaromatic compounds, 2,4-dinitrobenzenethiol and 4-chloro-2-nitrobenzenethiol, on silver sols can be selectively reduced to 2-amino-4-nitrobenzenethiol and 2-amino-4-chlorobenzenethiol simply by irradiating with a visible light in ambient conditions, and the selective photoreduction is a very facile process. The results of quantum chemical calculations are in good agreement with our experimental data. Copyright (c) 2012 John Wiley & Sons, Ltd.
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