Determination of the electronic structure of thiophene oligomers and extrapolation to polythiophene

Jones, Derek; Guerra, Maurizio; Favaretto, Laura; Modelli, Alberto; Fabrizio, M.; Distefano, Giuseppe

doi:10.1021/j100378a030

Cited by 122 publications

(133 citation statements)

References 6 publications

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“…Ionization energies were measured for thiophene oligomers up to pentamer in the gas phase with an accuracy of (0.05 eV. 25 The gas phase IP of the monomer has been determined many times. See for instance refs 2 and 38.…”

Section: Resultsmentioning

confidence: 99%

Modeling Photoelectron Spectra of Conjugated Oligomers with Time-Dependent Density Functional Theory

Salzner

2010

J. Phys. Chem. A

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With the aim of producing accurate band structures of conjugated systems by employing the states of cations, TDDFT calculations on conjugated oligomer radical cations of thiophene, furan, and pyrrole with one to eight rings were carried out. Benchmarking of density functional theory and ab initio methods on the thiophene monomer shows that the ∆SCF ionization potential (IP) is most accurate at the B3LYP/6-311G* level. Improvement of the basis set beyond 6-311G* leads to no further changes. The IP is closer to experiment at B3LYP/6-311G* than at CCSD(T)/CCPVQZ. For longer oligomers the ∆SCF IPs decrease too fast with increasing chain length with all density functionals. CCSD/6-311G* performs well if the geometries are optimized at the CCSD level. With MP2 geometries IPs decrease too fast. Peak positions in photoelectron spectra were determined by adding appropriate TDDFT excitation energies of radical cations to the ∆SCF IPs. The agreement with experiment and with Green function calculations shows that TDDFT excited states of radical cations at the B3LYP/6-311G* level are very accurate and that absorption energies can be employed to predict photoelectron spectra.

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Section: Resultsmentioning

confidence: 99%

Modeling Photoelectron Spectra of Conjugated Oligomers with Time-Dependent Density Functional Theory

Salzner

2010

J. Phys. Chem. A

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“…Various forms of optical spectroscopy together with theoretical interpretations have provided us with the location of the lowest-energy singlet excitations, [13][14][15][16][17][18][19][20][21][22][23][24][25][26] as well as in some cases the triplets. 27 As we will discuss below, the lowestenergy singlet excitations show a 1/N-like dependence ͑with N the number of rings͒ on the oligomer length, whereas the lowest triplets are considerably lower in energy.…”

Section: Introductionmentioning

confidence: 99%

Density-functional study of the evolution of the electronic structure of oligomers of thiophene: Towards a model Hamiltonian

et al. 2001

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Density-functional study of the evolution of the electronic structure of oligomers of thiophene Telesca, R.; Bolink, H.; Yunoki, S.; Hadziioannou, G.; Duijnen, P.Th. van; Snijders, J.G.; Jonkman, Harry; Sawatzky, G.A. Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Telesca, R., Bolink, H., Yunoki, S., Hadziioannou, G., Duijnen, P. T. V., Snijders, J. G., ... Sawatzky, G. A. (2001). Density-functional study of the evolution of the electronic structure of oligomers of thiophene: Towards a model Hamiltonian. Physical Review B, 6315(15), [155112]. DOI: 10.1103/PhysRevB.63.155112 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If 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.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. We present density-functional and time-dependent density-functional studies of the ground, ionic, and excited states of a series of oligomers of thiophene. We show that, for the physical properties, the most relevant highest occupied and lowest unoccupied molecular orbitals develop gradually from monomer molecular orbitals into occupied and unoccupied broad bands in the large length limit. We show that band gap and ionization potentials decrease with size, as found experimentally and from empirical calculations. This gives credence to a simple tight-binding model Hamiltonian approach to these systems. We demonstrate that the length dependence of the experimental excitation spectra for both singlet and triplet excitations can be very well explained with an extended Hubbard-like Hamiltonian, with a monomer on-site Coulomb and exchange interaction and a nearest-neighbor Coulomb interaction. We also study the ground and excited-state electronic structures as functions of the torsion angle between the units in a dimer, and find almost equal stabilities for the transoid and cisoid isomers, with a transition energy barrier for isomerization of only 4.3 kcal/mol. Fluctuations in the torsion angle turn out to be very low in energy, and therefore of great importance in describing even the room-temperature properties. At a torsion angle of 90°the hopping integral is switched off for the highest occupied molecular orbital levels because of symmetry, allowing a first-principles estimate of the on-site interaction minus the next-neighbor Coulomb interaction as it enters in a Hubbard-like model Hamiltonian.

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“…[1][2][3][4][5][6][7][8][9] The idea is that studies of the small oligomers will give the key to the understanding of the electronic structure of polythiophene. Working with small oligomers avoids problems such as those found in the synthesis of the polymer: the resulting polymer usually depends on the procedure employed for the synthesis, and consequently the spectroscopic experiments, as well as the physical properties of the material, are sensitive to the sample preparation.…”

Section: Introductionmentioning

confidence: 99%

A theoretical study of the electronic spectrum of bithiophene

Rubio

Merchán

Ortı́

et al. 1995

The Journal of Chemical Physics

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The electronic spectrum of bithiophene in the energy range up to 6.0 eV has been studied using multiconfigurational second order perturbation theory ͑CASPT2͒ and a basis set of ANO type, with split valence quality and including polarization functions on all heavy atoms. Calculations were performed at a planar ͑trans͒ and twisted geometry. The calculated ordering of the excited singlet states is 1

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Determination of the electronic structure of thiophene oligomers and extrapolation to polythiophene

Cited by 122 publications

References 6 publications

Modeling Photoelectron Spectra of Conjugated Oligomers with Time-Dependent Density Functional Theory

Modeling Photoelectron Spectra of Conjugated Oligomers with Time-Dependent Density Functional Theory

Density-functional study of the evolution of the electronic structure of oligomers of thiophene: Towards a model Hamiltonian

A theoretical study of the electronic spectrum of bithiophene

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