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Almawgani AHM, Makhlouf Fathy H, E Alfassam H, M El-Sherbeeny A, Hajjiah A, A Elsayed H, R Abukhadra M, Al Zoubi W, Semeda R, Ismail Fathy M, A H Al-Athwary A, Mehaney A. Fano resonance in one-dimensional quasiperiodic topological phononic crystals towards a stable and high-performance sensing tool. Sci Rep 2024; 14:12067. [PMID: 38802403 DOI: 10.1038/s41598-024-62268-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 05/15/2024] [Indexed: 05/29/2024] Open
Abstract
Phononic crystals (PnCs) emerge as an innovative sensor technology, especially for high-performance sensing applications. This study strives to advance this field by developing new designs of PnC structures that exhibit stability in the face of construction imperfections and deformations, focusing on the evolution of topological PnCs (TPnCs). These designs could be promising to overcome the problem of instability involved in most of the theoretical PnC sensors when they emerge in experimental verification. In particular, the fabrication process of any design could collide with some fluctuations in controlling the size of each component. Thus, Fano resonance is introduced through a one-dimensional (1D) quasiperiodic TPnC. To the best of the author's knowledge, this study is the first to observe Fano modes in liquid cavities through 1D PnCs. Various quasiperiodic PnC designs are employed to detect the temperature of alcohols (specifically propanol) across an extensive temperature range (160-240 °C). The effects of many geometrical parameters on the sensor stability, such as material thicknesses, are studied. Numerical findings demonstrated that the designed quasiperiodic topological PnCs based on Fibonacci sequence of the second order proved superior performance. This sensing tool provides sensitivity, quality factor and figure-of-merit values of 104,533.33 Hz/°C, 223.69 and 0.5221 (/°C), respectively, through temperature detection of propanol in the range of 160-240 °C.
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Affiliation(s)
- Abdulkarem H M Almawgani
- Electrical Engineering Department, College of Engineering, Najran University, 11001, Najran, Saudi Arabia
| | - Hamza Makhlouf Fathy
- Physics Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62512, Egypt
| | - Haifa E Alfassam
- Department of Biology, College of Science, Princess Nourah Bint Abdulrahman University, P.O. BOX 84428, 11671, Riyadh, Saudi Arabia
| | - Ahmed M El-Sherbeeny
- Industrial Engineering Department, College of Engineering, King Saud University, P.O. Box 800, 11421, Riyadh, Saudi Arabia
| | - Ali Hajjiah
- Department of Electrical Engineering, College of Engineering and Petroleum, Kuwait University, Kuwait City, Kuwait
| | - Hussein A Elsayed
- Physics Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62512, Egypt
- Department of Physics, College of Science, University of Ha'il, Ha'il P.O. Box 2440, Hail, Saudi Arabia
| | - Mostafa R Abukhadra
- Materials Technologies and Their Applications Lab, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
| | - Wail Al Zoubi
- Materials Electrochemistry Laboratory, School of Materials Science and Engineering, Yeungnam University, Gyeongsan, 38541, Republic of Korea
| | - Ramadan Semeda
- Physics Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62512, Egypt
| | - Moataz Ismail Fathy
- Physics Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62512, Egypt
| | | | - Ahmed Mehaney
- Physics Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62512, Egypt.
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2
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Cassiano TDSA, de Oliveira Neto PH, e Silva GM. Quasiparticle dynamics by effective [Formula: see text]-field distortion. Sci Rep 2022; 12:7967. [PMID: 35562391 PMCID: PMC9106660 DOI: 10.1038/s41598-022-11832-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/18/2022] [Indexed: 11/09/2022] Open
Abstract
Modeling dynamical processes of quasiparticles in low dimensional [Formula: see text]-conjugated systems is challenging due to electron-phonon coupling. We show that this interaction leads to linear potential energy terms in the lattice Lagrangian similar to a local "gravitational" field. The presence of quasiparticles deforms this field in a way analogous to a low-dimension solution of general relativity. Our calculations with analytical expressions for effective [Formula: see text]-fields yield the correct band structure and deliver proper time evolution of the quasiparticle's properties. Furthermore, we report a sharp reduction in the dynamics computational time up to two orders of magnitude, a result that has major simulation implications.
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3
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Ross AM, Osella S, Policht VR, Zheng M, Maggini M, Marangi F, Cerullo G, Gatti T, Scotognella F. Deciphering Photoinduced Charge Transfer Dynamics in a Cross-Linked Graphene-Dye Nanohybrid. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:3569-3581. [PMID: 35242271 PMCID: PMC8883522 DOI: 10.1021/acs.jpcc.1c10570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/04/2022] [Indexed: 06/14/2023]
Abstract
The search for synthetic materials that mimic natural photosynthesis by converting solar energy into other more useful forms of energy is an ever-growing research endeavor. Graphene-based materials, with their exceptional electronic and optical properties, are exemplary candidates for high-efficiency solar energy harvesting devices. High photoactivity can be conveniently achieved by functionalizing graphene with small molecule organic semiconductors whose band-gaps can be tuned by structural modification, leading to interactions between the π-conjugated electronic systems in both the semiconductor and graphene. Here we investigate the ultrafast transient optical properties of a cross-linked graphene-dye (diphenyl-dithiophenediketopyrrolopyrrole) nanohybrid material, in which oligomers of the organic semiconductor dye are covalently bound to a random network of few-layer graphene flakes, and compare the results to those obtained for the reference dye monomer. Using a combination of ultrafast transient absorption and two-dimensional electronic spectroscopy, we provide substantial evidence for photoinduced charge transfer that occurs within 18 ps in the nanohybrid system. Notably, subpicosecond photoinduced torsional relaxation observed in the constituent dye monomer is absent in the cross-linked nanohybrid system. Through density functional theory calculations, we compare the competing effects of covalent bonding, increasing conjugation length, and the presence of multiple graphene flakes. We find evidence that the observed ultrafast charge transfer process occurs through a superexchange mechanism in which the oligomeric dye bridge provides virtual states enabling charge transfer between graphene-dye covalent bond sites.
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Affiliation(s)
- Aaron M. Ross
- Department
of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Silvio Osella
- Chemical
and Biological Systems Simulation Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Veronica R. Policht
- Department
of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Meng Zheng
- Chemical
Sciences Department, Università degli
Studi di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Michele Maggini
- Chemical
Sciences Department, Università degli
Studi di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Fabio Marangi
- Department
of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
- Center
for Nano Science and Technology, Istituto
Italiano di Tecnologia, Via Pascolo, 70/3 Milano 20133, Italy
| | - Giulio Cerullo
- Department
of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Teresa Gatti
- Center
for Materials Research, Justus Liebig University, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
| | - Francesco Scotognella
- Department
of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
- Center
for Nano Science and Technology, Istituto
Italiano di Tecnologia, Via Pascolo, 70/3 Milano 20133, Italy
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4
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Sheng CX, Kim KH, Tong M, Yang C, Kang H, Park YW, Vardeny ZV. Ultrafast Transient Spectroscopy of Trans-Polyacetylene in the Midinfrared Spectral Range. PHYSICAL REVIEW LETTERS 2020; 124:017401. [PMID: 31976729 DOI: 10.1103/physrevlett.124.017401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 11/11/2019] [Indexed: 06/10/2023]
Abstract
Trans-polyacetylene [t-(CH)_{x}] possesses twofold ground state degeneracy. Using the Su-Schrieffer-Heeger Hamiltonian, scientists predicted charged solitons to be the primary photoexcitations in t-(CH)_{x}; this prediction, however, has led to sharp debate. To resolve this saga, we use subpicosecond transient photomodulation spectroscopy in the mid-IR spectral range (0.1-1.5 eV) in neat t-(CH)_{x} thin films. We show that odd-parity singlet excitons are the primary photoexcitations in t-(CH)_{x}, similar to many other nondegenerate π-conjugated polymers. The exciton transitions are characterized by two photoinduced absorption (PA) bands at 0.38 and 0.6 eV, and an associated photoluminescence band at ∼1.5 eV having similar polarization memory. The primary excitons undergo internal conversion within ∼100 fs to an even-parity (dark) singlet exciton with a PA band at ∼1.4 eV. We also find ultrafast photogeneration of charge polarons when pumping deep into the polymer continuum band, which are characterized by two other PA bands in the mid-IR and associated photoinduced IR vibrational modes.
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Affiliation(s)
- C X Sheng
- Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, USA
- School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, China
| | - K H Kim
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - M Tong
- Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, USA
| | - C Yang
- Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, USA
| | - H Kang
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
| | - Y W Park
- Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Z V Vardeny
- Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, USA
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Astakhova TY, Vinogradov GA, Kashin VA. Effect of External Factors on Physical and Chemical Transformations Polaron in an Electric Field as a Generator of Coherent Lattice Vibrations. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2019. [DOI: 10.1134/s1990793118050147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Wada Y, Enokida I, Yamamoto J, Furukawa Y. Raman imaging of carrier distribution in the channel of an ionic liquid-gated transistor fabricated with regioregular poly(3-hexylthiophene). SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 197:166-169. [PMID: 29398591 DOI: 10.1016/j.saa.2018.01.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 01/07/2018] [Accepted: 01/13/2018] [Indexed: 06/07/2023]
Abstract
Raman images of carriers (positive polarons) at the channel of an ionic liquid-gated transistor (ILGT) fabricated with regioregular poly(3-hexylthiophene) (P3HT) have been measured with excitation at 785 nm. The observed spectra indicate that carriers generated are positive polarons. The intensities of the 1415 cm-1 band attributed to polarons in the P3HT channel were plotted as Raman images; they showed the carrier density distribution. When the source-drain voltage VD is lower than the source-gate voltage VG (linear region), the carrier density was uniform. When VD is nearly equal to VG (saturation region), a negative carrier density gradient from the source electrode towards the drain electrode was observed. This carrier density distribution is associated with the observed current-voltage characteristics, which is not consistent with the "pinch-off" theory of inorganic semiconductor transistors.
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Affiliation(s)
- Y Wada
- Department of Advanced Science and Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - I Enokida
- Department of Advanced Science and Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - J Yamamoto
- Department of Chemistry and Biochemistry, Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Y Furukawa
- Department of Advanced Science and Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan; Department of Chemistry and Biochemistry, Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
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7
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Deb K, Bera A, Bhowmik KL, Saha B. Conductive polyaniline on paper as a flexible electronic material with controlled physical properties through vapor phase polymerization. POLYM ENG SCI 2018. [DOI: 10.1002/pen.24845] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Krishna Deb
- Department of Physics; National Institute of Technology Agartala; Jirania 799046 India
| | - Arun Bera
- Department of Physics; National Institute of Technology Agartala; Jirania 799046 India
| | - Kartick Lal Bhowmik
- Department of Physics; National Institute of Technology Agartala; Jirania 799046 India
- Department of Chemistry; Bir Bikram Memorial College; Agartala 799004 India
| | - Biswajit Saha
- Department of Physics; National Institute of Technology Agartala; Jirania 799046 India
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8
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Stock C, Rodriguez EE, Lee N, Demmel F, Fouquet P, Laver M, Niedermayer C, Su Y, Nemkovski K, Green MA, Rodriguez-Rivera JA, Kim JW, Zhang L, Cheong SW. Orphan Spins in the S=5/2 Antiferromagnet CaFe_{2}O_{4}. PHYSICAL REVIEW LETTERS 2017; 119:257204. [PMID: 29303328 DOI: 10.1103/physrevlett.119.257204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Indexed: 06/07/2023]
Abstract
CaFe_{2}O_{4} is an anisotropic S=5/2 antiferromagnet with two competing A (↑↑↓↓) and B (↑↓↑↓) magnetic order parameters separated by static antiphase boundaries at low temperatures. Neutron diffraction and bulk susceptibility measurements, show that the spins near these boundaries are weakly correlated and a carry an uncompensated ferromagnetic moment that can be tuned with a magnetic field. Spectroscopic measurements find these spins are bound with excitation energies less than the bulk magnetic spin waves and resemble the spectra from isolated spin clusters. Localized bound orphaned spins separate the two competing magnetic order parameters in CaFe_{2}O_{4}.
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Affiliation(s)
- C Stock
- School of Physics and Astronomy and Centre for Science at Extreme Conditions, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | - E E Rodriguez
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - N Lee
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
| | - F Demmel
- ISIS Facility, Rutherford Appleton Labs, Chilton, Didcot OX11 0QX, United Kingdom
| | - P Fouquet
- Institute Laue-Langevin, 6 rue Jules Horowitz, Boite Postale 156, 38042 Grenoble Cedex 9, France
| | - M Laver
- School of Metallurgy and Materials, University of Birmingham, B15 2TT, United Kingdom
| | - Ch Niedermayer
- Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Y Su
- Jülich Centre for Neuton Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, Lichtenbergstraße 1, D-85747 Garching, Germany
| | - K Nemkovski
- Jülich Centre for Neuton Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, Lichtenbergstraße 1, D-85747 Garching, Germany
| | - M A Green
- School of Physical Sciences, University of Kent, Canterbury CT2 7NH, United Kingdom
| | - J A Rodriguez-Rivera
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA
- Department of Materials Science, University of Maryland, College Park, Maryland 20742, USA
| | - J W Kim
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
| | - L Zhang
- Laboratory for Pohang Emergent Materials and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - S-W Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
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9
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Huynh UNV, Basel TP, Ehrenfreund E, Li G, Yang Y, Mazumdar S, Vardeny ZV. Transient Magnetophotoinduced Absorption Studies of Photoexcitations in π-Conjugated Donor-Acceptor Copolymers. PHYSICAL REVIEW LETTERS 2017; 119:017401. [PMID: 28731770 DOI: 10.1103/physrevlett.119.017401] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Indexed: 06/07/2023]
Abstract
We have utilized a plethora of transient and steady state optical and magneto-optical spectroscopies in a broad spectral range (0.25-2.5 eV) for elucidating the primary and long-lived photoexcitations in a low band-gap π-conjugated donor-acceptor (DA) copolymer used for efficient photovoltaic solar cells. We show that both singlet excitons (SE) and intrachain triplet-triplet (TT) pairs are photogenerated in the DA-copolymer chains. From the picosecond transient magnetic field response of these species we conclude that the SE and TT spin states are coupled. The TT decomposition into two intrachain geminate triplet excitons maintains spin coherence and thus their spin entanglement lasts into the microsecond time domain.
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Affiliation(s)
- Uyen N V Huynh
- Department of Physics & Astronomy, University of Utah, Salt Lake City, Utah 84112, USA
| | - Tek P Basel
- Department of Physics & Astronomy, University of Utah, Salt Lake City, Utah 84112, USA
| | - Eitan Ehrenfreund
- Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Gang Li
- Department of Materials Science & Engineering, University of California-Los Angeles, Los Angeles, California 90095, USA
| | - Yang Yang
- Department of Materials Science & Engineering, University of California-Los Angeles, Los Angeles, California 90095, USA
| | - S Mazumdar
- Department of Physics, University of Arizona, Tucson, Arizona 85721, USA
| | - Z Valy Vardeny
- Department of Physics & Astronomy, University of Utah, Salt Lake City, Utah 84112, USA
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10
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Deb K, Bera A, Saha B. Tuning of electrical and optical properties of polyaniline incorporated functional paper for flexible circuits through oxidative chemical polymerization. RSC Adv 2016. [DOI: 10.1039/c6ra16079d] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
An organic semiconductor polyaniline based material with outstanding physical properties was prepared on a flexible paper substrate.
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Affiliation(s)
- Krishna Deb
- Department of Physics
- National Institute of Technology Agartala
- Jirania
- India
| | - Arun Bera
- Department of Physics
- National Institute of Technology Agartala
- Jirania
- India
| | - Biswajit Saha
- Department of Physics
- National Institute of Technology Agartala
- Jirania
- India
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11
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Yamamoto J, Furukawa Y. Electronic and Vibrational Spectra of Positive Polarons and Bipolarons in Regioregular Poly(3-hexylthiophene) Doped with Ferric Chloride. J Phys Chem B 2015; 119:4788-94. [DOI: 10.1021/jp512654b] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jun Yamamoto
- Department of Chemistry and
Biochemistry, School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Yukio Furukawa
- Department of Chemistry and
Biochemistry, School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan
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13
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Gieseking RL, Mukhopadhyay S, Risko C, Marder SR, Brédas JL. 25th anniversary article: Design of polymethine dyes for all-optical switching applications: guidance from theoretical and computational studies. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:68-83. [PMID: 24302357 DOI: 10.1002/adma.201302676] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 07/29/2013] [Indexed: 06/02/2023]
Abstract
All-optical switching--controlling light with light--has the potential to meet the ever-increasing demand for data transmission bandwidth. The development of organic π-conjugated molecular materials with the requisite properties for all-optical switching applications has long proven to be a significant challenge. However, recent advances demonstrate that polymethine dyes have the potential to meet the necessary requirements. In this review, we explore the theoretical underpinnings that guide the design of π-conjugated materials for all-optical switching applications. We underline, from a computational chemistry standpoint, the relationships among chemical structure, electronic structure, and optical properties that make polymethines such promising materials.
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Affiliation(s)
- Rebecca L Gieseking
- School of Chemistry and Biochemistry Center for Organic Photonics and Electronics and Center for Organic Materials for All-Optical Switching, Georgia Institute of Technology, Atlanta, Georgia, 30332-0400, USA
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14
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Kaake LG, Jasieniak JJ, Bakus RC, Welch GC, Moses D, Bazan GC, Heeger AJ. Photoinduced Charge Generation in a Molecular Bulk Heterojunction Material. J Am Chem Soc 2012; 134:19828-38. [DOI: 10.1021/ja308949m] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
| | | | | | - Gregory C. Welch
- Department of Chemistry, Dalhousie University, Halifax, NS, Canada
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15
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Kasala K, Saravanamuttu K. A black beam borne by an incandescent field self-traps in a photopolymerizing medium. J Am Chem Soc 2012; 134:14195-200. [PMID: 22830388 DOI: 10.1021/ja305671b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report that a self-trapped black optical beam that is spatially and temporally incoherent forms spontaneously in a nascent photopolymerization system. The black beam inscribes a permanent cylindrical channel, which prevents the propagation of visible light even under passive conditions (in the absence of polymerization). The finding opens a powerful new mechanism to manipulate light signals from incoherent sources such as LEDs through selective suppression of light propagation. This contrasts with approaches employed by photonic crystals and optical waveguides, which concentrate and guide light intensity within spatially localized regions. The self-trapped black beam forms when a broad incandescent beam bearing a negligible depression was launched into a photopolymerizable medium. Because of refractive index changes caused by polymerization, the depression narrows, deepens, and continually rejects the visible spectrum of light until it stabilizes as a black beam that propagates over long distances (≫ effective Rayleigh range) without significant divergence. As refractive index changes due to polymerization are irreversible, the cylindrical region occupied by the self-trapped black beam is inscribed as a black channel waveguide in the medium.
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Affiliation(s)
- Kailash Kasala
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
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16
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Dai Y, Wei C, Blaisten-Barojas E. Bipolarons and polaron pairs in oligopyrrole dications. COMPUT THEOR CHEM 2012. [DOI: 10.1016/j.comptc.2012.05.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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17
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Roncaratti L, Gargano R, de Oliveira Neto P, da Cunha W, da Silva Filho D, e Silva G. Temperature-induced oscillating electric dipole in conjugated systems. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.05.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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18
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19
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Miranda RP, Fisher AJ, Stella L, Horsfield AP. A multiconfigurational time-dependent Hartree-Fock method for excited electronic states. II. Coulomb interaction effects in single conjugated polymer chains. J Chem Phys 2011; 134:244102. [PMID: 21721607 DOI: 10.1063/1.3600404] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Conjugated polymers have attracted considerable attention in the last few decades due to their potential for optoelectronic applications. A key step that needs optimisation is charge carrier separation following photoexcitation. To understand better the dynamics of the exciton prior to charge separation, we have performed simulations of the formation and dynamics of localised excitations in single conjugated polymer strands. We use a nonadiabatic molecular dynamics method which allows for the coupled evolution of the nuclear degrees of freedom and of multiconfigurational electronic wavefunctions. We show the relaxation of electron-hole pairs to form excitons and oppositely charged polaron pairs and discuss the modifications to the relaxation process predicted by the inclusion of the Coulomb interaction between the carriers. The issue of charge photogeneration in conjugated polymers in dilute solution is also addressed.
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Affiliation(s)
- R P Miranda
- UCL Department of Physics and Astronomy, University College London, London, United Kingdom.
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21
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Sinclair M, Moses D, Akagi K, Heeger AJ. Third Order Nonlinear Optical Susceptibility of Trans-(CH)x: A Degenerate Ground State Conjugated Polymer. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-109-205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTThe promise of conducting polymers as fast response nonlinear optical materials has been recently emphasized [1,3]. Polymers such as polyacetylene, polythiophene and the soluble (and processible) poly(3-alkylthienylenes) contain a high density of x-electrons, and they are known to exhibit photoinduced absorption and photoinduced bleaching, indicating major shifts of oscillator strength upon photoexcitation [2,4]. For polyacetylene, these nonlinear effects have been studied in detail in the picosecond [5a,b] and sub-picosecond [5c] time regime and correlated with the photoproduction of charge carriers through fast photoconductivity measurements [6]. The data have demonstrated ultra-fast response with nonlinear shifts in oscillator strength occurring at times of the order of 10-13 seconds. These resonant nonlinear optical properties are intrinsic; they originate from the nonlinearity of the self-localized photoexcitations [7] which characterize this class of polymers: solitons, polarons and bipolarons [4].
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Banerji N, Cowan S, Leclerc M, Vauthey E, Heeger AJ. Exciton formation, relaxation, and decay in PCDTBT. J Am Chem Soc 2010; 132:17459-70. [PMID: 21087001 DOI: 10.1021/ja105290e] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The nature and time evolution of the primary excitations in the pristine conjugated polymer, PCDTBT, are investigated by femtosecond-resolved fluorescence up-conversion spectroscopy. The extensive study includes data from PCDTBT thin film and from PCDTBT in chlorobenzene solution, compares the fluorescence dynamics for several excitation and emission wavelengths, and is complemented by polarization-sensitive measurements. The results are consistent with the photogeneration of mobile electrons and holes by interband π-π* transitions, which then self-localize within about 100 fs and evolve to a bound singlet exciton state in less than 1 ps. The excitons subsequently undergo successive migrations to lower energy localized states, which exist as a result of disorder. In parallel, there is also slow conformational relaxation of the polymer backbone. While the initial self-localization occurs faster than the time resolution of our experiment, the exciton formation, exciton migration, and conformational changes lead to a progressive relaxation of the inhomogeneously broadened emission spectrum with time constants ranging from about 500 fs to tens of picoseconds. The time scales found here for the relaxation processes in pristine PCDTBT are compared to the time scale (<0.2 ps) previously reported for photoinduced charge transfer in phase-separated PCDTBT:fullerene blends (Phys. Rev. B 2010, 81, 125210). We point out that exciton formation and migration in PCDTBT occur at times much longer than the ultrafast photoinduced electron transfer time in PCDTBT:fullerene blends. This disparity in time scales is not consistent with the commonly proposed idea that photoinduced charge separation occurs after diffusion of the polymer exciton to a fullerene interface. We therefore discuss alternative mechanisms that are consistent with ultrafast charge separation before localization of the primary excitation to form a bound exciton.
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Affiliation(s)
- Natalie Banerji
- Center for Polymers and Organic Solids, University of California at Santa Barbara, Santa Barbara, California 93106-5090, USA
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Majumdar P, Panda S. Elastic scattering of traveling phonons by discrete breathers as a time-periodic scatterer in the one-dimensional discrete nonlinear Schrödinger model: Exact analysis. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 82:036607. [PMID: 21230203 DOI: 10.1103/physreve.82.036607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2009] [Revised: 08/15/2010] [Indexed: 05/30/2023]
Abstract
Discrete nonlinear Schrödinger model is a nonlinear lattice model used to investigate different nonlinear phenomena arising in many physical contexts. In this work we used this model to observe linear traveling phonon scattering by time-periodic discrete breathers in the piecewise smooth (PWS) version of nonlinearity. In one-dimensional system the single-channel scattering is found to be elastic (with the incoming and outgoing fluxes of energy being equal to each other). Considering one-site symmetric breather solution we are able to calculate the exact expression for the transmission coefficient (T) or the ratio of the transmitted to incident flux of energy in such a system using transfer-matrix formalism. From the condition of perfect transmission ( T=1 , and hence reflection coefficient R=0 ) or the ratio of reflected to incident flux of energy for elastic scattering is zero, our observation shows that perfect transmission happens to appear at the threshold of a localized mode, which occurs at the band edge of the extended eigenmodes (plane waves). We have also presented the results obtained from the condition of perfect reflection. The advantage of using the PWS version of nonlinearity in the model is that all the results derived are exact. Numerical simulations complement our results.
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Affiliation(s)
- Priyadarshi Majumdar
- Jyotinagar Bidyasree Niketan H.S. School, 41 Jyotinagar, Kolkata 700 108, India.
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24
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Abstract
Considerable progress has taken place in the generation and application of ultrashort optical pulses. The methods and techniques for extending time-resolved measurements into the femtosecond (10(-15) second) time domain are described, and recent applications and fertile areas for investigation with femtosecond pulses are discussed.
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25
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Conwell EM, Rakhmanova SV. High field conduction in poly(p
-phenylene vinylene). Isr J Chem 2010. [DOI: 10.1560/q2h0-6k7x-v2hd-bbmu] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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26
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Kim J, Park S, Scherer NF. Ultrafast dynamics of polarons in conductive polyaniline: comparison of primary and secondary doped forms. J Phys Chem B 2009; 112:15576-87. [PMID: 19367915 DOI: 10.1021/jp803984f] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Time- and wavelength-resolved pump-probe measurements are performed on the conductive, primary and secondary doped, forms of polyaniline in solution to investigate the relaxation dynamics of photoexcited polarons. Contrasting dynamics observed in the two forms allow investigation of electronic (and structural) relaxation of this material. Pump pulse at 800 nm photoexcites an electron from the valence to polaron band, and subsequent relaxation dynamics are probed by a white light continuum pulse. Three distinct features are observed in the primary doped sample: (1) absorption near time zero in the 900-1025 nm probe wavelength region; (2) delayed absorption from 850 to 1025 nm; (3) pronounced oscillations with frequencies of 165 and 210 cm(-1). The first two features are associated with intraband absorptions to higher-lying states in the polaron band from the initial excited and conformationally changed intermediate states. The oscillations reflect torsional motions associated with photoexcitation and relaxation. In the secondary doped material, only bleaching and stimulated emission are observed throughout the whole spectral region; neither transient absorption signals nor oscillatory dynamics are observed. Kinetic modeling is performed to establish the mechanism of relaxation. We propose that the excited polaron relaxes nonradiatively to the ground state through an intermediate state(s) with a twisted geometry. Our measurements and analysis allow us to describe the structure of the polaron bands for primary and secondary doped polyaniline; they are in the small and large polaron limits, respectively, and are consistent with a bandgap for the primary doped form and without a bandgap (i.e., metallic) for the secondary doped material.
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Affiliation(s)
- Jeongho Kim
- Department of Chemistry and The James Franck Institute, University of Chicago, 929 E. 57th St., Chicago, Illinois 60637, USA
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27
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Zhang GP, Sun X, George TF. Nonlinear Optical Response and Ultrafast Dynamics in C60. J Phys Chem A 2009; 113:1175-88. [DOI: 10.1021/jp802244b] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- G. P. Zhang
- Department of Physics, Indiana State University, Terre Haute, Indiana 47809
| | - X. Sun
- Department of Physics, Fudan University, Shanghai 200433, China
| | - Thomas F. George
- Office of the Chancellor and Center for Nanoscience, Departments of Chemistry & Biochemistry and Physics & Astronomy, University of Missouri-St. Louis, St. Louis, Missouri 63121
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Hennig D, Chetverikov A, Velarde MG, Ebeling W. Electron capture and transport mediated by lattice solitons. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 76:046602. [PMID: 17995122 DOI: 10.1103/physreve.76.046602] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Indexed: 05/25/2023]
Abstract
We study electron transport in a one-dimensional molecular lattice chain. The molecules are linked by Morse interaction potentials. The electronic degree of freedom, expressed in terms of a tight binding system, is coupled to the longitudinal displacements of the molecules from their equilibrium positions along the axis of the lattice. More specifically, the distance between two sites influences in an exponential fashion the corresponding electronic transfer matrix element. We demonstrate that when an electron is injected in the undistorted lattice it causes a local deformation such that a compression results leading to a lowering of the electron's energy below the lower edge of the band of linear states. This corresponds to self-localization of the electron due to a polaronlike effect. Then, if a traveling soliton lattice deformation is launched a distance apart from the electron's position, upon encountering the polaronlike state it captures the latter dragging it afterwards along its path. Strikingly, even when the electron is initially uniformly distributed over the lattice sites a traveling soliton lattice deformation gathers the electronic amplitudes during its traversing of the lattice. Eventually, the electron state is strongly localized and moves coherently in unison with the soliton lattice deformation. This shows that for the achievement of coherent electron transport we need not start with the polaronic effect.
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Affiliation(s)
- D Hennig
- Instituto Pluridisciplinar, Universidad Complutense, Paseo Juan XXIII, 1, 28040 Madrid, Spain
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30
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Lüer L, Manzoni C, Cerullo G, Lanzani G, Vardeny ZV. Intra-chain exciton generation by charge recombination in substituted polyacetylenes. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.06.119] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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31
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32
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Su WP. Lattice Relaxation of Even-Parity Singlet Excited States in Polyacetylene. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259408039230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- W. P. Su
- a Deparment of Physics and Texas Center for Superconductivity , University of Houston , Houston , TX , 77204-5506
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33
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Furukawa Y, Yokonuma N, Tasumi M, Kuroda M, Nakayama J. Raman Studies of Doped Polythiophene and the Radical Cation and Dication of Quinquethiophene. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259408039238] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Yukio Furukawa
- a Department of Chemistry , School of Science, The University of Tokyo , Bunkyo-ku, Tokyo , 113 , Japan
| | - Nami Yokonuma
- a Department of Chemistry , School of Science, The University of Tokyo , Bunkyo-ku, Tokyo , 113 , Japan
| | - Mitsuo Tasumi
- a Department of Chemistry , School of Science, The University of Tokyo , Bunkyo-ku, Tokyo , 113 , Japan
| | - Masami Kuroda
- b Department of Chemistry , Faculty of Science, Saitama University , Urawa, Saitama , 338 , Japan
| | - Juzo Nakayama
- b Department of Chemistry , Faculty of Science, Saitama University , Urawa, Saitama , 338 , Japan
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34
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Vardeny ZV, Wei X. On the Excitonic Nature of the Photoluminescence in Polythiophene Revealed by ODMR Spectroscopy. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259408039277] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Z. V. Vardeny
- a Department of Physics , University of Utah , Salt Lake City , Utah , 84112
| | - Xing Wei
- a Department of Physics , University of Utah , Salt Lake City , Utah , 84112
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35
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Kobayashi T, Wang H, Wang Z, Otsubo T. Confined breather-type excitation in a quinoidal thiophene after sub-5fs pulse excitation. J Chem Phys 2006; 125:44103. [PMID: 16942130 DOI: 10.1063/1.2213977] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A quinoidal thiophene molecule which is a prototype of the repeated unit of s-trans-cis-polyacetylene was studied by sub-5 fs spectroscopy. A breatherlike mode modulation of both the amplitude and frequency of the C[Double Bond]C stretching was observed for the first time. It generates two sidebands of 2238 and 700 cm(-1) with a separation of 769 cm(-1) corresponding to the modulation frequency. The latter mode is very close to the C-S-C ring deformation, which indicate that this mode mediates coupling between the breather mode and the C(beta)-C(beta) stretching mode. It was also found that the breather-type excitation has a longer lifetime (2-3 ps) than in all-trans-polyacetylene (50 fs) due to its confinement.
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Affiliation(s)
- Takayoshi Kobayashi
- Department of Physics, University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo 113-0033, Japan.
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36
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Lin X, Li J, Först CJ, Yip S. Multiple self-localized electronic states in trans-polyacetylene. Proc Natl Acad Sci U S A 2006; 103:8943-6. [PMID: 16740663 PMCID: PMC1482545 DOI: 10.1073/pnas.0601314103] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Indexed: 11/18/2022] Open
Abstract
Electronic structure calculations on a conjugated polymer chain by Hartree-Fock and density functional theory show a sequence of self-localized states, which stand in contrast to the single self-localized soliton state described by the Su-Schrieffer-Heeger model Hamiltonian. An extended Hubbard model, which treats electron-electron interactions up to second neighbors, is constructed to demonstrate that the additional states arise from a strong band-bending effect due to the presence of localized electric fields of charged solitons. We suggest the optical response of these electronic states may be associated with the near-edge oscillations observed in photo-induced absorption spectra. Our calculations indicate further that in the presence of counterions, the additional localized states continue to exist. Implications regarding soliton mobility and high-resolution ion sensing are briefly discussed.
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Affiliation(s)
- Xi Lin
- *Departments of Nuclear Science and Engineering and Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139; and
| | - Ju Li
- Department of Materials Science and Engineering, Ohio State University, Columbus, OH 43210
| | - Clemens J. Först
- *Departments of Nuclear Science and Engineering and Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139; and
| | - Sidney Yip
- *Departments of Nuclear Science and Engineering and Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139; and
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37
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An Z, Wu CQ, Sun X. Dynamics of photogenerated polarons in conjugated polymers. PHYSICAL REVIEW LETTERS 2004; 93:216407. [PMID: 15601042 DOI: 10.1103/physrevlett.93.216407] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Indexed: 05/24/2023]
Abstract
Within a tight-binding electron-phonon interacting model, we investigate the dynamics of photoexcitations to address the generation mechanism of charged polarons in conjugated polymers by using a nonadiabatic evolution method. Besides the neutral polaron exciton which is well known, we identify a novel product of lattice dynamic relaxation from the photoexcited states in a few hundreds of femtoseconds, which is a mixed state composed of both charged polarons and neutral excitons. Our results show that the charged polarons are generated directly with a yield of about 25%, which is independent of the excitation energies, in good agreement with results from experiments. Effects of the conjugation length are also discussed.
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Affiliation(s)
- Z An
- Research Center for Theoretical Physics, Fudan University, Shanghai 200433, China
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38
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Förner W. Davydov soliton dynamics: Initial state, boundary conditions, and numerical procedure. J Comput Chem 2004. [DOI: 10.1002/jcc.540130304] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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39
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Förner W. Theoretical study of bipolaron dynamics in polyparaphenylene: I. Derivation of the formalism and density functional (DFT) calculations on neutral and charged model systems. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.theochem.2004.03.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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40
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Förner W, Badawi HM. Infrared and Raman spectra of polyparaphenylene dimers in their aromatic and quinoidal forms for the detection of bipolarons in the charge transport of conducting polymer samples. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.theochem.2004.01.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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41
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Tretiak S, Saxena A, Martin RL, Bishop AR. Photoexcited breathers in conjugated polyenes: an excited-state molecular dynamics study. Proc Natl Acad Sci U S A 2003; 100:2185-90. [PMID: 12594339 PMCID: PMC151316 DOI: 10.1073/pnas.0530132100] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2002] [Accepted: 01/08/2003] [Indexed: 11/18/2022] Open
Abstract
pi-conjugated polymers have become an important class of materials for electronic devices. Design of these devices requires understanding such processes as photochemical reactions, spatial dynamics of photoexcitations, and energy and charge transport, which in turn involve complex coupled electron-vibrational dynamics. Here we study nonlinear photoexcitation dynamics in the polyene oligomers by using a quantum-chemical method suitable for the simulation of excited-state molecular dynamics in extended molecular systems with sizes up to hundreds of atoms. The method is based on the adiabatic propagation of the ground-state and transition single-electron density matrices along the trajectory. The simulations reveal formation of a self-localized vibronic excitation ("breather" or multiquanta bound state) with a typical period of 34 fs and allows us to identify specific slow and fast nuclear motions strongly coupled to the electronic degrees of freedom. The effect of chain imperfections and chemical defects on the dynamics is also investigated. A complementary two-dimensional analysis of corresponding transition density matrices provides an efficient way to monitor time-dependent real-space localization of the photoexcitation by identifying the underlying changes in charge densities and bond orders. Possible correlated electronic and vibrational spectroscopic signatures of photoexcited breathers are predicted, and generalizations to energy localization in complex macromolecules are discussed.
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Affiliation(s)
- S Tretiak
- Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
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42
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Förner W, Utz W. Correlated ab initio and density functional calculations on small model molecules for the unit cell of polyparaphenylene in its aromatic and quinoidal forms: equilibrium geometries and vibrational spectra. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s0166-1280(02)00386-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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43
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Adachi S, Kobryanskii VM, Kobayashi T. Excitation of a breather mode of bound soliton pairs in trans-polyacetylene by sub-five-femtosecond optical pulses. PHYSICAL REVIEW LETTERS 2002; 89:027401. [PMID: 12097015 DOI: 10.1103/physrevlett.89.027401] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2002] [Indexed: 05/23/2023]
Abstract
Trans-polyacetylene with a degenerate ground state has a nonlinear excitation of soliton after photoexcitation, due to the electron-phonon coupling. The excess energy of an excited electron-hole pair over a soliton pair creation induces a breather oscillation characterized by collective stretching vibration of the carbon-carbon bonds. A time-frequency analysis of pump probe signal shows that instantaneous frequencies of stretching modes are modulated for approximately 50 fs after excitation and the modulation period is 44+/-3 fs consistent with the theoretical expectation, clearly verifying the breather.
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Affiliation(s)
- Shunsuke Adachi
- Department of Physics, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
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44
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Abad E, Masser T, ben-Avraham D. Lattice kinetics of diffusion-limited coalescence and annihilation with sources. ACTA ACUST UNITED AC 2002. [DOI: 10.1088/0305-4470/35/7/301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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45
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Johansson A, Stafström S. Polaron dynamics in a system of coupled conjugated polymer chains. PHYSICAL REVIEW LETTERS 2001; 86:3602-3605. [PMID: 11328033 DOI: 10.1103/physrevlett.86.3602] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2000] [Indexed: 05/23/2023]
Abstract
The motion of excitations such as polarons is believed to be of fundamental importance for the transport properties of conjugated polymers for the use in, e.g., polymer based LED's. We have investigated polaron dynamics in a system of coupled polymer chains in the presence of an external electric field. In particular, we focus on how a polaron migrates through the polymer lattice, i.e., the situation in which a polaron reaches a chain end and is scattered to the surrounding chains. We show that the outcome of this event strongly depends on the strength of the electric field, and we identify three different cases for the polaron migration.
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Affiliation(s)
- A Johansson
- Department of Physics and Measurement Technology, Linköping University, SE-581 83 Linköping, Sweden.
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46
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Affiliation(s)
- Svetlana V. Rakhmanova
- Contribution from Department of Chemistry, University of Rochester, Rochester, New York 14627
| | - Esther M. Conwell
- Contribution from Department of Chemistry, University of Rochester, Rochester, New York 14627
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49
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Hayes W, Ironside CN, Ryan JF, Steele RP, Taylor RA. Picosecond studies of luminescence of cis polyacetylene. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/16/20/008] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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50
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Wong KS, Hayes W, Hattori T, Taylor RA, Ryan JF, Kaneto K, Yoshino Y, Bloor D. Picosecond studies of luminescence in polythiophene and polydiacetylene. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/18/26/014] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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