Logsdail, Andrew ORCID: https://orcid.org/0000-0002-2277-415X and Johnston, Roy. L. 2012. Predicting the Optical Properties of Core-Shell and Janus Segregated Au-M Nanoparticles (M = Ag, Pd). Journal of Physical Chemistry C 116 (44) , pp. 23616-23628. 10.1021/jp306000u |
Abstract
An investigation of the optical properties of off-centered core–shell segregated Au–M (M = Ag, Pd) nanoalloys is conducted using the discrete-dipole approximation (DDA). While the secondary metal M is found to dominate the optical spectra in core-centered spherical particles, displacement of the core within the Au–M structure results in an increase in maximum extinction intensity, at the wavelength λmax, illustrating the potential for controlled tunability. The greatest effect is seen when the core is touching the particle surface and the nonhomogeneity of the shell covering is maximized. The increase in intensity at λmax is attributed to the greater division of the dielectric materials and thus a stronger response from the dominant dielectric. The intensity of response is also found to be mildly dependent on the segregated particles' orientation relative to the angle of the incoming electromagnetic radiation, k. Calculations are performed for elongated elliptical nanorods, with aspect ratios of 2, where core positioning is also found to play an important role in the position of λmax. Changes to the spectra for M = Pd are slight; however, the movement of the elliptical core in the AucoreAgshell results in significant shifting of λmax. We conclude that our observations will have profound implications for the use of optical absorption spectra in characterizing nonsymmetrically segregated nanoalloys.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Cardiff Catalysis Institute (CCI) Chemistry |
Publisher: | ACS Publications |
ISSN: | 1932-7447 |
Last Modified: | 01 Nov 2022 11:35 |
URI: | https://orca.cardiff.ac.uk/id/eprint/95474 |
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