Cargando…
Quantifying the Plasmonic Character of Optical Excitations in a Molecular J-Aggregate
[Image: see text] The definition of plasmon at the microscopic scale is far from being understood. Yet, it is very important to recognize plasmonic features in optical excitations, as they can inspire new applications and trigger new discoveries by analogy with the rich phenomenology of metal nanopa...
Autores principales: | , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American
Chemical Society
2019
|
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6524342/ https://www.ncbi.nlm.nih.gov/pubmed/30986064 http://dx.doi.org/10.1021/acs.jctc.9b00220 |
_version_ | 1783419540708786176 |
---|---|
author | Guerrini, Michele Calzolari, Arrigo Varsano, Daniele Corni, Stefano |
author_facet | Guerrini, Michele Calzolari, Arrigo Varsano, Daniele Corni, Stefano |
author_sort | Guerrini, Michele |
collection | PubMed |
description | [Image: see text] The definition of plasmon at the microscopic scale is far from being understood. Yet, it is very important to recognize plasmonic features in optical excitations, as they can inspire new applications and trigger new discoveries by analogy with the rich phenomenology of metal nanoparticle plasmons. Recently, the concepts of plasmonicity index and the generalized plasmonicity index (GPI) have been devised as computational tools to quantify the plasmonic nature of optical excitations. The question may arise whether any strong absorption band, possibly with some sort of collective character in its microscopic origin, shares the status of plasmon. Here we demonstrate that this is not always the case, by considering a well-known class of systems represented by J-aggregates molecular crystals, characterized by the intense J band of absorption. By means of first-principles simulations, based on a many-body perturbation theory formalism, we investigate the optical properties of a J-aggregate made of push–pull organic dyes. We show that the effect of aggregation is to lower the GPI associated with the J-band with respect to the isolated dye one, which corresponds to a nonplasmonic character of the electronic excitations. In order to rationalize our finding, we then propose a simplified one-dimensional theoretical model of the J-aggregate. A useful microscopic picture of what discriminates a collective molecular crystal excitation from a plasmon is eventually obtained. |
format | Online Article Text |
id | pubmed-6524342 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | American
Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-65243422019-05-20 Quantifying the Plasmonic Character of Optical Excitations in a Molecular J-Aggregate Guerrini, Michele Calzolari, Arrigo Varsano, Daniele Corni, Stefano J Chem Theory Comput [Image: see text] The definition of plasmon at the microscopic scale is far from being understood. Yet, it is very important to recognize plasmonic features in optical excitations, as they can inspire new applications and trigger new discoveries by analogy with the rich phenomenology of metal nanoparticle plasmons. Recently, the concepts of plasmonicity index and the generalized plasmonicity index (GPI) have been devised as computational tools to quantify the plasmonic nature of optical excitations. The question may arise whether any strong absorption band, possibly with some sort of collective character in its microscopic origin, shares the status of plasmon. Here we demonstrate that this is not always the case, by considering a well-known class of systems represented by J-aggregates molecular crystals, characterized by the intense J band of absorption. By means of first-principles simulations, based on a many-body perturbation theory formalism, we investigate the optical properties of a J-aggregate made of push–pull organic dyes. We show that the effect of aggregation is to lower the GPI associated with the J-band with respect to the isolated dye one, which corresponds to a nonplasmonic character of the electronic excitations. In order to rationalize our finding, we then propose a simplified one-dimensional theoretical model of the J-aggregate. A useful microscopic picture of what discriminates a collective molecular crystal excitation from a plasmon is eventually obtained. American Chemical Society 2019-04-15 2019-05-14 /pmc/articles/PMC6524342/ /pubmed/30986064 http://dx.doi.org/10.1021/acs.jctc.9b00220 Text en Copyright © 2019 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes. |
spellingShingle | Guerrini, Michele Calzolari, Arrigo Varsano, Daniele Corni, Stefano Quantifying the Plasmonic Character of Optical Excitations in a Molecular J-Aggregate |
title | Quantifying the Plasmonic Character of Optical Excitations
in a Molecular J-Aggregate |
title_full | Quantifying the Plasmonic Character of Optical Excitations
in a Molecular J-Aggregate |
title_fullStr | Quantifying the Plasmonic Character of Optical Excitations
in a Molecular J-Aggregate |
title_full_unstemmed | Quantifying the Plasmonic Character of Optical Excitations
in a Molecular J-Aggregate |
title_short | Quantifying the Plasmonic Character of Optical Excitations
in a Molecular J-Aggregate |
title_sort | quantifying the plasmonic character of optical excitations
in a molecular j-aggregate |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6524342/ https://www.ncbi.nlm.nih.gov/pubmed/30986064 http://dx.doi.org/10.1021/acs.jctc.9b00220 |
work_keys_str_mv | AT guerrinimichele quantifyingtheplasmoniccharacterofopticalexcitationsinamolecularjaggregate AT calzolariarrigo quantifyingtheplasmoniccharacterofopticalexcitationsinamolecularjaggregate AT varsanodaniele quantifyingtheplasmoniccharacterofopticalexcitationsinamolecularjaggregate AT cornistefano quantifyingtheplasmoniccharacterofopticalexcitationsinamolecularjaggregate |