Quantum chemical investigation of biexcitons in conjugated polymers

  title={Quantum chemical investigation of biexcitons in conjugated polymers},
  author={Melissa A. Pasquinelli and David J. Yaron},
  journal={Journal of Chemical Physics},
The formation of biexcitons in conjugated polymers is examined within the Pariser–Parr–Pople (PPP) model of polyacetylene. The calculations are done using a scattering formalism that provides a size-consistent description of excited states containing both single and double electron–hole pair excitations. The excited-state absorption spectrum from the 1 1Bu exciton state was calculated and examined for signatures of biexciton formation. Calculations were performed on polyenes with up to 9 unit… 
9 Citations

Figures and Tables from this paper

Second-order dispersion interactions in π-conjugated polymers.
The ground state and excited state second-order dispersion interactions between parallel π-conjugated polymers are calculated from the Pariser-Parr-Pople model using CI-singles theory and it is found that the strong dependence of ΔE(n) on inter-chain separation implies a strong dependency of ν ≃ 3.6 eV on density fluctuations.
Bipolaron recombination in conjugated polymers.
The model modified to include electron-electron interactions, the Brazovskii-Kirova symmetry breaking term and an external electric field is used to investigate the scattering process between a negative and a positive bipolaron in a system composed of two coupled polymer chains.
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Effect of interchain coupling on a biexciton in organic polymers
The effect of interchain coupling on the formation and the stability of a biexciton is studied in poly (p-phenylene vinylene) chains in the framework of the tight-binding approach. We obtain an
Electroluminescence enhancement in polymer light-emitting diodes through inelastic scattering of oppositely charged bipolarons.
The results indicate that the scattering and combination of oppositely charged bipolarons may provide guidance for improving the internal quantum efficiency for electroluminescence to as high as 75% in polymer light-emitting diodes.
Dynamical exciton decay in organic materials: the role of bimolecular recombination.
The dynamical decay of excitons is theoretically investigated using a kinetic Monte Carlo approach that addresses singlet exciton diffusion and reveals that two distinct exciton-exciton interaction channels produce different consequences concerning diffusion and spectroscopic properties.


Theory of biexcitons in Φconjugated polymers
Abstract Theoretical models of π-conjugated polymers that emphasize the Coulomb electron-electron correlations predict that the lowest optical excitation is to an exciton. We have extended our
Coulomb screening and exciton binding energies in conjugated polymers
Hartree–Fock solutions of the Pariser–Parr–Pople and MNDO Hamiltonians are shown to give reasonable predictions for the ionization potentials and electron affinities of gas-phase polyenes. However,
Biexcitons in π-conjugated oligomers: Intensity-dependent femtosecond transient-absorption study
We report femtosecond transient-absorption (TA) studies of a five-ring oligomer of poly({ital para}-phenylene vinylene) prepared in two different forms: solid-state films and dilute solutions. At
Exciton and biexciton signatures in femtosecond transient absorption of π-conjugated oligomers
We report femtosecond transient-absorption studies of a five-ring oligomer of polyphenylenevinylene prepared in two different forms: as solid-state films and dilute solutions. Both types of samples
Lasing from conjugated-polymer microcavities
FOLLOWING the discovery1 of electroluminescence in poly(p-phenylenevinylene) (PPV), considerable effort has been directed towards the realization of optoelectronic devices based on semiconducting
Unified picture of the photoexcitations in phenylene-based conjugated polymers: Universal spectral and dynamical features in subpicosecond transient absorption
Using subpicosecond transient absorption spectroscopy, we investigate the primary photoexcitations in thin films and solutions of several phenylene-based conjugated polymers and an oligomer. We
Excitonic Effects in the Optical Properties of Conjugated Polymers and Fullerenes
Abstract Important roles of excitons in the linear and nonlinear optical properties of conjugated polymers and fullerene crystals are demonstrated on the basis of calculations using the conifguration