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Reiker T, Liu Z, Winter C, Cappellari MV, Abradelo DG, Strassert CA, Zhang D, Zacharias H. Ultrafast electron dynamics in excited states of conjugated thiophene-fluorene organic polymer (pF8T2) thin films. Phys Chem Chem Phys 2024; 26:4736-4751. [PMID: 38251969 DOI: 10.1039/d3cp00502j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
The electronic states of poly(9,9-dioctylfluorenyl-alt-bithiophene) pF8T2 on H/Si(100) substrates, prototypical for organic photovoltaics, were investigated by ultrafast photoelectron spectroscopy and by time-resolved fluorescence studies. Occupied and unoccupied electronic states were analysed by ultraviolet photoelectron spectroscopy (UPS), static and dynamic femtosecond two-photon photoemission (2PPE), and time-correlated single photon counting (TCSPC). Time-resolved measurements allow assessment of population lifetimes of intermediate states. The combination of time-resolved photoelectron spectroscopy and fluorescence excitation allows following the electronic dynamics in excited states from the femtosecond to the nanosecond time scale. For this prototypical material the electron kinetic energy resolved lifetimes range from about a few tens of femtoseconds up to hundreds of picoseconds. After annealing these types of organic thin films the efficiency of organic solar cells usually increases. We show that annealing does not influence the initial ultrafast charge generation processes, but the long-lived states. However, the nanosecond scale fluorescence lifetimes measured by TCSPC are prolonged after annealing, which therefore is identified as the cause of a greater exciton diffusion range and thus is beneficial for charge carrier extraction.
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Affiliation(s)
- T Reiker
- Center for Soft Nanoscience, University of Münster, 48149 Münster, Germany.
- Physics Institute, University of Münster, 48149 Münster, Germany
| | - Z Liu
- Organic Solids Laboratory, Institute of Chemistry, Chinese Academy of Science, Beijing 100190, P. R. China
| | - C Winter
- Physics Institute, University of Münster, 48149 Münster, Germany
| | - M V Cappellari
- Center for Nanotechnology and Institute for Inorganic and Analytical Chemistry, University of Münster, Heisenbergstraße 11, 48149 Münster, Germany
| | - D Gonzalez Abradelo
- Center for Nanotechnology and Institute for Inorganic and Analytical Chemistry, University of Münster, Heisenbergstraße 11, 48149 Münster, Germany
| | - C A Strassert
- Center for Nanotechnology and Institute for Inorganic and Analytical Chemistry, University of Münster, Heisenbergstraße 11, 48149 Münster, Germany
| | - D Zhang
- Organic Solids Laboratory, Institute of Chemistry, Chinese Academy of Science, Beijing 100190, P. R. China
| | - H Zacharias
- Center for Soft Nanoscience, University of Münster, 48149 Münster, Germany.
- Physics Institute, University of Münster, 48149 Münster, Germany
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Zhang H, Li T, Liu B, Ma TN, Huang L, Bai ZM, Lu D. Effect and Mechanism of Solvent Properties on Solution Behavior and Films Condensed State Structure for the Semi-rigid Conjugated Polymers. CHINESE JOURNAL OF POLYMER SCIENCE 2021. [DOI: 10.1007/s10118-021-2555-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Martelo LM, das Neves TFP, Figueiredo J, Marques L, Fedorov A, Charas A, Berberan-Santos MN, Burrows HD. Towards the Development of a Low-Cost Device for the Detection of Explosives Vapors by Fluorescence Quenching of Conjugated Polymers in Solid Matrices. SENSORS 2017; 17:s17112532. [PMID: 29099776 PMCID: PMC5712976 DOI: 10.3390/s17112532] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 10/25/2017] [Accepted: 10/30/2017] [Indexed: 12/04/2022]
Abstract
Conjugated polymers (CPs) have proved to be promising chemosensory materials for detecting nitroaromatic explosives vapors, as they quickly convert a chemical interaction into an easily-measured high-sensitivity optical output. The nitroaromatic analytes are strongly electron-deficient, whereas the conjugated polymer sensing materials are electron-rich. As a result, the photoexcitation of the CP is followed by electron transfer to the nitroaromatic analyte, resulting in a quenching of the light-emission from the conjugated polymer. The best CP in our studies was found to be poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-bithiophene] (F8T2). It is photostable, has a good absorption between 400 and 450 nm, and a strong and structured fluorescence around 550 nm. Our studies indicate up to 96% quenching of light-emission, accompanied by a marked decrease in the fluorescence lifetime, upon exposure of the films of F8T2 in ethyl cellulose to nitrobenzene (NB) and 1,3-dinitrobenzene (DNB) vapors at room temperature. The effects of the polymeric matrix, plasticizer, and temperature have been studied, and the morphology of films determined by scanning electron microscopy (SEM) and confocal fluorescence microscopy. We have used ink jet printing to produce sensor films containing both sensor element and a fluorescence reference. In addition, a high dynamic range, intensity-based fluorometer, using a laser diode and a filtered photodiode was developed for use with this system.
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Affiliation(s)
- Liliana M Martelo
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
- Centro de Química-Física Molecular (CQFM) and the Institute of Nanoscience and Nanotechnology (IN), Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal.
| | | | - João Figueiredo
- Institute of Systems and Robotics (ISR), University of Coimbra, 3030-290 Coimbra, Portugal.
| | - Lino Marques
- Institute of Systems and Robotics (ISR), University of Coimbra, 3030-290 Coimbra, Portugal.
| | - Alexander Fedorov
- Institute of Systems and Robotics (ISR), University of Coimbra, 3030-290 Coimbra, Portugal.
| | - Ana Charas
- Instituto de Telecomunicações, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal.
| | - Mário N Berberan-Santos
- Centro de Química-Física Molecular (CQFM) and the Institute of Nanoscience and Nanotechnology (IN), Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal.
| | - Hugh D Burrows
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
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Farcas A, Assaf KI, Resmerita AM, Cantin S, Balan M, Aubert PH, Nau WM. Cucurbit[7]uril-based fluorene polyrotaxanes. Eur Polym J 2016. [DOI: 10.1016/j.eurpolymj.2016.08.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Pires F, Ferreira Q, Rodrigues CA, Morgado J, Ferreira FC. Neural stem cell differentiation by electrical stimulation using a cross-linked PEDOT substrate: Expanding the use of biocompatible conjugated conductive polymers for neural tissue engineering. Biochim Biophys Acta Gen Subj 2015; 1850:1158-68. [DOI: 10.1016/j.bbagen.2015.01.020] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 01/24/2015] [Accepted: 01/30/2015] [Indexed: 12/23/2022]
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6
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Fujiki M, Donguri Y, Zhao Y, Nakao A, Suzuki N, Yoshida K, Zhang W. Photon magic: chiroptical polarisation, depolarisation, inversion, retention and switching of non-photochromic light-emitting polymers in optofluidic medium. Polym Chem 2015. [DOI: 10.1039/c4py01337a] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A circularly polarised photon hand, l- and r-, was not a deterministic factor for the induced chiroptical sign of π-conjugated polymer aggregates. This anomaly originates from circular dichroism inversion characteristics between shorter and longer π–π* bands.
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Affiliation(s)
- Michiya Fujiki
- Graduate School of Materials Science
- Nara Institute of Science and Technology
- Ikoma
- Japan
| | - Yuri Donguri
- Graduate School of Materials Science
- Nara Institute of Science and Technology
- Ikoma
- Japan
| | - Yin Zhao
- Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
| | - Ayako Nakao
- Graduate School of Materials Science
- Nara Institute of Science and Technology
- Ikoma
- Japan
| | - Nozomu Suzuki
- Graduate School of Materials Science
- Nara Institute of Science and Technology
- Ikoma
- Japan
| | - Kana Yoshida
- Graduate School of Materials Science
- Nara Institute of Science and Technology
- Ikoma
- Japan
| | - Wei Zhang
- Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
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Huo MM, Liang R, Xing YD, Hu R, Zhao NJ, Zhang W, Fu LM, Ai XC, Zhang JP, Hou JH. Side-chain effects on the solution-phase conformations and charge photogeneration dynamics of low-bandgap copolymers. J Chem Phys 2014; 139:124904. [PMID: 24089801 DOI: 10.1063/1.4821751] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Solution-phase conformations and charge photogeneration dynamics of a pair of low-bandgap copolymers based on benzo[1,2-b:4,5-b(')]dithiophene (BDT) and thieno[3,4-b]thiophene (TT), differed by the respective carbonyl (-C) and ester (-E) substituents at the TT units, were comparatively investigated by using near-infrared time-resolved absorption (TA) spectroscopy at 25 °C and 120 °C. Steady-state and TA spectroscopic results corroborated by quantum chemical analyses prove that both PBDTTT-C and PBDTTT-E in chlorobenzene solutions are self-aggregated; however, the former bears a relatively higher packing order. Specifically, PBDTTT-C aggregates with more π-π stacked domains, whereas PBDTTT-E does with more random coils interacting strongly at the chain intersections. At 25 °C, the copolymers exhibit comparable exciton lifetimes (~1 ns) and fluorescence quantum yields (~2%), but distinctly different charge photogeneration dynamics: PBDTTT-C on photoexcitation gives rise to a branching ratio of charge separated (CS) over charge transfer (CT) states more than 20% higher than PBDTTT-E does, correlating with their photovoltaic performance. Temperature and excitation-wavelength dependent exciton∕charge dynamics suggest that the CT states localize at the chain intersections that are survivable up to 120 °C, and that the excitons and the CS states inhabit the stretched strands and the also thermally robust orderly stacked domains. The stable self-aggregation structures and the associated primary charge dynamics of the PBDTTT copolymers in solutions are suggested to impact intimately on the morphologies and the charge photogeneration efficiency of the solid-state photoactive layers.
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Affiliation(s)
- Ming-Ming Huo
- Center for Condensed Matter Science and Technology, Department of Physics, Harbin Institute of Technology, Harbin 150001, China
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Galvão AM, Di Paolo RE, Maçanita AL, Naqvi KR. Model for conformational relaxation of flexible conjugated polymers: application to p-phenylenevinylene trimers in nonpolar solvents. Chemphyschem 2013; 14:583-90. [PMID: 23364935 DOI: 10.1002/cphc.201200869] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Indexed: 11/08/2022]
Abstract
Photoexcitation of flexible conjugated polymers is invariably followed by a fast conformational/torsional relaxation towards a configuration favouring coplanarity of the conjugated segments. In general, the experimental relaxation rate constant (k(CR)) depends on the solvent viscosity (η) and temperature (T), and is not proportional to T/η. A theory capable of explaining the observed dependence of k(CR) on T and η over a wide range of these variables is not available. This gap is filled here by presenting a stochastic model that includes the participation of the oligomer side chain in storing and dissipating the stresses induced by photoexcitation. The model is able to account for the softening of solute-solvent interactions and its predictions are found to be in excellent agreement with the observed relaxation rate constants of a series of substituted p-phenylenevinylene trimers [ChemPhysChem 2009, 10, 448-454] on T, η and the size of the side-chains.
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Affiliation(s)
- Adelino M Galvão
- Centro de Química Estrutural, Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais s/n, 1049-001 Lisbon, Portugal.
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Xie LH, Yin CR, Lai WY, Fan QL, Huang W. Polyfluorene-based semiconductors combined with various periodic table elements for organic electronics. Prog Polym Sci 2012. [DOI: 10.1016/j.progpolymsci.2012.02.003] [Citation(s) in RCA: 248] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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10
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Li H, Sun S, Salim T, Bomma S, Grimsdale AC, Lam YM. Conjugated polymers based on dicarboxylic imide-substituted isothianaphthene and their applications in solar cells. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/pola.25021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Tapia MJ, Monteserín M, Burrows HD, Seixas de Melo JS, Pina J, Castro RAE, García S, Estelrich J. β-Phase Formation of Poly(9,9-dioctylfluorene) Induced by Liposome Phospholipid Bilayers. J Phys Chem B 2011; 115:5794-800. [DOI: 10.1021/jp2010666] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- María José Tapia
- Departamento de Química, Universidad de Burgos, Plaza Misael Bañuelos, Burgos 09001, Spain
| | - María Monteserín
- Departamento de Química, Universidad de Burgos, Plaza Misael Bañuelos, Burgos 09001, Spain
| | - Hugh D. Burrows
- Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | | | - João Pina
- Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | | | - Sonia García
- Facultat de Farmàcia, Universitat de Barcelona, Avda. Joan XXIII s/n 08028 Barcelona, Catalonia, Spain
| | - Joan Estelrich
- Facultat de Farmàcia, Universitat de Barcelona, Avda. Joan XXIII s/n 08028 Barcelona, Catalonia, Spain
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