1
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Sani U, Alatawi OM, Halawani NM, Gould JA, Knight JG, Cucinotta F. Hybridising inorganic materials with fluorescent BOPHY dyes: A structural and optical comparative study. Front Chem 2022; 10:921112. [PMID: 35836675 PMCID: PMC9274302 DOI: 10.3389/fchem.2022.921112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/14/2022] [Indexed: 11/13/2022] Open
Abstract
This study presents the design and characterization of new monochromatic light-harvesting systems based on inorganic porous materials hybridized with organic dye molecules within their structure. A new fluorescent BOPHY dye was prepared, characterized optically and used as both reference and synthetic precursor for two alkoxysilane derivatives that were incorporated separately within a silica structure. The dyes, one bearing one alkoxysilane group and the other one two, were co-condensed with tetraethyl orthosilicate to form a hybrid organo-silica framework, where they are found at specific locations. The structure of the new materials was analysed by powder XRD and TEM, which confirmed the presence of the hexagonal pore arrangement typical of mesoporous MCM-41 silica particles. The steady-state and time-resolved analysis showed that the particles where the dyes are most dispersed within the framework retain the highest fluorescence quantum yield, up to 0.63, in the green-yellow region of the visible spectrum. On the other hand, increasing the content of BOPHY units in the solid matrix seem to favour non-radiative deactivation pathways and aggregation phenomena, which lower the efficiency of light emission. The materials also exhibit interesting properties, such as a dual excited-state decay and fluorescence anisotropy. The short fluorescence lifetime, about 2 ns, matches the typical singlet lifetime of BOPHY dyes, whereas the long component, up to 20 ns, is attributed to delayed fluorescence, which could take place via charge recombination. Optical anisotropy experiments revealed that all materials show polarised light emission to a significant extent and, for most samples, it was also possible to determine a polarisation transfer decay trace, from 400 to 800 ps This is ascribed to the occurrence of energy migration between neighbouring dye units within the silica structure.
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Affiliation(s)
- Umar Sani
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Omar M. Alatawi
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Nuha M. Halawani
- Department of Chemistry, Faculty of Applied Science, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Jamie A. Gould
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Julian G. Knight
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Fabio Cucinotta
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- *Correspondence: Fabio Cucinotta,
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2
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Seidler B, Wahyuono RA, Wintergerst P, Ahner J, Hager MD, Rau S, Schubert US, Dietzek B. Red-light sensitized hole-conducting polymer for energy conversion. Phys Chem Chem Phys 2021; 23:18026-18034. [PMID: 34612276 DOI: 10.1039/d1cp03114g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a novel hole conductive polymer with photoactive Os(ii) complexes in the side chains. This PPV derivative can be activated upon absorption of red visible light and delivers notable photocurrents when used as photocathode material. Thus, the polymer presents as a stepping stone towards developing soft matter alternatives to NiO photocathodes, which function under visible light irradiation. To show the concept we combine electrical impedance spectroscopy with steady state spectroscopy. As light-driven hole injection from Os complex to the PPV polymer is thermodynamically feasible both based on reductive quenching of photoexcited PPV and based on oxidative quenching of the photoexcited Os chromophores we investigate the impact of illumination wavelengths on the photocathode behavior and photochemical stability of the material. While both blue and red light excitation, i.e., excitation of the chromophoric units PPV and excitation of the metal-to-ligand charge transfer transitions in the side-chain pendant Os chromophores yield cathodic photocurrents, the photochemical stability is drastically enhanced upon red-light excitation. Hence, the results of the investigations discussed show the validity of the concept developing red-light sensitized hole-conducting polymers for energy conversion.
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Affiliation(s)
- Bianca Seidler
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
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3
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Camacho R, Täuber D, Scheblykin IG. Fluorescence Anisotropy Reloaded-Emerging Polarization Microscopy Methods for Assessing Chromophores' Organization and Excitation Energy Transfer in Single Molecules, Particles, Films, and Beyond. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1805671. [PMID: 30721532 DOI: 10.1002/adma.201805671] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/12/2018] [Indexed: 06/09/2023]
Abstract
Fluorescence polarization is widely used to assess the orientation/rotation of molecules, and the excitation energy transfer between closely located chromophores. Emerging since the 1990s, single molecule fluorescence spectroscopy and imaging stimulate the application of light polarization for studying molecular organization and energy transfer beyond ensemble averaging. Here, traditional fluorescence polarization and linear dichroism methods used for bulk samples are compared with techniques specially developed for, or inspired by, single molecule fluorescence spectroscopy. Techniques for assessing energy transfer in anisotropic samples, where the traditional fluorescence anisotropy framework is not readily applicable, are discussed in depth. It is shown that the concept of a polarization portrait and the single funnel approximation can lay the foundation for alternative energy transfer metrics. Examples ranging from fundamental studies of photoactive materials (conjugated polymers, light-harvesting aggregates, and perovskite semiconductors) to Förster resonant energy transfer (FRET)-based biomedical imaging are presented. Furthermore, novel uses of light polarization for super-resolution optical imaging are mentioned as well as strategies for avoiding artifacts in polarization microscopy.
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Affiliation(s)
- Rafael Camacho
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - Daniela Täuber
- Chemical Physics and NanoLund, Lund University, P.O. Box 124, SE-22100, Lund, Sweden
- Biopolarisation, Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, D-07745, Jena, Germany
- Institute of Solid State Physics, FSU Jena, Helmholtzweg 3, D-07743, Jena, Germany
| | - Ivan G Scheblykin
- Chemical Physics and NanoLund, Lund University, P.O. Box 124, SE-22100, Lund, Sweden
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4
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Datko BD, Grey JK. Population dynamics of multiple triplet excitons revealed from time-dependent fluorescence quenching of single conjugated polymer chains. Sci Rep 2019; 9:817. [PMID: 30692627 PMCID: PMC6349865 DOI: 10.1038/s41598-018-37477-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 12/02/2018] [Indexed: 01/02/2023] Open
Abstract
The advent of multiple exciton harvesting schemes and prolonging exciton lifetimes to improve performance attributes of solar cells based on conjugated organic materials presents some interesting challenges that must be overcome in order to realize the full potential of these strategies. This is especially important for applications involving multi-chromophoric conjugated polymers where interactions between multiple spin-forbidden triplet excitons can be significant and are mediated by chain conformation. We use single molecule spectroscopic techniques to investigate interactions between multiple triplet excitons and emissive singlets by monitoring time-dependent fluorescence quenching on time scales commensurate with the triplet lifetime. Structurally related conjugated polymers differing by heteroatom substitution were targeted and we use a stochastic photodynamic model to numerically simulate the evolution of multi-exciton populations following photoexcitation. Single chains of poly(3-hexylthiophene) (P3HT) exhibit longer-lived triplet dynamics and larger steady-state triplet occupancies compared to those of poly(3-hexylselenophene) (P3HS), which has a larger reported triplet yield. Triplet populations evolve and relax much faster in P3HS which only becomes evident when considering all kinetic factors governing exciton population dynamics. Overall, we uncover new guidelines for effectively managing multi-exciton populations and interactions in conjugated polymers and improving their light harvesting efficiency.
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Affiliation(s)
- Benjamin D Datko
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - John K Grey
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM, 87131, USA.
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5
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Hu Z, Shao B, Geberth GT, Vanden Bout DA. Effects of molecular architecture on morphology and photophysics in conjugated polymers: from single molecules to bulk. Chem Sci 2018; 9:1101-1111. [PMID: 29675155 PMCID: PMC5887865 DOI: 10.1039/c7sc03465b] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 12/30/2017] [Indexed: 01/16/2023] Open
Abstract
A definitive comprehension of morphology and photophysics in conjugated polymers at multiple length scales demands both single molecule spectroscopy and well-controlled molecular architectures.
Conjugated polymers (CPs) possess a wide range of desirable properties, including accessible energetic bandgaps, synthetic versatility, and mechanical flexibility, which make them attractive for flexible and wearable optoelectronic devices. An accurate and comprehensive understanding about the morphology–photophysics relations in CPs lays the groundwork for their development in these applications. However, due to the complex roles of chemical structure, side-chains, backbone, and intramolecular interactions, CPs can exhibit heterogeneity in both their morphology and optoelectronic properties even at the single chain level. This molecular level heterogeneity together with complicated intermolecular interactions found in bulk CP materials severely obscures the deterministic information about the morphology and photophysics at different hierarchy levels. To counter this complexity and offer a clearer picture for the properties of CP materials, we highlight the approach of probing material systems with specific structural features via single molecule/aggregate spectroscopy (SMS). This review article covers recent advances achieved through such an approach regarding the important morphological and photophysical properties of CPs. After a brief review of the typical characteristics of CPs, we present detailed discussions of structurally well-defined model systems of CPs, from manipulated backbones and side-chains, up to nano-aggregates, studied with SMS to offer deterministic relations between morphology and photophysics from single chains building up to bulk states.
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Affiliation(s)
- Zhongjian Hu
- Department of Chemistry , University of Texas at Austin , USA .
| | - Beiyue Shao
- Department of Chemistry , University of Texas at Austin , USA .
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6
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Jiang Y, McNeill J. Light-Harvesting and Amplified Energy Transfer in Conjugated Polymer Nanoparticles. Chem Rev 2016; 117:838-859. [DOI: 10.1021/acs.chemrev.6b00419] [Citation(s) in RCA: 168] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Yifei Jiang
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | - Jason McNeill
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
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7
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Camposeo A, Pensack RD, Moffa M, Fasano V, Altamura D, Giannini C, Pisignano D, Scholes GD. Anisotropic Conjugated Polymer Chain Conformation Tailors the Energy Migration in Nanofibers. J Am Chem Soc 2016; 138:15497-15505. [PMID: 27933935 PMCID: PMC5133673 DOI: 10.1021/jacs.6b10761] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Indexed: 01/22/2023]
Abstract
Conjugated polymers are complex multichromophore systems, with emission properties strongly dependent on the electronic energy transfer through active subunits. Although the packing of the conjugated chains in the solid state is known to be a key factor to tailor the electronic energy transfer and the resulting optical properties, most of the current solution-based processing methods do not allow for effectively controlling the molecular order, thus making the full unveiling of energy transfer mechanisms very complex. Here we report on conjugated polymer fibers with tailored internal molecular order, leading to a significant enhancement of the emission quantum yield. Steady state and femtosecond time-resolved polarized spectroscopies evidence that excitation is directed toward those chromophores oriented along the fiber axis, on a typical time scale of picoseconds. These aligned and more extended chromophores, resulting from the high stretching rate and electric field applied during the fiber spinning process, lead to improved emission properties. Conjugated polymer fibers are relevant to develop optoelectronic plastic devices with enhanced and anisotropic properties.
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Affiliation(s)
- Andrea Camposeo
- Istituto
Nanoscienze-CNR, Euromediterranean Center
for Nanomaterial Modelling and Technology (ECMT), via Arnesano, I-73100 Lecce, Italy
| | - Ryan D. Pensack
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Maria Moffa
- Istituto
Nanoscienze-CNR, Euromediterranean Center
for Nanomaterial Modelling and Technology (ECMT), via Arnesano, I-73100 Lecce, Italy
| | - Vito Fasano
- Dipartimento
di Matematica e Fisica “Ennio De Giorgi”, Università del Salento, via Arnesano, I-73100 Lecce, Italy
| | - Davide Altamura
- Istituto
di Cristallografia (IC-CNR), via Amendola 122/O, I-70126 Bari, Italy
| | - Cinzia Giannini
- Istituto
di Cristallografia (IC-CNR), via Amendola 122/O, I-70126 Bari, Italy
| | - Dario Pisignano
- Istituto
Nanoscienze-CNR, Euromediterranean Center
for Nanomaterial Modelling and Technology (ECMT), via Arnesano, I-73100 Lecce, Italy
- Dipartimento
di Matematica e Fisica “Ennio De Giorgi”, Università del Salento, via Arnesano, I-73100 Lecce, Italy
| | - Gregory D. Scholes
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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8
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Lee SH, Yang J, Kim D. Structure-Dependent Electronic Interactions in Ethyne-Bridged Porphyrin Arrays Investigated by Single-Molecule Fluorescence Spectroscopy. J Phys Chem Lett 2016; 7:3676-3682. [PMID: 27575018 DOI: 10.1021/acs.jpclett.6b01531] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
By using single-molecule fluorescence spectroscopy, we have investigated the electronic interaction of ethyne-bridged porphyrin arrays (ZNE) depending on their structure. The fluorescence dynamics of ZNE show a large amount of one-step photobleaching behaviors, indicating the high degree of π-conjugation. The ratio of one-step photobleaching behavior decreased as the number of porphyrin units increased. This behavior indicates that the linear and shortest Z2E shows a strong electronic coupling between constituent porphyrin moieties. Structural properties and orientation of ZNE were also measured by wide-field excitation fluorescence spectroscopy (ExPFS) and defocused wide-field imaging (DWFI). The ExPFS and DWFI show that the structure of absorbing and emitting units of Z2E and Z3E are linear. On the other hand, star-shaped pentamer with five porphyrins acts as an absorbing unit, but unidirectional trimer moiety acts as an emitting unit in the Z5E molecule. Collectively, these studies provide further information on the electronic interaction depending on their structure and length.
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Affiliation(s)
- Sang Hyeon Lee
- Spectroscopy Laboratory for Functional π-electronic Systems and Department of Chemistry, Yonsei University , Seoul 120-749, Korea
| | - Jaesung Yang
- Spectroscopy Laboratory for Functional π-electronic Systems and Department of Chemistry, Yonsei University , Seoul 120-749, Korea
| | - Dongho Kim
- Spectroscopy Laboratory for Functional π-electronic Systems and Department of Chemistry, Yonsei University , Seoul 120-749, Korea
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9
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Zhu X, Shao B, Vanden Bout DA, Plunkett KN. Directing the Conformation of Oligo(phenylenevinylene) Polychromophores with Rigid, Nonconjugatable Morphons. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00067] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Xinju Zhu
- Department
of Chemistry and Biochemistry and the Materials Technology Center, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Beiyue Shao
- Center
for Nano- and Molecular Science and Technology, Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - David A. Vanden Bout
- Center
for Nano- and Molecular Science and Technology, Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Kyle N. Plunkett
- Department
of Chemistry and Biochemistry and the Materials Technology Center, Southern Illinois University, Carbondale, Illinois 62901, United States
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10
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Menezes DB, de Fátima Curcino da Silva S, Akcelrud L, Zambon Atvars TD, Balogh DT, Mascarenhas YP, Marletta A, Tozoni JR. Effects of the host molecular dynamics on the photoemission temperature dependence of host/guest photoluminescent blends. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Barisien T, Legrand L, Mu Z, Hameau S. Excitonic linewidth of organic quantum wires generated in reduced dimensionality matrices. Phys Chem Chem Phys 2016; 18:12928-37. [DOI: 10.1039/c6cp00629a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nanostructured crystalline film achieving a 2D bath for single conjugated polymer chain linewidth spectroscopy.
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Affiliation(s)
- Thierry Barisien
- Sorbonne Universités
- UPMC Université Paris 06
- CNRS-UMR 7588
- Institut des NanoSciences de Paris
- Paris
| | - Laurent Legrand
- Sorbonne Universités
- UPMC Université Paris 06
- CNRS-UMR 7588
- Institut des NanoSciences de Paris
- Paris
| | - Zhao Mu
- Sorbonne Universités
- UPMC Université Paris 06
- CNRS-UMR 7588
- Institut des NanoSciences de Paris
- Paris
| | - Sophie Hameau
- Sorbonne Universités
- UPMC Université Paris 06
- CNRS-UMR 7588
- Institut des NanoSciences de Paris
- Paris
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12
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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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13
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Camacho R, Tubasum S, Southall J, Cogdell RJ, Sforazzini G, Anderson HL, Pullerits T, Scheblykin IG. Fluorescence polarization measures energy funneling in single light-harvesting antennas--LH2 vs conjugated polymers. Sci Rep 2015; 5:15080. [PMID: 26478272 PMCID: PMC4609963 DOI: 10.1038/srep15080] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 09/09/2015] [Indexed: 01/15/2023] Open
Abstract
Numerous approaches have been proposed to mimic natural photosynthesis using artificial antenna systems, such as conjugated polymers (CPs), dendrimers, and J-aggregates. As a result, there is a need to characterize and compare the excitation energy transfer (EET) properties of various natural and artificial antennas. Here we experimentally show that EET in single antennas can be characterized by 2D polarization imaging using the single funnel approximation. This methodology addresses the ability of an individual antenna to transfer its absorbed energy towards a single pool of emissive states, using a single parameter called energy funneling efficiency (ε). We studied individual peripheral antennas of purple bacteria (LH2) and single CP chains of 20 nm length. As expected from a perfect antenna, LH2s showed funneling efficiencies close to unity. In contrast, CPs showed lower average funneling efficiencies, greatly varying from molecule to molecule. Cyclodextrin insulation of the conjugated backbone improves EET, increasing the fraction of CPs possessing ε = 1. Comparison between LH2s and CPs shows the importance of the protection systems and the protein scaffold of LH2, which keep the chromophores in functional form and at such geometrical arrangement that ensures excellent EET.
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Affiliation(s)
- Rafael Camacho
- Chemical Physics, Lund University, PO Box 124, Lund, SE-22100, Sweden
| | - Sumera Tubasum
- Chemical Physics, Lund University, PO Box 124, Lund, SE-22100, Sweden
| | - June Southall
- Glasgow Biomedical Research Centre, University of Glasgow, G12 8QQ, United Kingdom
| | - Richard J Cogdell
- Glasgow Biomedical Research Centre, University of Glasgow, G12 8QQ, United Kingdom
| | - Giuseppe Sforazzini
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - Harry L Anderson
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - Tõnu Pullerits
- Chemical Physics, Lund University, PO Box 124, Lund, SE-22100, Sweden
| | - Ivan G Scheblykin
- Chemical Physics, Lund University, PO Box 124, Lund, SE-22100, Sweden
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14
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Park H, Hoang DT, Paeng K, Kaufman LJ. Localizing exciton recombination sites in conformationally distinct single conjugated polymers by super-resolution fluorescence imaging. ACS NANO 2015; 9:3151-3158. [PMID: 25743935 DOI: 10.1021/acsnano.5b00086] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
To thoroughly elucidate how molecular conformation and photophysical properties of conjugated polymers (CPs) are related requires simultaneous probing of both. Previous efforts used fluorescence imaging with one nanometer accuracy (FIONA) to image CPs, which allowed simultaneous estimation of molecular conformation and probing of fluorescence intensity decay. We show that calculating the molecular radius of gyration for putative folded and unfolded poly(2-methoxy-5-(2'-ethylhexyloxy)1,4-phenylenevinylene) (MEH-PPV) molecules using FIONA underestimates molecular extension by averaging over emitters during localization. In contrast, employing algorithms based on single molecule high resolution imaging with photobleaching (SHRImP), including an approach we term all-frames SHRImP, allows localization of individual emitters. SHRImP processing corroborates that compact MEH-PPV molecules have distinct photophysical properties from extended ones. Estimated radii of gyration for isolated 168 kDa MEH-PPV molecules immobilized in polystyrene and exhibiting either stepwise or continuous intensity decays are found to be 12.6 and 25.3 nm, respectively, while the distance between exciton recombination sites is estimated to be ∼10 nm independent of molecular conformation.
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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
| | - Laura J Kaufman
- †Department of Chemistry, Columbia University, New York, New York 10027, United States
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15
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Bjorgaard JA, Köse ME. Simulations of singlet exciton diffusion in organic semiconductors: a review. RSC Adv 2015. [DOI: 10.1039/c4ra12409j] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Recent advances in exciton diffusion simulations in conjugated materials are presented in this review.
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Affiliation(s)
- Josiah A. Bjorgaard
- Center for Nonlinear Studies
- Theoretical Division
- Los Alamos National Laboratory
- Los Alamos
- USA
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16
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Bhatta RS, Tsige M. Chain length and torsional dependence of exciton binding energies in P3HT and PTB7 conjugated polymers: A first-principles study. POLYMER 2014. [DOI: 10.1016/j.polymer.2014.04.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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17
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Di Camillo D, Fasano V, Ruggieri F, Santucci S, Lozzi L, Camposeo A, Pisignano D. Near-field electrospinning of light-emitting conjugated polymer nanofibers. NANOSCALE 2013; 5:11637-42. [PMID: 24114142 PMCID: PMC3835073 DOI: 10.1039/c3nr03094f] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Accepted: 09/15/2013] [Indexed: 05/22/2023]
Abstract
The authors report on the realization of ordered arrays of light-emitting conjugated polymer nanofibers by near-field electrospinning. The fibers, made from poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], have diameters of a few hundreds of nanometers and their emission peaked at 560 nm. The observed blue-shift compared to the emission from reference films is attributed to different polymer packing in the nanostructures. Optical confinement in the fibers is also analyzed through self-waveguided emission. These results open interesting perspectives for the realization of complex and ordered architectures by light-emitting nanofibers, such as photonic circuits, and for the precise positioning and integration of conjugated polymer fibers into light-emitting devices.
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Affiliation(s)
- Daniela Di Camillo
- Dipartimento di Scienze Fisiche e Chimiche , Università degli Studi dell'Aquila , via Vetoio , I-67100 L'Aquila , Italy .
| | - Vito Fasano
- Dipartimento di Matematica e Fisica “Ennio De Giorgi” , Università del Salento , via Arnesano I-73100 Lecce , Italy .
- Center for Biomolecular Nanotechnologies @UNILE , Istituto Italiano di Tecnologia (IIT) , via Barsanti 1 , I-73010 Arnesano , LE , Italy
| | - Fabrizio Ruggieri
- Dipartimento di Scienze Fisiche e Chimiche , Università degli Studi dell'Aquila , via Vetoio , I-67100 L'Aquila , Italy .
| | - Sandro Santucci
- Dipartimento di Scienze Fisiche e Chimiche , Università degli Studi dell'Aquila , via Vetoio , I-67100 L'Aquila , Italy .
| | - Luca Lozzi
- Dipartimento di Scienze Fisiche e Chimiche , Università degli Studi dell'Aquila , via Vetoio , I-67100 L'Aquila , Italy .
| | - Andrea Camposeo
- Center for Biomolecular Nanotechnologies @UNILE , Istituto Italiano di Tecnologia (IIT) , via Barsanti 1 , I-73010 Arnesano , LE , Italy
- National Nanotechnology Laboratory of Istituto Nanoscienze-CNR , via Arnesano , I-73100 Lecce , Italy .
| | - Dario Pisignano
- Dipartimento di Matematica e Fisica “Ennio De Giorgi” , Università del Salento , via Arnesano I-73100 Lecce , Italy .
- Center for Biomolecular Nanotechnologies @UNILE , Istituto Italiano di Tecnologia (IIT) , via Barsanti 1 , I-73010 Arnesano , LE , Italy
- National Nanotechnology Laboratory of Istituto Nanoscienze-CNR , via Arnesano , I-73100 Lecce , Italy .
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18
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Kisley L, Chang WS, Cooper D, Mansur AP, Landes CF. Extending single molecule fluorescence observation time by amplitude-modulated excitation. Methods Appl Fluoresc 2013; 1:037001-37001. [PMID: 24587894 DOI: 10.1088/2050-6120/1/3/037001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We present a hardware-based method that can improve single molecule fluorophore observation time by up to 1500% and super-localization by 47% for the experimental conditions used. The excitation was modulated using an acousto-optic modulator (AOM) synchronized to the data acquisition and inherent data conversion time of the detector. The observation time and precision in super-localization of four commonly used fluorophores were compared under modulated and traditional continuous excitation, including direct total internal reflectance excitation of Alexa 555 and Cy3, non-radiative Förster resonance energy transfer (FRET) excited Cy5, and direct epi-fluorescence wide field excitation of Rhodamine 6G. The proposed amplitude-modulated excitation does not perturb the chemical makeup of the system or sacrifice signal and is compatible with multiple types of fluorophores. Amplitude-modulated excitation has practical applications for any fluorescent study utilizing an instrumental setup with time-delayed detectors.
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19
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Effect of trans
- and cis
-isomeric defects on the localization of the charged excitations in π-conjugated organic polymers. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/polb.23291] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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20
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Nayyar IH, Batista ER, Tretiak S, Saxena A, Smith DL, Martin RL. Role of Geometric Distortion and Polarization in Localizing Electronic Excitations in Conjugated Polymers. J Chem Theory Comput 2013; 9:1144-54. [DOI: 10.1021/ct300837d] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Iffat H. Nayyar
- Theoretical
Division and Center for Nonlinear Studies and ‡Center for Integrated Nanotechnologies, Los Alamos National Laboratory, New
Mexico 87545, United States
- NanoScience Technology Center and ∥Department of Physics, University of Central Florida, Orlando,
Florida 32826, United States
| | - Enrique R. Batista
- Theoretical
Division and Center for Nonlinear Studies and ‡Center for Integrated Nanotechnologies, Los Alamos National Laboratory, New
Mexico 87545, United States
- NanoScience Technology Center and ∥Department of Physics, University of Central Florida, Orlando,
Florida 32826, United States
| | - Sergei Tretiak
- Theoretical
Division and Center for Nonlinear Studies and ‡Center for Integrated Nanotechnologies, Los Alamos National Laboratory, New
Mexico 87545, United States
- NanoScience Technology Center and ∥Department of Physics, University of Central Florida, Orlando,
Florida 32826, United States
| | - Avadh Saxena
- Theoretical
Division and Center for Nonlinear Studies and ‡Center for Integrated Nanotechnologies, Los Alamos National Laboratory, New
Mexico 87545, United States
- NanoScience Technology Center and ∥Department of Physics, University of Central Florida, Orlando,
Florida 32826, United States
| | - Darryl L. Smith
- Theoretical
Division and Center for Nonlinear Studies and ‡Center for Integrated Nanotechnologies, Los Alamos National Laboratory, New
Mexico 87545, United States
- NanoScience Technology Center and ∥Department of Physics, University of Central Florida, Orlando,
Florida 32826, United States
| | - Richard L. Martin
- Theoretical
Division and Center for Nonlinear Studies and ‡Center for Integrated Nanotechnologies, Los Alamos National Laboratory, New
Mexico 87545, United States
- NanoScience Technology Center and ∥Department of Physics, University of Central Florida, Orlando,
Florida 32826, United States
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21
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Stangl T, Bange S, Schmitz D, Würsch D, Höger S, Vogelsang J, Lupton JM. Temporal Switching of Homo-FRET Pathways in Single-Chromophore Dimer Models of π-Conjugated Polymers. J Am Chem Soc 2012; 135:78-81. [DOI: 10.1021/ja3108643] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Thomas Stangl
- Institut für Experimentelle
und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Sebastian Bange
- Institut für Experimentelle
und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Daniela Schmitz
- Kekulé-Institut für
Organische Chemie und Biochemie der Universität Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
| | - Dominik Würsch
- Institut für Experimentelle
und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Sigurd Höger
- Kekulé-Institut für
Organische Chemie und Biochemie der Universität Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
| | - Jan Vogelsang
- Institut für Experimentelle
und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - John M. Lupton
- Institut für Experimentelle
und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
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22
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Martin TP, Wise AJ, Busby E, Gao J, Roehling JD, Ford MJ, Larsen DS, Moulé AJ, Grey JK. Packing dependent electronic coupling in single poly(3-hexylthiophene) H- and J-aggregate nanofibers. J Phys Chem B 2012; 117:4478-87. [PMID: 23214454 DOI: 10.1021/jp308586k] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Nanofibers (NFs) of the prototype conjugated polymer, poly(3-hexylthiophene) (P3HT), displaying H- and J-aggregate character are studied using temperature- and pressure-dependent photoluminescence (PL) spectroscopy. Single J-aggregate NF spectra show a decrease of the 0-0/0-1 vibronic intensity ratio from ~2.0 at 300 K to ~1.3 at 4 K. Temperature-dependent PL line shape parameters (i.e., 0-0 energies and 0-0/0-1 intensity ratios) undergo an abrupt change in the range of ~110-130 K suggesting a change in NF chain packing. Pressure-dependent PL lifetimes also show increased contributions from an instrument-limited decay component which is attributed to greater torsional disorder of the P3HT backbone upon decreasing NF volume. It is proposed that the P3HT alkyl side groups change their packing arrangement from a type I to type II configuration causing a decrease in J-aggregate character (lower intrachain order) in both temperature- and pressure-dependent PL spectra. Chain packing dependent exciton and polaron relaxation and recombination dynamics in NF aggregates are next studied using transient absorption spectroscopy (TAS). TAS data reveal faster polaron recombination dynamics in H-type P3HT NFs indicative of interchain delocalization whereas J-type NFs exhibit delayed recombination suggesting that polarons (in addition to excitons) are more delocalized along individual chains. Both time-resolved and steady-state spectra confirm that excitons and polarons in J-type NFs are predominantly intrachain in nature that can acquire interchain character with small structural (chain packing) perturbations.
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Affiliation(s)
- Thomas P Martin
- Department of Chemistry and Chemical Biology, MSC03 2060, University of New Mexico, Albuquerque, New Mexico 87131, USA
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23
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Bolinger JC, Traub MC, Brazard J, Adachi T, Barbara PF, Vanden Bout DA. Conformation and energy transfer in single conjugated polymers. Acc Chem Res 2012; 45:1992-2001. [PMID: 22775295 DOI: 10.1021/ar300012k] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In contrast to the detailed understanding of inorganic materials, researchers lack a comprehensive view of how the properties of bulk organic materials arise from their individual components. For conjugated polymers to eventually serve as low cost semiconductor layers in electronic devices, researchers need to better understand their functionality. For organics, traditional materials science measurements tend to destroy the species of interest, especially at low concentrations. However, fluorescence continues to be a remarkably flexible, relatively noninvasive tool for probing the properties of individual molecules and allows researchers to carry out a broad range of experiments based on a relatively simple concept. In addition, the sensitivity of single-molecule spectroscopy allows researchers to see the properties of an individual component that would be masked in the bulk phase. In this Account, we examine several photophysical properties of different conjugated polymers using single-molecule spectroscopy. In these experiments, we probed the relationship between the conformation of single conjugated polymer chains and the distance scale and efficiency of energy transfer within the polymer. Recent studies used polarization anisotropy measurements on single polymer chains to study chain folding following spin-casting from solution. This Account summarizes the effects of monomer regioregularity and backbone rigidity, by comparing a regiorandom phenylene vinylene (MEH-PPV) with both a regiorandom and regioregular thiophene (P3HT). Synthesis of novel polymers allowed us to explore the role of different conformation-directing inclusions in a PPV backbone. We showed that these inclusions control the conformation of individual chains and that molecular dynamics can predict these structural effects. In situ solvent vapor annealing studies explored the dynamics of polymer chains as well as the effect of solvent evaporation on the structural equilibrium of the polymer. We observed that a slower rate of solvent evaporation results in a narrow population of highly ordered polymer chains. These highly ordered single chains serve as a model system to probe the effect of conformation on energy transfer following excitation in single MEH-PPV polymer chains in two distinct experiments. In the first, we correlated the anisotropy of the fluorescence emission of individual chains with the anisotropy of their fluorescence excitation. Using this data, we derived a model for energy transfer in a conjugated polymer, simulating chromophores along a chain, coupled via Förster energy transfer. In the second experiment, super-resolution measurements demonstrated the ability of single-molecule spectroscopy to directly visualize energy transfer along a polymer chain embedded in a model device environment. A capacitive device allowed for controlled localization of hole polarons onto the polymer chain. These positive charges subsequently quenched local excitations, providing insight into the range of energy transfer in these single polymer molecules. As researchers continue to characterize conjugated polymer films and develop methods for creating multichain systems, single-molecule techniques will provide a greater understanding of how polymer morphology influences interchain interactions and will lead to a richer description of the electronic properties of bulk conjugated polymer films.
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24
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Camacho R, Thomsson D, Yadav D, Scheblykin I. Quantitative characterization of light-harvesting efficiency in single molecules and nanoparticles by 2D polarization microscopy: Experimental and theoretical challenges. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2012.03.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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25
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Adachi T, Lakhwani G, Traub MC, Ono RJ, Bielawski CW, Barbara PF, Vanden Bout DA. Conformational Effect on Energy Transfer in Single Polythiophene Chains. J Phys Chem B 2012; 116:9866-72. [DOI: 10.1021/jp306674t] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Takuji Adachi
- Center for Nano and Molecular Science and Technology,
Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, United States
| | - Girish Lakhwani
- Center for Nano and Molecular Science and Technology,
Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, United States
| | - Matthew C. Traub
- Center for Nano and Molecular Science and Technology,
Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, United States
| | - Robert J. Ono
- Center for Nano and Molecular Science and Technology,
Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, United States
| | - Christopher W. Bielawski
- Center for Nano and Molecular Science and Technology,
Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, United States
| | - Paul F. Barbara
- Center for Nano and Molecular Science and Technology,
Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, United States
| | - David A. Vanden Bout
- Center for Nano and Molecular Science and Technology,
Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, United States
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26
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Lin CJ, Liu YH, Peng SM, Yang JS. Photoluminescence and trans → cis Photoisomerization of Aminostyrene-Conjugated Phenylpyridine C^N Ligands and Their Complexes with Platinum(II): The Styryl Position and the Amino Substituent Effects. J Phys Chem B 2012; 116:8222-32. [DOI: 10.1021/jp304893c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Che-Jen Lin
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Yi-Hung Liu
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Shie-Ming Peng
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Jye-Shane Yang
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
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27
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Zhu X, Traub MC, Vanden Bout DA, Plunkett KN. Well-Defined Alternating Copolymers of Oligo(phenylenevinylene)s and Flexible Chains. Macromolecules 2012. [DOI: 10.1021/ma300430e] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xinju Zhu
- Department
of Chemistry and
Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Matthew C. Traub
- Department of Chemistry and
Biochemistry and the Center for Nano and Molecular Science and Technology, University of Texas at Austin, Austin, Texas 78712,
United States
| | - David A. Vanden Bout
- Department of Chemistry and
Biochemistry and the Center for Nano and Molecular Science and Technology, University of Texas at Austin, Austin, Texas 78712,
United States
| | - Kyle N. Plunkett
- Department
of Chemistry and
Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, United States
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28
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Vogelsang J, Lupton JM. Solvent Vapor Annealing of Single Conjugated Polymer Chains: Building Organic Optoelectronic Materials from the Bottom Up. J Phys Chem Lett 2012; 3:1503-1513. [PMID: 26285629 DOI: 10.1021/jz300294m] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Optoelectronic devices based on organic materials show a strong relationship between the morphological structure of the material and the function of the device. One of the grand challenges in improving the efficiencies of these devices is hence achieving morphological control throughout the entire course of processing. One of the most important postprocessing methods is solvent vapor annealing, which has repeatedly demonstrated its utility in improving the efficiency of organic-material-based devices by changing bulk-film morphology. This Perspective discusses the recent impact of single-molecule spectroscopy techniques in unraveling morphological changes and molecular dynamics and presents solvent vapor annealing as a tool to build organic optoelectronic materials from the bottom up. In particular, we discuss examples of how solvent vapor annealing at the single-chain level can be split into two different regimes, (i) the solvation regime, in which intrachain interactions and molecular dynamics during solvent vapor annealing can be probed, and (ii) the aggregation regime, in which the influence of interchain interactions can be probed. Finally, it will be shown that solvent vapor annealing in the aggregation regime can be used to build highly ordered mesoscopic objects with distinct properties such as long-range energy transfer.
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Affiliation(s)
- Jan Vogelsang
- §Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - John M Lupton
- §Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
- †Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, United States
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29
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Bernardinelli OD, Cassemiro SM, Nunes LAO, Atvars TDZ, Akcelrud L, deAzevedo ER. Correlations between Conjugation Length, Macromolecular Dynamics, and Photophysics of Phenylene-Vinylene/Aliphatic Multiblock Copolymers. J Phys Chem B 2012; 116:5993-6002. [DOI: 10.1021/jp2117517] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- O. D. Bernardinelli
- Instituto de Física de
São Carlos, Universidade de São Paulo, Caixa Postal 369, CEP 13560-970, São Carlos, São
Paulo, Brazil
| | - S. M. Cassemiro
- Paulo Scarpa Polymer Laboratory, Federal University of Parana, CP 19044, CEP 81531-990,
Curitiba, PR, Brazil
| | - L. A. O. Nunes
- Instituto de Física de
São Carlos, Universidade de São Paulo, Caixa Postal 369, CEP 13560-970, São Carlos, São
Paulo, Brazil
| | - T. D. Z. Atvars
- Chemistry Institute, State University of Campinas (Unicamp), Caixa Postal
6154, CEP 13084-971, Campinas, SP, Brazil
| | - L. Akcelrud
- Paulo Scarpa Polymer Laboratory, Federal University of Parana, CP 19044, CEP 81531-990,
Curitiba, PR, Brazil
| | - E. R. deAzevedo
- Instituto de Física de
São Carlos, Universidade de São Paulo, Caixa Postal 369, CEP 13560-970, São Carlos, São
Paulo, Brazil
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30
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Traub MC, Vogelsang J, Plunkett KN, Nuckolls C, Barbara PF, Vanden Bout DA. Unmasking bulk exciton traps and interchain electronic interactions with single conjugated polymer aggregates. ACS NANO 2012; 6:523-529. [PMID: 22208575 DOI: 10.1021/nn203860u] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
For conjugated polymer materials, there is currently a major gap in understanding between the fundamental properties observed in single molecule measurements and the bulk electronic properties extracted from measurements of highly heterogeneous thin films. New materials and methodologies are needed to follow the evolution from single chain to bulk film properties as multiple chains begin to interact. In this work, we used a controlled solvent vapor annealing process to assemble single chains of phenylene-vinylene conjugated polymers into aggregates that can be individually spectroscopically interrogated. This approach allowed us to probe the effects of interchain coupling in isolated conjugated polymer nanodomains of controlled size. By assembling these aggregates from building blocks of both pristine MEH-PPV and MEH-PPV derivatives containing structure-directing ortho- or para-terphenyl inclusions, we were able to control the ordering of these nanodomains as measured by single aggregate polarization anisotropy measurments. Depending on the individual chain constituents, these aggregates varied from highly anisotropic to nearly isotropic, respectively facilitating or inhibiting interchain coupling. From the single chain fluorescence lifetimes, we demonstrated that these structure directing inclusions effectively break the phenylene-vinylene conjugation, allowing us to differentiate interchain electronic effects from those due to hyper-extended conjugation. We observed well-defined bathochromic shifts in the fluorescence spectra of the aggregates containing extensive interchain interactions, indicating that low-energy exciton traps in MEH-PPV are the result of coupling interactions between neighboring chain segments. These results demonstrate the power of the synthetic inclusion approach to control properties at not just the single chain level, but as a comprehensive approach toward ground-up design of bulk electronic properties.
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Affiliation(s)
- Matthew C Traub
- Department of Chemistry and Biochemistry and the Center for Nano and Molecular Science and Technology, The University of Texas at Austin, Austin, Texas 78712, USA
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