Population and coherence dynamics in large conjugated porphyrin nanorings
Autor(a) principal: | |
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Data de Publicação: | 2022 |
Outros Autores: | , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/257901 |
Resumo: | In photosynthesis, nature exploits the distinctive electronic properties of chromophores arranged in supramolecular rings for efficient light harvesting. Among synthetic supramolecular cyclic structures, porphyrin nanorings have attracted considerable attention as they have a resemblance to naturally occurring light-harvesting structures but offer the ability to control ring size and the level of disorder. Here, broadband femtosecond transient absorption spectroscopy, with pump pulses in resonance with either the high or the low energy sides of the inhomogeneously broadened absorption spectrum, is used to study the population dynamics and ground and excited state vibrational coherence in large porphyrin nanorings. A series of fully conjugated, alkyne bridged, nanorings constituted of between ten and forty porphyrin units is studied. Pump-wavelength dependent fast spectral evolution is found. A fast rise or decay of the stimulated emission is found when large porphyrin nanorings are excited on, respectively, the high or low energy side of the absorption spectrum. Such dynamics are consistent with the hypothesis of a variation in transition dipole moment across the inhomogeneously broadened ground state ensemble. The observed dynamics indicate the interplay of nanoring conformation and oscillator strength. Oscillatory dynamics on the sub-ps time domain are observed in both pumping conditions. A combined analysis of the excitation wavelength-dependent transient spectra along with the amplitude and phase evolution of the oscillations allows assignment to vibrational wavepackets evolving on either ground or excited states electronic potential energy surfaces. Even though porphyrin nanorings support highly delocalized electronic wavefunctions, with coherence length spanning tens of chromophores, the measured vibrational coherences remain localised on the monomers. The main contributions to the beatings are assigned to two vibrational modes localised on the porphyrin cores: a Zn–N stretching mode and a skeletal methinic/pyrrolic C–C stretching and in-plane bending mode. |
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Bressan, GiovanniJirasek, MichaelRoy, PalasAnderson, HarryMeech, StephenHeisler, Ismael Andre2023-05-10T03:27:56Z20222041-6520http://hdl.handle.net/10183/257901001165282In photosynthesis, nature exploits the distinctive electronic properties of chromophores arranged in supramolecular rings for efficient light harvesting. Among synthetic supramolecular cyclic structures, porphyrin nanorings have attracted considerable attention as they have a resemblance to naturally occurring light-harvesting structures but offer the ability to control ring size and the level of disorder. Here, broadband femtosecond transient absorption spectroscopy, with pump pulses in resonance with either the high or the low energy sides of the inhomogeneously broadened absorption spectrum, is used to study the population dynamics and ground and excited state vibrational coherence in large porphyrin nanorings. A series of fully conjugated, alkyne bridged, nanorings constituted of between ten and forty porphyrin units is studied. Pump-wavelength dependent fast spectral evolution is found. A fast rise or decay of the stimulated emission is found when large porphyrin nanorings are excited on, respectively, the high or low energy side of the absorption spectrum. Such dynamics are consistent with the hypothesis of a variation in transition dipole moment across the inhomogeneously broadened ground state ensemble. The observed dynamics indicate the interplay of nanoring conformation and oscillator strength. Oscillatory dynamics on the sub-ps time domain are observed in both pumping conditions. A combined analysis of the excitation wavelength-dependent transient spectra along with the amplitude and phase evolution of the oscillations allows assignment to vibrational wavepackets evolving on either ground or excited states electronic potential energy surfaces. Even though porphyrin nanorings support highly delocalized electronic wavefunctions, with coherence length spanning tens of chromophores, the measured vibrational coherences remain localised on the monomers. The main contributions to the beatings are assigned to two vibrational modes localised on the porphyrin cores: a Zn–N stretching mode and a skeletal methinic/pyrrolic C–C stretching and in-plane bending mode.application/pdfengChemical Science. Cambridge. Vol. 13, n. 33 (Sept. 2022), p. 9624–9636FotoluminescênciaEspectroscopia RamanPorfirinasDinâmica populacionalPopulation and coherence dynamics in large conjugated porphyrin nanoringsEstrangeiroinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSTEXT001165282.pdf.txt001165282.pdf.txtExtracted Texttext/plain62121http://www.lume.ufrgs.br/bitstream/10183/257901/2/001165282.pdf.txt713feec5db09e47a9fe7e9cfacc3a479MD52ORIGINAL001165282.pdfTexto completo (inglês)application/pdf1862321http://www.lume.ufrgs.br/bitstream/10183/257901/1/001165282.pdf0a604e75ef7f1860bc509aa2daeb6b8bMD5110183/2579012023-08-04 03:33:54.719691oai:www.lume.ufrgs.br:10183/257901Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2023-08-04T06:33:54Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
Population and coherence dynamics in large conjugated porphyrin nanorings |
title |
Population and coherence dynamics in large conjugated porphyrin nanorings |
spellingShingle |
Population and coherence dynamics in large conjugated porphyrin nanorings Bressan, Giovanni Fotoluminescência Espectroscopia Raman Porfirinas Dinâmica populacional |
title_short |
Population and coherence dynamics in large conjugated porphyrin nanorings |
title_full |
Population and coherence dynamics in large conjugated porphyrin nanorings |
title_fullStr |
Population and coherence dynamics in large conjugated porphyrin nanorings |
title_full_unstemmed |
Population and coherence dynamics in large conjugated porphyrin nanorings |
title_sort |
Population and coherence dynamics in large conjugated porphyrin nanorings |
author |
Bressan, Giovanni |
author_facet |
Bressan, Giovanni Jirasek, Michael Roy, Palas Anderson, Harry Meech, Stephen Heisler, Ismael Andre |
author_role |
author |
author2 |
Jirasek, Michael Roy, Palas Anderson, Harry Meech, Stephen Heisler, Ismael Andre |
author2_role |
author author author author author |
dc.contributor.author.fl_str_mv |
Bressan, Giovanni Jirasek, Michael Roy, Palas Anderson, Harry Meech, Stephen Heisler, Ismael Andre |
dc.subject.por.fl_str_mv |
Fotoluminescência Espectroscopia Raman Porfirinas Dinâmica populacional |
topic |
Fotoluminescência Espectroscopia Raman Porfirinas Dinâmica populacional |
description |
In photosynthesis, nature exploits the distinctive electronic properties of chromophores arranged in supramolecular rings for efficient light harvesting. Among synthetic supramolecular cyclic structures, porphyrin nanorings have attracted considerable attention as they have a resemblance to naturally occurring light-harvesting structures but offer the ability to control ring size and the level of disorder. Here, broadband femtosecond transient absorption spectroscopy, with pump pulses in resonance with either the high or the low energy sides of the inhomogeneously broadened absorption spectrum, is used to study the population dynamics and ground and excited state vibrational coherence in large porphyrin nanorings. A series of fully conjugated, alkyne bridged, nanorings constituted of between ten and forty porphyrin units is studied. Pump-wavelength dependent fast spectral evolution is found. A fast rise or decay of the stimulated emission is found when large porphyrin nanorings are excited on, respectively, the high or low energy side of the absorption spectrum. Such dynamics are consistent with the hypothesis of a variation in transition dipole moment across the inhomogeneously broadened ground state ensemble. The observed dynamics indicate the interplay of nanoring conformation and oscillator strength. Oscillatory dynamics on the sub-ps time domain are observed in both pumping conditions. A combined analysis of the excitation wavelength-dependent transient spectra along with the amplitude and phase evolution of the oscillations allows assignment to vibrational wavepackets evolving on either ground or excited states electronic potential energy surfaces. Even though porphyrin nanorings support highly delocalized electronic wavefunctions, with coherence length spanning tens of chromophores, the measured vibrational coherences remain localised on the monomers. The main contributions to the beatings are assigned to two vibrational modes localised on the porphyrin cores: a Zn–N stretching mode and a skeletal methinic/pyrrolic C–C stretching and in-plane bending mode. |
publishDate |
2022 |
dc.date.issued.fl_str_mv |
2022 |
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2023-05-10T03:27:56Z |
dc.type.driver.fl_str_mv |
Estrangeiro info:eu-repo/semantics/article |
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001165282 |
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http://hdl.handle.net/10183/257901 |
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eng |
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dc.relation.ispartof.pt_BR.fl_str_mv |
Chemical Science. Cambridge. Vol. 13, n. 33 (Sept. 2022), p. 9624–9636 |
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