1
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Klenner MA, Cagnes M, Wood K, Mita K, Kishimoto M, Darwish T. Decagram scale production of deuterated mineral oil and polydecene as solvents for polymer studies in neutron scattering. Polym Chem 2020. [DOI: 10.1039/d0py00690d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Decagram scale syntheses of deuterated mineral oil (d-MO) and poly(1-decene) (d-PD) were achieved by direct catalytic hydrothermal H/D exchange reaction in D2O.
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Affiliation(s)
- Mitchell A. Klenner
- National Deuteration Facility (NDF)
- Australian Nuclear Science and Technology Organisation (ANSTO)
- Sydney
- Australia
| | - Marina Cagnes
- National Deuteration Facility (NDF)
- Australian Nuclear Science and Technology Organisation (ANSTO)
- Sydney
- Australia
| | - Kathleen Wood
- Australian Centre for Neutron Scattering (ACNS)
- Australian Nuclear Science and Technology Organisation (ANSTO)
- Sydney
- Australia
| | - Kazuki Mita
- Process Technology Laboratory
- Mitsui Chemicals
- Inc
- Sodegaura
- Japan
| | | | - Tamim Darwish
- National Deuteration Facility (NDF)
- Australian Nuclear Science and Technology Organisation (ANSTO)
- Sydney
- Australia
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2
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van de Laar T, Hooiveld E, Higler R, van der Scheer P, Sprakel J. Gel Trapping Enables Optical Spectroscopy of Single Solvated Conjugated Polymers in Equilibrium. ACS NANO 2019; 13:13185-13195. [PMID: 31647632 PMCID: PMC6887849 DOI: 10.1021/acsnano.9b06164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 10/24/2019] [Indexed: 06/10/2023]
Abstract
Single-molecule studies have provided a wealth of insight into the photophysics of conjugated polymers in the solid and desolvated state. Desolvating conjugated chains, e.g., by their embedding in inert solid matrices, invariably leads to chain collapse and the formation of intermolecular aggregates, which have a pronounced effect on their properties. By contrast, the luminescent properties of individual semiconducting polymers in their solvated and thermodynamic state remain largely unexplored. In this paper, we demonstrate a versatile gel trapping technique that enables the chemistry-free immobilization and interrogation of individual conjugated macromolecules, which retain a fully equilibrated conformation by contrast to conventional solid-state immobilization methods. We show how the technique can be used to record full luminescence spectra of single chains, to evaluate their time-resolved fluorescence, and to probe their photodynamics. Finally, we explore how the photophysics of different conjugated polymers is strongly affected by desolvation and chain collapse.
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3
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Ho XL, Wang YH, Chen PJ, Woon WY, White JD. MEH-PPV photophysics: insights from the influence of a nearby 2D quencher. NANOTECHNOLOGY 2019; 30:065702. [PMID: 30524048 DOI: 10.1088/1361-6528/aaf148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The effect of 2D quenching on single chain photophysics was investigated by spin coating 13 nm thick films of polystyrene lightly doped with MEH-PPV onto CVD grown graphene and observing the changes in several photoluminescent (PL) observables. With 99% of the PL quenched, we found a 60% drop in the PL lifetime, along with a significant blue-shift of the PL emission due to the preferential quenching of emission at longer wavelengths. During photo-bleaching, the blue spectral shift observed for isolated polymers was eliminated in the presence of the quencher up until 70% of the polymer was photo-bleached. Results were interpreted using a static disorder induced conjugation length distribution model. The quencher, by opening up a new non-radiative decay channel, ensures that excitons do not have sufficient time to migrate to nearby lower energy chromophores. The reduction of energy transfer into the lowest-energy chromophores thus reduces their rate of photo-bleaching. Finally, the difference between the quenched and non-quenched spectra allows the rate of energy transfer along the polymer backbone to be estimated at ∼2 ns-1.
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Affiliation(s)
- Xuan Long Ho
- Dept of Electrical Engineering, Yuan Ze University, Chung-Li, Taoyuan City, Taiwan
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4
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Towards optically responsive smart materials: electronic interactions between polymeric semiconductor and photochromic molecule. CHEMICAL PAPERS 2018. [DOI: 10.1007/s11696-018-0399-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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5
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Controlling Morphology and Aggregation in Semiconducting Polymers: The Role of Solvents on Lasing Emission in Poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene-vinylene]. MATERIALS 2017; 10:ma10070706. [PMID: 28773082 PMCID: PMC5551749 DOI: 10.3390/ma10070706] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 06/13/2017] [Accepted: 06/23/2017] [Indexed: 11/16/2022]
Abstract
Systematic experiments were performed to investigate solvent-dependent morphology and aggregation of the semiconducting polymer film poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene-vinylene] (MEH-PPV), which was span-cast from nonaromatic strong polarity solvents tetrahydrofuran (THF), trichloromethane (TCM) and aromatic weak polarity solvents chlorobenzene (CB), toluene, and p-xylene. The results indicated that the conformation of the spin-cast MEH-PPV films with weak aggregation such as THF and TCM demonstrated excellent lasing emission performances because of inhibiting the fluorescence quenching induced by bi-molecule process. The Atomic Force Microscope (AFM) images confirmed the distinct morphologies of the spin-cast MEH-PPV films. The amplified spontaneous emission (ASE) was investigated in a simple asymmetric slab planar waveguide structure by methods of variable stripe length (VSL) and shifting excitation stripe (SES). The amplified spontaneous emission (ASE) experiments confirmed the distinct polymer chain conformation. The conformation, which preserved from the spin-cast process, indicated the distinct interactions between solvents and MEH-PPV polymer chains. The pure film spectra were performed to confirm the effect of distinct conformation on the material energy level. This work provides insights into the morphology and aggregation effect of the spin-cast polymer films on the performances of lasers.
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6
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Wu EC, Stubbs RE, Peteanu LA, Jemison R, McCullough RD, Wildeman J. Detection of Ultralow Concentrations of Non-emissive Conjugated Polymer Aggregates via Fluorescence Correlation Spectroscopy. J Phys Chem B 2017; 121:5413-5421. [DOI: 10.1021/acs.jpcb.7b01918] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Eric C. Wu
- Department
of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Regan E. Stubbs
- Department
of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Linda A. Peteanu
- Department
of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Racquel Jemison
- Department
of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Richard D. McCullough
- Department
of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Jurjen Wildeman
- Zernike Institute of Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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7
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Peteanu LA, Chowdhury S, Wildeman J, Sfeir MY. Exciton–Exciton Annihilation as a Probe of Interchain Interactions in PPV–Oligomer Aggregates. J Phys Chem B 2017; 121:1707-1714. [DOI: 10.1021/acs.jpcb.6b11250] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Linda A. Peteanu
- Department
of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Sanchari Chowdhury
- Department
of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Jurjen Wildeman
- Zernike Institute of Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Matthew Y. Sfeir
- Center
for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
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8
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Kennes K, Dedecker P, Hutchison JA, Fron E, Uji-i H, Hofkens J, Van der Auweraer M. Field-Controlled Charge Separation in a Conductive Matrix at the Single-Molecule Level: Toward Controlling Single-Molecule Fluorescence Intermittency. ACS OMEGA 2016; 1:1383-1392. [PMID: 30023508 PMCID: PMC6044678 DOI: 10.1021/acsomega.6b00207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 11/09/2016] [Indexed: 06/07/2023]
Abstract
The fluorescence intermittency or "blinking" of single molecules of ATTO647N (ATTO) in the conductive matrix polyvinylcarbazole (PVK) is described in the presence of an external applied electric field. It is shown that due to the energy distribution of the highest occupied molecular orbital (HOMO) level of PVK, which is energetically close to the HOMO of ATTO, sporadic electron transfer occurs. As a result, the on/off dynamics of blinking can be influenced by the electric field. This field will, depending on the respective position and orientation of the dye/polymer system with respect to those of the electrodes, either enhance or suppress electron transfer from PVK to ATTO as well as the back electron transfer from reduced ATTO to PVK. After the charge-transfer step, the applied field will pull the hole in PVK away from the dye, increasing the overall time the dye resides in a dark state.
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Affiliation(s)
- Koen Kennes
- Molecular
Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
| | - Peter Dedecker
- Molecular
Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
| | - James A. Hutchison
- ISIS
& icFRC, University of Strasbourg and
CNRS UMR 7006, 8 allée
Gaspard Monge, Strasbourg 67000, France
- School
of Chemistry and Bio21 Institute, University
of Melbourne, Melbourne, Victoria 3010, Australia
| | - Eduard Fron
- Molecular
Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
| | - Hiroshi Uji-i
- Molecular
Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
- RIES, Hokkaido
University, N20W10, Kita-Ward, Sapporo 001-0020, Japan
| | - Johan Hofkens
- Molecular
Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
- RIES, Hokkaido
University, N20W10, Kita-Ward, Sapporo 001-0020, Japan
| | - Mark Van der Auweraer
- Molecular
Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
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9
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Rajwar D, Ammanath G, Cheema JA, Palaniappan A, Yildiz UH, Liedberg B. Tailoring Conformation-Induced Chromism of Polythiophene Copolymers for Nucleic Acid Assay at Resource Limited Settings. ACS APPLIED MATERIALS & INTERFACES 2016; 8:8349-8357. [PMID: 26956217 DOI: 10.1021/acsami.5b12171] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Here we report on the design and synthesis of cationic water-soluble thiophene copolymers as reporters for colorimetric detection of microRNA (miRNA) in human plasma. Poly(3-alkoxythiophene) (PT) polyelectrolytes with controlled ratios of pendant groups such as triethylamine/1-methyl imidazole were synthesized for optimizing interaction with target miRNA sequence (Tseq). Incorporation of specific peptide nucleic acid (PNA) sequences with the cationic polythiophenes yielded distinguishable responses upon formation of fluorescent PT-PNA-Tseq triplex and weakly fluorescent PT-Tseq duplex, thereby enabling selective detection of target miRNA. Unlike homopolymers of PT (hPT), experimental results indicate the possibility of utilizing copolymers of PT (cPT) with appropriate ratios of pendant groups for miRNA assay in complex matrices such as plasma. As an illustration, colorimetric responses were obtained for lung cancer associated miRNA sequence (mir21) in human plasma, with a detection limit of 10 nM, illustrating the feasibility of proposed methodology for clinical applications without involving sophisticated instrumentation. The described methodology therefore possesses high potential for low-cost nucleic acid assays in resource-limited settings.
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Affiliation(s)
- Deepa Rajwar
- School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798
| | - Gopal Ammanath
- School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798
| | - Jamal Ahmed Cheema
- School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798
| | - Alagappan Palaniappan
- School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798
| | - Umit Hakan Yildiz
- Department of Chemistry, Izmir Institute of Technology , Urla, 35430 Izmir, Turkey
| | - Bo Liedberg
- School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798
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10
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Park H, Hoang DT, Paeng K, Yang J, Kaufman LJ. Conformation-Dependent Photostability among and within Single Conjugated Polymers. NANO LETTERS 2015; 15:7604-7609. [PMID: 26438977 DOI: 10.1021/acs.nanolett.5b03409] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The relationship between photostability and conformation of 2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene (MEH-PPV) conjugated polymers was studied via excitation polarization modulation depth (M) measurements. Upon partial photobleaching, M distributions of collapsed, highly ordered MEH-PPV molecules shifted toward lower values. Conversely, M distributions of MEH-PPV molecules with random coil conformations moved toward higher values after partial photobleaching. Monte Carlo simulations of randomly distributed dipole moments along polymer chains subjected to partial photobleaching revealed that a statistical effect leads to an increase in peak M value. Decreases in M values seen experimentally in the population of MEH-PPV molecules with high M values, however, are due to conformation-dependent photostability within single MEH-PPV polymers. We show that, while folded MEH-PPV molecules are relatively more photostable than extended MEH-PPV molecules in an ensemble, extended portions of particular molecules are more photostable than folded domains within single MEH-PPV molecules.
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Affiliation(s)
- Heungman Park
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Dat Tien Hoang
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Keewook Paeng
- Department of Chemistry, Columbia University , New York, New York 10027, United States
- Department of Chemistry, Sungkyunkwan University , Suwon 440-746, Republic of Korea
| | - Jaesung Yang
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Laura J Kaufman
- Department of Chemistry, Columbia University , New York, New York 10027, United States
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11
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Urbánek P, Kuřitka I, Daniš S, Toušková J, Toušek J. Thickness threshold of structural ordering in thin MEH-PPV films. POLYMER 2014. [DOI: 10.1016/j.polymer.2014.05.054] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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12
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Chen SA, Jen TH, Lu HH. A Review on the Emitting Species in Conjugated Polymers for Photo- and Electro-luminescence. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.201000067] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Chen PY, Rassamesard A, Chen HL, Chen SA. Conformation and Fluorescence Property of Poly(3-hexylthiophene) Isolated Chains Studied by Single Molecule Spectroscopy: Effects of Solvent Quality and Regioregularity. Macromolecules 2013. [DOI: 10.1021/ma400852q] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pei-Yin Chen
- Department of Chemical Engineering
and Frontier Research Center on Fundamental and Applied Sciences of
Matters, National Tsing Hua University,
Hsin-Chu 30013, Taiwan
| | - Areefen Rassamesard
- Department of Science (Physics),
Faculty of Science and Technology, Prince of Songkla University, Pattani Campus, Pattani 94000, Thailand
| | - Hsin-Lung Chen
- Department of Chemical Engineering
and Frontier Research Center on Fundamental and Applied Sciences of
Matters, National Tsing Hua University,
Hsin-Chu 30013, Taiwan
| | - Show-An Chen
- Department of Chemical Engineering
and Frontier Research Center on Fundamental and Applied Sciences of
Matters, National Tsing Hua University,
Hsin-Chu 30013, Taiwan
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14
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Steyrleuthner R, Schubert M, Howard I, Klaumünzer B, Schilling K, Chen Z, Saalfrank P, Laquai F, Facchetti A, Neher D. Aggregation in a High-Mobility n-Type Low-Bandgap Copolymer with Implications on Semicrystalline Morphology. J Am Chem Soc 2012; 134:18303-17. [DOI: 10.1021/ja306844f] [Citation(s) in RCA: 340] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Ian Howard
- Max Planck Institute for Polymer Research, D-55021 Mainz, Germany
| | | | | | - Zhihua Chen
- Polyera Corporation, Skokie, Illinois
60077, United States
| | | | - Frédéric Laquai
- Max Planck Institute for Polymer Research, D-55021 Mainz, Germany
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15
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Chan NY, Hao XT, Smith TA, Dunstan DE. Conformational and photophysical changes in conjugated polymers exposed to Couette shear. J Phys Chem B 2011; 115:6838-42. [PMID: 21553834 DOI: 10.1021/jp111787b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Conjugated polymers in solution exhibit interesting photophysical behavior, which is dictated by their molecular conformation. The conformations and resulting photophysics can be altered by deformational flows such as simple shear. Solutions of poly[2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) in dimethylformamide (DMF) show large decreases in fluorescence intensity as a function of shear rate, combined with significant spectral shifts upon exposure to shear. The excitation and emission spectra shift toward shorter wavelengths, indicating a change in conformation with shortened conjugated segment lengths attributed to compressive hydrodynamic forces in flow. Addition of poly(methyl methacrylate) to the solutions is shown to alter the fluorescence emission spectral behavior, which we ascribe to energy transfer from the higher energy, short segments to a small population of lower energy conjugated segments. The measured fluorescence changes were not reversible upon cessation of shear, demonstrating that permanent conformational changes are induced by flow.
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Affiliation(s)
- Nikko Y Chan
- Department of Chemical and Biomolecular Engineering, University of Melbourne, Melbourne, Victoria, Australia
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16
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Hu Z, Zou J, Deibel C, Gesquiere AJ, Zhai L. Single-Molecule Spectroscopy and AFM Morphology Studies of a Diblock Copolymer Consisting of Poly(3-hexylthiophene) and Fullerene. MACROMOL CHEM PHYS 2010. [DOI: 10.1002/macp.201000482] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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Li TD, Inigo AR, Fann W, White JD, Huang YF, Wei PK. Development of a Controlled Environment Near-Field Optical Microscope for Organic Thin Film Studies. J CHIN CHEM SOC-TAIP 2010. [DOI: 10.1002/jccs.201000069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Lin H, Hania RP, Bloem R, Mirzov O, Thomsson D, Scheblykin IG. Single chain versus single aggregate spectroscopy of conjugated polymers. Where is the border? Phys Chem Chem Phys 2010; 12:11770-7. [DOI: 10.1039/c001120g] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Determining the absolute, chemical-heterogeneity-corrected molar mass averages, distribution, and solution conformation of random copolymers. Anal Bioanal Chem 2009; 396:1589-98. [DOI: 10.1007/s00216-009-3320-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 11/12/2009] [Accepted: 11/15/2009] [Indexed: 10/20/2022]
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20
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Lin H, Tian Y, Zapadka K, Persson G, Thomsson D, Mirzov O, Larsson PO, Widengren J, Scheblykin IG. Fate of excitations in conjugated polymers: single-molecule spectroscopy reveals nonemissive "dark" regions in MEH-PPV individual chains. NANO LETTERS 2009; 9:4456-4461. [PMID: 19860455 DOI: 10.1021/nl9027473] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Single chains of the conjugated polymer MEH-PPV (poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene)) were studied with wide-field fluorescence microscopy (dispersion in inert polymer matrices) and with fluorescence correlation spectroscopy (chloroform solution). The fluorescence yield of individual molecules in matrices was found to be 1-2 orders of magnitude lower than that in solution and it decreased substantially with increasing chain length. It suggests that isolation of MEH-PPV molecules in polymer matrices creates favorable conditions for photogeneration of nonemissive primary excited states.
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Affiliation(s)
- Hongzhen Lin
- Chemical Physics and Pure and Applied Biochemistry, Lund University, Box 124, 22100 Lund, Sweden
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21
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Pensack RD, Banyas KM, Barbour LW, Hegadorn M, Asbury JB. Ultrafast vibrational spectroscopy of charge-carrier dynamics in organic photovoltaic materials. Phys Chem Chem Phys 2009; 11:2575-91. [DOI: 10.1039/b817113k] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Souza A, Cossiello R, Plivelic T, Mantovani G, Faria G, Atvars T, Torriani I, Bonagamba T, deAzevedo E. Temperature dependence of molecular dynamics and supramolecular aggregation in MEH-PPV films: A solid-state NMR, X-ray and fluorescence spectroscopy study. Eur Polym J 2008. [DOI: 10.1016/j.eurpolymj.2008.09.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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23
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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.
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Affiliation(s)
- Emanuelle R Simas
- Instituto de Química de São Carlos, Universidade de São Paulo, 13560-590, São Carlos SP, Brasil
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24
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Lin H, Tabaei SR, Thomsson D, Mirzov O, Larsson PO, Scheblykin IG. Fluorescence Blinking, Exciton Dynamics, and Energy Transfer Domains in Single Conjugated Polymer Chains. J Am Chem Soc 2008; 130:7042-51. [DOI: 10.1021/ja800153d] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hongzhen Lin
- Chemical Physics and Pure and Applied Biochemistry, Lund University, Box 124, 22100 Lund, Sweden
| | - Seyed R. Tabaei
- Chemical Physics and Pure and Applied Biochemistry, Lund University, Box 124, 22100 Lund, Sweden
| | - Daniel Thomsson
- Chemical Physics and Pure and Applied Biochemistry, Lund University, Box 124, 22100 Lund, Sweden
| | - Oleg Mirzov
- Chemical Physics and Pure and Applied Biochemistry, Lund University, Box 124, 22100 Lund, Sweden
| | - Per-Olof Larsson
- Chemical Physics and Pure and Applied Biochemistry, Lund University, Box 124, 22100 Lund, Sweden
| | - Ivan G. Scheblykin
- Chemical Physics and Pure and Applied Biochemistry, Lund University, Box 124, 22100 Lund, Sweden
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25
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Fückel B, Köhn A, Harding ME, Diezemann G, Hinze G, Basché T, Gauss J. Theoretical investigation of electronic excitation energy transfer in bichromophoric assemblies. J Chem Phys 2008; 128:074505. [DOI: 10.1063/1.2829531] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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26
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Pullerits T, Mirzov O, Scheblykin IG. Conformational fluctuations and large fluorescence spectral diffusion in conjugated polymer single chains at low temperatures. J Phys Chem B 2007; 109:19099-107. [PMID: 16853463 DOI: 10.1021/jp052189c] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The fluorescence of single chains of the conductive polymer poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) was studied by means of single-molecule spectroscopy at 15 K. MEH-PPV was deposited onto a surface from a toluene solution and covered with a polymer cap layer of poly(vinyl alcohol) spin-coated from an aqueous solution for protection against air. Because MEH-PPV is insoluble in water, such sample preparation guarantees that MEH-PPV chains do not mix with the cap polymer. We found that this "host matrix free" environment results in substantially stronger fluorescence spectral diffusion than that observed for conjugated polymer single chains embedded into polymer matrices. The average spectral diffusion range was 500 cm(-1), and the maximum registered value reached 1100 cm(-1), which is approximately 6 times larger than the values reported before. We analyzed spectral diffusion by observation of temporal evolution of the fluorescence intensity, the position of the maximum, and the width of fluorescence spectra. We propose that the transition energy shifts are caused by the differences of the London dispersive forces in slightly different polymer chain conformations. Such conformational changes are possible even at low temperatures because the MEH-PPV single chains in our samples have more freedom for fluctuations than in the usual "in host" arrangement.
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Affiliation(s)
- T Pullerits
- Chemical Physics, Lund University, P.O. Box 124, 22100 Lund, Sweden
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27
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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.
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Affiliation(s)
- Ivan G Scheblykin
- Department of Chemical Physics, Lund University, Box 124, 221 00 Lund, Sweden
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28
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Muls B, Uji-I H, Melnikov S, Moussa A, Verheijen W, Soumillion JP, Josemon J, Müllen K, Hofkens J. Direct measurement of the end-to-end distance of individual polyfluorene polymer chains. Chemphyschem 2007; 6:2286-94. [PMID: 16217812 DOI: 10.1002/cphc.200500235] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Wide-field imaging of individual multichromophoric molecules and successive photobleaching were used to determine, accurately, the relative position of the chromophores in such systems. First, a polyphenylene dendrimer with well-defined geometry was used to establish the accuracy in localization that can be obtained by this methodology. For a signal-to-noise ratio of 20, interchromophoric distances could be measured with 4 nm accuracy. Next, the method was used to determine the end-to-end distribution of an end-capped polyfluorene polymer. From comparison between the experimental and simulated distributions, information on the conformation of the polymer could be deduced. It was found that the polymer has a nonlinear conformation. A conjugation length of six monomer units gave the best fit of the experimental data to the proposed model.
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Affiliation(s)
- Benoît Muls
- Université catholique de Louvain, Place L. Pasteur 1, 1348 Louvain-la-Neuve, Belgium
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29
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Influences of local polymer–solvent π–π-interaction on dynamics of phenyl ring rotation and its role on photophysics of conjugated polymer. Eur Polym J 2007. [DOI: 10.1016/j.eurpolymj.2006.11.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Solvent effects on phototriggered conformational changes in an azobenzene-functionalized poly(p-phenylene vinylene). J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2006.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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31
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Smith TM, Hazelton N, Peteanu LA, Wildeman J. Electrofluorescence of MEH-PPV and Its Oligomers: Evidence for Field-Induced Fluorescence Quenching of Single Chains. J Phys Chem B 2006; 110:7732-42. [PMID: 16610868 DOI: 10.1021/jp054264p] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electrofluorescence (Stark) spectroscopy has been used to measure the trace of the change in polarizability (trDeltaalpha) and the absolute value of the change in dipole moment (|Deltamu|) of the electroluminescent polymer poly[2-methoxy,5-(2'-ethyl-hexoxy)-1,4-phenylene vinylene] (MEH-PPV) and several model oligomers in solvent glass matrixes. From electrofluorescence, the measured values of trDeltaalpha increase from 500 +/- 60 A(3) in OPPV-5 to 2000 +/- 200 A(3) in MEH-PPV. The good agreement found between these values and those measured by electroabsorption suggests the electronic properties do not differ strongly between absorption and emission, in contrast to earlier predictions. Evidence of electric-field-induced fluorescence quenching of MEH-PPV in dilute solvent glasses was found. When normalized to the square of the applied electric field, the magnitude of quench is comparable to that reported in the literature for thin films of MEH-PPV. In addition, fluorescence quenching was also observed in the oligomers with a magnitude that increases with increasing chain length. By using the values of trDeltaalpha measured by electrofluorescence, a model is developed to qualitatively explain the chain length dependence to the fluorescence quench observed in the oligomers as a function of exciton delocalization along the oligomer backbone. Various explanations for the origin of this quenching behavior and its chain length dependence are considered.
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Affiliation(s)
- Timothy M Smith
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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32
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Barzykin AV, Tachiya M. Stochastic Model of Photodynamics in Multichromophoric Conjugated Polymers. J Phys Chem B 2006; 110:7068-72. [PMID: 16571024 DOI: 10.1021/jp056088q] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A stochastic model of triplet exciton dynamics in multichromophoric conjugated polymers is presented and analyzed in detail, with a focus on the single molecule spectroscopy observables. The model deals with the evolution of a discrete statistical distribution of triplets in isolated polymer molecules. This approach should provide more accurate quantitative information on the dynamic processes involved, as compared to the previously used two-state model which assumes that a conjugated polymer cannot contain more than one triplet. In particular, it allows for determination of the triplet-triplet annihilation rate.
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Affiliation(s)
- A V Barzykin
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan
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33
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Traiphol R, Sanguansat P, Srikhirin T, Kerdcharoen T, Osotchan T. Spectroscopic Study of Photophysical Change in Collapsed Coils of Conjugated Polymers: Effects of Solvent and Temperature. Macromolecules 2006. [DOI: 10.1021/ma052512+] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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34
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Harbron EJ, Vicente DA, Hadley DH, Imm MR. Phototriggered Fluorescence Color Changes in Azobenzene-Functionalized Conjugated Polymers. J Phys Chem A 2005; 109:10846-53. [PMID: 16331927 DOI: 10.1021/jp054394y] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report fluorescence studies of phototriggered changes in spectral position and shape for two azobenzene-functionalized poly(p-phenylenevinylene) derivatives, poly(2-methoxy-5-(4-phenylazophenyl-4'-(1,10-dioxydecyl))-1,4-phenylenevinylene) (MPA-10-PPV) and poly(2-hexyloxy-5-(4-phenylazophenyl-4'-(1,10-dioxydecyl))-1,4-phenylenevinylene) (HPA-10-PPV). Upon trans --> cis azobenzene photoisomerization, small (ca. 1 nm) blue shifts in spectral position are observed for MPA-10-PPV in 100% toluene, a good solvent for this polymer. These shifts are reversed upon visible irradiation and can be cycled many times. To probe the dependence of these shifts on initial polymer conformation, a dichloromethane-methanol cosolvent study was performed in which the solvent quality was decreased incrementally to induce a reduction in polymer coil dimensions. Unirradiated dichloromethane solutions of both MPA-10-PPV and HPA-10-PPV showed a red shift and reduction in quantum yield with increasing methanol concentration as expected based on literature results for other poly(p-phenylenevinylene) derivatives. These changes have been attributed to a dramatic conformational collapse by others and occur for these azo polymers over the 30-60% (v/v) methanol range. While little or no light-induced spectral shifting was observed at low (<or=20%) and high (>or=70%) methanol concentrations, significant spectral shifts were observed for both polymers upon azobenzene photoisomerization in solutions with 30-60% methanol, the same range over which the polymer undergoes collapse to a highly coiled state. The largest shifts are visible to the eye, with a 65:35 (v/v) dichloromethane-methanol solution of HPA-10-PPV showing yellow-orange fluorescence when the azobenzenes are trans, green fluorescence when they are cis, and yellow-orange again after the azobenzenes are returned to the trans state. We attribute these color changes to a reversible UV-phototriggered expansion of polymer coil dimensions that occurs as a result of trans --> cis azobenzene side chain isomerization and provide temperature data to support this conclusion.
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Affiliation(s)
- Elizabeth J Harbron
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA.
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35
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Excited state dynamics of a conformationally disordered conjugated polymer: A comparison of solutions and film. Chem Phys 2005. [DOI: 10.1016/j.chemphys.2005.04.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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36
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Mirzov O, Pullerits T, Cichos F, von Borczyskowski C, Scheblykin I. Large spectral diffusion of conjugated polymer single molecule fluorescence at low temperature. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.04.044] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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37
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Ito S, Aoki H. Nano-Imaging of Polymers by Optical Microscopy. POLYMER ANALYSIS POLYMER THEORY 2005. [DOI: 10.1007/b135562] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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38
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Rønne C, Trägårdh J, Hessman D, Sundström V. Temperature effect on single chain MEH-PPV spectra. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.02.068] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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39
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Mirzov O, Cichos F, von Borczyskowski C, Scheblykin I. Direct exciton quenching in single molecules of MEH-PPV at 77 K. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.01.066] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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40
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Fritz KP, Scholes GD. Alignment of Conjugated Polymers in a Nematic Liquid-Crystal Host. J Phys Chem B 2003. [DOI: 10.1021/jp0347872] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Karolina P. Fritz
- Lash Miller Chemical Laboratories, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6 Canada
| | - Gregory D. Scholes
- Lash Miller Chemical Laboratories, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6 Canada
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41
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Schwartz BJ. Conjugated polymers as molecular materials: how chain conformation and film morphology influence energy transfer and interchain interactions. Annu Rev Phys Chem 2003; 54:141-72. [PMID: 12524429 DOI: 10.1146/annurev.physchem.54.011002.103811] [Citation(s) in RCA: 837] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The electronic structure of conjugated polymers is of current interest because of the wide range of potential applications for such materials in optoelectronic devices. It is increasingly clear that the electronic properties of conjugated polymers depend sensitively on the physical conformation of the polymer chains and the way the chains pack together in films. This article reviews the evidence that interchain electronic species do form in conjugated polymer films, and that their number and chemical nature depend on processing conditions; the chain conformation, degree of interchain contact, and rate of energy transfer can be controlled by factors such as choice of solvent, polymer concentration, thermal annealing, presence of electrically charged side groups, and encapsulation of the polymer chains in mesoporous silica. Taken together, the results reconcile many contradictions in the literature and provide a prescription for the optimization of conjugated polymer film morphology for device applications.
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Affiliation(s)
- Benjamin J Schwartz
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095-1569, USA.
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42
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Sarzi Sartori S, De Feyter S, Hofkens J, Van der Auweraer M, De Schryver F, Brunner K, Hofstraat JW. Host Matrix Dependence on the Photophysical Properties of Individual Conjugated Polymer Chains. Macromolecules 2002. [DOI: 10.1021/ma025786v] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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43
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Schaller RD, Snee PT, Johnson JC, Lee LF, Wilson KR, Haber LH, Saykally RJ, Nguyen TQ, Schwartz BJ. Nanoscopic interchain aggregate domain formation in conjugated polymer films studied by third harmonic generation near-field scanning optical microscopy. J Chem Phys 2002. [DOI: 10.1063/1.1499479] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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44
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Nguyen TQ, Schwartz BJ. Ionomeric control of interchain interactions, morphology, and the electronic properties of conjugated polymer solutions and films. J Chem Phys 2002. [DOI: 10.1063/1.1468215] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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