First-principles calculation of the three-dimensional band structure of poly(phenylene vinylene)

Costa, P.; Dandrea, R. G.; Conwell, E. M.

doi:10.1103/physrevb.47.1800

Cited by 113 publications

(58 citation statements)

References 41 publications

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“…From band structure calculations by Gomes da Costa et al on PPV, it was concluded that the presence of localized charge carriers should be attributed to the presence of defects or impurities rather than to a self-localized polaron. 29 Furthermore, Brocks has performed density functional theory calculations on thiophenes that show that self-localized polarons are not very likely in polythiophene. 30 The effects of dynamic fluctuations and polaron formation are under active investigation at present.…”

Section: Resultsmentioning

confidence: 99%

Intramolecular Charge Transport along Isolated Chains of Conjugated Polymers: Effect of Torsional Disorder and Polymerization Defects

et al. 2002

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Recently, it has become possible to measure the mobility of charges along isolated chains of conjugated polymers. The mobility of holes along poly(phenylenevinylene) and polythiophene backbones were reported to be 0.43 and 0.02 cm 2 V -1 s -1, respectively. The large difference between the mobility of holes on poly-(phenylenevinylene) and polythiophene chains can be attributed to deviations from the coplanar alignment of structural units in the polymer backbone. The effect of such torsional disorder on intramolecular hole transport is studied theoretically in this paper using a model based on the tight-binding approximation. The calculated ratio of hole mobilities along poly(phenylenevinylene) and polythiophene chains was found to be in agreement with experimental findings. For both polymers, estimated mobilities become consistent with the experimental values if polymerization defects and chain end effects are included in the calculations. This suggests that even higher mobilities than those reported here can be realized by improving the effective conjugation along the polymer chain.

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Section: Resultsmentioning

confidence: 99%

Intramolecular Charge Transport along Isolated Chains of Conjugated Polymers: Effect of Torsional Disorder and Polymerization Defects

et al. 2002

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“…[8][9][10][11] The Kohn-Sham gaps in these calculations are typically 40% smaller than the optical band gap ͑absorption gap͒. In cases where calculations for both isolated chains and the crystalline situation were performed, small differences ͑0.1 to 0.2 eV for gaps of ϳ3.0 eV) in Kohn-Sham band gaps were found.…”

Section: -7͔͒ Binding Energies Have Been Proposedmentioning

confidence: 99%

“…In cases where calculations for both isolated chains and the crystalline situation were performed, small differences ͑0.1 to 0.2 eV for gaps of ϳ3.0 eV) in Kohn-Sham band gaps were found. 10,11 However, it is well known that the Kohn-Sham eigenvalues formally cannot be interpreted as excited state energies. 12 Moreover, excitonic effects are not taken into account in these calculations.…”

Section: -7͔͒ Binding Energies Have Been Proposedmentioning

confidence: 99%

Ab initioprediction of the electronic and optical excitations in polythiophene: Isolated chains versus bulk polymer

et al. 2000

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initio prediction of the electronic and optical excitations in polythiophene : isolated chains versus bulk polymer. Physical Review B, 61(23), 15817-15826. DOI: 10.1103/PhysRevB.61.15817 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. We calculate the electronic and optical excitations of polythiophene using the GW ͑G stands for one-electron Green function, W for the screened Coulomb interaction͒ approximation for the electronic self-energy, and include excitonic effects by solving the electron-hole Bethe-Salpeter equation. Two different situations are studied: excitations on isolated chains and excitations on chains in crystalline polythiophene. The dielectric tensor for the crystalline situation is obtained by modeling the polymer chains as polarizable line objects, with a long-wavelength polarizability tensor obtained from the ab initio polarizability function of the isolated chain. With this model dielectric tensor we construct a screened interaction for the crystalline case, including both intra-and interchain screening. In the crystalline situation both the quasiparticle band gap and the exciton binding energies are drastically reduced in comparison with the isolated chain. However, the optical gap is hardly affected. We expect this result to be relevant for conjugated polymers in general.

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“…The DFT results therefore suggest that the existence of localized charges in solids should be attributed to impurities or defects in the films or crystals. 36 These defects can be of a chemical nature, such as polymerization mistakes causing cross-links or broken conjugation. 37 Moreover, the localization of charges can be induced by conformational defects caused by inter-chain interactions.…”

Section: Geometry Changes Upon Introduction Of a Chargementioning

confidence: 99%

Theoretical and experimental studies of the opto-electronic properties of positively charged oligo(phenylene vinylene)s: Effects of chain length and alkoxy substitution

Grozema¹,

Candeias

Swart³

et al. 2002

The Journal of Chemical Physics

106

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In this paper a combined experimental and quantum chemical study of the geometry and opto-electronic properties of unsubstituted and dialkoxy-sustituted phenylene-vinylene oligomers ͑PV's͒ is presented. The optical absorption spectra for PV cations with different chain lengths and substitution patterns were measured using pulse radiolysis with time-resolved spectrophotometric detection from 1380 to 500 nm ͑0.9 to 2.5 eV͒. The geometries of the PV's studied were optimized using density functional theory ͑DFT͒ for both the neutral and singly charged molecule. The spectra for the PV radical cations were then calculated using singly excited configuration interaction with an intermediate neglect of differential overlap reference wave function method together with the DFT geometry. The agreement between experimental and theoretical absorption energies is excellent; most of the calculated radical cation absorption energies are within 0.15 eV of the experimental values. The pattern of dialkoxy-substitution is found to have a large effect on the optical absorption spectrum of the cation. Using the calculated charge distribution it is shown that the degree of delocalization of the charge correlates with the energy of the lowest absorption band. If alkoxy side chains are present on some of the rings the positive charge tends to localize at those sites.

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First-principles calculation of the three-dimensional band structure of poly(phenylene vinylene)

Cited by 113 publications

References 41 publications

Intramolecular Charge Transport along Isolated Chains of Conjugated Polymers: Effect of Torsional Disorder and Polymerization Defects

Intramolecular Charge Transport along Isolated Chains of Conjugated Polymers: Effect of Torsional Disorder and Polymerization Defects

Ab initioprediction of the electronic and optical excitations in polythiophene: Isolated chains versus bulk polymer

Theoretical and experimental studies of the opto-electronic properties of positively charged oligo(phenylene vinylene)s: Effects of chain length and alkoxy substitution

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