1
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Zbiri M, Guilbert AAY. Dynamics of Polyalkylfluorene Conjugated Polymers: Insights from Neutron Spectroscopy and Molecular Dynamics Simulations. J Phys Chem B 2024; 128:6197-6206. [PMID: 38885432 DOI: 10.1021/acs.jpcb.4c01760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
The dynamics of the conjugated polymers poly(9,9-dioctylfluorene) (PF8) and poly(9,9-didodecylfluorene) (PF12), differing by the length of their side chains, is investigated in the amorphous phase using the temperature-dependent quasielastic neutron scattering (QENS) technique. The neutron spectroscopy measurements are synergistically underpinned by molecular dynamics (MD) simulations. The probe is focused on the picosecond time scale, where the structural dynamics of both PF8 and PF12 would mainly be dominated by the motions of their side chains. The measurements highlighted temperature-induced dynamics, reflected in the broadening of the QENS spectra upon heating. The MD simulations reproduced well the observations; hence, the neutron measurements validate the MD force fields, the adopted amorphous model structures, and the numerical procedure. As the QENS spectra are dominated by the signal from the hydrogens on the backbones and side chains of PF8 and PF12, extensive analysis of the MD simulations allowed the following: (i) tagging these hydrogens, (ii) estimating their contributions to the self-part of the van Hove functions and hence to the QENS spectra, and (iii) determining the activation energies of the different motions involving the tagged hydrogens. PF12 is found to exhibit QENS spectra broader than those of PF8, indicating a more pronounced motion of the didodecyl chains of PF12 as compared to dioctyl chains of PF8. This is in agreement with the outcome of our MD analysis: (i) confirming a lower glass transition temperature of PF12 compared to PF8, (ii) showing PF12 having a lower density than PF8, and (iii) highlighting lower activation energies of the motions of PF12 in comparison with PF8. This study helped to gain insights into the temperature-induced side-chain dynamics of the PF8 and PF12 conjugated polymers, influencing their stability, which could potentially impact, on the practical side, the performance of the associated optoelectronic active layer.
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Affiliation(s)
- Mohamed Zbiri
- Institut Laue-Langevin, 71 Avenue des Martyrs, Grenoble Cedex 9 38042, France
| | - Anne A Y Guilbert
- Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, U.K
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2
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Mejri H, Haidisch A, Krebsbach P, Seiberlich M, Hernandez-Sosa G, Perevedentsev A. Gas-assisted blade-coating of organic semiconductors: molecular assembly, device fabrication and complex thin-film structuring. NANOSCALE 2022; 14:17743-17753. [PMID: 36421075 DOI: 10.1039/d2nr05947a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The competitive performance of optoelectronic devices based on advanced organic semiconductors increasingly calls for suitably scalable processing schemes to capitalise on their application potential. With performance benchmarks typically established by spin-coating fabrication, doctor-blade deposition represents a widely available roll-to-roll-compatible means for the preparation of large-area samples and establishing the device upscaling potential. However, the inherently slower film formation kinetics often result in unfavourable active layer microstructures, requiring empirical and material-inefficient optimisation of solutions to reach the performance of spin-coated devices. Here we present a versatile approach to achieving performance parity for spin- and blade-coated devices using in situ gas-assisted drying enabled by a modular 3D-printed attachment. This is illustrated for organic photodetectors (OPDs) featuring bulk heterojunction active layers comprising blends of P3HT and PM6 polymer donors with the nonfullerene acceptor ITIC. Compared to conventionally blade-coated devices, mild drying gas pressures of 0.5-2 bar yield up to a 10-fold enhancement of specific detectivity by maximising external quantum efficiency and suppressing dark-current. Furthermore, controlling gas flux distribution enables one-step fabrication of 1D chain conformation and 2D chain orientation patterns in, respectively, PFO and P3HT:N2200 blend films, opening the possibility for high-throughput fabrication of devices with complex structured active layers.
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Affiliation(s)
- Hadhemi Mejri
- Light Technology Institute, Karlsruhe Institute of Technology, Engesser Str. 13, 76131 Karlsruhe, Germany.
- InnovationLab, Speyerer Str. 4, 69115 Heidelberg, Germany
| | - Anika Haidisch
- Light Technology Institute, Karlsruhe Institute of Technology, Engesser Str. 13, 76131 Karlsruhe, Germany.
- InnovationLab, Speyerer Str. 4, 69115 Heidelberg, Germany
| | - Peter Krebsbach
- Light Technology Institute, Karlsruhe Institute of Technology, Engesser Str. 13, 76131 Karlsruhe, Germany.
- InnovationLab, Speyerer Str. 4, 69115 Heidelberg, Germany
| | - Mervin Seiberlich
- Light Technology Institute, Karlsruhe Institute of Technology, Engesser Str. 13, 76131 Karlsruhe, Germany.
- InnovationLab, Speyerer Str. 4, 69115 Heidelberg, Germany
| | - Gerardo Hernandez-Sosa
- Light Technology Institute, Karlsruhe Institute of Technology, Engesser Str. 13, 76131 Karlsruhe, Germany.
- InnovationLab, Speyerer Str. 4, 69115 Heidelberg, Germany
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Aleksandr Perevedentsev
- Light Technology Institute, Karlsruhe Institute of Technology, Engesser Str. 13, 76131 Karlsruhe, Germany.
- InnovationLab, Speyerer Str. 4, 69115 Heidelberg, Germany
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3
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Siemons N, Pearce D, Cendra C, Yu H, Tuladhar SM, Hallani RK, Sheelamanthula R, LeCroy GS, Siemons L, White AJP, McCulloch I, Salleo A, Frost JM, Giovannitti A, Nelson J. Impact of Side-Chain Hydrophilicity on Packing, Swelling, and Ion Interactions in Oxy-Bithiophene Semiconductors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2204258. [PMID: 35946142 DOI: 10.1002/adma.202204258] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/28/2022] [Indexed: 06/15/2023]
Abstract
Exchanging hydrophobic alkyl-based side chains to hydrophilic glycol-based side chains is a widely adopted method for improving mixed-transport device performance, despite the impact on solid-state packing and polymer-electrolyte interactions being poorly understood. Presented here is a molecular dynamics (MD) force field for modeling alkoxylated and glycolated polythiophenes. The force field is validated against known packing motifs for their monomer crystals. MD simulations, coupled with X-ray diffraction (XRD), show that alkoxylated polythiophenes will pack with a "tilted stack" and straight interdigitating side chains, whilst their glycolated counterpart will pack with a "deflected stack" and an s-bend side-chain configuration. MD simulations reveal water penetration pathways into the alkoxylated and glycolated crystals-through the π-stack and through the lamellar stack respectively. Finally, the two distinct ways triethylene glycol polymers can bind to cations are revealed, showing the formation of a metastable single bound state, or an energetically deep double bound state, both with a strong side-chain length dependence. The minimum energy pathways for the formation of the chelates are identified, showing the physical process through which cations can bind to one or two side chains of a glycolated polythiophene, with consequences for ion transport in bithiophene semiconductors.
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Affiliation(s)
- Nicholas Siemons
- Department of Physics, Imperial College, London, Exhibition Rd, South Kensington, London, SW7 2AZ, UK
| | - Drew Pearce
- Department of Physics, Imperial College, London, Exhibition Rd, South Kensington, London, SW7 2AZ, UK
| | - Camila Cendra
- Department of Materials Science and Engineering, Stanford University, 450 Serra Mall, Stanford, CA, 94305, USA
| | - Hang Yu
- Department of Physics, Imperial College, London, Exhibition Rd, South Kensington, London, SW7 2AZ, UK
| | - Sachetan M Tuladhar
- Department of Physics, Imperial College, London, Exhibition Rd, South Kensington, London, SW7 2AZ, UK
| | - Rawad K Hallani
- Physical Sciences and Engineering Division, KAUST Solar Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
| | - Rajendar Sheelamanthula
- Physical Sciences and Engineering Division, KAUST Solar Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
| | - Garrett S LeCroy
- Department of Materials Science and Engineering, Stanford University, 450 Serra Mall, Stanford, CA, 94305, USA
| | - Lucas Siemons
- Structural biology of cells and viruses laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Andrew J P White
- Chemical Crystallography Laboratory, Department of Chemistry, Imperial College London White City Campus, 82 Wood Lane, London, W12 0BZ, UK
| | - Iain McCulloch
- Department of Chemistry, University of Oxford, Oxford, OX1 2JD, UK
| | - Alberto Salleo
- Department of Materials Science and Engineering, Stanford University, 450 Serra Mall, Stanford, CA, 94305, USA
| | - Jarvist M Frost
- Department of Physics, Imperial College, London, Exhibition Rd, South Kensington, London, SW7 2AZ, UK
| | - Alexander Giovannitti
- Department of Materials Science and Engineering, Stanford University, 450 Serra Mall, Stanford, CA, 94305, USA
| | - Jenny Nelson
- Department of Physics, Imperial College, London, Exhibition Rd, South Kensington, London, SW7 2AZ, UK
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4
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Wang B, Ye H, Riede M, Bradley DDC. Chain Conformation Control of Fluorene-Benzothiadiazole Copolymer Light-Emitting Diode Efficiency and Lifetime. ACS APPLIED MATERIALS & INTERFACES 2021; 13:2919-2931. [PMID: 33411508 DOI: 10.1021/acsami.0c18490] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The β-phase, in which the intermonomer torsion angle of a fraction of chain segments approaches ∼180°, is an intriguing conformational microstructure of the widely studied light-emitting polymer poly(9,9-dioctylfluorene) (PFO). Its generation can in turn be used to significantly improve the performance of PFO emission-layer-based light-emitting diodes (LEDs). Here, we report the generation of β-phase chain segments in a copolymer, 90F8:10BT, containing 90% 9,9-dioctylfluorene (F8) and 10% 2,1,3-benzothiadiazole (BT) units and show that significant improvements in performance also ensue for LEDs with β-phase 90F8:10BT emission layers, generalizing the earlier PFO results. The β-phase was induced by both solvent vapor annealing and dipping copolymer thin films into a solvent/nonsolvent mixture. Subsequent absorption spectra show the characteristic fluorene β-phase peak at ∼435 nm, but luminescence spectra (∼530 nm peak) and quantum yields barely change, with the emission arising following efficient energy transfer to the lowest-lying excited states localized in the vicinity of the BT units. For ∼5% β-phase chain segment fraction relative to 0% β-phase, the LED luminance at 10 V increased by ∼25% to 5940 cd m-2, the maximum external quantum efficiency by ∼61 to 1.91%, and the operational stability from 64% luminance retention after 20 h of operation to 90%. Detailed studies addressing the underlying device physics identify a reduced hole injection barrier, higher hole mobility, correspondingly more balanced electron and hole charge transport, and decreased carrier trapping as the dominant factors. These results confirm the effectiveness of chain conformation control for fluorene-based homo- and copolymer device optimization.
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Affiliation(s)
- Bingjun Wang
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Hao Ye
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Moritz Riede
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Donal D C Bradley
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
- Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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Zhou M, He Z, Chen Y, Zhu L, Li L, Li J. Synthesis, Self-assembly, and Fluorescence Application of Bottlebrush Polyfluorene-g-Polycaprolactone with Conjugated Backbone and Crystalline Brushes. Macromol Rapid Commun 2020; 42:e2000544. [PMID: 33331036 DOI: 10.1002/marc.202000544] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/08/2020] [Indexed: 01/09/2023]
Abstract
A series of bottlebrush copolymers with conjugated backbone and crystalline branch chains, polyfluorene-g-polycaprolactone (PF-g-PCL), are synthesized by combining Suzuki cross-coupling polymerization and cationic ring-opening polymerization. The PF-g-PCLs are prepared to self-assembled in solution and thin film. Due to the J-type aggregation of the polyfluorene main chains, the self-assembly spherical micelles have been observed. Meanwhile, in film, they exhibited self-assembly ringed spherulites because of the PF microregions in the bottlebrush copolymer. As a result of the interruption of PCL side chains, the aggregation tendency of PF main chains is weakened. And both the polymer solution and solid can overcome the aggregation-caused quenching to provide more pronounced fluorescence. Especially, owing to the good processability of the PF-g-PCL, as a fluorescent ink for different substrates, they can easily be prepared as high-brightness fluorescent films that are invisible under ambient light.
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Affiliation(s)
- Mi Zhou
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, China
| | - Zejian He
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, China
| | - Yulong Chen
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, China
| | - Liangliang Zhu
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, China
| | - Li Li
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, China
| | - Jie Li
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, China
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6
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Wollmann J, Kahle FJ, Bauer I, Köhler A, Strohriegl P. Versatile Approach to Well-Defined Oligofluorenes and Polyfluorenes with Low Dispersity. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01887] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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7
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Du B, Yi J, Yan H, Wang T. Temperature Induced Aggregation of Organic Semiconductors. Chemistry 2020; 27:2908-2919. [DOI: 10.1002/chem.202002559] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Baocai Du
- School of Materials Science and Engineering Wuhan University of Technology Wuhan 430070 China
| | - Jicheng Yi
- Department of Chemistry and Energy Institute The Hong Kong University of Science and Technology Clear Water Bay Hong Kong
| | - He Yan
- Department of Chemistry and Energy Institute The Hong Kong University of Science and Technology Clear Water Bay Hong Kong
| | - Tao Wang
- School of Materials Science and Engineering Wuhan University of Technology Wuhan 430070 China
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8
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Rapid and high-resolution patterning of microstructure and composition in organic semiconductors using 'molecular gates'. Nat Commun 2020; 11:3610. [PMID: 32680991 PMCID: PMC7367850 DOI: 10.1038/s41467-020-17361-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 06/24/2020] [Indexed: 11/26/2022] Open
Abstract
Photolithography has been a major enabling tool for miniaturisation of silicon devices that underpinned the electronics revolution. Rapid, high-resolution patterning of key material characteristics would, similarly, accelerate the advent of molecular electronics and photonics. Here we advance a versatile approach employing local diffusion of functional small-molecular compounds through a solution-processed ‘molecular gate’ interlayer. Diffusion is activated using laser light or solvent vapour jets―a process that can be finely modulated down to molecule-on-demand deposition precision with almost photolithographic resolution (<5 μm) and speeds (3 mm s–1). Examples of principal pattern types are presented including molecular conformation for integrated photonics; chain orientation for polarised security features and micro-engineered electronics; and doping with local conductivity values >3 S cm–1 for improved electronic devices. Finally, we demonstrate the unique capability for one-step patterning of multiple functionalities by spatially modulating composition in ternary blends, leading to locally tunable photoluminescence from blue to red. Although high‐resolution methods such as photolithography allow for organic semiconductor patterning, they are often limited by their high complexity. Here, the authors report a versatile “molecular gate”‐based method for micro‐patterning organic semiconductor films.
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9
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Liu YD, Zhang Q, Yu XH, Liu JG, Han YC. Increasing the Content of β Phase of Poly(9,9-dioctylfluorene) by Synergistically Controlling Solution Aggregation and Extending Film-forming Time. CHINESE JOURNAL OF POLYMER SCIENCE 2019. [DOI: 10.1007/s10118-019-2259-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Eggimann HJ, Le Roux F, Herz LM. How β-Phase Content Moderates Chain Conjugation and Energy Transfer in Polyfluorene Films. J Phys Chem Lett 2019; 10:1729-1736. [PMID: 30900449 DOI: 10.1021/acs.jpclett.9b00483] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Poly(9,9-dioctylfluorene) (PFO) is a blue-light-emitting polymer exhibiting two distinct phases, namely, the disordered "glassy" phase and a more ordered β-phase. We investigate how a systematic increase in the fraction of β-phase present in PFO films controls chain conformation, photoluminescence quantum efficiency (PLQE), and the resonant energy transfer from the glassy to the β-phase. All films are prepared by the same technique, using paraffin oil as an additive to the spin-coating solution, allowing systematic tuning of the β-phase fraction. The PFO films exhibit high PLQE with values increasing to 0.72 for increasing fractions of β-phase present, with the β-phase chain conformation becoming more planar and including more repeat units. Differences in Förster radii calculated from the overlap of steady-state absorptance and emission spectra and from time-resolved ultrafast photoluminescence transients indicate that exciton diffusion within the glassy phase plays an important role in the energy transfer process.
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Affiliation(s)
- Hannah J Eggimann
- Department of Physics , University of Oxford, Clarendon Laboratory , Parks Road , Oxford OX1 3PU , United Kingdom
| | - Florian Le Roux
- Department of Physics , University of Oxford, Clarendon Laboratory , Parks Road , Oxford OX1 3PU , United Kingdom
| | - Laura M Herz
- Department of Physics , University of Oxford, Clarendon Laboratory , Parks Road , Oxford OX1 3PU , United Kingdom
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11
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Reichenberger M, Kroh D, Matrone GMM, Schötz K, Pröller S, Filonik O, Thordardottir ME, Herzig EM, Bässler H, Stingelin N, Köhler A. Controlling aggregate formation in conjugated polymers by spin-coating below the critical temperature of the disorder-order transition. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/polb.24562] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Daniel Kroh
- Experimental Physics II, University of Bayreuth; Bayreuth 95440 Germany
| | - Giovanni M. M. Matrone
- Department of Materials and Center for Plastic Electronics; Imperial College London; London SW7 2AZ United Kingdom
| | - Konstantin Schötz
- Experimental Physics II, University of Bayreuth; Bayreuth 95440 Germany
| | - Stephan Pröller
- Herzig Group, Munich School of Engineering (MSE), Technische Universität München, Lichtenbergstr. 4a; Garching 85748 Germany
| | - Oliver Filonik
- Herzig Group, Munich School of Engineering (MSE), Technische Universität München, Lichtenbergstr. 4a; Garching 85748 Germany
| | - Margret E. Thordardottir
- Herzig Group, Munich School of Engineering (MSE), Technische Universität München, Lichtenbergstr. 4a; Garching 85748 Germany
| | - Eva M. Herzig
- Dynamics and Structure Formation; University of Bayreuth; Bayreuth 95440 Germany
| | - Heinz Bässler
- Bayreuth Institute of Macromolecular Research (BIMF), University of Bayreuth; Bayreuth 95440 Germany
| | - Natalie Stingelin
- Department of Materials and Center for Plastic Electronics; Imperial College London; London SW7 2AZ United Kingdom
- School of Materials Science & Engineering and School of Chemical & Biomolecular Engineering; Georgia Institute of Technology; Atlanta Georgia 30332
| | - Anna Köhler
- Experimental Physics II, University of Bayreuth; Bayreuth 95440 Germany
- Bayreuth Institute of Macromolecular Research (BIMF), University of Bayreuth; Bayreuth 95440 Germany
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12
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Braendle A, Perevedentsev A, Cheetham NJ, Stavrinou PN, Schachner JA, Mösch-Zanetti NC, Niederberger M, Caseri WR. Homoconjugation in poly(phenylene methylene)s: A case study of non-π-conjugated polymers with unexpected fluorescent properties. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/polb.24305] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Andreas Braendle
- Department of Materials; Multifunctional Materials, ETH Zürich; Vladimir-Prelog-Weg 5 Zürich 8093 Switzerland
| | - Aleksandr Perevedentsev
- Department of Materials; Polymer Technology, ETH Zürich; Vladimir-Prelog-Weg 5 Zürich 8093 Switzerland
| | - Nathan J. Cheetham
- Department of Physics and Centre for Plastic Electronics; Imperial College London; London SW7 2AZ United Kingdom
| | - Paul N. Stavrinou
- Department of Engineering Science; University of Oxford; Oxford OX1 3PJ United Kingdom
| | - Jörg A. Schachner
- Institute of Chemistry, Inorganic Chemistry, University of Graz; Schubertstrasse 1 Graz 8010 Austria
| | - Nadia C. Mösch-Zanetti
- Institute of Chemistry, Inorganic Chemistry, University of Graz; Schubertstrasse 1 Graz 8010 Austria
| | - Markus Niederberger
- Department of Materials; Multifunctional Materials, ETH Zürich; Vladimir-Prelog-Weg 5 Zürich 8093 Switzerland
| | - Walter R. Caseri
- Department of Materials; Multifunctional Materials, ETH Zürich; Vladimir-Prelog-Weg 5 Zürich 8093 Switzerland
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Hai TAP, Sugimoto R. Synthesis and characterization of copolymers composed of 3-hexylthiophene and fluorene via chemical oxidation with FeCl3. Polym J 2016. [DOI: 10.1038/pj.2016.90] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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14
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Perevedentsev A, Chander N, Kim JS, Bradley DDC. Spectroscopic properties of poly(9,9-dioctylfluorene) thin films possessing varied fractions of β-phase chain segments: enhanced photoluminescence efficiency via conformation structuring. JOURNAL OF POLYMER SCIENCE. PART B, POLYMER PHYSICS 2016; 54:1995-2006. [PMID: 28344383 PMCID: PMC5347961 DOI: 10.1002/polb.24106] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 05/23/2016] [Indexed: 11/25/2022]
Abstract
Poly(9,9-dioctylfluorene) (PFO) is a widely studied blue-emitting conjugated polymer, the optoelectronic properties of which are strongly affected by the presence of a well-defined chain-extended "β-phase" conformational isomer. In this study, optical and Raman spectroscopy are used to systematically investigate the properties of PFO thin films featuring a varied fraction of β-phase chain segments. Results show that the photoluminescence quantum efficiency (PLQE) of PFO films is highly sensitive to both the β-phase fraction and the method by which it was induced. Notably, a PLQE of ∼69% is measured for PFO films possessing a ∼6% β-phase fraction induced by immersion in solvent/nonsolvent mixtures; this value is substantially higher than the average PLQE of ∼55% recorded for other β-phase films. Furthermore, a linear relationship is observed between the intensity ratios of selected Raman peaks and the β-phase fraction determined by commonly used absorption calibrations, suggesting that Raman spectroscopy can be used as an alternative means to quantify the β-phase fraction. As a specific example, spatial Raman mapping is used to image a mm-scale β-phase stripe patterned in a glassy PFO film, with the extracted β-phase fraction showing excellent agreement with the results of optical spectroscopy. © 2016 The Authors. Journal of Polymer Science Part B: Polymer Physics Published by Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1995-2006.
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Affiliation(s)
- Aleksandr Perevedentsev
- Department of Materials Eidgenössische Technische Hochschule (ETH) Zürich Vladimir-Prelog-Weg 5 Zürich 8093 Switzerland; Department of Physics and Centre for Plastic Electronics Imperial College London, South Kensington Campus London SW7 2AZ United Kingdom
| | - Nathan Chander
- Department of Physics and Centre for Plastic Electronics Imperial College London, South Kensington Campus London SW7 2AZ United Kingdom
| | - Ji-Seon Kim
- Department of Physics and Centre for Plastic Electronics Imperial College London, South Kensington Campus London SW7 2AZ United Kingdom
| | - Donal D C Bradley
- Department of Physics and Centre for Plastic Electronics Imperial College London, South Kensington Campus London SW7 2AZ United Kingdom; Engineering Science and Physics Departments, Mathematical, Physical and Life Sciences Division University of Oxford 9 Parks Road Oxford OX1 3PD United Kingdom
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