SERS in PAH-Os and gold nanoparticle self-assembled multilayers

We present a detailed structural and surface-enhanced Raman scattering (SERS) study of poly(allylamine) modified with Os (byp)2 ClPyCHO (PAH-Os) and gold nanoparticles self-assembled multilayers [PAH-Os+ (Au-nanoparticlesPAH-Os)n, n=1 and 5]. Atomic force microscopy and variable-angle spectroscopic...

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Autores principales:	Calvo, Ernesto Julio, Bonazzola, Cecilia
Publicado:	2005
Materias:	Electronic transition Gold nanoparticles Raman resonance Self-assembled multilayers Amplification Atomic force microscopy Ellipsometry Gold Nanostructured materials Polyamides Self assembly Spectroscopic analysis Multilayers
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v123_n4_p_Tognalli http://hdl.handle.net/20.500.12110/paper_00219606_v123_n4_p_Tognalli
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_00219606_v123_n4_p_Tognalli
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spelling	paper:paper_00219606_v123_n4_p_Tognalli2023-06-08T14:44:10Z SERS in PAH-Os and gold nanoparticle self-assembled multilayers Calvo, Ernesto Julio Bonazzola, Cecilia Electronic transition Gold nanoparticles Raman resonance Self-assembled multilayers Amplification Atomic force microscopy Ellipsometry Gold Nanostructured materials Polyamides Self assembly Spectroscopic analysis Multilayers We present a detailed structural and surface-enhanced Raman scattering (SERS) study of poly(allylamine) modified with Os (byp)2 ClPyCHO (PAH-Os) and gold nanoparticles self-assembled multilayers [PAH-Os+ (Au-nanoparticlesPAH-Os)n, n=1 and 5]. Atomic force microscopy and variable-angle spectroscopic ellipsometry measurements indicate that the first nanoparticle layer grows homogenously by partially covering the substrate without clustering. Analyzing the sample thickness and roughness we infer that the growth process advances thereafter by filling with nanoparticles the interstitial spaces between the previously adsorbed nanoparticles. After five immersion steps the multilayers reach a more compact structure. The interaction between plasmons of near-gold nanoparticles provides a new optical absorption around 650 nm which, in addition, allows a more effective SERS process in that spectral region than at the single-plasmon resonance (∼530 nm). We compare the electronic resonance Raman and SERS amplification mechanisms in these self-assembled multilayers analyzing Raman resonance scans and Raman intensity micromaps. As a function of nanoparticle coverage we observe large changes in the Raman intensity scans, with maxima that shift from the electronic transitions, to the plasmon resonance, and finally to the coupled-plasmon absorption. The Raman micromaps, on the other hand, evidence huge intensity inhomogeneities which we relate to "hot spots." Numerical discrete dipole approximation calculations including the interaction between gold nanoparticles are presented, providing a qualitative model for the coupled-plasmon absorption and redshifted Raman hot spots in these samples. © 2005 American Institute of Physics. Fil:Calvo, E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Bonazzola, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2005 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v123_n4_p_Tognalli http://hdl.handle.net/20.500.12110/paper_00219606_v123_n4_p_Tognalli
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Electronic transition Gold nanoparticles Raman resonance Self-assembled multilayers Amplification Atomic force microscopy Ellipsometry Gold Nanostructured materials Polyamides Self assembly Spectroscopic analysis Multilayers
spellingShingle	Electronic transition Gold nanoparticles Raman resonance Self-assembled multilayers Amplification Atomic force microscopy Ellipsometry Gold Nanostructured materials Polyamides Self assembly Spectroscopic analysis Multilayers Calvo, Ernesto Julio Bonazzola, Cecilia SERS in PAH-Os and gold nanoparticle self-assembled multilayers
topic_facet	Electronic transition Gold nanoparticles Raman resonance Self-assembled multilayers Amplification Atomic force microscopy Ellipsometry Gold Nanostructured materials Polyamides Self assembly Spectroscopic analysis Multilayers
description	We present a detailed structural and surface-enhanced Raman scattering (SERS) study of poly(allylamine) modified with Os (byp)2 ClPyCHO (PAH-Os) and gold nanoparticles self-assembled multilayers [PAH-Os+ (Au-nanoparticlesPAH-Os)n, n=1 and 5]. Atomic force microscopy and variable-angle spectroscopic ellipsometry measurements indicate that the first nanoparticle layer grows homogenously by partially covering the substrate without clustering. Analyzing the sample thickness and roughness we infer that the growth process advances thereafter by filling with nanoparticles the interstitial spaces between the previously adsorbed nanoparticles. After five immersion steps the multilayers reach a more compact structure. The interaction between plasmons of near-gold nanoparticles provides a new optical absorption around 650 nm which, in addition, allows a more effective SERS process in that spectral region than at the single-plasmon resonance (∼530 nm). We compare the electronic resonance Raman and SERS amplification mechanisms in these self-assembled multilayers analyzing Raman resonance scans and Raman intensity micromaps. As a function of nanoparticle coverage we observe large changes in the Raman intensity scans, with maxima that shift from the electronic transitions, to the plasmon resonance, and finally to the coupled-plasmon absorption. The Raman micromaps, on the other hand, evidence huge intensity inhomogeneities which we relate to "hot spots." Numerical discrete dipole approximation calculations including the interaction between gold nanoparticles are presented, providing a qualitative model for the coupled-plasmon absorption and redshifted Raman hot spots in these samples. © 2005 American Institute of Physics.
author	Calvo, Ernesto Julio Bonazzola, Cecilia
author_facet	Calvo, Ernesto Julio Bonazzola, Cecilia
author_sort	Calvo, Ernesto Julio
title	SERS in PAH-Os and gold nanoparticle self-assembled multilayers
title_short	SERS in PAH-Os and gold nanoparticle self-assembled multilayers
title_full	SERS in PAH-Os and gold nanoparticle self-assembled multilayers
title_fullStr	SERS in PAH-Os and gold nanoparticle self-assembled multilayers
title_full_unstemmed	SERS in PAH-Os and gold nanoparticle self-assembled multilayers
title_sort	sers in pah-os and gold nanoparticle self-assembled multilayers
publishDate	2005
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v123_n4_p_Tognalli http://hdl.handle.net/20.500.12110/paper_00219606_v123_n4_p_Tognalli
work_keys_str_mv	AT calvoernestojulio sersinpahosandgoldnanoparticleselfassembledmultilayers AT bonazzolacecilia sersinpahosandgoldnanoparticleselfassembledmultilayers
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SERS in PAH-Os and gold nanoparticle self-assembled multilayers

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