Electromagnetic enhancement of ordered silver nanorod arrays evaluated by discrete dipole approximation
The enhancement factor (EF) of surface-enhanced Raman scattering (SERS) from two-dimensional (2D) hexagonal silver nanorod (AgNR) arrays were investigated in terms of electromagnetic (EM) mechanism by using the discrete dipole approximation (DDA) method. The dependence of EF on several parameters, i...
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| Format: | Article |
| Language: | English |
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Beilstein-Institut
2015-03-01
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| Series: | Beilstein Journal of Nanotechnology |
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| Online Access: | https://doi.org/10.3762/bjnano.6.69 |
| _version_ | 1818927536708517888 |
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| author | Guoke Wei Jinliang Wang Yu Chen |
| author_facet | Guoke Wei Jinliang Wang Yu Chen |
| author_sort | Guoke Wei |
| collection | DOAJ |
| description | The enhancement factor (EF) of surface-enhanced Raman scattering (SERS) from two-dimensional (2D) hexagonal silver nanorod (AgNR) arrays were investigated in terms of electromagnetic (EM) mechanism by using the discrete dipole approximation (DDA) method. The dependence of EF on several parameters, i.e., structure, length, excitation wavelength, incident angle and polarization, and gap size has been investigated. “Hotspots” were found distributed in the gaps between adjacent nanorods. Simulations of AgNR arrays of different lengths revealed that increasing the rod length from 374 to 937 nm (aspect ratio from 2.0 to 5.0) generated more “hotspots” but not necessarily increased EF under both 514 and 532 nm excitation. A narrow lateral gap (in the incident plane) was found to result in strong EF, while the dependence of EF on the diagonal gap (out of the incident plane) showed an oscillating behavior. The EF of the array was highly dependent on the angle and polarization of the incident light. The structure of AgNR and the excitation wavelength were also found to affect the EF. The EF of random arrays was stronger than that of an ordered one with the same average gap of 21 nm, which could be explained by the exponential dependence of EF on the lateral gap size. Our results also suggested that absorption rather than extinction or scattering could be a good indicator of EM enhancement. It is expected that the understanding of the dependence of local field enhancement on the structure of the nanoarrays and incident excitations will shine light on the optimal design of efficient SERS substrates and improved performance. |
| first_indexed | 2024-12-20T03:14:35Z |
| format | Article |
| id | doaj.art-a7a4f40bc26a4eb2a4b1f12cd321a92c |
| institution | Directory Open Access Journal |
| issn | 2190-4286 |
| language | English |
| last_indexed | 2024-12-20T03:14:35Z |
| publishDate | 2015-03-01 |
| publisher | Beilstein-Institut |
| record_format | Article |
| series | Beilstein Journal of Nanotechnology |
| spelling | doaj.art-a7a4f40bc26a4eb2a4b1f12cd321a92c2022-12-21T19:55:22ZengBeilstein-InstitutBeilstein Journal of Nanotechnology2190-42862015-03-016168669610.3762/bjnano.6.692190-4286-6-69Electromagnetic enhancement of ordered silver nanorod arrays evaluated by discrete dipole approximationGuoke Wei0Jinliang Wang1Yu Chen2Department of Physics, Beihang University, Beijing 100191, ChinaDepartment of Physics, Beihang University, Beijing 100191, ChinaPhotophysics Group, Centre for Molecular Nanometrology, Department of Physics, SUPA, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG, UKThe enhancement factor (EF) of surface-enhanced Raman scattering (SERS) from two-dimensional (2D) hexagonal silver nanorod (AgNR) arrays were investigated in terms of electromagnetic (EM) mechanism by using the discrete dipole approximation (DDA) method. The dependence of EF on several parameters, i.e., structure, length, excitation wavelength, incident angle and polarization, and gap size has been investigated. “Hotspots” were found distributed in the gaps between adjacent nanorods. Simulations of AgNR arrays of different lengths revealed that increasing the rod length from 374 to 937 nm (aspect ratio from 2.0 to 5.0) generated more “hotspots” but not necessarily increased EF under both 514 and 532 nm excitation. A narrow lateral gap (in the incident plane) was found to result in strong EF, while the dependence of EF on the diagonal gap (out of the incident plane) showed an oscillating behavior. The EF of the array was highly dependent on the angle and polarization of the incident light. The structure of AgNR and the excitation wavelength were also found to affect the EF. The EF of random arrays was stronger than that of an ordered one with the same average gap of 21 nm, which could be explained by the exponential dependence of EF on the lateral gap size. Our results also suggested that absorption rather than extinction or scattering could be a good indicator of EM enhancement. It is expected that the understanding of the dependence of local field enhancement on the structure of the nanoarrays and incident excitations will shine light on the optimal design of efficient SERS substrates and improved performance.https://doi.org/10.3762/bjnano.6.69discrete dipole approximation (DDA)enhancement factornear-fieldsilver nanorod arraysurface-enhanced Raman scattering (SERS) |
| spellingShingle | Guoke Wei Jinliang Wang Yu Chen Electromagnetic enhancement of ordered silver nanorod arrays evaluated by discrete dipole approximation Beilstein Journal of Nanotechnology discrete dipole approximation (DDA) enhancement factor near-field silver nanorod array surface-enhanced Raman scattering (SERS) |
| title | Electromagnetic enhancement of ordered silver nanorod arrays evaluated by discrete dipole approximation |
| title_full | Electromagnetic enhancement of ordered silver nanorod arrays evaluated by discrete dipole approximation |
| title_fullStr | Electromagnetic enhancement of ordered silver nanorod arrays evaluated by discrete dipole approximation |
| title_full_unstemmed | Electromagnetic enhancement of ordered silver nanorod arrays evaluated by discrete dipole approximation |
| title_short | Electromagnetic enhancement of ordered silver nanorod arrays evaluated by discrete dipole approximation |
| title_sort | electromagnetic enhancement of ordered silver nanorod arrays evaluated by discrete dipole approximation |
| topic | discrete dipole approximation (DDA) enhancement factor near-field silver nanorod array surface-enhanced Raman scattering (SERS) |
| url | https://doi.org/10.3762/bjnano.6.69 |
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