Plasmon Spectroscopy for Subnanometric Copper Particles: Dielectric Function and Core–Shell Sizing

Autores
Santillán, Jesica María José; Videla, Fabián Alfredo; Scaffardi, Lucía Beatriz; Schinca, Daniel Carlos
Año de publicación
2012
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
In the last years, there has been a growing interest in the study of transition metal nanoparticles (Nps) due to their potential applications in several fields of science and technology. In particular, their optical properties are governed by the characteristics of the dielectric function of the metal, its size and environment. This work analyses the separated contribution of free and bound electrons on the optical properties of copper Nps. Usually, the contribution of free electrons to the dielectric function is corrected for particle size through the modification of the damping constant, which is changed as usual introducing a term inversely proportional to the particle’s radius to account for the extra collisions with the boundary when the size approaches the electronic mean free path limit (about 10 nm). For bound electron contribution, the interband transitions from the d-band to the conduction band are considered together with the fact that the electronic density of states in the conduction band must be made size-dependent to account for the larger spacing between electronic energy levels as the particle decreases in size below 2 nm. Taking into account these specific modifications of free and bound electron contributions to the dielectric function, it was possible to fit the bulk complex dielectric function, and consequently, determine optical parameters and band energy values such as the coefficient for bound electron contribution Qbulk = 2 × 1024, gap energy Eg = 1.95 eV, Fermi energy EF = 2.15 eV, and damping constant for bound electrons γb = 1.15 × 1014 Hz. With both size-dependent contributions to the dielectric function, extinction spectra of copper Nps in the subnanometer radius range can be calculated using Mie’s theory and its behaviour with size can be analysed. These studies are applied to fit experimental extinction spectra of very small spherical core–shell Cu–Cu2O Nps generated by ultrafast laser ablation of a solid target in water. Theoretical calculations for subnanometric core radius are in excellent agreement with experimental results obtained from core–shell colloidal Nps. From the fitting, it is possible determining core radius and shell thickness of the Nps, showing that optical extinction spectroscopy is a good complementary technique to standard high-resolution electron microscopy for sizing spherical nanometric-subnanometric Nps.
Centro de Investigaciones Ópticas
Facultad de Ingeniería
Materia
Ciencias Exactas
Cu–Cu2O nanoparticles
Copper dielectric function
Subnanometric size
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/144996

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spelling Plasmon Spectroscopy for Subnanometric Copper Particles: Dielectric Function and Core–Shell SizingSantillán, Jesica María JoséVidela, Fabián AlfredoScaffardi, Lucía BeatrizSchinca, Daniel CarlosCiencias ExactasCu–Cu2O nanoparticlesCopper dielectric functionSubnanometric sizeIn the last years, there has been a growing interest in the study of transition metal nanoparticles (Nps) due to their potential applications in several fields of science and technology. In particular, their optical properties are governed by the characteristics of the dielectric function of the metal, its size and environment. This work analyses the separated contribution of free and bound electrons on the optical properties of copper Nps. Usually, the contribution of free electrons to the dielectric function is corrected for particle size through the modification of the damping constant, which is changed as usual introducing a term inversely proportional to the particle’s radius to account for the extra collisions with the boundary when the size approaches the electronic mean free path limit (about 10 nm). For bound electron contribution, the interband transitions from the d-band to the conduction band are considered together with the fact that the electronic density of states in the conduction band must be made size-dependent to account for the larger spacing between electronic energy levels as the particle decreases in size below 2 nm. Taking into account these specific modifications of free and bound electron contributions to the dielectric function, it was possible to fit the bulk complex dielectric function, and consequently, determine optical parameters and band energy values such as the coefficient for bound electron contribution Qbulk = 2 × 1024, gap energy Eg = 1.95 eV, Fermi energy EF = 2.15 eV, and damping constant for bound electrons γb = 1.15 × 1014 Hz. With both size-dependent contributions to the dielectric function, extinction spectra of copper Nps in the subnanometer radius range can be calculated using Mie’s theory and its behaviour with size can be analysed. These studies are applied to fit experimental extinction spectra of very small spherical core–shell Cu–Cu2O Nps generated by ultrafast laser ablation of a solid target in water. Theoretical calculations for subnanometric core radius are in excellent agreement with experimental results obtained from core–shell colloidal Nps. From the fitting, it is possible determining core radius and shell thickness of the Nps, showing that optical extinction spectroscopy is a good complementary technique to standard high-resolution electron microscopy for sizing spherical nanometric-subnanometric Nps.Centro de Investigaciones ÓpticasFacultad de Ingeniería2012-06-07info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf341-348http://sedici.unlp.edu.ar/handle/10915/144996enginfo:eu-repo/semantics/altIdentifier/issn/1557-1955info:eu-repo/semantics/altIdentifier/issn/1557-1963info:eu-repo/semantics/altIdentifier/doi/10.1007/s11468-012-9395-8info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by/4.0/Creative Commons Attribution 4.0 International (CC BY 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:32:32Zoai:sedici.unlp.edu.ar:10915/144996Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:32:33.028SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Plasmon Spectroscopy for Subnanometric Copper Particles: Dielectric Function and Core–Shell Sizing
title Plasmon Spectroscopy for Subnanometric Copper Particles: Dielectric Function and Core–Shell Sizing
spellingShingle Plasmon Spectroscopy for Subnanometric Copper Particles: Dielectric Function and Core–Shell Sizing
Santillán, Jesica María José
Ciencias Exactas
Cu–Cu2O nanoparticles
Copper dielectric function
Subnanometric size
title_short Plasmon Spectroscopy for Subnanometric Copper Particles: Dielectric Function and Core–Shell Sizing
title_full Plasmon Spectroscopy for Subnanometric Copper Particles: Dielectric Function and Core–Shell Sizing
title_fullStr Plasmon Spectroscopy for Subnanometric Copper Particles: Dielectric Function and Core–Shell Sizing
title_full_unstemmed Plasmon Spectroscopy for Subnanometric Copper Particles: Dielectric Function and Core–Shell Sizing
title_sort Plasmon Spectroscopy for Subnanometric Copper Particles: Dielectric Function and Core–Shell Sizing
dc.creator.none.fl_str_mv Santillán, Jesica María José
Videla, Fabián Alfredo
Scaffardi, Lucía Beatriz
Schinca, Daniel Carlos
author Santillán, Jesica María José
author_facet Santillán, Jesica María José
Videla, Fabián Alfredo
Scaffardi, Lucía Beatriz
Schinca, Daniel Carlos
author_role author
author2 Videla, Fabián Alfredo
Scaffardi, Lucía Beatriz
Schinca, Daniel Carlos
author2_role author
author
author
dc.subject.none.fl_str_mv Ciencias Exactas
Cu–Cu2O nanoparticles
Copper dielectric function
Subnanometric size
topic Ciencias Exactas
Cu–Cu2O nanoparticles
Copper dielectric function
Subnanometric size
dc.description.none.fl_txt_mv In the last years, there has been a growing interest in the study of transition metal nanoparticles (Nps) due to their potential applications in several fields of science and technology. In particular, their optical properties are governed by the characteristics of the dielectric function of the metal, its size and environment. This work analyses the separated contribution of free and bound electrons on the optical properties of copper Nps. Usually, the contribution of free electrons to the dielectric function is corrected for particle size through the modification of the damping constant, which is changed as usual introducing a term inversely proportional to the particle’s radius to account for the extra collisions with the boundary when the size approaches the electronic mean free path limit (about 10 nm). For bound electron contribution, the interband transitions from the d-band to the conduction band are considered together with the fact that the electronic density of states in the conduction band must be made size-dependent to account for the larger spacing between electronic energy levels as the particle decreases in size below 2 nm. Taking into account these specific modifications of free and bound electron contributions to the dielectric function, it was possible to fit the bulk complex dielectric function, and consequently, determine optical parameters and band energy values such as the coefficient for bound electron contribution Qbulk = 2 × 1024, gap energy Eg = 1.95 eV, Fermi energy EF = 2.15 eV, and damping constant for bound electrons γb = 1.15 × 1014 Hz. With both size-dependent contributions to the dielectric function, extinction spectra of copper Nps in the subnanometer radius range can be calculated using Mie’s theory and its behaviour with size can be analysed. These studies are applied to fit experimental extinction spectra of very small spherical core–shell Cu–Cu2O Nps generated by ultrafast laser ablation of a solid target in water. Theoretical calculations for subnanometric core radius are in excellent agreement with experimental results obtained from core–shell colloidal Nps. From the fitting, it is possible determining core radius and shell thickness of the Nps, showing that optical extinction spectroscopy is a good complementary technique to standard high-resolution electron microscopy for sizing spherical nanometric-subnanometric Nps.
Centro de Investigaciones Ópticas
Facultad de Ingeniería
description In the last years, there has been a growing interest in the study of transition metal nanoparticles (Nps) due to their potential applications in several fields of science and technology. In particular, their optical properties are governed by the characteristics of the dielectric function of the metal, its size and environment. This work analyses the separated contribution of free and bound electrons on the optical properties of copper Nps. Usually, the contribution of free electrons to the dielectric function is corrected for particle size through the modification of the damping constant, which is changed as usual introducing a term inversely proportional to the particle’s radius to account for the extra collisions with the boundary when the size approaches the electronic mean free path limit (about 10 nm). For bound electron contribution, the interband transitions from the d-band to the conduction band are considered together with the fact that the electronic density of states in the conduction band must be made size-dependent to account for the larger spacing between electronic energy levels as the particle decreases in size below 2 nm. Taking into account these specific modifications of free and bound electron contributions to the dielectric function, it was possible to fit the bulk complex dielectric function, and consequently, determine optical parameters and band energy values such as the coefficient for bound electron contribution Qbulk = 2 × 1024, gap energy Eg = 1.95 eV, Fermi energy EF = 2.15 eV, and damping constant for bound electrons γb = 1.15 × 1014 Hz. With both size-dependent contributions to the dielectric function, extinction spectra of copper Nps in the subnanometer radius range can be calculated using Mie’s theory and its behaviour with size can be analysed. These studies are applied to fit experimental extinction spectra of very small spherical core–shell Cu–Cu2O Nps generated by ultrafast laser ablation of a solid target in water. Theoretical calculations for subnanometric core radius are in excellent agreement with experimental results obtained from core–shell colloidal Nps. From the fitting, it is possible determining core radius and shell thickness of the Nps, showing that optical extinction spectroscopy is a good complementary technique to standard high-resolution electron microscopy for sizing spherical nanometric-subnanometric Nps.
publishDate 2012
dc.date.none.fl_str_mv 2012-06-07
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
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info:eu-repo/semantics/altIdentifier/issn/1557-1963
info:eu-repo/semantics/altIdentifier/doi/10.1007/s11468-012-9395-8
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
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eu_rights_str_mv openAccess
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