Systematic characterization of excited states in conjugated polymers

M. Chandross, Y. Shimoi, Sumitendra Mazumdar

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We present the first complete systematic characterization of the excited states in conjugated polymers. Our results are relevant for the understanding of the photophysics of these materials. We perform full configuration interaction calculations in an exciton basis within which a long chain polymer is considered as coupled molecular units. Complete pictorial descriptions of all excited states are obtained. In linear chain polymers such as the polyacetylenes and polydiacetylenes the 1Bu is an exciton, and the fundamental two-photon states can be broadly classified into triplet-triplet (TT), charge-transfer (CT) and singlet-singlet (SS) excitations. In the above CT refers to charge-transfer from one unit to another, and TT and SS are two electron-two hole excitations. In TT the spin angular momenta of two different triplet excitations combine to give an overall singlet, while the individual excitations are singlets in SS. The 2Ag is classified as TT. The mAg, an even parity state that plays a strong role in nonlinear optics, is a correlated CT state. The SS states occur higher in energy and for moderate exciton binding split into the biexciton and two-exciton continuum. The calculations can be easily extended to the polyphenylenes, for which the characterization of excited states continues to be possible. These theoretical results are useful in explaining a variety of third order nonlinear optical spectroscopic measurements as well as picosecond photoinduced absorption.

Original languageEnglish (US)
Pages (from-to)1001-1006
Number of pages6
JournalSynthetic Metals
Volume85
Issue number1-3
StatePublished - Mar 15 1997

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Conjugated polymers
Excited states
Excitons
Charge transfer
polymers
charge transfer
excitons
excitation
Polymers
Polyacetylenes
Nonlinear optics
Angular momentum
Photons
polyacetylene
nonlinear optics
configuration interaction
atomic energy levels
LDS 751
Electrons
parity

Keywords

  • Multiphoton absorption spectroscopy
  • Photoinduced absorption spectroscopy
  • Semi-empirical models and model calculations

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Polymers and Plastics

Cite this

Systematic characterization of excited states in conjugated polymers. / Chandross, M.; Shimoi, Y.; Mazumdar, Sumitendra.

In: Synthetic Metals, Vol. 85, No. 1-3, 15.03.1997, p. 1001-1006.

Research output: Contribution to journalArticle

Chandross, M, Shimoi, Y & Mazumdar, S 1997, 'Systematic characterization of excited states in conjugated polymers', Synthetic Metals, vol. 85, no. 1-3, pp. 1001-1006.
Chandross, M. ; Shimoi, Y. ; Mazumdar, Sumitendra. / Systematic characterization of excited states in conjugated polymers. In: Synthetic Metals. 1997 ; Vol. 85, No. 1-3. pp. 1001-1006.
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