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Kelm A, Ostapko J, Gajewska A, Sánchez-Iglesias A, Waluk J. Spectral and photophysical modifications of porphyrins attached to core-shell nanoparticles. Theory and experiment. Methods Appl Fluoresc 2021; 9. [PMID: 34256360 DOI: 10.1088/2050-6120/ac1400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/13/2021] [Indexed: 12/30/2022]
Abstract
Plasmonic nanostructures, of which gold nanoparticles are the most elementary example, owe their unique properties to localized surface plasmons (LSP), the modes of free electron oscillation. LSP alter significantly electromagnetic field in the nanostructure neighborhood (i.e., near-field), which can modify the electric dipole transition rates in organic emitters. This study aims at investigating the influence of Au@SiO2core-shell nanoparticles on the photophysics of porphyrins covalently attached to the nanoparticles surface. Guided by theoretical predictions, three sets of gold nanoparticles of different sizes were coated with a silica layer of similar thickness. The outer silica surface was functionalized with either free-basemeso-tetraphenylporphyrin or its zinc complex. Absorption and emission bands of porphyrin overlap in energy with a gold nanoparticle LSP resonance that provides the field enhancement. Silica separates the emitters from the gold surface, while the gold core size tunes the energy of the LSP resonance. The signatures of weak-coupling regime have been observed. Apart from modified emission profiles and shortened S1lifetimes, Q band part intensity of the excitation spectra significantly increased with respect to the Soret band. The results were explained using classical transfer matrix simulations and electronic states kinetics, taking into account the photophysical properties of each chromophore. The calculations could reasonably well predict and explain the experimental outcomes. The discrepancies between the two were discussed.
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Affiliation(s)
- A Kelm
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - J Ostapko
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - A Gajewska
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - A Sánchez-Iglesias
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo de Miramón 194, 20014 Donostia-San Sebastián, Spain.,Centro de Investigación Biomédica en Red, Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Paseo de Miramón 194, 20014 Donostia-San Sebastián, Spain
| | - J Waluk
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.,Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland
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Zhang J, Youssef AH, Dörfler A, Kolhatkar G, Merlen A, Ruediger A. Sample induced intensity variations of localized surface plasmon resonance in tip-enhanced Raman spectroscopy. OPTICS EXPRESS 2020; 28:25998-26006. [PMID: 32906877 DOI: 10.1364/oe.403345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 08/04/2020] [Indexed: 06/11/2023]
Abstract
Tip-enhanced spectroscopy techniques, in particular tip-enhanced Raman spectroscopy (TERS), rely on a localized surface plasmon resonance (LSPR). This LSPR depends on the near field antenna, its material and shape, and the surrounding medium with respect to its relative permittivity and the volume fraction of the optical near field occupied by the sample. Here, we investigate the effects of the surface composition and topography on the change of the LSPR intensity in tip-enhanced spectroscopy on SrTiO3 nanoislands by monitoring the LSPR enhanced luminescence of gold tips. Our experimental results and analytical estimates indicate that by affecting the effective permittivity of the dielectric environment at the tip apex, the material composition as well as topography of the studied sample induce a change in LSPR intensity. This result significantly helps the understanding of the evolution or origin of the LSPR intensity during a typical TERS measurement, which in turn leads to a more accurate assessment of the relative intensity of different Raman modes in TERS.
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Youssef AH, Zhang J, Dörfler A, Kolhatkar G, Merlen A, Ruediger A. Topography-induced variations of localized surface plasmon resonance in tip-enhanced Raman configuration. OPTICS EXPRESS 2020; 28:14161-14168. [PMID: 32403876 DOI: 10.1364/oe.389565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/31/2020] [Indexed: 06/11/2023]
Abstract
We report on topography-induced changes of the localized surface plasmon resonance (LSPR) enhanced luminescence of gold tip on SrTiO3 nanostructures with apertureless scanning near-field optical microscopy (aSNOM) in tip-enhanced Raman spectroscopy (TERS) configuration. Our experimental and simulated results indicate that the averaged refractive index of the dielectric environment of the tip apex containing both air and SrTiO3 in variable volume ratios, is dependent on the topography of the sample. This reveals that the local topography has to be taken into consideration as an additional contribution to the position of the LSPR.
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Kolhatkar G, Merlen A, Zhang J, Dab C, Wallace GQ, Lagugné-Labarthet F, Ruediger A. Optical near-field mapping of plasmonic nanostructures prepared by nanosphere lithography. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:1536-1543. [PMID: 29977686 PMCID: PMC6009220 DOI: 10.3762/bjnano.9.144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 04/21/2018] [Indexed: 06/08/2023]
Abstract
We introduce a simple, fast, efficient and non-destructive method to study the optical near-field properties of plasmonic nanotriangles prepared by nanosphere lithography. Using a rectangular Fourier filter on the blurred signal together with filtering of the lower spatial frequencies to remove the far-field contribution, the pure near-field contributions of the optical images were extracted. We performed measurements using two excitation wavelengths (532.1 nm and 632.8 nm) and two different polarizations. After the processing of the optical images, the distribution of hot spots can be correlated with the topography of the structures, as indicated by the presence of brighter spots at the apexes of the nanostructures. This technique is validated by comparison of the results to numerical simulations, where agreement is obtained, thereby confirming the near-field nature of the images. Our approach does not require any advanced equipment and we suggest that it could be applied to any type of sample, while keeping the measurement times reasonably short.
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Affiliation(s)
- Gitanjali Kolhatkar
- Institut National de la Recherche Scientifique - Énergie, Matériaux, Télécommunications, 1650 Boulevard Lionel-Boulet, J3X 1S2, Varennes, Québec, Canada
| | - Alexandre Merlen
- IM2NP, UMR CNRS 7334, Aix Marseille Université et Université de Toulon, Site de l’Université de Toulon, 83957 La Garde Cedex, France
- Institut Fresnel UMR 7249, Aix-Marseille Université, CNRS, École Centrale de Marseille, 13013 Marseille, France
| | - Jiawei Zhang
- Institut National de la Recherche Scientifique - Énergie, Matériaux, Télécommunications, 1650 Boulevard Lionel-Boulet, J3X 1S2, Varennes, Québec, Canada
| | - Chahinez Dab
- Institut National de la Recherche Scientifique - Énergie, Matériaux, Télécommunications, 1650 Boulevard Lionel-Boulet, J3X 1S2, Varennes, Québec, Canada
| | - Gregory Q Wallace
- Western University (The University of Western Ontario), Chemistry Department and Centre for Materials and Biomaterials, 1151 Richmond Street, London, ON, N6A5B7, Canada
| | - François Lagugné-Labarthet
- Western University (The University of Western Ontario), Chemistry Department and Centre for Materials and Biomaterials, 1151 Richmond Street, London, ON, N6A5B7, Canada
| | - Andreas Ruediger
- Institut National de la Recherche Scientifique - Énergie, Matériaux, Télécommunications, 1650 Boulevard Lionel-Boulet, J3X 1S2, Varennes, Québec, Canada
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