1
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Carta A, Wittmann B, Kreger K, Schmidt HW, Jansen TLC, Hildner R. Spatial Correlations Drive Long-Range Transport and Trapping of Excitons in Single H-Aggregates: Experiment and Theory. J Phys Chem Lett 2024; 15:2697-2707. [PMID: 38427597 PMCID: PMC10946646 DOI: 10.1021/acs.jpclett.3c03586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/03/2024]
Abstract
Describing long-range energy transport is a crucial step, both toward deepening our knowledge on natural light-harvesting systems and toward developing novel photoactive materials. Here, we combine experiment and theory to resolve and reproduce energy transport on pico- to nanosecond time scales in single H-type supramolecular nanofibers based on carbonyl-bridged triarylamines (CBT). Each nanofiber shows energy transport dynamics over long distances up to ∼1 μm, despite exciton trapping at specific positions along the nanofibers. Using a minimal Frenkel exciton model including disorder, we demonstrate that spatial correlations in the normally distributed site energies are crucial to reproduce the experimental data. In particular, we can observe the long-range and subdiffusive nature of the exciton dynamics as well as the trapping behavior of excitons in specific locations of the nanofiber. This trapping behavior introduces a net directionality or asymmetry in the exciton dynamics as observed experimentally.
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Affiliation(s)
- Alberto Carta
- Materials
Theory, Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Bernd Wittmann
- Spectroscopy
of Soft Matter, University of Bayreuth, 95440 Bayreuth, Germany
| | - Klaus Kreger
- Macromolecular
Chemistry and Bavarian Polymer Institute, University of Bayreuth, 95440 Bayreuth, Germany
| | - Hans-Werner Schmidt
- Macromolecular
Chemistry and Bavarian Polymer Institute, University of Bayreuth, 95440 Bayreuth, Germany
| | - Thomas L. C. Jansen
- Zernike
Institute for Advanced Materials, University
of Groningen, 9747 AG Groningen, The Netherlands
| | - Richard Hildner
- Zernike
Institute for Advanced Materials, University
of Groningen, 9747 AG Groningen, The Netherlands
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2
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Kurilovich AA, Mantsevich VN, Chechkin AV, Palyulin VV. Negative diffusion of excitons in quasi-two-dimensional systems. Phys Chem Chem Phys 2024; 26:922-935. [PMID: 38088027 DOI: 10.1039/d3cp03521b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
We show how two different mobile-immobile type models explain the observation of negative diffusion of excitons reported in experimental studies in quasi-two-dimensional semiconductor systems. The main reason for the effect is the initial trapping and a delayed release of free excitons in the area close to the original excitation spot. The density of trapped excitons is not registered experimentally. Hence, the signal from the free excitons alone includes the delayed release of not diffusing trapped particles. This is seen as the narrowing of the exciton density profile or decrease of mean-squared displacement which is then interpreted as a negative diffusion. The effect is enhanced with the increase of recombination intensity as well as the rate of the exciton-exciton binary interactions.
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Affiliation(s)
- Aleksandr A Kurilovich
- Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, 121205, Moscow, Russia
| | - Vladimir N Mantsevich
- Chair of Semiconductors and Cryoelectronics, Physics department, Lomonosov Moscow State University, 119991, Moscow, Russia
| | - Aleksei V Chechkin
- Faculty of Pure and Applied Mathematics, Hugo Steinhaus Center, Wroclaw University of Science and Technology, Wyspianskiego 27, 50-370 Wroclaw, Poland
- Institute for Physics & Astronomy, University of Potsdam, D-14476 Potsdam-Golm, Germany
- Akhiezer Institute for Theoretical Physics National Science Center "Kharkov Institute of Physics and Technology", 61108, Kharkov, Ukraine
| | - Vladimir V Palyulin
- Applied AI centre, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, Moscow, 121205, Russia.
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3
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Stäter S, Wenzel FA, Welz H, Kreger K, Köhler J, Schmidt HW, Hildner R. Directed Gradients in the Excited-State Energy Landscape of Poly(3-hexylthiophene) Nanofibers. J Am Chem Soc 2023. [PMID: 37315116 DOI: 10.1021/jacs.3c02117] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Funneling excitation energy toward lower energy excited states is a key concept in photosynthesis, which is often realized with at most two chemically different types of pigment molecules. However, current synthetic approaches to establish energy funnels, or gradients, typically rely on Förster-type energy-transfer cascades along many chemically different molecules. Here, we demonstrate an elegant concept for a gradient in the excited-state energy landscape along micrometer-long supramolecular nanofibers based on the conjugated polymer poly(3-hexylthiophene), P3HT, as the single component. Precisely aligned P3HT nanofibers within a supramolecular superstructure are prepared by solution processing involving an efficient supramolecular nucleating agent. Employing hyperspectral imaging, we find that the lowest-energy exciton band edge continuously shifts to lower energies along the nanofibers' growth direction. We attribute this directed excited-state energy gradient to defect fractionation during nanofiber growth. Our concept provides guidelines for the design of supramolecular structures with an intrinsic energy gradient for nanophotonic applications.
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Affiliation(s)
- Sebastian Stäter
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Felix A Wenzel
- Macromolecular Chemistry I and Bavarian Polymer Institute, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Hannes Welz
- Macromolecular Chemistry I and Bavarian Polymer Institute, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Klaus Kreger
- Macromolecular Chemistry I and Bavarian Polymer Institute, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Jürgen Köhler
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
- Bavarian Polymer Institute and Bayreuther Institut für Makromolekülforschung (BIMF), University of Bayreuth, 95440 Bayreuth, Germany
| | - Hans-Werner Schmidt
- Macromolecular Chemistry I and Bavarian Polymer Institute, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Richard Hildner
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
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4
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Kurilovich AA, Mantsevich VN, Mardoukhi Y, Stevenson KJ, Chechkin AV, Palyulin VV. Non-Markovian diffusion of excitons in layered perovskites and transition metal dichalcogenides. Phys Chem Chem Phys 2022; 24:13941-13950. [PMID: 35621272 DOI: 10.1039/d2cp00557c] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The diffusion of excitons in perovskites and transition metal dichalcogenides shows clear anomalous, subdiffusive behaviour in experiments. In this paper we develop a non-Markovian mobile-immobile model which provides an explanation of this behaviour through paired theoretical and simulation approaches. The simulation model is based on a random walk on a 2D lattice with randomly distributed deep traps such that the trapping time distribution involves slowly decaying power-law asymptotics. The theoretical model uses coupled diffusion and rate equations for free and trapped excitons, respectively, with an integral term responsible for trapping. The model provides a good fitting of the experimental data, thus, showing a way for quantifying the exciton diffusion dynamics.
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Affiliation(s)
- Aleksandr A Kurilovich
- Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, 121205, Moscow, Russia
| | - Vladimir N Mantsevich
- Chair of Semiconductors and Cryoelectronics & Quantum Technology Center, Physics Department, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Yousof Mardoukhi
- Institute for Physics & Astronomy, University of Potsdam, D-14476 Potsdam-Golm, Germany
| | - Keith J Stevenson
- Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, 121205, Moscow, Russia
| | - Aleksei V Chechkin
- Institute for Physics & Astronomy, University of Potsdam, D-14476 Potsdam-Golm, Germany.,Faculty of Pure and Applied Mathematics, Hugo Steinhaus Center, Wroclaw University of Science and Technology, Wyspianskiego 27, 50-370 Wroclaw, Poland.,Akhiezer Institute for Theoretical Physics National Science Center "Kharkov Institute of Physics and Technology", 61108, Kharkov, Ukraine
| | - Vladimir V Palyulin
- RAIC Center, Skolkovo Institute of Science and Technology, 121205, Moscow, Russia.
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5
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Wittmann B, Biskup T, Kreger K, Köhler J, Schmidt HW, Hildner R. All-optical manipulation of singlet exciton transport in individual supramolecular nanostructures by triplet gating. NANOSCALE HORIZONS 2021; 6:998-1005. [PMID: 34731228 DOI: 10.1039/d1nh00514f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Directed transport of singlet excitation energy is a key process in natural light-harvesting systems and a desired feature in assemblies of functional organic molecules for organic electronics and nanotechnology applications. However, progress in this direction is hampered by the lack of concepts and model systems. Here we demonstrate an all-optical approach to manipulate singlet exciton transport pathways within supramolecular nanostructures via singlet-triplet annihilation, i.e., to enforce an effective motion of singlet excitons along a predefined direction. For this proof-of-concept, we locally photo-generate a long-lived triplet exciton population and subsequently a singlet exciton population on single bundles of H-type supramolecular nanofibres using two temporally and spatially separated laser pulses. The local triplet exciton population operates as a gate for the singlet exciton transport since singlet-triplet annihilation hinders singlet exciton motion across the triplet population. We visualize this manipulation of singlet exciton transport via the fluorescence signal from the singlet excitons, using a detection-beam scanning approach combined with time-correlated single-photon counting. Our reversible, all-optical manipulation of singlet exciton transport can pave the way to realising new design principles for functional photonic nanodevices.
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Affiliation(s)
- Bernd Wittmann
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Till Biskup
- Institute of Physical Chemistry, University of Freiburg, Albertstraße 21, 79104 Freiburg, Germany
| | - Klaus Kreger
- Macromolecular Chemistry I, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
- Bavarian Polymer Institute, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Jürgen Köhler
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
- Bavarian Polymer Institute, Universitätsstraße 30, 95447 Bayreuth, Germany
- Bayreuth Institute of Macromolecular Research (BIMF), University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Hans-Werner Schmidt
- Macromolecular Chemistry I, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
- Bavarian Polymer Institute, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Richard Hildner
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
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6
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Kunsel T, Jansen TLC, Knoester J. Scaling relations of exciton diffusion in linear aggregates with static and dynamic disorder. J Chem Phys 2021; 155:134305. [PMID: 34624980 DOI: 10.1063/5.0065206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Exciton diffusion plays an important role in many opto-electronic processes and phenomena. Understanding the interplay of intermolecular coupling, static energetic disorder, and dephasing caused by environmental fluctuations (dynamic disorder) is crucial to optimize exciton diffusion under various physical conditions. We report on a systematic analysis of the exciton diffusion constant in linear aggregates using the Haken-Strobl-Reineker model to describe this interplay. We numerically investigate the static-disorder scaling of (i) the diffusion constant in the limit of small dephasing rate, (ii) the dephasing rate at which the diffusion is optimized, and (iii) the value of the diffusion constant at the optimal dephasing rate. Three scaling regimes are found, associated with, respectively, fully delocalized exciton states (finite-size effects), weakly localized states, and strongly localized states. The scaling powers agree well with analytically estimated ones. In particular, in the weakly localized regime, the numerical results corroborate the so-called quantum Goldilocks principle to find the optimal dephasing rate and maximum diffusion constant as a function of static disorder, while in the strong-localization regime, these quantities can be derived fully analytically.
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Affiliation(s)
- T Kunsel
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - T L C Jansen
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - J Knoester
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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7
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Pandya R, Alvertis AM, Gu Q, Sung J, Legrand L, Kréher D, Barisien T, Chin AW, Schnedermann C, Rao A. Exciton Diffusion in Highly-Ordered One Dimensional Conjugated Polymers: Effects of Back-Bone Torsion, Electronic Symmetry, Phonons and Annihilation. J Phys Chem Lett 2021; 12:3669-3678. [PMID: 33829788 PMCID: PMC8154834 DOI: 10.1021/acs.jpclett.1c00193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
Many optoelectronic devices based on organic materials require rapid and long-range singlet exciton transport. Key factors controlling exciton transport include material structure, exciton-phonon coupling and electronic state symmetry. Here, we employ femtosecond transient absorption microscopy to study the influence of these parameters on exciton transport in one-dimensional conjugated polymers. We find that excitons with 21Ag- symmetry and a planar backbone exhibit a significantly higher diffusion coefficient (34 ± 10 cm2 s-1) compared to excitons with 11Bu+ symmetry (7 ± 6 cm2 s-1) with a twisted backbone. We also find that exciton transport in the 21Ag- state occurs without exciton-exciton annihilation. Both 21Ag- and 11Bu+ states are found to exhibit subdiffusive behavior. Ab initio GW-BSE calculations reveal that this is due to the comparable strengths of the exciton-phonon interaction and exciton coupling. Our results demonstrate the link between electronic state symmetry, backbone torsion and phonons in exciton transport in π-conjugated polymers.
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Affiliation(s)
- Raj Pandya
- Cavendish
Laboratory, University of Cambridge, J.J. Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
| | - Antonios M. Alvertis
- Cavendish
Laboratory, University of Cambridge, J.J. Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
| | - Qifei Gu
- Cavendish
Laboratory, University of Cambridge, J.J. Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
| | - Jooyoung Sung
- Cavendish
Laboratory, University of Cambridge, J.J. Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
| | - Laurent Legrand
- Sorbonne
Université, CNRS, Institut
des NanoSciences de Paris, INSP, 4 place Jussieu, F-75005 Paris, France
| | - David Kréher
- Sorbonne
Université, CNRS, Institut
Parisien de Chimie Moléculaire (IPCM) UMR 8232, Chimie des
Polymères, 4 Place
Jussieu, 75005 Paris, France
| | - Thierry Barisien
- Sorbonne
Université, CNRS, Institut
des NanoSciences de Paris, INSP, 4 place Jussieu, F-75005 Paris, France
| | - Alex W. Chin
- Sorbonne
Université, CNRS, Institut
des NanoSciences de Paris, INSP, 4 place Jussieu, F-75005 Paris, France
| | - Christoph Schnedermann
- Cavendish
Laboratory, University of Cambridge, J.J. Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
| | - Akshay Rao
- Cavendish
Laboratory, University of Cambridge, J.J. Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
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8
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Wittmann B, Wiesneth S, Motamen S, Simon L, Serein-Spirau F, Reiter G, Hildner R. Energy transport and light propagation mechanisms in organic single crystals. J Chem Phys 2020; 153:144202. [PMID: 33086831 DOI: 10.1063/5.0019832] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Unambiguous information about spatiotemporal exciton dynamics in three-dimensional nanometer- to micrometer-sized organic structures is difficult to obtain experimentally. Exciton dynamics can be modified by annihilation processes, and different light propagation mechanisms can take place, such as active waveguiding and photon recycling. Since these various processes and mechanisms can lead to similar spectroscopic and microscopic signatures on comparable time scales, their discrimination is highly demanding. Here, we study individual organic single crystals grown from thiophene-based oligomers. We use time-resolved detection-beam scanning microscopy to excite a local singlet exciton population and monitor the subsequent broadening of the photoluminescence (PL) signal in space and on pico- to nanosecond time scales. Combined with Monte Carlo simulations, we were able to exclude photon recycling for our system, whereas leakage radiation upon active waveguiding leads to an apparent PL broadening of about 20% compared to the initial excitation profile. Exciton-exciton annihilation becomes important at high excitation fluence and apparently accelerates the exciton dynamics leading to apparently increased diffusion lengths. At low excitation fluences, the spatiotemporal PL broadening results from singlet exciton diffusion with diffusion lengths of up to 210 nm. Surprisingly, even in structurally highly ordered single crystals, the transport dynamics is subdiffusive and shows variations between different crystals, which we relate to varying degrees of static and dynamic electronic disorders.
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Affiliation(s)
- Bernd Wittmann
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Stephan Wiesneth
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Sajedeh Motamen
- Institute of Physics, University of Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany
| | - Laurent Simon
- Université de Strasbourg (UdS)-Université de Haute Alsace (UHA), Institut de Science des Matériaux de Mulhouse (IS2M), UMR 7361-CNRS, 3bis rue Alfred Werner, 68093 Mulhouse, France
| | - Françoise Serein-Spirau
- Institut Charles Gerhardt de Montpellier, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, UMR 5353-CNRS, Equipe Architectures Moleculaires et Materiaux Nanostructures (AM2N), 8 Rue de l'Ecole Normale, 34090 Montpellier Cedex 05, France
| | - Günter Reiter
- Institute of Physics, University of Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany
| | - Richard Hildner
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
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9
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Wittmann B, Wenzel FA, Wiesneth S, Haedler AT, Drechsler M, Kreger K, Köhler J, Meijer EW, Schmidt HW, Hildner R. Enhancing Long-Range Energy Transport in Supramolecular Architectures by Tailoring Coherence Properties. J Am Chem Soc 2020; 142:8323-8330. [PMID: 32279503 PMCID: PMC7212519 DOI: 10.1021/jacs.0c01392] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
Efficient
long-range energy transport along supramolecular architectures
of functional organic molecules is a key step in nature for converting
sunlight into a useful form of energy. Understanding and manipulating
these transport processes on a molecular and supramolecular scale
is a long-standing goal. However, the realization of a well-defined
system that allows for tuning morphology and electronic properties
as well as for resolution of transport in space and time is challenging.
Here we show how the excited-state energy landscape and thus the coherence
characteristics of electronic excitations can be modified by the hierarchical
level of H-type supramolecular architectures. We visualize, at room
temperature, long-range incoherent transport of delocalized singlet
excitons on pico- to nanosecond time scales in single supramolecular
nanofibers and bundles of nanofibers. Increasing the degree of coherence,
i.e., exciton delocalization, via supramolecular architectures enhances
exciton diffusivities up to 1 order of magnitude. In particular, we
find that single supramolecular nanofibers exhibit the highest diffusivities
reported for H-aggregates so far.
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Affiliation(s)
- Bernd Wittmann
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Felix A Wenzel
- Macromolecular Chemistry and Bavarian Polymer Institute, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany.,Institute for Complex Molecular Systems, Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands
| | - Stephan Wiesneth
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Andreas T Haedler
- Macromolecular Chemistry and Bavarian Polymer Institute, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany.,Institute for Complex Molecular Systems, Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands
| | - Markus Drechsler
- Bavarian Polymer Institute, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Klaus Kreger
- Macromolecular Chemistry and Bavarian Polymer Institute, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Jürgen Köhler
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - E W Meijer
- Institute for Complex Molecular Systems, Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands
| | - Hans-Werner Schmidt
- Macromolecular Chemistry and Bavarian Polymer Institute, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Richard Hildner
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany.,Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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10
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Morisue M, Omagari S, Ueno I, Nakanishi T, Hasegawa Y, Yamamoto S, Matsui J, Sasaki S, Hikima T, Sakurai S. Fully Conjugated Porphyrin Glass: Collective Light-Harvesting Antenna for Near-Infrared Fluorescence beyond 1 μm. ACS OMEGA 2018; 3:4466-4474. [PMID: 30023894 PMCID: PMC6044875 DOI: 10.1021/acsomega.8b00566] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 04/18/2018] [Indexed: 06/08/2023]
Abstract
Expanded π-systems with a narrow highest occupied molecular orbital-lowest unoccupied molecular orbital band gap encounter deactivation of excitons due to the "energy gap law" and undesired aggregation. This dilemma generally thwarts the near-infrared (NIR) luminescence of organic π-systems. A sophisticated cofacially stacked π-system is known to involve exponentially tailed disorder, which displays exceptionally red-shifted fluorescence even as only a marginal emission component. Enhancement of the tail-state fluorescence might be advantageous to achieve NIR photoluminescence with an expected collective light-harvesting antenna effect as follows: (i) efficient light-harvesting capacity due to intense electronic absorption, (ii) a long-distance exciton migration into the tail state based on a high spatial density of the chromophore site, and (iii) substantial transmission of NIR emission to circumvent the inner filter effect. Suppression of aggregation-induced quenching of fluorescence could realize collective light-harvesting antenna for NIR-luminescence materials. This study discloses an enhanced tail-state NIR fluorescence of a self-standing porphyrin film at 1138 nm with a moderate quantum efficiency based on a fully π-conjugated porphyrin that adopts an amorphous form, called "porphyrin glass".
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Affiliation(s)
- Mitsuhiko Morisue
- Faculty
of Molecular Chemistry and Engineering and Faculty of Fiber Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Shun Omagari
- Graduate
School of Engineering, Hokkaido University, North 13 West 8, Kita-ku, Sapporo 060-8628, Japan
| | - Ikuya Ueno
- Faculty
of Molecular Chemistry and Engineering and Faculty of Fiber Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Takayuki Nakanishi
- Graduate
School of Engineering, Hokkaido University, North 13 West 8, Kita-ku, Sapporo 060-8628, Japan
| | - Yasuchika Hasegawa
- Graduate
School of Engineering, Hokkaido University, North 13 West 8, Kita-ku, Sapporo 060-8628, Japan
| | - Shunsuke Yamamoto
- Institute
of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Jun Matsui
- Department
of Science, Yamagata University, Kojirakawa-cho, Yamagata 990-8560, Japan
| | - Sono Sasaki
- Faculty
of Molecular Chemistry and Engineering and Faculty of Fiber Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Takaaki Hikima
- RIKEN SPring-8
Center, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Shinichi Sakurai
- Faculty
of Molecular Chemistry and Engineering and Faculty of Fiber Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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11
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Méndez-Bermúdez JA, Aguilar-Sánchez R. Information-Length Scaling in a Generalized One-Dimensional Lloyd's Model. ENTROPY 2018; 20:e20040300. [PMID: 33265391 PMCID: PMC7512818 DOI: 10.3390/e20040300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 03/29/2018] [Accepted: 04/08/2018] [Indexed: 01/28/2023]
Abstract
We perform a detailed numerical study of the localization properties of the eigenfunctions of one-dimensional (1D) tight-binding wires with on-site disorder characterized by long-tailed distributions: For large ϵ , P ( ϵ ) ∼ 1 / ϵ 1 + α with α ∈ ( 0 , 2 ] ; where ϵ are the on-site random energies. Our model serves as a generalization of 1D Lloyd's model, which corresponds to α = 1 . In particular, we demonstrate that the information length β of the eigenfunctions follows the scaling law β = γ x / ( 1 + γ x ) , with x = ξ / L and γ ≡ γ ( α ) . Here, ξ is the eigenfunction localization length (that we extract from the scaling of Landauer's conductance) and L is the wire length. We also report that for α = 2 the properties of the 1D Anderson model are effectively reproduced.
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Affiliation(s)
- J. A. Méndez-Bermúdez
- Instituto de Física, Benemérita Universidad Autónoma de Puebla, Puebla 72570, Mexico
- Correspondence: ; Tel.: +52-222-229-5610
| | - R. Aguilar-Sánchez
- Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570, Mexico
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12
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Hestand NJ, Spano FC. Expanded Theory of H- and J-Molecular Aggregates: The Effects of Vibronic Coupling and Intermolecular Charge Transfer. Chem Rev 2018; 118:7069-7163. [PMID: 29664617 DOI: 10.1021/acs.chemrev.7b00581] [Citation(s) in RCA: 727] [Impact Index Per Article: 121.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The electronic excited states of molecular aggregates and their photophysical signatures have long fascinated spectroscopists and theoreticians alike since the advent of Frenkel exciton theory almost 90 years ago. The influence of molecular packing on basic optical probes like absorption and photoluminescence was originally worked out by Kasha for aggregates dominated by Coulombic intermolecular interactions, eventually leading to the classification of J- and H-aggregates. This review outlines advances made in understanding the relationship between aggregate structure and photophysics when vibronic coupling and intermolecular charge transfer are incorporated. An assortment of packing geometries is considered from the humble molecular dimer to more exotic structures including linear and bent aggregates, two-dimensional herringbone and "HJ" aggregates, and chiral aggregates. The interplay between long-range Coulomb coupling and short-range charge-transfer-mediated coupling strongly depends on the aggregate architecture leading to a wide array of photophysical behaviors.
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Affiliation(s)
- Nicholas J Hestand
- Department of Chemistry , Temple University , Philadelphia , Pennsylvania 19122 , United States
| | - Frank C Spano
- Department of Chemistry , Temple University , Philadelphia , Pennsylvania 19122 , United States
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13
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Lüer L, Rajendran SK, Stoll T, Ganzer L, Rehault J, Coles DM, Lidzey D, Virgili T, Cerullo G. Lévy Defects in Matrix-Immobilized J Aggregates: Tracing Intra-and Intersegmental Exciton Relaxation. J Phys Chem Lett 2017; 8:547-552. [PMID: 28045534 DOI: 10.1021/acs.jpclett.6b02704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
One-dimensional J aggregates present narrow and intense absorption and emission spectra that are interesting for photonics applications. Matrix immobilization of the aggregates, as required for most device architectures, has recently been shown to induce a non-Gaussian (Lévy type) defect distribution with heavy tails, expected to influence exciton relaxation. Here we perform two-dimensional electronic spectroscopy (2DES) in one-dimensional J aggregates of the cyanine dye TDBC, immobilized in a gel matrix, and we quantitatively model 2DES maps by nonlinear optimization coupled to quantum mechanical calculations of the transient excitonic response. We find that immobilization causes strong non-Gaussian off-diagonal disorder, leading to a segmentation of the chains. Intersegmental exciton transfer is found to proceed on the picosecond time scale, causing a long-lasting excitation memory. These findings can be used to inform the design of optoelectronic devices based on J aggregates as they allow for control of exciton properties by disorder management.
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Affiliation(s)
- Larry Lüer
- IMDEA Nanociencia , C/Faraday 9, 28049 Cantoblanco, Madrid, Spain
| | - Sai Kiran Rajendran
- Dipartimento di Fisica, IFN-CNR , Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
- School of Physics and Astronomy, University of St. Andrews , St. Andrews, Fife KY16 9SS, United Kingdom
| | - Tatjana Stoll
- Dipartimento di Fisica, IFN-CNR , Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
| | - Lucia Ganzer
- Dipartimento di Fisica, IFN-CNR , Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
| | - Julien Rehault
- Dipartimento di Fisica, IFN-CNR , Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
- Paul Scherrer Institut , 5232 Villigen PSI, Switzerland
| | - David M Coles
- Department of Physics and Astronomy, University of Sheffield , Sheffield S3 7RH, United Kingdom
| | - David Lidzey
- Department of Physics and Astronomy, University of Sheffield , Sheffield S3 7RH, United Kingdom
| | - Tersilla Virgili
- Dipartimento di Fisica, IFN-CNR , Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
| | - Giulio Cerullo
- Dipartimento di Fisica, IFN-CNR , Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
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14
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Méndez-Bermúdez JA, Martínez-Mendoza AJ, Gopar VA, Varga I. Lloyd-model generalization: Conductance fluctuations in one-dimensional disordered systems. Phys Rev E 2016; 93:012135. [PMID: 26871052 DOI: 10.1103/physreve.93.012135] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Indexed: 11/07/2022]
Abstract
We perform a detailed numerical study of the conductance G through one-dimensional (1D) tight-binding wires with on-site disorder. The random configurations of the on-site energies ε of the tight-binding Hamiltonian are characterized by long-tailed distributions: For large ε, P(ε)∼1/ε^{1+α} with α∈(0,2). Our model serves as a generalization of the 1D Lloyd model, which corresponds to α=1. First, we verify that the ensemble average 〈-lnG〉 is proportional to the length of the wire L for all values of α, providing the localization length ξ from 〈-lnG〉=2L/ξ. Then, we show that the probability distribution function P(G) is fully determined by the exponent α and 〈-lnG〉. In contrast to 1D wires with standard white-noise disorder, our wire model exhibits bimodal distributions of the conductance with peaks at G=0 and 1. In addition, we show that P(lnG) is proportional to G^{β}, for G→0, with β≤α/2, in agreement with previous studies.
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Affiliation(s)
- J A Méndez-Bermúdez
- Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado Postal J-48, Puebla 72570, Mexico
| | - A J Martínez-Mendoza
- Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado Postal J-48, Puebla 72570, Mexico.,Elméleti Fizika Tanszék, Fizikai Intézet, Budapesti Műszaki és Gazdaságtudományi Egyetem, H-1521 Budapest, Hungary
| | - V A Gopar
- Departamento de Física Teórica, Facultad de Ciencias, and BIFI, Universidad de Zaragoza, Pedro Cerbuna 12, E-50009, Zaragoza, Spain
| | - I Varga
- Elméleti Fizika Tanszék, Fizikai Intézet, Budapesti Műszaki és Gazdaságtudományi Egyetem, H-1521 Budapest, Hungary
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15
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Abstract
Recent experiments aimed at probing the dynamics of excitons have revealed that semiconducting films composed of disordered molecular subunits, unlike expectations for their perfectly ordered counterparts, can exhibit a time-dependent diffusivity in which the effective early time diffusion constant is larger than that of the steady state. This observation has led to speculation about what role, if any, microscopic disorder may play in enhancing exciton transport properties. In this article, we present the results of a model study aimed at addressing this point. Specifically, we introduce a general model, based upon Förster theory, for incoherent exciton diffusion in a material composed of independent molecular subunits with static energetic disorder. Energetic disorder leads to heterogeneity in molecule-to-molecule transition rates, which we demonstrate has two important consequences related to exciton transport. First, the distribution of local site-specific hopping rates is broadened in a manner that results in a decrease in average exciton diffusivity relative to that in a perfectly ordered film. Second, since excitons prefer to make transitions that are downhill in energy, the steady state distribution of exciton energies is biased toward low-energy molecular subunits, those that exhibit reduced diffusivity relative to a perfectly ordered film. These effects combine to reduce the net diffusivity in a manner that is time dependent and grows more pronounced as disorder is increased. Notably, however, we demonstrate that the presence of energetic disorder can give rise to a population of molecular subunits with exciton transfer rates exceeding those of subunits in an energetically uniform material. Such enhancements may play an important role in processes that are sensitive to molecular-scale fluctuations in exciton density field.
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Affiliation(s)
- Elizabeth M Y Lee
- †Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - William A Tisdale
- †Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Adam P Willard
- ‡Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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16
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Schönleber DW, Eisfeld A, Genkin M, Whitlock S, Wüster S. Quantum simulation of energy transport with embedded Rydberg aggregates. PHYSICAL REVIEW LETTERS 2015; 114:123005. [PMID: 25860741 DOI: 10.1103/physrevlett.114.123005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Indexed: 06/04/2023]
Abstract
We show that an array of ultracold Rydberg atoms embedded in a laser driven background gas can serve as an aggregate for simulating exciton dynamics and energy transport with a controlled environment. Energetic disorder and decoherence introduced by the interaction with the background gas atoms can be controlled by the laser parameters. This allows for an almost ideal realization of a Haken-Reineker-Strobl-type model for energy transport. The transport can be monitored using the same mechanism that provides control over the environment. The degree of decoherence is traced back to information gained on the excitation location through the monitoring, turning the setup into an experimentally accessible model system for studying the effects of quantum measurements on the dynamics of a many-body quantum system.
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Affiliation(s)
- D W Schönleber
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
| | - A Eisfeld
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
| | - M Genkin
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
| | - S Whitlock
- Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
| | - S Wüster
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
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17
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Aragó J, Troisi A. Dynamics of the excitonic coupling in organic crystals. PHYSICAL REVIEW LETTERS 2015; 114:026402. [PMID: 25635554 DOI: 10.1103/physrevlett.114.026402] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Indexed: 05/22/2023]
Abstract
We show that the excitonic coupling in molecular crystals undergoes a very large fluctuation at room temperature as a result of the combined thermal motions of the nuclei. This observation dramatically affects the description of exciton transport in organic crystals and any other phenomenon (like singlet fission or exciton dissociation) that originates from an exciton in a molecular crystal or thin film. This unexpected result is due to the predominance of the short-range excitonic coupling mechanisms (exchange, overlap, and charge-transfer mediated) over the Coulombic excitonic coupling for molecules in van der Waals contact. To quantify this effect we develop a procedure to evaluate accurately the short-range excitonic coupling (via a diabatization scheme) along a molecular dynamics trajectory of the representative molecular crystals of anthracene and tetracene.
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Affiliation(s)
- Juan Aragó
- Department of Chemistry and Centre for Scientific Computing, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Alessandro Troisi
- Department of Chemistry and Centre for Scientific Computing, University of Warwick, Coventry CV4 7AL, United Kingdom
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18
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Merdasa A, Jiménez ÁJ, Camacho R, Meyer M, Würthner F, Scheblykin IG. Single Lévy states-disorder induced energy funnels in molecular aggregates. NANO LETTERS 2014; 14:6774-6781. [PMID: 25349900 DOI: 10.1021/nl5021188] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Using fluorescence super-resolution microscopy we studied simultaneous spectral, spatial localization, and blinking behavior of individual 1D J-aggregates. Excitons migrating 100 nm are funneled to a trap appearing as an additional red-shifted blinking fluorescence band. We propose that the trap is a Frenkel exciton state formed much below the main exciton band edge due to an environmentally induced heavy-tailed Lévy disorder. This points to disorder engineering as a new avenue in controlling light-harvesting in molecular ensembles.
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Affiliation(s)
- Aboma Merdasa
- Chemical Physics, Lund University , P.O. Box 124, 22100 Lund, Sweden
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19
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Visualization of exciton transport in ordered and disordered molecular solids. Nat Commun 2014; 5:3646. [DOI: 10.1038/ncomms4646] [Citation(s) in RCA: 220] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 03/13/2014] [Indexed: 12/25/2022] Open
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20
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Genway S, Lesanovsky I, Garrahan JP. Localization in space and time in disordered-lattice open quantum dynamics. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:042129. [PMID: 24827214 DOI: 10.1103/physreve.89.042129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Indexed: 06/03/2023]
Abstract
We study a two-dimensional tight-binding lattice for excitons with on-site disorder, coupled to a thermal environment at infinite temperature. The disorder acts to localize an exciton spatially, while the environment generates dynamics which enable exploration of the lattice. Although the steady state of the system is trivially uniform, we observe a rich dynamics and uncover a dynamical phase transition in the space of temporal trajectories. This transition is identified as a localization in the dynamics generated by the bath. We explore spatial features in the dynamics and employ a generalization of the inverse participation ratio to deduce an ergodic timescale for the lattice.
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Affiliation(s)
- Sam Genway
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Igor Lesanovsky
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Juan P Garrahan
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
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21
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Abstract
The photophysical behavior of organic semiconductors is governed by their excitonic states. In this review, I classify the three different exciton types (Frenkel singlet, Frenkel triplet, and charge transfer) typically encountered in organic semiconductors. Experimental challenges that arise in the study of solid-state organic systems are discussed. The steady-state spectroscopy of intermolecular delocalized Frenkel excitons is described, using crystalline tetracene as an example. I consider the problem of a localized exciton diffusing in a disordered matrix in detail, and experimental results on conjugated polymers and model systems suggest that energetic disorder leads to subdiffusive motion. Multiexciton processes such as singlet fission and triplet fusion are described, emphasizing the role of spin state coherence and magnetic fields in studying singlet ↔ triplet pair interconversion. Singlet fission provides an example of how all three types of excitons (triplet, singlet, and charge transfer) may interact to produce useful phenomena for applications such as solar energy conversion.
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