Comparative study of the electronic structure and conduction properties of polypyrrole, polythiophene, and polyfuran and their copolymers

Bakhshi, A.K.; Ladik, J.; Seel, M.

doi:10.1103/physrevb.35.704

Cited by 110 publications

(43 citation statements)

References 47 publications

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“…It is considered that, with increasing n, the pyrrole and the thiophene units effectively contribute to heightening the HOMO level and to lowering the LUMO level, respectively. 8,26 Thus, it has been concluded that TPTn has the most promising tunable quantum-well structure of the three sets of the oligomers here studied.…”

Section: Resultsmentioning

confidence: 96%

Molecular Orbital Study on Electron Confinement Characteristics in Heteroaromatic Oligomers

Nobutoki

Koezuka

1996

J. Phys. Chem.

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A molecular orbital study on heteroaromatic oligomers has been performed to investigate their electron confinement characteristics. The semiempirical MNDO-SCF-MO (modified neglect of diatomic overlap selfconsistent-field molecular orbital) method was used to calculate the electronic structures of the oligomers as a function of the unit number for the three sets of heteroaromatic oligomers X n Y n X n with unit cells X and Y, n ) 1-4. They are X ) benzene, Y ) pyrrole, X ) benzene, Y ) thiophene, and X ) thiophene, Y ) pyrrole, respectively. The electronic structures of the oligomers have been analyzed by means of the degree of occurrence of the electron confinement divided into the sequences of X units and of Y units. The analyses indicate that the oligomers with X ) thiophene, Y ) pyrrole can have the most promising tunable quantumwell structure by controlling the unit number in the oligomers studied. The effect of the confinement characteristics of the oligomers on the static second-order hyperpolarizability is also discussed.

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Section: Resultsmentioning

confidence: 96%

Molecular Orbital Study on Electron Confinement Characteristics in Heteroaromatic Oligomers

Nobutoki

Koezuka

1996

J. Phys. Chem.

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“…[49][50][51] In the oligomer studies the issue of bipolaron formation was not addressed and the interpretation of polymer results remains controversial. 8,12,13,16,17,20,22,23,25,[52][53][54][55] Electronic structures of PPy and OPs have been investigated theoretically before; 20,[56][57][58][59][60][61][62][63][64][65][66][67][68][69][70] however, we are not aware of calculations of absorption spectra during the doping process of pyrrole oligomers or polymers. We have recently calculated such spectra for polyenes 71 and OTs.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Modeling of the Doping Process in Polypyrrole by Calculating UV/Vis Absorption Spectra of Neutral and Charged Oligomers

Okur

Salzner

2008

J. Phys. Chem. A

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Changes in absorption spectra during doping of oligopyrroles were investigated with time-dependent density functional theory on optimized structures of neutral, singly, and doubly charged pyrrole oligomers with up to 24 rings. In the absence of counterions, defects are delocalized. Counterions induce localization. For dications two polarons on the same chain are preferred over a bipolaron. Intragap absorptions arise in charged species, no matter whether defects are localized or delocalized. Cations and dications give rise to two sub-band transitions. The cation peaks have lower energies than those of dications. The first excitations of cations have lower oscillator strengths than the second; for dications the second peak is weaker than the first. For very long oligomers, the second sub-band absorption vanishes and a third one appears at higher energy. The behavior of pyrrole oligomers is analogous to that of thiophene oligomers. Theoretical UV spectra for cations and dications of short oligomers (six to eight rings) match experimental spectra of polypyrrole at low and at high doping levels, respectively. The error in the theoretical calculations is about 0.4 eV, slightly larger than for thiophene oligomers at the same level of theory.

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“…The corresponding experimental geometries of the monomers [24] were used for the internal geometry of the heterocycles. Bond lengths between rings were set at 1.49 A as in the earlier calculations of these systems and their derivatives [5,6,.…”

Section: Methodsmentioning

confidence: 99%

“…The stoichiometry of their copolymers is six pyrroles to one terthiophene, and its conductivity lies between that of PPY (10'-ld R-' cm-') and PTP (10-3-10-2 R-' cm-'). Copolymers of PY and TP in the molar ratio (2 : 1) have also been investigated theoretically by us [5]. An alternating copolymer of PY and TP has been prepared by Naitoh [16] using 2,2' thienylpyrrole as the starting material.…”

Section: Introductionmentioning

confidence: 99%

Electronic structure of poly(pyrrole–thiophene) copolymers: Design of polymeric quasi‐one‐dimensional superlattices

Bakhshi

Ladik

1992

Int J of Quantum Chemistry

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Ab initio band structure results of polypyrrole (PPY) and polythiophene (PTP) obtained with a double-zeta basis set are reported. The electronic density of states (ws) of the various quasione-dimensional copolymers (superlattices) of the type (A,B.h, ( A = pyrrole; B = thiophene) have been calculated numerically within the ab initio SCF tight-binding approximation. These copolymers on the basis of the band positions of PPY and PTP are found to belong to the class of type I1 (staggered) superlattices. The trends in their electronic properties as a function of (i) composition (m/n), (ii) block sizes m and n, and (iii) arrangement of blocks in the copolymer chain are discussed.

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Comparative study of the electronic structure and conduction properties of polypyrrole, polythiophene, and polyfuran and their copolymers

Cited by 110 publications

References 47 publications

Molecular Orbital Study on Electron Confinement Characteristics in Heteroaromatic Oligomers

Molecular Orbital Study on Electron Confinement Characteristics in Heteroaromatic Oligomers

Theoretical Modeling of the Doping Process in Polypyrrole by Calculating UV/Vis Absorption Spectra of Neutral and Charged Oligomers

Electronic structure of poly(pyrrole–thiophene) copolymers: Design of polymeric quasi‐one‐dimensional superlattices

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