Tags

Type your tag names separated by a space and hit enter

Dependence of the enhanced optical scattering efficiency relative to that of absorption for gold metal nanorods on aspect ratio, size, end-cap shape, and medium refractive index.
J Phys Chem B. 2005 Nov 03; 109(43):20331-8.JP

Abstract

The current intense interest in the properties of plasmonic nanostructures for their applications in chemical and biochemical sensors, medical diagnostics and therapeutics, and biological imaging is fundamentally based on their enhanced optical absorption and scattering properties. In this study, the optical extinction, absorption, and scattering efficiencies were calculated as a function of shape definition, aspect ratio, surrounding medium, and material selection. The discrete dipole approximation method was used, which is known to be a very useful and versatile computational tool for particles with any arbitrary shape. Relative contribution of scattering to the total extinction for the longitudinal mode was found to be significantly dependent on the aspect ratio of the nanorod in a somewhat complex manner, different from a typical linear relationship for the resonance wavelength. A slight elongation of Au nanosphere gives rise to a drastic increase in the relative scattering efficiency, which eventually reaches a maximum and begins to decrease with further increase in the aspect ratio. This is ascribed to the increasing absorptive contribution from the larger imaginary dielectric function of the metal particle in the longer wavelength region where the red-shifted excitation of the longitudinal resonance mode occurs. For transverse mode exhibiting the blue-shift in the resonance peak, on the contrary, the absorption efficiency is relatively enhanced compared to the scattering efficiency with increasing aspect ratio. This is thought to result from the dominant effect of the interband transition present in this wavelength region. Besides the dependence of plasmonic characteristics on the aspect ratio of nanorod, the DDA results for a small change of the end-cap shape and the index of the surrounding medium lead us to conclude that there exist two competing key factors: a weighting factor assigned to the shape parameter and the dielectric function of the metal particle, which control the relative enhancement in the scattering and absorption as well as the linearity of resonance wavelength with regard to the aspect ratio.

Authors+Show Affiliations

Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA.No affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

16853630

Citation

Lee, Kyeong-Seok, and Mostafa A. El-Sayed. "Dependence of the Enhanced Optical Scattering Efficiency Relative to That of Absorption for Gold Metal Nanorods On Aspect Ratio, Size, End-cap Shape, and Medium Refractive Index." The Journal of Physical Chemistry. B, vol. 109, no. 43, 2005, pp. 20331-8.
Lee KS, El-Sayed MA. Dependence of the enhanced optical scattering efficiency relative to that of absorption for gold metal nanorods on aspect ratio, size, end-cap shape, and medium refractive index. J Phys Chem B. 2005;109(43):20331-8.
Lee, K. S., & El-Sayed, M. A. (2005). Dependence of the enhanced optical scattering efficiency relative to that of absorption for gold metal nanorods on aspect ratio, size, end-cap shape, and medium refractive index. The Journal of Physical Chemistry. B, 109(43), 20331-8.
Lee KS, El-Sayed MA. Dependence of the Enhanced Optical Scattering Efficiency Relative to That of Absorption for Gold Metal Nanorods On Aspect Ratio, Size, End-cap Shape, and Medium Refractive Index. J Phys Chem B. 2005 Nov 3;109(43):20331-8. PubMed PMID: 16853630.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Dependence of the enhanced optical scattering efficiency relative to that of absorption for gold metal nanorods on aspect ratio, size, end-cap shape, and medium refractive index. AU - Lee,Kyeong-Seok, AU - El-Sayed,Mostafa A, PY - 2006/7/21/pubmed PY - 2006/7/21/medline PY - 2006/7/21/entrez SP - 20331 EP - 8 JF - The journal of physical chemistry. B JO - J Phys Chem B VL - 109 IS - 43 N2 - The current intense interest in the properties of plasmonic nanostructures for their applications in chemical and biochemical sensors, medical diagnostics and therapeutics, and biological imaging is fundamentally based on their enhanced optical absorption and scattering properties. In this study, the optical extinction, absorption, and scattering efficiencies were calculated as a function of shape definition, aspect ratio, surrounding medium, and material selection. The discrete dipole approximation method was used, which is known to be a very useful and versatile computational tool for particles with any arbitrary shape. Relative contribution of scattering to the total extinction for the longitudinal mode was found to be significantly dependent on the aspect ratio of the nanorod in a somewhat complex manner, different from a typical linear relationship for the resonance wavelength. A slight elongation of Au nanosphere gives rise to a drastic increase in the relative scattering efficiency, which eventually reaches a maximum and begins to decrease with further increase in the aspect ratio. This is ascribed to the increasing absorptive contribution from the larger imaginary dielectric function of the metal particle in the longer wavelength region where the red-shifted excitation of the longitudinal resonance mode occurs. For transverse mode exhibiting the blue-shift in the resonance peak, on the contrary, the absorption efficiency is relatively enhanced compared to the scattering efficiency with increasing aspect ratio. This is thought to result from the dominant effect of the interband transition present in this wavelength region. Besides the dependence of plasmonic characteristics on the aspect ratio of nanorod, the DDA results for a small change of the end-cap shape and the index of the surrounding medium lead us to conclude that there exist two competing key factors: a weighting factor assigned to the shape parameter and the dielectric function of the metal particle, which control the relative enhancement in the scattering and absorption as well as the linearity of resonance wavelength with regard to the aspect ratio. SN - 1520-6106 UR - https://www.unboundmedicine.com/medline/citation/16853630/Dependence_of_the_enhanced_optical_scattering_efficiency_relative_to_that_of_absorption_for_gold_metal_nanorods_on_aspect_ratio_size_end_cap_shape_and_medium_refractive_index_ L2 - https://doi.org/10.1021/jp054385p DB - PRIME DP - Unbound Medicine ER -
Try the Free App:
Prime PubMed app for iOS iPhone iPad
Prime PubMed app for Android
Prime PubMed is provided
free to individuals by:
Unbound Medicine.