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8. The rotation of NO3− as a probe of molecular ion - water interactions

Author

Ogden T., Odelius M., Keiding S.R., Knak Jensen S., Nielsen J.B., Thøgersen J., Réhault J., and Helbing J.

Subjects
Physics, QC1-999
Abstract

The hydration dynamics of aqueous nitrate, NO3−(aq), is studied by 2D-IR spectroscopy, UV-IR- and UV-UV transient absorption spectroscopy. The experimental results are compared to Car-Parinello molecular dynamics (MD) simulations. The 2D-IR measurements and MD simulations of the non-degenerate asymmetric stretch vibrations of nitrate reveal an intermodal energy exchange occurring on a 0.2 ps time scale related to hydrogen bond fluctuations. The transient absorption measurements find that the nitrate ions rotate in 2 ps. The MD simulations indicate that the ion rotation is associated with the formation of new hydrogen bonds. The 2 ps rotation time thus indicates that the hydration shell of aqueous nitrate is rather labile.

Published
2013
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9. Exploring the polarization degrees of freedom in collinear two-dimensional infrared spectroscopy

Author

Helbing J. and Réhault J.

Subjects
Physics, QC1-999
Abstract

We exploit the polarization degrees of freedom in order to optimize interferometer-based 2D-IR spectroscopy in the pump-probe geometry. Signals can be amplified, scattering background can be fully eliminated and intramolecular angles can be determined with improved accuracy. Simple manipulation of the polarization of all four fields gives direct access to individual tensor elements and dispersive signals.

Published
2013
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13. Multiset multivariate curve resolution of transient absorption spectroscopy data to model ultrafast photodynamics

Author

Debus, B., Devos, O., Orio, M., Réhault, J., Burdzinski, G., Ruckebusch, C., Sliwa, M., Institute of Chemistry, St Petersburg State University (SPbU), Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), Physikalisch-Chemisches Institut [Zürich], Universität Zürich [Zürich] = University of Zurich (UZH), Faculty of Physics, Adam Mickiewicz University in Poznań (UAM), and Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry
Published
2015

14. Fourier transform spectroscopy in the vibrational fingerprint region with a birefringent interferometer

Author

Réhault, J, Borrego-Varillas, R, Oriana, A, Manzoni, C, Hauri, C P, Helbing, Jan; https://orcid.org/0000-0003-3911-8519, Cerullo, G, Réhault, J, Borrego-Varillas, R, Oriana, A, Manzoni, C, Hauri, C P, Helbing, Jan; https://orcid.org/0000-0003-3911-8519, and Cerullo, G

Abstract

We introduce a birefringent interferometer for Fourier transform (FT) spectroscopy in the mid-infrared, covering the vibrational fingerprint region (5-10 µm, 1000-2000 cm−1), which is crucial for molecular identification. Our interferometer employs the crystal calomel (Hg2Cl2), which combines high birefringence (ne-no≈0.55) with a broad transparency range (0.38-20 µm). We adopt a design based on birefringent wedges, which is simple and compact and guarantees excellent delay accuracy and long-term stability. We demonstrate FTIR spectroscopy, with a frequency resolution of 3 cm−1, as well as two-dimensional IR (2DIR) spectroscopy. Our setup can be extended to other spectroscopic modalities such as vibrational circular dichroism and step-scan FT spectroscopy.

Published
2017

16. Nano-confinement of radical interaction to tailor fast switching photochromic materials

Author

Sliwa, M., Debus, B., Hatano, S., Katayama, T., Vitale, R., Orio, M., Choël, M., Piard Jonathan, Métivier, R., Réhault, J., Ruckebusch, C., Nakatani, K., Abe, J., Miyasaka, H., Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry, School of Science and Engineering, Aoyama Gakuin University (AGU), Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires (PPSM), École normale supérieure - Cachan (ENS Cachan)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Physikalisch-Chemisches Institut [Zürich], Universität Zürich [Zürich] = University of Zurich (UZH), Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University [Osaka], and Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry
Published
2013

19. Stabilization of volatile Ti(BH4)3 by nano-confinement in a metal-organic framework

Author

Callini, E., Szilágyi, P., Paskevicius, M., Stadie, N., Réhault, J., Buckley, Craig, Borgschulte, A., Züttel, A., Callini, E., Szilágyi, P., Paskevicius, M., Stadie, N., Réhault, J., Buckley, Craig, Borgschulte, A., and Züttel, A.

Abstract

Liquid complex hydrides are a new class of hydrogen storage materials with several advantages over solid hydrides, e.g. they are flexible in shape, they are a flowing fluid and their convective properties facilitate heat transport. The physical and chemical properties of a gaseous hydride change when the molecules are adsorbed on a material with a large specific surface area, due to the interaction of the adsorbate with the surface of the host material and the reduced number of collisions between the hydride molecules. In this paper we report the synthesis and stabilization of gaseous Ti(BH4)3. The compound was successfully stabilized through adsorption in nanocavities. Ti(BH4)3, upon synthesis in its pure form, spontaneously and rapidly decomposes into diborane and titanium hydride at room temperature in an inert gas, e.g. argon. Ti(BH4)3 adsorbed in the cavities of a metal organic framework is stable for several months at ambient temperature and remains stable up to 350 K under vacuum. The adsorbed Ti(BH4)3 reaches approximately twice the density of the gas phase. The specific surface area (BET, N2 adsorption) of the MOF decreased from 1200 m2 g−1 to 770 m2 g−1 upon Ti(BH4)3 adsorption.

Published
2015

20. Bridged Photochromic diarylethenes investigated by ultrafast absorption spectroscopy: evidences for two distinct photocyclization pathways

Author

Aloïse, S., Pawlowska, Z., Sliwa, M., Réhault, J., Buntinx, G., Poizat, O., Perrier, A., Maurel, F., Takeshita, M., Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS (UMR_7086)), Université Paris Diderot - Paris 7 (UPD7)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Faculty of Science Engineering, Saga University [Japon], Laboratoire de Spectrochimie Infrarouge et Raman - UMR 8516 (LASIR), Centre National de la Recherche Scientifique (CNRS)-Université de Lille, Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), and Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Published
2010

21. Crustal structure of a young margin pair: New results across the Liguro-Provencal Basin from wide-angle seismic tomography

Author

Gailler, A., Klingelhoefer, F., Olivet, J.-L., Aslanian, D., Afilhado, A., Bache, François, Beslier, M.-O., Cosquer, E., Deschamps, Anne, Droz, Laurence, Gorini, Christian, Moulin, M., Nouzé, H., Oudet, J., Pascucci, V., Perrot, Julie, Rabineau, Marina, Réhault, J.-P., Allano, L., Begot, Jacques, Crozon, J., Fernagu, P., Labahn, E., Pelleau, P., Théreau, E., Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Géoazur (GEOAZUR 6526), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Unité de recherche Géosciences Marines (Ifremer) (GM), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, Inversion (geology), [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 010502 geochemistry & geophysics, 01 natural sciences, Geochemistry and Petrology, Lithosphere, Oceanic crust, NW-Mediterranean Basin, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, Petrology, 0105 earth and related environmental sciences, conjugate margins, Continental crust, Crust, Western Sardinia, travel-time tomography, wide-angle seismic, crustal structure, Detachment fault, Tectonics, Geophysics, Space and Planetary Science, Seismic tomography, Gulf of Lions, Geology, Seismology
Abstract

International audience; Tomographic inversion of two wide-angle seismic profiles acquired during the Sardinia cruise (2006) on the conjugate Gulf of Lions-West Sardinia margins pair offers insight into the deep structure of this young basin. It is the first combined conjugate margins study in this area based on deep seismic data. Modelling of the two conjugate profiles reveals that the conjugate margins are symmetric in term of crustal velocity structure, with a partitioning in three similar regions: (1) a zone of low crustal vertical velocity gradients and a crustal thickness of 18 to 10 km, interpreted to be thinned continental crust, (2) a transitional zone characterised by high lower crustal velocities, non-typical of continental or normal oceanic crust, and (3) a 4- to 5-km-thick crust showing vertical velocity gradients and relative velocity ranges typical of oceanic crust. This latter region is interpreted to be a thin oceanic crust resulting from a tectonic heritage and the possible influence of a cool slab back-arc basin. Although the three regions are found on both sides of the margin, they are asymmetric in terms of the width of these domains, wide and smooth along the Gulf of Lions margin, and narrow and abrupt along its conjugate Sardinia side. The width of Region 2 is larger on the Gulf of Lions side (~ 90 km) than on the Sardinia side (~ 40 km). Crustal thickness in Region 3 is about 1 km thinner on the Sardinia side than on its conjugate. In Region 1 the crustal thickness is lower on the Sardinia side at a given distance from the shelf break. The differences in width of Region 2 and in crustal thickness might be due to the origin as a back-arc basin of the NW-Mediterranean basin, with the final breakup located closer to the Western Sardinia margin, also probably linked to the complex tectonic history of the region. Our results do not support a simple shear mechanism of the opening of the basin along a lithospheric detachment fault.

Published
2009
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22. Investigation of 1,2-dicyano[2,n]metacyclophan-1-enes photochromism by time resolved absorption spectroscopy

Author

Aloïse, S., Sliwa, M., Pawlowska, Z., Réhault, J., Buntinx, G., Poizat, O., Takeshita, M., Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), and Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL)

Published
2008

23. Exploring the photochromism of salicylideneanilines with IR transient spectroscopies and chemometrics modelling

Author

Sliwa, M., Ruckebusch, C., Réhault, J., Aloïse, S., Poizat, O., Buntinx, G., Naumov, P., Burdzinski, G., Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), Graduate School of Engineering, Osaka University [Osaka], Quantum Electronics Laboratory, Adam Mickiewicz University in Poznań (UAM), and Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Published
2008

24. Exploring the photochromism of salicylidene anilines with transient spectroscopies and chemometric modeling

Author

Sliwa, M., Ruckebusch, C., Réhault, J., Aloïse, S., Poizat, O., Naumov, P., Nakatani, Keitaro, Asahi, T., Hofkens, Johan, Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires (PPSM), École normale supérieure - Cachan (ENS Cachan)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Department of Applied Physics, Osaka University, Osaka University [Osaka], Department of Applied Physics, Dpt of Applied Physics, Osaka University, département chimie, Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), and Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Published
2008

25. Temperature measurements in AlGaN/GaN HEMTs using time resolved UV micro-Raman spectroscopy

Author

Lancry, O., Pichonat, E., Réhault, J., Moreau, M., Gaquière, Christophe, Turrell, S., Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), and Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Published
2008

26. Photochimie de molécules photochromes et molécules modèles par spectroscopie d'absorption ultrarapide et résolution multivariée des données

Author

Aloïse, S., Réhault, J., Ruckebusch, C., Pawlowska, Z., Poizat, O., Buntinx, G., Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), and Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Published
2008

27. Development of time-resolved UV Micro-Raman spectroscopy to analyse self-heating effects in AlGaN/GaN HEMTs

Author

Lancry, O., Pichonat, E., Réhault, J., Myriam MOREAU, Christophe Gaquière, Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), and Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Published
2008

29. Meta and Para Effects in the Ultrafast Excited-State Dynamics of the Green Fluorescent Protein Chromophores1

Author

Solntsev, K.M., Poizat, O., Dong, J., Réhault, J., Lou, Y., Burda, C., Tolbert, L.M., School of Chemistry and Biochemistry [Atlanta], Georgia Institute of Technology [Atlanta], Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes et de Recherches Lasers et Applications (CERLA), Université de Lille, Sciences et Technologies, Center for Chemical Dynamics and Nanomaterials Research, Case Western Reserve University [Cleveland], and Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, [CHIM.OTHE]Chemical Sciences/Other
Abstract

Femtosecond transient absorption and fluorescence upconversion experiments have been performed to investigate the photoinduced dynamics of the meta isomer of the green fluorescent protein chromophore, m-HBDI, and its O-methylated derivative, m-MeOBDI, in various solvent mixtures at neutral, acidic, and basic pH. The para isomer, p-HBDI, and its O- and N-methylated derivatives, p-MeOBDI and p-HBDIMe+, were also studied for comparison. In all cases, fast quenching of the excited S1 state by internal conversion (IC) to the ground state was observed. In the para compounds, IC, presumably promoted by the internal twisting, arises in

Published
2008
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30. Résolution multivariée de spectres d'absorption transitoire femtoseconde

Author

Ruckebusch, C., Aloïse, S., Blanchet, L., Duponchel, L., Réhault, J., Huvenne, J.P., Buntinx, G., Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), and Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Published
2006

31. Recent time-resolved absorption investigation of the photophysical processes in some organic photochromic compounds

Author

Aloïse, S., Buntinx, G., Moine, B., Poizat, O., Réhault, J., Moustrou, C., Lokshin, V., Samat, A., Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), Groupe de chimie organique et matériaux moléculaires (GCOMM), Université de la Méditerranée - Aix-Marseille 2-Centre National de la Recherche Scientifique (CNRS), and Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Published
2006

38. The rotation of NO3 - as a probe of molecular ion - water interactions.

Author

Thøgersen, J., Nielsen, J. B., Knak Jensen, S., Keiding, S. R., Odelius, M., Ogden, T., Réhault, J., and Helbing, J.

Subjects
NITRATES, ULTRAVIOLET spectroscopy, INFRARED spectroscopy, FLUCTUATIONS (Physics), AQUEOUS solutions
Abstract

The hydration dynamics of aqueous nitrate, NO3 -(aq), is studied by 2D-IR spectroscopy, UV-IR- and UV-UV transient absorption spectroscopy. The experimental results are compared to Car-Parinello molecular dynamics (MD) simulations. The 2DIR measurements and MD simulations of the non-degenerate asymmetric stretch vibrations of nitrate reveal an intermodal energy exchange occurring on a 0.2 ps time scale related to hydrogen bond fluctuations. The transient absorption measurements find that the nitrate ions rotate in 2 ps. The MD simulations indicate that the ion rotation is associated with the formation of new hydrogen bonds. The 2 ps rotation time thus indicates that the hydration shell of aqueous nitrate is rather labile [ABSTRACT FROM AUTHOR]

Published
2013
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40. Synthesis and ultrafast spectroscopy of photochromic nanoparticles with fast thermal back reaction

Author

Sliwa, M., Debus, B., Hatano, S., Katayama, T., Vitale, R., Orio, M., Choël, M., Piard Jonathan, Métivier, R., Réhault, J., Ruckebusch, C., Nakatani, K., Abe, J., Miyasaka, H., Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), Department of Chemistry, School of Science and Engineering, Aoyama Gakuin University (AGU), Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires (PPSM), École normale supérieure - Cachan (ENS Cachan)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Physikalisch-Chemisches Institut [Zürich], Universität Zürich [Zürich] = University of Zurich (UZH), Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University [Osaka], and Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry

42. Direct visualization of the charge transfer state dynamics in dilute-donor organic photovoltaic blends.

Author

Moore GJ, Günther F, Yallum KM, Causa' M, Jungbluth A, Réhault J, Riede M, Ortmann F, and Banerji N

Abstract

The interconversion dynamics between charge transfer state charges (CTCs) and separated charges (SCs) is still an unresolved issue in the field of organic photovoltaics. Here, a transient absorption spectroscopy (TAS) study of a thermally evaporated small-molecule:fullerene system (α6T:C 60 ) in different morphologies (dilute intermixed and phase separated) is presented. Spectral decomposition reveals two charge species with distinct absorption characteristics and different dynamics. Using time-dependent density functional theory, these species are identified as CTCs and SCs, where the spectral differences arise from broken symmetry in the charge transfer state that turns forbidden transitions into allowed ones. Based on this assignment, a kinetic model is formulated allowing the characterization of the charge generation, separation, and recombination mechanisms. We find that SCs are either formed directly from excitons within a few picoseconds or more slowly (~30-80 ps) from reversible splitting of CTCs. These findings constitute the first unambiguous observation of spectrally resolved CTCs and SCs., Competing Interests: Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Published
2024
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43. A Quasi-2D Polypyrrole Film with Band-Like Transport Behavior and High Charge-Carrier Mobility.

Author

Liu K, Réhault J, Liang B, Hambsch M, Zhang Y, Seçkin S, Zhou Y, Shivhare R, Zhang P, Polozij M, König TAF, Qi H, Zhou S, Fery A, Mannsfeld SCB, Kaiser U, Heine T, Banerji N, Dong R, and Feng X

Abstract

Quasi-2D (q2D) conjugated polymers (CPs) are polymers that consist of linear CP chains assembled through non-covalent interactions to form a layered structure. In this work, the synthesis of a novel crystalline q2D polypyrrole (q2DPPy) film at the air/H 2 SO 4 (95%) interface is reported. The unique interfacial environment facilitates chain extension, prevents disorder, and results in a crystalline, layered assembly of protonated quinoidal chains with a fully extended conformation in its crystalline domains. This unique structure features highly delocalized π-electron systems within the extended chains, which is responsible for the low effective mass and narrow electronic bandgap. Thus, the temperature-dependent charge-transport properties of q2DPPy are investigated using the van der Pauw (vdP) method and terahertz time-domain spectroscopy (THz-TDS). The vdP method reveals that the q2DPPy film exhibits a semiconducting behavior with a thermally activated hopping mechanism in long-range transport between the electrodes. Conversely, THz-TDS reveals a band-like transport, indicating intrinsic charge transport up to a record short-range high THz mobility of ≈107.1 cm 2 V -1 s -1 ., (© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

Published
2023
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44. Electrochemical Doping in Ordered and Disordered Domains of Organic Mixed Ionic-Electronic Conductors.

Author

Cavassin P, Holzer I, Tsokkou D, Bardagot O, Réhault J, and Banerji N

Abstract

Conjugated polymers are increasingly used as organic mixed ionic-electronic conductors in electrochemical applications for neuromorphic computing, bioelectronics, and energy harvesting. The design of efficient electrochemical devices relies on large modulations of the polymer conductivity, fast doping/dedoping kinetics, and high ionic uptake. In this work, structure-property relations are established and control of these parameters by the co-existence of order and disorder in the phase morphology is demonstrated. Using in situ time-resolved spectroelectrochemistry, resonant Raman, and terahertz (THz) conductivity measurements, the electrochemical doping in the different morphological domains of poly(3-hexylthiophene) (P3HT) is investigated. The main finding is that bipolarons are found preferentially in disordered polymer regions, where they are formed faster and are thermodynamically more favored. On the other hand, polarons show a preference for ordered domains, leading to drastically different bipolaron/polaron ratios and doping/dedoping dynamics in the distinct regions. A significant enhancement of the electronic conductivity is evident when bipolarons start forming in the disordered regions, while the presence of bipolarons in the ordered regions is detrimental for transport. This study provides significant advances in the understanding of the impact of morphology on the electrochemical doping of conjugated polymers and the induced increase in conductivity., (© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

Published
2023
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45. High-resolution phase-sensitive sum frequency generation spectroscopy by time-domain ptychography.

Author

Schweizer T, Nicolau BG, Cavassin P, Feurer T, Banerji N, and Réhault J

Abstract

We demonstrate that time-domain ptychography, when applied to a set of broadband vibrational sum frequency spectra, reconstructs amplitude and phase of the vibrational free induction decay from an interfacial sample with a resolution that is independent of up-converting pulse bandwidth and spectrometer resolution. These important improvements require no modifications to most standard homodyne setups, and the method is applicable to other coherent homodyne spectroscopies such as coherent anti-Stokes Raman spectroscopy and transient grating spectroscopy.

Published
2020

46. Sub-picosecond charge-transfer at near-zero driving force in polymer:non-fullerene acceptor blends and bilayers.

Author

Zhong Y, Causa' M, Moore GJ, Krauspe P, Xiao B, Günther F, Kublitski J, Shivhare R, Benduhn J, BarOr E, Mukherjee S, Yallum KM, Réhault J, Mannsfeld SCB, Neher D, Richter LJ, DeLongchamp DM, Ortmann F, Vandewal K, Zhou E, and Banerji N

Abstract

Organic photovoltaics based on non-fullerene acceptors (NFAs) show record efficiency of 16 to 17% and increased photovoltage owing to the low driving force for interfacial charge-transfer. However, the low driving force potentially slows down charge generation, leading to a tradeoff between voltage and current. Here, we disentangle the intrinsic charge-transfer rates from morphology-dependent exciton diffusion for a series of polymer:NFA systems. Moreover, we establish the influence of the interfacial energetics on the electron and hole transfer rates separately. We demonstrate that charge-transfer timescales remain at a few hundred femtoseconds even at near-zero driving force, which is consistent with the rates predicted by Marcus theory in the normal region, at moderate electronic coupling and at low re-organization energy. Thus, in the design of highly efficient devices, the energy offset at the donor:acceptor interface can be minimized without jeopardizing the charge-transfer rate and without concerns about a current-voltage tradeoff.

Published
2020
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47. Ultrafast Carotenoid to Retinal Energy Transfer in Xanthorhodopsin Revealed by the Combination of Transient Absorption and Two-Dimensional Electronic Spectroscopy.

Author

Segatta F, Gdor I, Réhault J, Taioli S, Friedman N, Sheves M, Rivalta I, Ruhman S, Cerullo G, and Garavelli M

Abstract

By comparing two-dimensional electronic spectroscopy (2DES) and Pump-Probe (PP) measurements on xanthorhodopsin (XR) and reduced-xanthorhodopsin (RXR) complexes, the ultrafast carotenoid-to-retinal energy transfer pathway is revealed, at very early times, by an excess of signal amplitude at the associated cross-peak and by the carotenoid bleaching reduction due to its ground state recovery. The combination of the measured 2DES and PP spectroscopic data with theoretical modelling allows a clear identification of the main experimental signals and a comprehensive interpretation of their origin and dynamics. The remarkable velocity of the energy transfer, despite the non-negligible energy separation between the two chromophores, and the analysis of the underlying transport mechanism, highlight the role played by the ground state carotenoid vibrations in assisting the process., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2018
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48. Time-domain measurement of optical activity by an ultrastable common-path interferometer.

Author

Preda F, Perri A, Réhault J, Dutta B, Helbing J, Cerullo G, and Polli D

Abstract

We introduce a novel configuration for the broadband measurement of the optical activity of molecules, combining time-domain detection with heterodyne amplification. A birefringent common-path polarization-division interferometer creates two phase-locked replicas of the input light with orthogonal polarization. The more intense replica interacts with the sample, producing a chiral free-induction decay field, which interferes with the other replica, acting as a time-delayed phase-coherent local oscillator. By recording the delay-dependent interferogram, we obtain by a Fourier transform both the circular dichroism and circular birefringence spectra. Our compact, low-cost setup accepts ultrashort light pulses, making it suitable for measurement of transient optical activity.

Published
2018
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49. Two-Dimensional Electronic Spectroscopy Unravels sub-100 fs Electron and Hole Relaxation Dynamics in Cd-Chalcogenide Nanostructures.

Author

Stoll T, Branchi F, Réhault J, Scotognella F, Tassone F, Kriegel I, and Cerullo G

Abstract

We use two-dimensional electronic spectroscopy (2DES) to disentangle the separate electron and hole relaxation pathways and dynamics of CdTe nanorods on a sub-100 fs time scale. By simultaneously exciting and probing the first three excitonic transitions (S1, S2, and S3) and exploiting the unique combination of high temporal and spectral resolution of 2DES, we derive a complete picture for the state-selective carrier relaxation. We find that hot holes relax from the 1Σ 3/2 to the 1Σ 1/2 state (S2 → S1) with 30 ± 10 fs time constant, and the hot electrons relax from the Σ' to the Σ state (S3 → S1) with 50 ± 10 fs time constant. This observation would not have been possible with conventional transient absorption spectroscopy due to the spectral congestion of the transitions and the very fast relaxation time scales.

Published
2017
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50. Tracking the coherent generation of polaron pairs in conjugated polymers.

Author

De Sio A, Troiani F, Maiuri M, Réhault J, Sommer E, Lim J, Huelga SF, Plenio MB, Rozzi CA, Cerullo G, Molinari E, and Lienau C

Abstract

The optical excitation of organic semiconductors not only generates charge-neutral electron-hole pairs (excitons), but also charge-separated polaron pairs with high yield. The microscopic mechanisms underlying this charge separation have been debated for many years. Here we use ultrafast two-dimensional electronic spectroscopy to study the dynamics of polaron pair formation in a prototypical polymer thin film on a sub-20-fs time scale. We observe multi-period peak oscillations persisting for up to about 1 ps as distinct signatures of vibronic quantum coherence at room temperature. The measured two-dimensional spectra show pronounced peak splittings revealing that the elementary optical excitations of this polymer are hybridized exciton-polaron-pairs, strongly coupled to a dominant underdamped vibrational mode. Coherent vibronic coupling induces ultrafast polaron pair formation, accelerates the charge separation dynamics and makes it insensitive to disorder. These findings open up new perspectives for tailoring light-to-current conversion in organic materials.

Published
2016
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