1
|
Fischermeier D, Turkin A, Selby J, Lambert C, Mitrić R. Simulation of exciton spectra in disordered supramolecular polymers: exciton localization in cisoid indolenine squaraine hexamers. Phys Chem Chem Phys 2023; 26:219-229. [PMID: 38055887 DOI: 10.1039/d3cp04557a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
In order to understand the effects of disorder and defects in oligomers and polymers on the localization of excitons, we investigated the spectral properties of the squaraine B hexamer using long range corrected tight-binding TDDFT (lc-TDDFTB) and Frenkel-exciton model based calculations. Employing classical molecular dynamics, the cisoid indolenine squaraine hexamers helix was propagated in DCM and acetone to obtain ensembles of realistic structures, which naturally exhibit considerable disorder. The trajectories together with several model squaraine systems were studied to show the profound effects of disorder in the superstructure and disorder of the local monomer geometry on optical properties like absorption and exciton localization. We further compared lc-TDDFTB and exciton theory derived spectral data to related experimental data on absorption, exciton transfer and localization in squaraine polymers and oligomers.
Collapse
Affiliation(s)
- David Fischermeier
- Institut für Physikalische und Theoretische Chemie, Julius-Maximilians-Universität Würzburg, Emil-Fischer-Str. 42, 97074 Würzburg, Germany.
| | - Arthur Turkin
- Institut für Organische Chemie, Universitüt Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Joshua Selby
- Institut für Organische Chemie, Universitüt Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Christoph Lambert
- Institut für Organische Chemie, Universitüt Würzburg, Am Hubland, D-97074 Würzburg, Germany.
- Center for Nanosystems Chemistry, Universität Würzburg, Theodor-Boveri-Weg, D-97074 Würzburg, Germany
| | - Roland Mitrić
- Institut für Physikalische und Theoretische Chemie, Julius-Maximilians-Universität Würzburg, Emil-Fischer-Str. 42, 97074 Würzburg, Germany.
| |
Collapse
|
2
|
Dimitriev OP. Dynamics of Excitons in Conjugated Molecules and Organic Semiconductor Systems. Chem Rev 2022; 122:8487-8593. [PMID: 35298145 DOI: 10.1021/acs.chemrev.1c00648] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The exciton, an excited electron-hole pair bound by Coulomb attraction, plays a key role in photophysics of organic molecules and drives practically important phenomena such as photoinduced mechanical motions of a molecule, photochemical conversions, energy transfer, generation of free charge carriers, etc. Its behavior in extended π-conjugated molecules and disordered organic films is very different and very rich compared with exciton behavior in inorganic semiconductor crystals. Due to the high degree of variability of organic systems themselves, the exciton not only exerts changes on molecules that carry it but undergoes its own changes during all phases of its lifetime, that is, birth, conversion and transport, and decay. The goal of this review is to give a systematic and comprehensive view on exciton behavior in π-conjugated molecules and molecular assemblies at all phases of exciton evolution with emphasis on rates typical for this dynamic picture and various consequences of the above dynamics. To uncover the rich variety of exciton behavior, details of exciton formation, exciton transport, exciton energy conversion, direct and reverse intersystem crossing, and radiative and nonradiative decay are considered in different systems, where these processes lead to or are influenced by static and dynamic disorder, charge distribution symmetry breaking, photoinduced reactions, electron and proton transfer, structural rearrangements, exciton coupling with vibrations and intermediate particles, and exciton dissociation and annihilation as well.
Collapse
Affiliation(s)
- Oleg P Dimitriev
- V. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine, pr. Nauki 41, Kyiv 03028, Ukraine
| |
Collapse
|
3
|
Raicoski ML, Vivas MG. Photobleaching Kinetics of MEH-PPV in Solution: The Role of Conformational Disorder. J Phys Chem B 2021; 125:9887-9894. [PMID: 34415151 DOI: 10.1021/acs.jpcb.1c05498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Semiconductor polymers are the foundation of organic electronics due to their remarkable optical features, ability to form a thin film, and low cost compared to silicon. However, some of them have intense photobleaching under UV-blue radiation, compromising several applications. In this context, we have investigated the conformational disorder effect on the real-time photobleaching kinetics of a poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV)/chloroform solution under deep-blue radiation. Our results pointed out that a 405 nm diode laser initially causes a significant conformational disorder in the π-conjugated backbone of MEH-PPV as revealed by the Huang-Rhys factor. As a result, a new vibrational mode arises with an energy separation of 230 meV, indicating the substitution of the vinyl (C═C) by carbonyl (C═O) bonds. Then, the conformational disorder reaches a maximum value at some tens of minutes, which is inversely proportional to the polymer concentration, and after that, a random chain scission occurs. Consequently, the effective conjugation length of MEH-PPV in chloroform decreases from nine to three coplanar repetitive units after 1 h of excitation, producing a drastic drop in photoluminescence. Finally, we show that the photobleaching steps are mapped through the conformational disorder.
Collapse
Affiliation(s)
- Michelle Leifeld Raicoski
- Laboratório de Espectroscopia Óptica e Fotônica, Universidade Federal de Alfenas, Poços de Caldas, MG 37715-400, Brazil
| | - Marcelo Gonçalves Vivas
- Laboratório de Espectroscopia Óptica e Fotônica, Universidade Federal de Alfenas, Poços de Caldas, MG 37715-400, Brazil
| |
Collapse
|
4
|
Photocathodes beyond NiO: charge transfer dynamics in a π-conjugated polymer functionalized with Ru photosensitizers. Sci Rep 2021; 11:2787. [PMID: 33531588 PMCID: PMC7854750 DOI: 10.1038/s41598-021-82395-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 01/19/2021] [Indexed: 11/09/2022] Open
Abstract
A conductive polymer (poly(p-phenylenevinylene), PPV) was covalently modified with RuII complexes to develop an all-polymer photocathode as a conceptual alternative to dye-sensitized NiO, which is the current state-of-the-art photocathode in solar fuels research. Photocathodes require efficient light-induced charge-transfer processes and we investigated these processes within our photocathodes using spectroscopic and spectro-electrochemical techniques. Ultrafast hole-injection dynamics in the polymer were investigated by transient absorption spectroscopy and charge transfer at the electrode-electrolyte interface was examined with chopped-light chronoamperometry. Light-induced hole injection from the photosensitizers into the PPV backbone was observed within 10 ps and the resulting charge-separated state (CSS) recombined within ~ 5 ns. This is comparable to CSS lifetimes of conventional NiO-photocathodes. Chopped-light chronoamperometry indicates enhanced charge-transfer at the electrode-electrolyte interface upon sensitization of the PPV with the RuII complexes and p-type behavior of the photocathode. The results presented here show that the polymer backbone behaves like classical molecularly sensitized NiO photocathodes and operates as a hole accepting semiconductor. This in turn demonstrates the feasibility of all-polymer photocathodes for application in solar energy conversion.
Collapse
|
5
|
Di Maiolo F, Brey D, Binder R, Burghardt I. Quantum dynamical simulations of intra-chain exciton diffusion in an oligo (para-phenylene vinylene) chain at finite temperature. J Chem Phys 2020; 153:184107. [PMID: 33187420 DOI: 10.1063/5.0027588] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We report on quantum dynamical simulations of exciton diffusion in an oligo(para-phenylene vinylene) chain segment with 20 repeat units (OPV-20) at finite temperature, complementary to our recent study of the same system at T = 0 K [R. Binder and I. Burghardt, J. Chem. Phys. 152, 204120 (2020)]. Accurate quantum dynamical simulations are performed using the multi-layer multi-configuration time-dependent Hartree method as applied to a site-based Hamiltonian comprising 20 electronic states of Frenkel type and 460 vibrational modes, including site-local quinoid-distortion modes along with site-correlated bond-length alternation (BLA) modes, ring torsional modes, and an explicit harmonic-oscillator bath. A first-principles parameterized Frenkel-Holstein type Hamiltonian is employed, which accounts for correlations between the ring torsional modes and the anharmonically coupled BLA coordinates located at the same junction. Thermally induced fluctuations of the torsional modes are described by a stochastic mean-field approach, and their impact on the excitonic motion is characterized in terms of the exciton mean-squared displacement. A normal diffusion regime is observed under periodic boundary conditions, apart from transient localization features. Even though the polaronic exciton species are comparatively weakly bound, exciton diffusion is found to be a coherent-rather than hopping type-process, driven by the fluctuations of the soft torsional modes. Similar to the previous observations for oligothiophenes, the evolution for the most part exhibits a near-adiabatic dynamics of local exciton ground states (LEGSs) that adjust to the local conformational dynamics. However, a second mechanism, involving resonant transitions between neighboring LEGSs, gains importance at higher temperatures.
Collapse
Affiliation(s)
- Francesco Di Maiolo
- Institute for Physical and Theoretical Chemistry, Goethe University, Max-von-Laue-Str. 7, 60438 Frankfurt/Main, Germany
| | - Dominik Brey
- Institute for Physical and Theoretical Chemistry, Goethe University, Max-von-Laue-Str. 7, 60438 Frankfurt/Main, Germany
| | - Robert Binder
- Institute for Physical and Theoretical Chemistry, Goethe University, Max-von-Laue-Str. 7, 60438 Frankfurt/Main, Germany
| | - Irene Burghardt
- Institute for Physical and Theoretical Chemistry, Goethe University, Max-von-Laue-Str. 7, 60438 Frankfurt/Main, Germany
| |
Collapse
|
6
|
Hegger R, Binder R, Burghardt I. First-Principles Quantum and Quantum-Classical Simulations of Exciton Diffusion in Semiconducting Polymer Chains at Finite Temperature. J Chem Theory Comput 2020; 16:5441-5455. [PMID: 32786907 DOI: 10.1021/acs.jctc.0c00351] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We report on first-principles quantum-dynamical and quantum-classical simulations of photoinduced exciton dynamics in oligothiophene chain segments, representative of intrachain exciton migration in the poly(3-hexylthiophene) (P3HT) polymer. Following up on our recent study (Binder R.; Burghardt, I. Faraday Discuss. 2020, 221, 406), multilayer multiconfiguration time-dependent Hartree calculations for a short oligothiophene segment comprising 20 monomer units (OT-20) are carried out to obtain full quantum-dynamical simulations at finite temperature. These are employed to benchmark mean-field Ehrenfest calculations, which are shown to give qualitatively correct results for the present system. Periodic boundary conditions turn out to significantly improve earlier estimates of diffusion coefficients. Using the Ehrenfest approach, a series of calculations are subsequently carried out for larger lattices (OT-40 to OT-80), leading to estimates for temperature-dependent mean-squared displacements, which are found to exhibit a near-linear dependence as a function of time. The resulting diffusion coefficient estimates are an increasing function of temperature, whose detailed functional form depends on the degree of static disorder. With a realistic static disorder parameter (σs ≃ 0.06 eV), the diffusion coefficients decrease from D ∼ 1 × 10-2 cm2 s-1 to D ∼ 1 × 10-3 cm2 s-1, in qualitative agreement with experimental data for P3HT. The dynamical scenario obtained from our simulations shows that exciton migration in P3HT-type chains is a largely adiabatic process throughout the temperature regime we investigated (i.e., T = 50-300 K). The resulting picture of exciton migration is a coherent, but not bandlike, motion of an exciton-polaron driven by fluctuations induced by low-frequency modes. This process acquires partial hopping character if static disorder becomes prominent and Anderson localization sets in.
Collapse
Affiliation(s)
- Rainer Hegger
- Institute for Physical and Theoretical Chemistry, Goethe University, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany
| | - Robert Binder
- Institute for Physical and Theoretical Chemistry, Goethe University, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany
| | - Irene Burghardt
- Institute for Physical and Theoretical Chemistry, Goethe University, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany
| |
Collapse
|
7
|
Binder R, Bonfanti M, Lauvergnat D, Burghardt I. First-principles description of intra-chain exciton migration in an oligo(para-phenylene vinylene) chain. I. Generalized Frenkel-Holstein Hamiltonian. J Chem Phys 2020; 152:204119. [PMID: 32486686 DOI: 10.1063/5.0004510] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A generalized Frenkel-Holstein Hamiltonian is constructed to describe exciton migration in oligo(para-phenylene vinylene) chains, based on excited state electronic structure data for an oligomer comprising 20 monomer units (OPV-20). Time-dependent density functional theory calculations using the ωB97XD hybrid functional are employed in conjunction with a transition density analysis to study the low-lying singlet excitations and demonstrate that these can be characterized to a good approximation as a Frenkel exciton manifold. Based on these findings, we employ the analytic mapping procedure of Binder et al. [J. Chem. Phys. 141, 014101 (2014)] to translate one-dimensional (1D) and two-dimensional (2D) potential energy surface (PES) scans to a fully anharmonic, generalized Frenkel-Holstein (FH) Hamiltonian. A 1D PES scan is carried out for intra-ring quinoid distortion modes, while 2D PES scans are performed for the anharmonically coupled inter-monomer torsional and vinylene bridge bond length alternation modes. The kinetic energy is constructed in curvilinear coordinates by an exact numerical procedure, using the TNUM Fortran code. As a result, a fully molecular-based, generalized FH Hamiltonian is obtained, which is subsequently employed for quantum exciton dynamics simulations, as shown in Paper II [R. Binder and I. Burghardt, J. Chem. Phys. 152, 204120 (2020)].
Collapse
Affiliation(s)
- Robert Binder
- Institute for Physical and Theoretical Chemistry, Goethe University, Max-von-Laue-Str. 7, 60438 Frankfurt/Main, Germany
| | - Matteo Bonfanti
- Institute for Physical and Theoretical Chemistry, Goethe University, Max-von-Laue-Str. 7, 60438 Frankfurt/Main, Germany
| | - David Lauvergnat
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR 8000, 91405 Orsay, France
| | - Irene Burghardt
- Institute for Physical and Theoretical Chemistry, Goethe University, Max-von-Laue-Str. 7, 60438 Frankfurt/Main, Germany
| |
Collapse
|
8
|
Binder R, Burghardt I. First-principles quantum simulations of exciton diffusion on a minimal oligothiophene chain at finite temperature. Faraday Discuss 2020; 221:406-427. [PMID: 31596291 DOI: 10.1039/c9fd00066f] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
High-dimensional multiconfigurational quantum dynamics simulations are carried out at finite temperature to simulate exciton diffusion on an oligothiophene chain, representative of a segment of the poly(3-hexylthiophene) (P3HT) polymer. The ab initio parametrized site-based Hamiltonian of Binder et al. [Phys. Rev. Lett., 2018, 120, 227401] is employed to model a 20-site system, including intra-ring and inter-ring high-frequency modes as well as torsional modes which undergo thermal fluctuations induced by an explicit harmonic oscillator bath. The system-bath dynamics is treated within the setting of a stochastic mean-field Schrödinger equation. For the 20-site excitonic system, a total of 20 Frenkel states and 248 modes are propagated using the multi-layer multi-configuration time-dependent Hartree (ML-MCTDH) method. The resulting dynamics can be interpreted in terms of the coherent motion of an exciton-polaron quasi-particle stochastically driven by torsional fluctuations. This dynamics yields a near-linear mean squared displacement (MSD) as a function of time, from which a diffusion coefficient can be deduced which increases with temperature, up to 5.7 × 10-3 cm2 s-1 at T = 300 K.
Collapse
Affiliation(s)
- Robert Binder
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt am Main, Germany.
| | | |
Collapse
|
9
|
Rana D, Jovanov V, Wagner V, Materny A, Donfack P. Insights into ultrafast charge-pair dynamics in P3HT:PCBM devices under the influence of static electric fields. RSC Adv 2020; 10:42754-42764. [PMID: 35514888 PMCID: PMC9058153 DOI: 10.1039/d0ra07935a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/16/2020] [Indexed: 12/16/2022] Open
Abstract
Polymer-fullerene blends based on poly(3-hexylthiophene-2,5-diyl) (P3HT) and phenyl-C61-butyric-acid methyl ester (PCBM) have been extensively studied as promising bulk heterojunction materials for organic semiconductor devices with improved performance. In these donor–acceptor systems where the bulk morphology plays a crucial role, the generation and subsequent decay mechanisms of photoexcitation species are still not completely understood. In this work, we use femtosecond transient absorption spectroscopy to investigate P3HT:PCBM diodes under the influence of applied static electric fields in comparison to P3HT:PCBM thin films. At the same time, we try to present a detailed overview about work already done on these donor–acceptor systems. The excited state dynamics obtained at 638 nm from P3HT:PCBM thin films are found to be similar to those observed earlier in neat P3HT films, while those obtained in the P3HT:PCBM devices are affected by field-induced exciton dissociation, resulting not only in comparatively slower decay dynamics, but also in bimolecular deactivation processes. External electric fields are expected to enhance charge generation in the investigated P3HT:PCBM devices by dissociating excitons and loosely bound intermediate species like polaron pairs (PPs) and charge transfer (CT) excitons, which can already dissociate only due to the intrinsic fields at the donor–acceptor interfaces. Our results clearly establish the formation of PP-like transient species different from CT excitons in the P3HT:PCBM devices as a result of a field-induced diffusion-controlled exciton dissociation process. We find that the loosely bound transient species formed in this way also are reduced in part via a bimolecular annihilation process resulting in charge loss in typical donor–acceptor P3HT:PCBM bulk heterojunction semiconductor devices, which is a rather interesting finding important for a better understanding of the performance of these devices. Electric field effects in P3HT:PCBM solar cell result in polaron-pair-like secondary photoexcitation species showing slower and bimolecular decay characteristics.![]()
Collapse
Affiliation(s)
- Debkumar Rana
- Physics and Earth Sciences
- Jacobs University Bremen
- 28759 Bremen
- Germany
| | - Vladislav Jovanov
- Physics and Earth Sciences
- Jacobs University Bremen
- 28759 Bremen
- Germany
| | - Veit Wagner
- Physics and Earth Sciences
- Jacobs University Bremen
- 28759 Bremen
- Germany
| | - Arnulf Materny
- Physics and Earth Sciences
- Jacobs University Bremen
- 28759 Bremen
- Germany
| | - Patrice Donfack
- Physics and Earth Sciences
- Jacobs University Bremen
- 28759 Bremen
- Germany
| |
Collapse
|
10
|
Rana D, Donfack P, Jovanov V, Wagner V, Materny A. Ultrafast polaron-pair dynamics in a poly(3-hexylthiophene-2,5-diyl) device influenced by a static electric field: insights into electric-field-related charge loss. Phys Chem Chem Phys 2019; 21:21236-21248. [DOI: 10.1039/c9cp03736e] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Photogenerated polaron-pair ultrafast dynamics in poly(3-hexylthiophene)-based devices are found to be influenced by external electric fields via delayed field-induced singlet exciton dissociation, yielding a bimolecular decay contribution.
Collapse
Affiliation(s)
- Debkumar Rana
- Physics and Earth Sciences, Jacobs University Bremen
- 28759 Bremen
- Germany
| | - Patrice Donfack
- Physics and Earth Sciences, Jacobs University Bremen
- 28759 Bremen
- Germany
| | - Vladislav Jovanov
- Physics and Earth Sciences, Jacobs University Bremen
- 28759 Bremen
- Germany
| | - Veit Wagner
- Physics and Earth Sciences, Jacobs University Bremen
- 28759 Bremen
- Germany
| | - Arnulf Materny
- Physics and Earth Sciences, Jacobs University Bremen
- 28759 Bremen
- Germany
| |
Collapse
|
11
|
Schreck MH, Breitschwerdt L, Marciniak H, Holzapfel M, Schmidt D, Würthner F, Lambert C. fs–ps Exciton dynamics in a stretched tetraphenylsquaraine polymer. Phys Chem Chem Phys 2019; 21:15346-15355. [DOI: 10.1039/c9cp02900a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A squaraine polymer shows surprisingly fast light induced energy transfer between two different structural sections on the ps/fs time scale.
Collapse
Affiliation(s)
- Maximilian H. Schreck
- Institute of Organic Chemistry
- Center for Nanosystems Chemistry
- Universität Würzburg
- D-97074 Würzburg
- Germany
| | - Lena Breitschwerdt
- Institute of Organic Chemistry
- Center for Nanosystems Chemistry
- Universität Würzburg
- D-97074 Würzburg
- Germany
| | - Henning Marciniak
- Institute of Organic Chemistry
- Center for Nanosystems Chemistry
- Universität Würzburg
- D-97074 Würzburg
- Germany
| | - Marco Holzapfel
- Institute of Organic Chemistry
- Center for Nanosystems Chemistry
- Universität Würzburg
- D-97074 Würzburg
- Germany
| | - David Schmidt
- Institute of Organic Chemistry
- Center for Nanosystems Chemistry
- Universität Würzburg
- D-97074 Würzburg
- Germany
| | - Frank Würthner
- Institute of Organic Chemistry
- Center for Nanosystems Chemistry
- Universität Würzburg
- D-97074 Würzburg
- Germany
| | - Christoph Lambert
- Institute of Organic Chemistry
- Center for Nanosystems Chemistry
- Universität Würzburg
- D-97074 Würzburg
- Germany
| |
Collapse
|
12
|
Liang R, Cotton SJ, Binder R, Hegger R, Burghardt I, Miller WH. The symmetrical quasi-classical approach to electronically nonadiabatic dynamics applied to ultrafast exciton migration processes in semiconducting polymers. J Chem Phys 2018; 149:044101. [DOI: 10.1063/1.5037815] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Ruibin Liang
- Department of Chemistry and Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, Berkeley,
California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720,
USA
| | - Stephen J. Cotton
- Department of Chemistry and Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, Berkeley,
California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720,
USA
| | - Robert Binder
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt/Main,
Germany
| | - Rainer Hegger
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt/Main,
Germany
| | - Irene Burghardt
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt/Main,
Germany
| | - William H. Miller
- Department of Chemistry and Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, Berkeley,
California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720,
USA
| |
Collapse
|
13
|
Binder R, Lauvergnat D, Burghardt I. Conformational Dynamics Guides Coherent Exciton Migration in Conjugated Polymer Materials: First-Principles Quantum Dynamical Study. PHYSICAL REVIEW LETTERS 2018; 120:227401. [PMID: 29906150 DOI: 10.1103/physrevlett.120.227401] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Indexed: 06/08/2023]
Abstract
We report on high-dimensional quantum dynamical simulations of photoinduced exciton migration in a single-chain oligothiophene segment, in view of elucidating the controversial nature of the elementary exciton transport steps in semiconducting polymers. A novel first-principles parametrized Frenkel J aggregate Hamiltonian is employed that goes significantly beyond the standard Frenkel-Holstein Hamiltonian. Departing from a nonequilibrium state created by photoexcitation, these simulations provide evidence of an ultrafast two-timescale process at low temperatures, involving exciton-polaron formation within tens of femtoseconds (fs), followed by torsional relaxation on an ∼400 fs timescale. The second step is the driving force for exciton migration, as initial conjugation breaks are removed by dynamical planarization. The quantum coherent nature of the elementary exciton migration step is consistent with experimental observations highlighting the correlated and vibrationally coherent nature of the dynamics on ultrafast timescales.
Collapse
Affiliation(s)
- Robert Binder
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438 Frankfurt, Germany
| | - David Lauvergnat
- Laboratoire de Chimie Physique, Université Paris-Sud, UMR 8000, 91405 Orsay, France
| | - Irene Burghardt
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438 Frankfurt, Germany
| |
Collapse
|
14
|
Binder R, Polkehn M, Ma T, Burghardt I. Ultrafast exciton migration in an HJ-aggregate: Potential surfaces and quantum dynamics. Chem Phys 2017. [DOI: 10.1016/j.chemphys.2016.09.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
15
|
Eckstein A, Karpicz R, Augulis R, Redeckas K, Vengris M, Namal I, Hertel T, Gulbinas V. Excitation quenching in polyfluorene polymers bound to (6,5) single-wall carbon nanotubes. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2015.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
16
|
Song P, Li Y, Ma F, Pullerits T, Sun M. Photoinduced Electron Transfer in Organic Solar Cells. CHEM REC 2016; 16:734-53. [PMID: 26853631 DOI: 10.1002/tcr.201500244] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Indexed: 11/07/2022]
Abstract
Electron transfer (ET) is the key process in light-driven charge separation reactions in organic solar cells. The current review summarizes the progress in theoretical modelling of ET in these materials. First we give an account of ET, with a description originating from Marcus theory. We systematically go through all the relevant parameters and show how they depend on different material properties, and discuss the consequences such dependencies have for the performance of the devices. Finally, we present a set of visualization methods which have proven to be very useful in analyzing the elementary processes in absorption and charge separation events. Such visualization tools help us to understand the properties of the photochemical and photobiological systems in solar cells.
Collapse
Affiliation(s)
- Peng Song
- Department of Physics, Liaoning University, Shenyang, 110036, P. R. China.,Beijing National Laboratory for Condensed Matter Physics, Institute of Physics Chinese Academy of Science, Beijing, 100190, P. R. China.,State Key laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics Chinese Academy of Science, Dalian, 116023, P. R. China
| | - Yuanzuo Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics Chinese Academy of Science, Beijing, 100190, P. R. China.,College of Science, Northeast Forestry University, Harbin, 150040, P. R. China
| | - Fengcai Ma
- Department of Physics, Liaoning University, Shenyang, 110036, P. R. China
| | - Tõnu Pullerits
- Department of Chemical Physics, Lund University, Box 124, Lund, 22100, Sweden.,State Key laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics Chinese Academy of Science, Dalian, 116023, P. R. China
| | - Mengtao Sun
- Department of Physics, Liaoning University, Shenyang, 110036, P. R. China.,Beijing National Laboratory for Condensed Matter Physics, Institute of Physics Chinese Academy of Science, Beijing, 100190, P. R. China
| |
Collapse
|
17
|
Mulazzi E, Galli DE, Lefrant S, Wéry J, Massuyeau F, Faulques E. Dynamics of charge migration in poly(para-phenylene vinylene) films and nanocomposites with single walled carbon nanotubes. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:045304. [PMID: 26744381 DOI: 10.1088/0953-8984/28/4/045304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present in this paper a comprehensive study of the migration dynamics of the charges underlying transient photoluminescence (PL) processes in poly(para-phenylene vinylene) (PPV) samples from room temperature to 13 K. In order to interpret experimental data, we have modelled the long-time PL decays (from 100 to 1000 ps) using a time function proportional to [Formula: see text] in which the parameter α is evaluated in a Monte Carlo simulation on polymeric chains. The one dimensional chains (2000 sites long) are formed by random sequences of long and short conjugated segments whose bimodal distributions have been elaborated in previous works in order to reproduce the PL band shapes and peak positions. Intra-chain and inter-chain dynamics are taken into account in the migration of the photogenerated charges from short to long conjugated segments. The statistical analysis is performed by averaging over a total of 10(6) trials for each initial conditions. The values of α have been determined for pristine PPV films and PPV composite films with single-walled carbon nanotubes. This theoretical analysis is in good agreement with experimental data and provides a coherent description for the migration of the photogenerated charges in such inhomogeneous polymeric systems.
Collapse
Affiliation(s)
- E Mulazzi
- Dipartimento di Fisica, Università degli Studi di Milano and European Theoretical Spectroscopy Facility (ETSF), via Celoria 16, 20133 Milano, Italy
| | | | | | | | | | | |
Collapse
|
18
|
Thiessen A, Würsch D, Jester SS, Aggarwal AV, Idelson A, Bange S, Vogelsang J, Höger S, Lupton JM. Exciton Localization in Extended π-Electron Systems: Comparison of Linear and Cyclic Structures. J Phys Chem B 2015; 119:9949-58. [DOI: 10.1021/acs.jpcb.5b02091] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alexander Thiessen
- Department
of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, United States
| | - Dominik Würsch
- Institut
für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany
| | - Stefan-S. Jester
- Kekulé-Institut
für Organische Chemie und Biochemie der Universität Bonn, 53121 Bonn, Germany
| | - A. Vikas Aggarwal
- Kekulé-Institut
für Organische Chemie und Biochemie der Universität Bonn, 53121 Bonn, Germany
| | - Alissa Idelson
- Kekulé-Institut
für Organische Chemie und Biochemie der Universität Bonn, 53121 Bonn, Germany
| | - Sebastian Bange
- Institut
für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany
| | - Jan Vogelsang
- Institut
für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany
| | - Sigurd Höger
- Kekulé-Institut
für Organische Chemie und Biochemie der Universität Bonn, 53121 Bonn, Germany
| | - John M. Lupton
- Department
of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, United States
- Institut
für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany
| |
Collapse
|
19
|
Lambert C, Koch F, Völker SF, Schmiedel A, Holzapfel M, Humeniuk A, Röhr MIS, Mitric R, Brixner T. Energy Transfer Between Squaraine Polymer Sections: From Helix to Zigzag and All the Way Back. J Am Chem Soc 2015; 137:7851-61. [DOI: 10.1021/jacs.5b03644] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christoph Lambert
- Institut
für Organische Chemie, ‡Center for Nanosystems Chemistry
(CNC), and §Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Federico Koch
- Institut
für Organische Chemie, ‡Center for Nanosystems Chemistry
(CNC), and §Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Sebastian F. Völker
- Institut
für Organische Chemie, ‡Center for Nanosystems Chemistry
(CNC), and §Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Alexander Schmiedel
- Institut
für Organische Chemie, ‡Center for Nanosystems Chemistry
(CNC), and §Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Marco Holzapfel
- Institut
für Organische Chemie, ‡Center for Nanosystems Chemistry
(CNC), and §Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Alexander Humeniuk
- Institut
für Organische Chemie, ‡Center for Nanosystems Chemistry
(CNC), and §Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Merle I. S. Röhr
- Institut
für Organische Chemie, ‡Center for Nanosystems Chemistry
(CNC), and §Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Roland Mitric
- Institut
für Organische Chemie, ‡Center for Nanosystems Chemistry
(CNC), and §Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Tobias Brixner
- Institut
für Organische Chemie, ‡Center for Nanosystems Chemistry
(CNC), and §Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| |
Collapse
|
20
|
Bjorgaard JA, Köse ME. Simulations of singlet exciton diffusion in organic semiconductors: a review. RSC Adv 2015. [DOI: 10.1039/c4ra12409j] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Recent advances in exciton diffusion simulations in conjugated materials are presented in this review.
Collapse
Affiliation(s)
- Josiah A. Bjorgaard
- Center for Nonlinear Studies
- Theoretical Division
- Los Alamos National Laboratory
- Los Alamos
- USA
| | | |
Collapse
|
21
|
Parkinson P, Kondratuk DV, Menelaou C, Gong JQ, Anderson HL, Herz LM. Chromophores in Molecular Nanorings: When Is a Ring a Ring? J Phys Chem Lett 2014; 5:4356-4361. [PMID: 26273987 DOI: 10.1021/jz5022153] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The topology of a conjugated molecule plays a significant role in controlling both the electronic properties and the conformational manifold that the molecule may explore. Fully π-conjugated molecular nanorings are of particular interest, as their lowest electronic transition may be strongly suppressed as a result of symmetry constraints. In contrast, the simple Kasha model predicts an enhancement in the radiative rate for corresponding linear oligomers. Here we investigate such effects in linear and cyclic conjugated molecules containing between 6 and 42 butadiyne-linked porphyrin units (corresponding to 600 C-C bonds) as pure monodisperse oligomers. We demonstrate that as the diameter of the nanorings increases beyond ∼10 nm, its electronic properties tend toward those of a similarly sized linear molecule as a result of excitation localization on a subsegment of the ring. However, significant differences persist in the nature of the emitting dipole polarization even beyond this limit, arising from variations in molecular curvature and conformation.
Collapse
Affiliation(s)
- Patrick Parkinson
- †Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Dmitry V Kondratuk
- ‡Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Christopher Menelaou
- †Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Juliane Q Gong
- †Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Harry L Anderson
- ‡Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Laura M Herz
- †Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| |
Collapse
|
22
|
|
23
|
Heitzer HM, Savoie BM, Marks TJ, Ratner MA. Organic Photovoltaics: Elucidating the Ultra-Fast Exciton Dissociation Mechanism in Disordered Materials. Angew Chem Int Ed Engl 2014; 53:7456-60. [DOI: 10.1002/anie.201402568] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Indexed: 11/07/2022]
|
24
|
Heitzer HM, Savoie BM, Marks TJ, Ratner MA. Organic Photovoltaics: Elucidating the Ultra-Fast Exciton Dissociation Mechanism in Disordered Materials. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201402568] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
25
|
Völker SF, Schmiedel A, Holzapfel M, Böhm C, Lambert C. Charge transfer dynamics in squaraine-naphthalene diimide copolymers. Phys Chem Chem Phys 2013; 15:19831-44. [PMID: 24145596 DOI: 10.1039/c3cp53455c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The synthesis of an alternating squaraine-naphthalene diimide donor-acceptor low band gap polymer (1.14-1.40 eV) as well as its monomolecular analogue is presented. Spectroelectrochemistry experiments and transient absorption spectroscopy in the fs-time regime reveal an ultrafast population of a charge separated state for both polymer and monomer. Local excitation of the squaraine moiety is followed by population of intermediate states, presumably charge transfer states, followed by full charge separation, which occurs within a ca. 2 ps. Charge recombination takes place within 5.2 ps, probably because the system is close to the Marcus optimal region for barrierless ET. For the polymer, measurements of the transient absorption anisotropy show that neither charge nor does energy transfer take place within the lifetime of the charge separated state, indicating that this state is essentially confined within one donor-acceptor pair.
Collapse
Affiliation(s)
- Sebastian F Völker
- Institut für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | | | | | | | | |
Collapse
|
26
|
Binder R, Wahl J, Römer S, Burghardt I. Coherent exciton transport driven by torsional dynamics: a quantum dynamical study of phenylene-vinylene type conjugated systems. Faraday Discuss 2013; 163:205-22; discussion 243-75. [DOI: 10.1039/c3fd20148a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
27
|
Nelson T, Fernandez-Alberti S, Roitberg AE, Tretiak S. Conformational disorder in energy transfer: beyond Förster theory. Phys Chem Chem Phys 2013; 15:9245-56. [DOI: 10.1039/c3cp50857a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
28
|
Schmid SA, Abbel R, Schenning APHJ, Meijer EW, Herz LM. Energy transfer processes along a supramolecular chain of π-conjugated molecules. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2012; 370:3787-801. [PMID: 22753826 DOI: 10.1098/rsta.2011.0205] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We have investigated the energy transfer dynamics in a supramolecular linear polymer chain comprising oligofluorene (OF) energy donor units linked by quadruple hydrogen-bonding groups, and oligophenylene (OPV) chain ends that act as energy acceptors. Using femtosecond spectroscopy, we followed the dynamics of energy transfer from the main chain of OF units to the OPV chain ends and simulated these data taking a Monte Carlo approach that included different extents of electronic wave function delocalization for the energy donor and acceptor. Best correlations between experimental and theoretical results were obtained for the assumption of electronic coupling occurring between a localized donor dipole moment and a delocalized acceptor moment. These findings emphasize that geometric relaxation following initial excitation of the donor needs to be taken into account, as it leads to a localization of the donor's excited state wave function prior to energy transfer. In addition, our simulations show that the energy transfer from the main chain to the ends is dominated by an interplay between slow and spatially limited exciton migration along the OF segments comprising the main chain and the comparatively faster hetero-transfer to the end-cap acceptors from directly adjoining OF segments. These results clearly support the description of host-guest energy transfer in linear polymer chains as a two-step mechanism with exciton diffusion in the host being a prerequisite to energy transfer to the guest.
Collapse
Affiliation(s)
- S A Schmid
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | | | | | | | | |
Collapse
|
29
|
Exciton diffusion, annihilation and their role in the charge carrier generation in fluorene based copolymers. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2012.02.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
30
|
Rodríguez-Córdoba W, Sierra CA, Ochoa Puentes C, Lahti PM, Peon J. Photoinduced Energy Transfer in Bichromophoric Pyrene–PPV Oligomer Systems: The Role of Flexible Donor–Acceptor Bridges. J Phys Chem B 2012; 116:3490-503. [DOI: 10.1021/jp208602q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- William Rodríguez-Córdoba
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad
Universitaria, 04510, México, D.F., México
| | - Cesar A. Sierra
- Universidad Nacional de Colombia, Departamento de Química,
Bogotá AA 14490, Colombia
| | | | - Paul M. Lahti
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts
01003, United States
| | - Jorge Peon
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad
Universitaria, 04510, México, D.F., México
| |
Collapse
|
31
|
Chiu M, Kee TW, Huang DM. Coarse-Grained Simulations of the Effects of Chain Length, Solvent Quality, and Chemical Defects on the Solution-Phase Morphology of MEH-PPV Conjugated Polymers. Aust J Chem 2012. [DOI: 10.1071/ch12029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A mesoscale coarse-grained model of the conjugated polymer poly(2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) in implicit solvent is developed. The model is parametrized to reproduce the local structure and dynamics of an atomistic simulation model and accounts for the effects of solvent quality and saturation chemical defects on the polymer structure. Polymers with defect concentrations of 0 to 10 % are simulated using Langevin dynamics in tetrahydrofuran (THF) and in a model poor solvent for chain lengths and solution concentrations used experimentally. The polymer chains are extended in THF and collapse into compact structures in the poor solvent. The radius of gyration decreases with defect content in THF and agrees quantitatively with experiment. The structures formed in poor solvent by chains with 300 monomer units change from toroidal to cylindrical with increasing defect content, while chains containing 1000 monomers form cylinders regardless of defect content. These results have implications for energy transfer in MEH-PPV.
Collapse
|
32
|
Al-Hariri LA, Zheng L, Yang W, Schlenoff JB. Thermal Elimination of Precursors to Poly(phenylenevinylene) with a Macrocounterion versus a Small Counterion: A Coordinated Experimental and Simulation Study. Macromolecules 2011. [DOI: 10.1021/ma200930d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lara A. Al-Hariri
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Lianqing Zheng
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Wei Yang
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Joseph B. Schlenoff
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| |
Collapse
|
33
|
Simas ER, Gehlen MH, Pinto MFS, Siqueira J, Misoguti L. Intrachain Energy Migration to Weak Charge-Transfer State in Polyfluorene End-Capped with Naphthalimide Derivative. J Phys Chem A 2010; 114:12384-90. [DOI: 10.1021/jp108168f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Emanuelle R Simas
- Instituto de Química de São Carlos, Universidade de São Paulo, 13560-590, São Carlos-SP, Brasil
| | | | | | | | | |
Collapse
|
34
|
Colby KA, Burdett JJ, Frisbee RF, Zhu L, Dillon RJ, Bardeen CJ. Electronic energy migration on different time scales: concentration dependence of the time-resolved anisotropy and fluorescence quenching of Lumogen Red in poly(methyl methacrylate). J Phys Chem A 2010; 114:3471-82. [PMID: 20170138 DOI: 10.1021/jp910277j] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electronic energy transfer plays an important role in many types of organic electronic devices. Forster-type theories of exciton diffusion provide a way to calculate diffusion constants and lengths, but their applicability to amorphous polymer systems must be evaluated. In this paper, the perylenediimide dye Lumogen Red in a poly(methyl methacrylate) host matrix is used to test theories of exciton motion over Lumogen Red concentrations (C(LR)'s) ranging from 1 x 10(-4) to 5 x 10(-2) M. Two experimental quantities are measured. First, time-resolved anisotropy decays in films containing only Lumogen Red provide an estimate of the initial energy transfer rate from the photoexcited molecule. Second, the Lumogen Red lifetime decays in mixed systems where the dyes Malachite Green and Rhodamine 700 act as energy acceptors are measured to estimate the diffusive quenching of the exciton. From the anisotropy measurements, it is found that theory accurately predicts both the C(LR)(-2) concentration dependence of the polarization decay time tau(pol), as well as its magnitude to within 30%. The theory also predicts that the diffusive quenching rate is proportional to C(LR)(alpha), where alpha ranges between 1.00 and 1.33. Experimentally, it is found that alpha = 1.1 +/- 0.2 when Malachite Green is used as an acceptor, and alpha = 1.2 +/- 0.2 when Rhodamine 700 is the acceptor. On the basis of the theory that correctly describes the anisotropy data, the exciton diffusion constant is projected to be 4-9 nm(2)/ns. By use of several different analysis methods for the quenching data, the experimental diffusion constant is found to be in the range of 0.32-1.20 nm(2)/ns. Thus the theory successfully describes the early time anisotropy data but fails to quantitatively describe the quenching experiments which are sensitive to motion on longer time scales. The data are consistent with the idea that orientational and energetic disorder leads to a time-dependent exciton migration rate, suggesting that simple diffusion models cannot accurately describe exciton motion within this system.
Collapse
Affiliation(s)
- Kathryn A Colby
- Department of Chemistry, University of California, Riverside, Riverside, California 92521, USA
| | | | | | | | | | | |
Collapse
|
35
|
Lupton JM. Single-molecule spectroscopy for plastic electronics: materials analysis from the bottom-up. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2010; 22:1689-721. [PMID: 20496402 DOI: 10.1002/adma.200902306] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
pi-conjugated polymers find a range of applications in electronic devices. These materials are generally highly disordered in terms of chain length and chain conformation, besides being influenced by a variety of chemical and physical defects. Although this characteristic can be of benefit in certain device applications, disorder severely complicates materials analysis. Accurate analytical techniques are, however, crucial to optimising synthetic procedures and assessing overall material purity. Fortunately, single-molecule spectroscopic techniques have emerged as an unlikely but uniquely powerful approach to unraveling intrinsic material properties from the bottom up. Building on the success of such techniques in the life sciences, single-molecule spectroscopy is finding increasing applicability in materials science, effectively enabling the dissection of the bulk down to the level of the individual molecular constituent. This article reviews recent progress in single molecule spectroscopy of conjugated polymers as used in organic electronics.
Collapse
Affiliation(s)
- John M Lupton
- Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA.
| |
Collapse
|
36
|
Shie SC, Lee CK, Hua CC, Chen SA. A Predictive Coarse-Grained Model for Semiflexible Polymers in Specific Solvents. MACROMOL THEOR SIMUL 2010. [DOI: 10.1002/mats.200900075] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
37
|
Saini S, Bagchi B. Photophysics of conjugated polymers: interplay between Förster energy migration and defect concentration in shaping a photochemical funnel in PPV. Phys Chem Chem Phys 2010; 12:7427-33. [DOI: 10.1039/c003217d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
38
|
Guo M, Varnavski O, Narayanan A, Mongin O, Majoral JP, Blanchard-Desce M, Goodson T. Investigations of energy migration in an organic dendrimer macromolecule for sensory signal amplification. J Phys Chem A 2009; 113:4763-71. [PMID: 19317441 DOI: 10.1021/jp8112123] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The issue of macromolecular exciton delocalization length and fluorescence sensing of energetic materials is investigated and modeled from results of nonlinear optical and time-resolved spectroscopy. By using two- and three-photon absorption techniques the fluorescence quenching effects of an organic dendrimer for sensing TNT were carried out. The Stern-Volmer plots for the set of dendrimers were examined and a large quenching constant for the dendrimer G4 was obtained (1400 M(-1)). The quenching constant was found to increase with the dendrimer generation number. The mechanism for the enhanced sensitivity of the dendrimer system was examined by probing the exciton dynamics with femtosecond fluorescence up-conversion. Fluorescence lifetime measurements revealed a multicomponent relaxation that varied with dendrimer generation. Fluorescence anisotropy decay measurements were used to probe the exciton migration length in these dendrimer systems and for the large structure the excitation migration area covers approximately 20 units. All of these results were used in a model that describes the exciton localization length with the fluorescence quenching strength. The use of time-resolved techniques allows for a closer and more detailed description of the mechanism of sensory amplification in organic macromolecules.
Collapse
Affiliation(s)
- Meng Guo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | | | | | | | | | | | | |
Collapse
|
39
|
Minevičiūtė I, Gulbinas V, Franckevičius M, Vaišnoras R, Marcos M, Serrano J. Exciton migration and quenching in poly(propylene imine) dendrimers. Chem Phys 2009. [DOI: 10.1016/j.chemphys.2009.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
40
|
Dykstra TE, Hennebicq E, Beljonne D, Gierschner J, Claudio G, Bittner ER, Knoester J, Scholes GD. Conformational disorder and ultrafast exciton relaxation in PPV-family conjugated polymers. J Phys Chem B 2009; 113:656-67. [PMID: 19105646 DOI: 10.1021/jp807249b] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We report combined experimental and theoretical studies of excitation relaxation in poly[2-methoxy,5-(2'-ethyl-hexoxy)-1,4-phenylenevinylene] (MEH-PPV), oligophenylenevinylene (OPV) molecules of varying length, and model PPV chains. We build on the paradigm that the basic characteristics of conjugated polymers are decided by conformational subunits defined by conjugation breaks caused by torsional disorder along the chain. The calculations reported here indicate that for conjugated polymers like those in the PPV family, these conformational subunits electronically couple to neighboring subunits, forming subtly delocalized collective states of nanoscale excitons that determine the polymer optical properties. We find that relaxation among these exciton states can lead to a decay of anisotropy on ultrafast time scales. Unlike in Forster energy transfer, the exciton does not necessarily translate over a large distance. Nonetheless, the disorder in the polymer chain means that even small changes in the exciton size or location has a significant effect on the relaxation pathway and therefore the anisotropy decay.
Collapse
Affiliation(s)
- Tieneke E Dykstra
- Lash-Miller Chemical Laboratories, Institute for Optical Sciences and Centre for Quantum Information and Quantum Control, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6 Canada
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Collini E, Scholes GD. Electronic and Vibrational Coherences in Resonance Energy Transfer along MEH-PPV Chains at Room Temperature. J Phys Chem A 2009; 113:4223-41. [DOI: 10.1021/jp810757x] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Elisabetta Collini
- Lash-Miller Chemical Laboratories, Institute for Optical Sciences and Centre for Quantum Information and Quantum Control, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Gregory D. Scholes
- Lash-Miller Chemical Laboratories, Institute for Optical Sciences and Centre for Quantum Information and Quantum Control, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| |
Collapse
|
42
|
Singh J, Bittner ER, Beljonne D, Scholes GD. Fluorescence depolarization in poly[2-methoxy-5-((2-ethylhexyl)oxy)-1,4-phenylenevinylene]: Sites versus eigenstates hopping. J Chem Phys 2009; 131:194905. [DOI: 10.1063/1.3259549] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
43
|
Simas ER, Gehlen MH, Glogauer A, Akcelrud L. Excited-state dynamics of polyfluorene derivatives in solution. J Phys Chem A 2008; 112:5054-9. [PMID: 18481838 DOI: 10.1021/jp711934d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The excited-state dynamics of two polyfluorene copolymers, one fully conjugated containing phenylene vinylene units alternated with 9,9'-dihexylfluorenyl groups and the other segmented by -(CH2)8- spacer, were studied in dilute solution of different solvents using a picosecond single-photon timing technique. The excited-state dynamics of the segmented copolymer follows the Förster resonant energy-transfer model which describes intrachain energy-transfer kinetics among random oriented chromophores. Energy transfer is confirmed by analysis of fluorescence anisotropy relaxation with the measurement of a short decay component of about 60 ps. The fluorescence decay surface of the fully conjugated copolymer is biexponential with decay times of about 470 and 900 ps, ascribed to deactivation of chain moieties containing trans and cis isomers already in a photostationary condition. Thus, energy transfer is very fast due to the conjugated nature and rigid-rod-like structure of this copolymer chain.
Collapse
Affiliation(s)
- Emanuelle R Simas
- Instituto de Química de São Carlos, Universidade de São Paulo, 13560-590, São Carlos SP, Brasil
| | | | | | | |
Collapse
|
44
|
Solvent-induced photoemissions of high-energy chromophores of conjugated Polymer MEH-PPV: Role of conformational disorder. Macromol Res 2008. [DOI: 10.1007/bf03218857] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
45
|
Nakamura T, Araki Y, Ito O, Takimiya K, Otsubo T. Fluorescence Up-Conversion Study of Excitation Energy Transport Dynamics in Oligothiophene−Fullerene Linked Dyads. J Phys Chem A 2008; 112:1125-32. [DOI: 10.1021/jp710115z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Takumi Nakamura
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, Miyagi 980-8577, Japan, and Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
| | - Yasuyuki Araki
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, Miyagi 980-8577, Japan, and Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
| | - Osamu Ito
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, Miyagi 980-8577, Japan, and Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
| | - Kazuo Takimiya
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, Miyagi 980-8577, Japan, and Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
| | - Tetsuo Otsubo
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, Miyagi 980-8577, Japan, and Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
| |
Collapse
|
46
|
Di Paolo RE, Seixas de Melo J, Pina J, Burrows HD, Morgado J, Maçanita AL. Conformational Relaxation ofp-Phenylenevinylene Trimers in Solution Studied by Picosecond Time-Resolved Fluorescence. Chemphyschem 2007; 8:2657-64. [DOI: 10.1002/cphc.200700548] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
47
|
Gulbinas V, Minevičiūtė I, Hertel D, Wellander R, Yartsev A, Sundström V. Exciton diffusion and relaxation in methyl-substituted polyparaphenylene polymer films. J Chem Phys 2007; 127:144907. [DOI: 10.1063/1.2790901] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
48
|
Grimm S, Tabatabai D, Scherer A, Michaelis J, Frank I. Chromophore Localization in Conjugated Polymers: Molecular Dynamics Simulation. J Phys Chem B 2007; 111:12053-8. [DOI: 10.1021/jp072032f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- S. Grimm
- Department of Chemistry and Biochemistry, Center for Nanoscience and Nanosystems Initiative Munich, Ludwig Maximilians University Munich, 81337 Munich, Germany
| | - D. Tabatabai
- Department of Chemistry and Biochemistry, Center for Nanoscience and Nanosystems Initiative Munich, Ludwig Maximilians University Munich, 81337 Munich, Germany
| | - A. Scherer
- Department of Chemistry and Biochemistry, Center for Nanoscience and Nanosystems Initiative Munich, Ludwig Maximilians University Munich, 81337 Munich, Germany
| | - J. Michaelis
- Department of Chemistry and Biochemistry, Center for Nanoscience and Nanosystems Initiative Munich, Ludwig Maximilians University Munich, 81337 Munich, Germany
| | - I. Frank
- Department of Chemistry and Biochemistry, Center for Nanoscience and Nanosystems Initiative Munich, Ludwig Maximilians University Munich, 81337 Munich, Germany
| |
Collapse
|
49
|
Westenhoff S, Beenken WJD, Yartsev A, Greenham NC. Conformational disorder of conjugated polymers. J Chem Phys 2007; 125:154903. [PMID: 17059289 DOI: 10.1063/1.2358682] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Conformational disorder of conjugated polymers is an important issue to be understood and quantified. In this paper we present a new method to assess the chain conformation of conjugated polymers based on measurements of intrachain energy transfer. The chain conformation is modeled on the basis of monomer-monomer interactions, such as torsion, bending, and stretching of the connecting bond. The latter two potentials are assumed to be harmonic, while the torsional potential was calculated by density functional theory using B3-LYP functional with the SVP basis set. The energy transfer dynamics of excitons on these chains are quantitatively simulated using Forster-type line-dipole energy transfer. This allows us to compare the simulated ground state conformation of single polymer chains to ultrafast depolarization experiments of poly [3-(2,5-dioctylphenyl)thiophene] in solution. We identify torsional rotation as the main contributor to conformational disorder and find that this disorder is mainly controlled by the energy difference between syn and anti bonds.
Collapse
Affiliation(s)
- Sebastian Westenhoff
- Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CH3 0HE, United Kingdom.
| | | | | | | |
Collapse
|
50
|
Scheblykin IG, Yartsev A, Pullerits T, Gulbinas V, Sundström V. Excited State and Charge Photogeneration Dynamics in Conjugated Polymers. J Phys Chem B 2007; 111:6303-21. [PMID: 17521181 DOI: 10.1021/jp068864f] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Conjugated polymers are becoming interesting materials for a range of optoelectronic applications. However, their often complex electronic and structural properties prevent establishment of straightforward property-function relationships. In this paper, we summarize recent results on the photophysics and excited state dynamics of conjugated polymers, in order to paint a picture of exciton formation, quenching, and generation of charge carriers.
Collapse
Affiliation(s)
- Ivan G Scheblykin
- Department of Chemical Physics, Lund University, Box 124, 221 00 Lund, Sweden
| | | | | | | | | |
Collapse
|