1
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Beer P, Reichstein PM, Schötz K, Raithel D, Thelakkat M, Köhler J, Panzer F, Hildner R. Disorder in P3HT Nanoparticles Probed by Optical Spectroscopy on P3HT- b-PEG Micelles. J Phys Chem A 2021; 125:10165-10173. [PMID: 34797986 PMCID: PMC8647091 DOI: 10.1021/acs.jpca.1c08377] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We employ photoluminescence (PL) spectroscopy on individual nanoscale aggregates of the conjugated polymer poly(3-hexylthiophene), P3HT, at room temperature (RT) and at low temperature (LT) (1.5 K), to unravel different levels of structural and electronic disorder within P3HT nanoparticles. The aggregates are prepared by self-assembly of the block copolymer P3HT-block-poly(ethylene glycol) (P3HT-b-PEG) into micelles, with the P3HT aggregates constituting the micelles' core. Irrespective of temperature, we find from the intensity ratio between the 0-1 and 0-0 peaks in the PL spectra that the P3HT aggregates are of H-type nature, as expected from π-stacked conjugated thiophene backbones. Moreover, the distributions of the PL peak ratios demonstrate a large variation of disorder between micelles (inter-aggregate disorder) and within individual aggregates (intra-aggregate disorder). Upon cooling from RT to LT, the PL spectra red-shift by 550 cm-1, and the energy of the (effective) carbon-bond stretch mode is reduced by 100 cm-1. These spectral changes indicate that the P3HT backbone in the P3HT-b-PEG copolymer does not fully planarize before aggregation at RT and that upon cooling, partial planarization occurs. This intra-chain torsional disorder is ultimately responsible for the intra- and inter-aggregate disorder. These findings are supported by temperature-dependent absorption spectra on thin P3HT films. The interplay between intra-chain, intra-aggregate, and inter-aggregate disorder is key for the bulk photophysical properties of nanoparticles based on conjugated polymers, for example, in hierarchical (super-) structures. Ultimately, these properties determine the usefulness of such structures in hybrid organic-inorganic materials, for example, in (bio-)sensing and optoelectronics applications.
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Affiliation(s)
- Patrick Beer
- Spectroscopy of Soft Matter, University of Bayreuth, 95440 Bayreuth, Germany
| | - Paul M Reichstein
- Applied Functional Polymers, University of Bayreuth, 95440 Bayreuth, Germany
| | - Konstantin Schötz
- Soft Matter Optoelectronics, University of Bayreuth, 95440 Bayreuth, Germany
| | - Dominic Raithel
- Spectroscopy of Soft Matter, University of Bayreuth, 95440 Bayreuth, Germany
| | - Mukundan Thelakkat
- Applied Functional Polymers, University of Bayreuth, 95440 Bayreuth, Germany.,Bavarian Polymer Institute, University of Bayreuth, 95440 Bayreuth, Germany.,Bayreuther Institut für Makromolekülforschung (BIMF), University of Bayreuth, 95440 Bayreuth, Germany
| | - Jürgen Köhler
- Spectroscopy of Soft Matter, University of Bayreuth, 95440 Bayreuth, Germany.,Bavarian Polymer Institute, University of Bayreuth, 95440 Bayreuth, Germany.,Bayreuther Institut für Makromolekülforschung (BIMF), University of Bayreuth, 95440 Bayreuth, Germany
| | - Fabian Panzer
- Soft Matter Optoelectronics, University of Bayreuth, 95440 Bayreuth, Germany
| | - Richard Hildner
- Spectroscopy of Soft Matter, University of Bayreuth, 95440 Bayreuth, Germany.,Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
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2
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Raul BAL, Luponosov YN, Yang W, Surin NM, Douhéret O, Min J, Jansen TLC, Ponomarenko SA, Pshenichnikov MS. Excited state dynamics and exciton diffusion in triphenylamine/dicyanovinyl push-pull small molecule for organic optoelectronics. Sci Rep 2020; 10:21198. [PMID: 33273567 PMCID: PMC7713310 DOI: 10.1038/s41598-020-78197-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/17/2020] [Indexed: 11/11/2022] Open
Abstract
Triphenylamine-based small push–pull molecules have recently attracted substantial research attention due to their unique optoelectronic properties. Here, we investigate the excited state de-excitation dynamics and exciton diffusion in TPA-T-DCV-Ph-F small molecule, having simple chemical structure with asymmetrical architecture and end-capped with electron-withdrawing p-fluorodicyanovinyl group. The excited state lifetime in diluted solutions (0.04 ns in toluene and 0.4 ns in chloroform) are found to be surprisingly shorter compared to the solid state (3 ns in PMMA matrix). Time-dependent density functional theory indicates that this behavior originates from non-radiative relaxation of the excited state through a conical intersection between the ground and singlet excited state potential energy surfaces. Exciton diffusion length of ~ 16 nm in solution processed films was retrieved by employing time-resolved photoluminescence volume quenching measurements with Monte Carlo simulations. As means of investigating the device performance of TPA-T-DCV-Ph-F, we manufactured solution and vacuum processed bulk heterojunction solar cells that yielded efficiencies of ~ 1.5% and ~ 3.7%, respectively. Our findings demonstrate that the short lifetime in solutions does not hinder per se long exciton diffusion length in films thereby granting applications of TPA-T-DCV-Ph-F and similar push–pull molecules in vacuum and solution processable devices.
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Affiliation(s)
- Benedito A L Raul
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, the Netherlands
| | - Yuriy N Luponosov
- Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya 70, Moscow, 117393, Russia.,Chemistry Department, Moscow State University, 1/3 Leninskie Gory, Moscow, 119991, Russia
| | - Wenyan Yang
- The Institute for Advanced Studies, Wuhan University, Wuhan City, 430072, Hubei Province, China
| | - Nikolay M Surin
- Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya 70, Moscow, 117393, Russia
| | - Olivier Douhéret
- Materia Nova R&D Center, Avenue Nicolas Copernic 3, 7000, Mons, Belgium
| | - Jie Min
- The Institute for Advanced Studies, Wuhan University, Wuhan City, 430072, Hubei Province, China.,Key Laboratory of Materials Processing and Mold (Zhengzhou University), Ministry of Education, Zhengzhou, 450002, China
| | - Thomas L C Jansen
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, the Netherlands
| | - Sergei A Ponomarenko
- Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya 70, Moscow, 117393, Russia.,Chemistry Department, Moscow State University, 1/3 Leninskie Gory, Moscow, 119991, Russia
| | - Maxim S Pshenichnikov
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, the Netherlands.
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3
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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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4
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Wilma K, Shu CC, Scherf U, Hildner R. Visualizing Hidden Ultrafast Processes in Individual Molecules by Single-Pulse Coherent Control. J Am Chem Soc 2018; 140:15329-15335. [DOI: 10.1021/jacs.8b08674] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kevin Wilma
- Soft Matter Spectroscopy, University of Bayreuth, 95440 Bayreuth, Germany
| | - Chuan-Cun Shu
- Institute of Super-Microstructure and Ultrafast Process in Advanced Materials, School of Physics and Electronics, Central South University, Changsha 410083, China
- School of Engineering and Information Technology, University of New South Wales, Canberra, Australian Capital Territory 2600, Australia
| | - Ullrich Scherf
- Fachbereich C − Mathematik und Naturwissenschaften and Institut für Polymertechnologie, Universität Wuppertal, 42097 Wuppertal, Germany
| | - Richard Hildner
- Soft Matter Spectroscopy, University of Bayreuth, 95440 Bayreuth, Germany
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5
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Baderschneider S, Scherf U, Köhler J, Hildner R. Influence of the Conjugation Length on the Optical Spectra of Single Ladder-Type (p-Phenylene) Dimers and Polymers. J Phys Chem A 2016; 120:233-40. [PMID: 26696134 DOI: 10.1021/acs.jpca.5b10879] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We employ low-temperature single-molecule photoluminescence spectroscopy on a π-conjugated ladder-type (p-phenylene) dimer and the corresponding polymer methyl-substituted ladder-type poly(p-phenylene), MeLPPP, to study the impact of the conjugation length (π-electron delocalization) on their optical properties on a molecular scale. Our data show that the linear electron-phonon coupling to intramolecular vibrational modes is very sensitive to the conjugation length, a well-known behavior of organic (macro-) molecules. In particular, the photoluminescence spectra of single dimers feature a rather strong low-energy (150 cm(-1)) skeletal mode of the backbone, which does not appear in the spectra of individual chromophores on single MeLPPP chains. We attribute this finding to a strongly reduced electron-phonon coupling strength and/or vibrational energy of this mode for MeLPPP with its more delocalized π-electron system as compared to the dimer. In contrast, the line widths of the purely electronic zero-phonon lines (ZPL) in single-molecule spectra do not show differences between the dimer and MeLPPP; for both systems the ZPLs are apparently broadened by fast unresolved spectral diffusion. Finally, we demonstrate that the low-temperature ensemble photoluminescence spectrum of the dimer cannot be reproduced by the distribution of spectral positions of the ZPLs. The dimer's bulk spectrum is rather apparently broadened by electron-phonon coupling to the low-energy skeletal mode, whereas for MeLPPP the inhomogeneous bulk line shape resembles the distribution of spectral positions of the ZPLs of single chromophores.
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Affiliation(s)
- Sebastian Baderschneider
- Experimentalphysik IV and Bayreuth Institute for Macromolecular Research (BIMF), Universität Bayreuth , 95440 Bayreuth, Germany
| | - Uli Scherf
- Fachbereich C - Mathematik und Naturwissenschaften and Institut für Polymertechnologie, Universität Wuppertal , Gauss-Strasse 20, 42097 Wuppertal, Germany
| | - Jürgen Köhler
- Experimentalphysik IV and Bayreuth Institute for Macromolecular Research (BIMF), Universität Bayreuth , 95440 Bayreuth, Germany
| | - Richard Hildner
- Experimentalphysik IV and Bayreuth Institute for Macromolecular Research (BIMF), Universität Bayreuth , 95440 Bayreuth, Germany
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6
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Single Molecule Studies of a Ladder Type Conjugated Polymer: Vibronic Spectra, Line Widths, and Energy Transfer. Macromol Rapid Commun 2015; 36:1096-102. [DOI: 10.1002/marc.201400739] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 02/25/2015] [Indexed: 11/07/2022]
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7
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Albuquerque RQ, Hofmann CC, Köhler J, Köhler A. Diffusion-Limited Energy Transfer in Blends of Oligofluorenes with an Anthracene Derivative. J Phys Chem B 2011; 115:8063-70. [DOI: 10.1021/jp202333w] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rodrigo Q. Albuquerque
- Experimental Physics II, Universität Bayreuth Universitätstrasse 30, 95440 Bayreuth, Germany
| | - Christiane C. Hofmann
- Experimental Physics IV, Universität Bayreuth Universitätstrasse 30, 95440 Bayreuth, Germany
| | - Jürgen Köhler
- Experimental Physics IV, Universität Bayreuth Universitätstrasse 30, 95440 Bayreuth, Germany
| | - Anna Köhler
- Experimental Physics II, Universität Bayreuth Universitätstrasse 30, 95440 Bayreuth, Germany
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8
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Stöferle T, Moll N, Wahlbrink T, Bolten J, Mollenhauer T, Scherf U, Mahrt RF. Ultracompact silicon/polymer laser with an absorption-insensitive nanophotonic resonator. NANO LETTERS 2010; 10:3675-3678. [PMID: 20722400 DOI: 10.1021/nl102149y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A planar nanophotonic Fabry-Perot-like resonator that can defy strong absorption of about 20 000 cm(-1) in the cavity material is demonstrated. Visible laser emission is observed from two silicon subwavelength-sized high index contrast gratings with embedded polymer gain material. The size of the laser is reduced by an order of magnitude compared to established designs based on photonic bandgap structures. As silicon constitutes the most common carrier for electronics, the cost-efficient integration of compact laser sources for visible wavelengths comes within reach.
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Affiliation(s)
- Thilo Stöferle
- IBM Research - Zurich, Saumerstrasse 4, CH-8803 Rüschlikon, Switzerland.
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9
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High photoluminescence quantum yield due to intramolecular energy transfer in the Super Yellow conjugated copolymer. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.03.030] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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10
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Hildner R, Winterling L, Lemmer U, Scherf U, Köhler J. Single-molecule spectroscopy on a ladder-type conjugated polymer: electron-phonon coupling and spectral diffusion. Chemphyschem 2009; 10:2524-34. [PMID: 19708051 DOI: 10.1002/cphc.200900445] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We employ low-temperature single-molecule spectroscopy combined with pattern recognition techniques for data analysis on a methyl-substituted ladder-type poly(para-phenylene) (MeLPPP) to investigate the electron-phonon coupling to low-energy vibrational modes as well as the origin of the strong spectral diffusion processes observed for this conjugated polymer. The results indicate weak electron-phonon coupling to low-frequency vibrations of the surrounding matrix of the chromophores, and that low-energy intrachain vibrations of the conjugated backbone do not couple to the electronic transitions of MeLPPP at low temperatures. Furthermore, these findings suggest that the main line-broadening mechanism of the zero-phonon lines of MeLPPP is fast, unresolved spectral diffusion, which arises from conformational fluctuations of the side groups attached to the MeLPPP backbone as well as of the surrounding host material.
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Affiliation(s)
- Richard Hildner
- Experimentalphysik IV and Bayreuther Institut für Makromolekülforschung (BIMF), Universität Bayreuth, Universitätsstrasse 30, 95447 Bayreuth, Germany
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11
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Toffanin S, Capelli R, Hwu TY, Wong KT, Plötzing T, Först M, Muccini M. Molecular Host−Guest Energy-Transfer System with an Ultralow Amplified Spontaneous Emission Threshold Employing an Ambipolar Semiconducting Host Matrix. J Phys Chem B 2009; 114:120-7. [DOI: 10.1021/jp909003n] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Stefano Toffanin
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via P. Gobetti 101, I-40129 Bologna, Italy, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and RWTH Aachen University, Institut für Halbleitertechnik, Sommerfeldstrasse 24, 52074 Aachen, Germany
| | - Raffaella Capelli
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via P. Gobetti 101, I-40129 Bologna, Italy, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and RWTH Aachen University, Institut für Halbleitertechnik, Sommerfeldstrasse 24, 52074 Aachen, Germany
| | - Tsyr-Yuan Hwu
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via P. Gobetti 101, I-40129 Bologna, Italy, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and RWTH Aachen University, Institut für Halbleitertechnik, Sommerfeldstrasse 24, 52074 Aachen, Germany
| | - Ken-Tsung Wong
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via P. Gobetti 101, I-40129 Bologna, Italy, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and RWTH Aachen University, Institut für Halbleitertechnik, Sommerfeldstrasse 24, 52074 Aachen, Germany
| | - Tobias Plötzing
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via P. Gobetti 101, I-40129 Bologna, Italy, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and RWTH Aachen University, Institut für Halbleitertechnik, Sommerfeldstrasse 24, 52074 Aachen, Germany
| | - Michael Först
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via P. Gobetti 101, I-40129 Bologna, Italy, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and RWTH Aachen University, Institut für Halbleitertechnik, Sommerfeldstrasse 24, 52074 Aachen, Germany
| | - Michele Muccini
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via P. Gobetti 101, I-40129 Bologna, Italy, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and RWTH Aachen University, Institut für Halbleitertechnik, Sommerfeldstrasse 24, 52074 Aachen, Germany
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12
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Ernst D, Hildner R, Hippius C, Würthner F, Köhler J. Photoblinking dynamics in single calix[4]arene-linked perylene bisimide dimers. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.09.096] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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13
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Hofmann CC, Bauer P, Haque SA, Thelakkat M, Köhler J. Energy- and charge-transfer processes in flexible organic donor-acceptor dyads. J Chem Phys 2009; 131:144512. [DOI: 10.1063/1.3245955] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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14
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Laquai F, Park YS, Kim JJ, Basché T. Excitation Energy Transfer in Organic Materials: From Fundamentals to Optoelectronic Devices. Macromol Rapid Commun 2009; 30:1203-31. [DOI: 10.1002/marc.200900309] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Accepted: 05/12/2009] [Indexed: 11/09/2022]
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15
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16
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Hildner R, Lemmer U, Scherf U, Köhler J. Continuous-wave two-photon spectroscopy on a ladder-type conjugated polymer. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.10.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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