On the physical limitations for radio frequency absorption in gold nanoparticle suspensions
Nordebo, Sven LU ; Dalarsson, Mariana ; Ivanenko, Yevhen LU ; Sjöberg, Daniel LU
and Bayford, Richard
(2017)
In Journal of Physics D: Applied Physics
50(15).
- Abstract
This paper presents a study of the physical limitations for radio frequency absorption in gold nanoparticle (GNP) suspensions. A spherical geometry is considered consisting of a spherical suspension of colloidal GNPs characterized as an arbitrary passive dielectric material which is immersed in an arbitrary lossy medium. A relative heating coefficient and a corresponding optimal near field excitation are defined, taking the skin effect of the surrounding medium into account. The classical Mie theory for lossy media is also revisited, and it is shown that the optimal permittivity function yielding a maximal absorption inside the spherical suspension is a conjugate match with respect to the surrounding lossy material. A convex... (More)
This paper presents a study of the physical limitations for radio frequency absorption in gold nanoparticle (GNP) suspensions. A spherical geometry is considered consisting of a spherical suspension of colloidal GNPs characterized as an arbitrary passive dielectric material which is immersed in an arbitrary lossy medium. A relative heating coefficient and a corresponding optimal near field excitation are defined, taking the skin effect of the surrounding medium into account. The classical Mie theory for lossy media is also revisited, and it is shown that the optimal permittivity function yielding a maximal absorption inside the spherical suspension is a conjugate match with respect to the surrounding lossy material. A convex optimization approach is used to investigate the broadband realizability of an arbitrary passive material to approximate the desired conjugate match over a finite bandwidth, similar to the approximation of a metamaterial. A narrowband realizability study shows that for a surrounding medium consisting of a weak electrolyte solution, the electromagnetic heating, due to the electrophoretic (plasmonic) resonance phenomena inside the spherical GNP suspension, can be significant in the microwave regime, provided that the related Drude parameters can be tuned into (or near to) resonance. As a demonstration, some realistic Drude parameters are investigated concerning the volume fraction, mass, and friction constant of the GNPs. The amount of charge that can be accommodated by the GNPs is identified as one of the most important design parameters. However, the problem of reliably modelling, measuring and controlling the charge number of coated GNPs is not yet fully understood, and is still an open research issue in this field. The presented theory and related physical limitations provide a useful framework for further research in this direction. Future research is also aimed at an expansion towards arbitrary suspension geometries and the inclusion of thermodynamical analysis.
(Less)
- author
- Nordebo, Sven
LU
; Dalarsson, Mariana
; Ivanenko, Yevhen
LU
; Sjöberg, Daniel
LU
and Bayford, Richard
- organization
- publishing date
- 2017-03-09
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- gold nanoparticles, Mie theory, optimal absorption
- in
- Journal of Physics D: Applied Physics
- volume
- 50
- issue
- 15
- article number
- 155401
- publisher
- IOP Publishing
- external identifiers
-
- wos:000397500500001
- scopus:85016154351
- ISSN
- 0022-3727
- DOI
- 10.1088/1361-6463/aa5a89
- language
- English
- LU publication?
- yes
- id
- e418149a-2609-4b03-a198-9a455972d5e0
- date added to LUP
- 2017-04-05 14:30:28
- date last changed
- 2025-01-07 10:51:41
@article{e418149a-2609-4b03-a198-9a455972d5e0,
abstract = {{<p>This paper presents a study of the physical limitations for radio frequency absorption in gold nanoparticle (GNP) suspensions. A spherical geometry is considered consisting of a spherical suspension of colloidal GNPs characterized as an arbitrary passive dielectric material which is immersed in an arbitrary lossy medium. A relative heating coefficient and a corresponding optimal near field excitation are defined, taking the skin effect of the surrounding medium into account. The classical Mie theory for lossy media is also revisited, and it is shown that the optimal permittivity function yielding a maximal absorption inside the spherical suspension is a conjugate match with respect to the surrounding lossy material. A convex optimization approach is used to investigate the broadband realizability of an arbitrary passive material to approximate the desired conjugate match over a finite bandwidth, similar to the approximation of a metamaterial. A narrowband realizability study shows that for a surrounding medium consisting of a weak electrolyte solution, the electromagnetic heating, due to the electrophoretic (plasmonic) resonance phenomena inside the spherical GNP suspension, can be significant in the microwave regime, provided that the related Drude parameters can be tuned into (or near to) resonance. As a demonstration, some realistic Drude parameters are investigated concerning the volume fraction, mass, and friction constant of the GNPs. The amount of charge that can be accommodated by the GNPs is identified as one of the most important design parameters. However, the problem of reliably modelling, measuring and controlling the charge number of coated GNPs is not yet fully understood, and is still an open research issue in this field. The presented theory and related physical limitations provide a useful framework for further research in this direction. Future research is also aimed at an expansion towards arbitrary suspension geometries and the inclusion of thermodynamical analysis.</p>}},
author = {{Nordebo, Sven and Dalarsson, Mariana and Ivanenko, Yevhen and Sjöberg, Daniel and Bayford, Richard}},
issn = {{0022-3727}},
keywords = {{gold nanoparticles; Mie theory; optimal absorption}},
language = {{eng}},
month = {{03}},
number = {{15}},
publisher = {{IOP Publishing}},
series = {{Journal of Physics D: Applied Physics}},
title = {{On the physical limitations for radio frequency absorption in gold nanoparticle suspensions}},
url = {{http://dx.doi.org/10.1088/1361-6463/aa5a89}},
doi = {{10.1088/1361-6463/aa5a89}},
volume = {{50}},
year = {{2017}},
}