Photoinduced neutral solitons up to room temperature in soluble<i>trans</i>-polyacetylene

Paraschuk, Dmitry Yu.; Kulakov, T. A.; Kobryanskii, V.M.

doi:10.1103/physrevb.50.907

Cited by 15 publications

(4 citation statements)

References 11 publications

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“…Indeed, some conjugated polymers show this correlation. For example, highly ordered polyacetelyne in the form of nanoparticles (nanopolyacetelene) exhibits exactly the same trend, that is, the correlation of the enhanced order with the absence of long-lived charged excitations. , …”

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confidence: 86%

“…For example, highly ordered polyacetelyne in the form of nanoparticles (nanopolyacetelene) exhibits exactly the same trend, that is, the correlation of the enhanced order with the absence of long-lived charged excitations. 27,28 The SPV technique directly probes spatially separated charges, in contrast to the PIA technique that does not give PPV/TNF blend. The pristine MEH-PPV film demonstrates the SPV signal closely following its absorption spectrum starting at ∼2 eV.…”

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confidence: 99%

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Acceptor-Enhanced Local Order in Conjugated Polymer Films

Parashchuk¹,

Grigorian

Levin³

et al. 2013

J. Phys. Chem. Lett.

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Disorder in conjugated polymers is a general drawback that limits their use in organic electronics. We show that an archetypical conjugated polymer, MEH-PPV, enhances its local structural and electronic order upon addition of an electronic acceptor, trinitrofluorenone (TNF). First, acceptor addition in MEH-PPV results in a highly structured XRD pattern characteristic for semicrystalline conjugated polymers. Second, the surface roughness of the MEH-PPV films increases upon small acceptor addition, implying formation of crystalline nanodomains. Third, the low-frequency Raman features of the polymer are narrowed upon TNF addition and indicate decreased inhomogeneous broadening. Finally, the photoinduced absorption and surface photovoltage spectroscopy data show that photoexcited and dark polymer intragap electronic states assigned to deep defects disappear in the blend. We relate the enhanced order to formation of a charge-transfer complex between MEH-PPV and TNF in the electronic ground state. These findings may be of high importance to control structural properties as they demonstrate an approach to increasing the order of a conjugated polymer by using an acceptor additive.

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confidence: 86%

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confidence: 99%

Acceptor-Enhanced Local Order in Conjugated Polymer Films

Parashchuk¹,

Grigorian

Levin³

et al. 2013

J. Phys. Chem. Lett.

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“…We can estimate E gap from figure 2 (E 10 gap = ω + − ω − = 0.84 eV). Note that E 6 gap = E 8 gap = E 10 gap = 0.84 eV does not agree with the experimental value E exp gap ≈ 1.8 eV [1,43], which indicates that effective Hamiltonian (1) with set II parameters does not describe the PA very well. We also see that large dominant structures at energies |ω| < 5 − 6 eV correspond to the band width W = 4t 0 .…”

Section: The One-particle Density Functionmentioning

confidence: 79%

Spectral density functions for polyacetylene within the Peierls - Hubbard model

Góra

Rościszewski

1996

J. Phys.: Condens. Matter

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A Peierls - Hubbard Hamiltonian suitable for the description of polyacetylene electronic structure is studied. We employ the Lanczos method to calculate the ground-state properties and single-particle spectral density functions appropriate for the description of the photoemission and the inverse photoemission spectra. The data obtained confirm that the dimerized polyacetylene is more stable than an undimerized one and elucidate how the Coulomb and the electron - phonon interactions open up a charge-transfer gap near the Fermi level. In particular we found that the value of the gap increases when the electron - phonon interaction is switched on.

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“…It is likely that charged solitons are generated exclusively on PA defects. These measurements show that the content of defects in PA substantially affects the parameters of the PA spectrum 5. The anomalous frequency dispersion, which is associated with defects interrupting the conjugation length of the chain, indicates a narrower distribution of conjugated chain lengths6 than other trans ‐PA modifications 7.…”

Section: Introductionmentioning

confidence: 85%

High‐pressure Raman spectroscopy of nanoparticle polyacetylene in a poly(vinyl‐butyral) matrix

McIntire

Zhao²,

Kobryanskii

et al. 2011

J Raman Spectroscopy

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The pressure-induced Raman shifts of six vibrational bands of 20% and 50% trans-polyacetylene nanoparticles in poly(vinylbutyral) matrix films (NPA/PVB) were studied from 0 to 45 kbar using a diamond anvil cell (DAC). The Raman shifts did not depend on the thickness of the two samples studied. Two of the vibrational bands displayed peak positions that depended on the isomeric compositions, with the 20% trans-NPA/PVB bands being slightly blue-shifted relative to the 50% trans-NPA/PVB bands over the 45 kbar pressure range. The Raman bands of NPA/PVB associated with the trans form initially exhibited a relatively large shift at low pressures (P < 10 kbar) along with a drastic change in their band profile. In order to investigate the relative shielding of the vibrational modes studied, a Grüneisen analysis of the pressure-induced shifts was conducted by estimating the parameters of the Murnaghan equation of state for solid polyacetylene (PA). Four of the six vibrational modes were found to be sensitive to compression of the interchain void space, while the other two modes were insensitive, indicating that they are relatively shielded from the compression of the sample.

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Photoinduced neutral solitons up to room temperature in solubletrans-polyacetylene

Cited by 15 publications

References 11 publications

Acceptor-Enhanced Local Order in Conjugated Polymer Films

Acceptor-Enhanced Local Order in Conjugated Polymer Films

Spectral density functions for polyacetylene within the Peierls - Hubbard model

High‐pressure Raman spectroscopy of nanoparticle polyacetylene in a poly(vinyl‐butyral) matrix

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