Fundamental Electrochemical Studies of Polyacetylene

J. H. Kaufman, T. C. Chung, A. J. Heeger

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

We report an electrochemical and in situ optical study of doping processes in polyacetylene. Electrochemical voltage spectroscopy (EVS) is used to characterize the energies of charge injection and removal, as well as the kinetics of these processes. In situ optical spectroscopy provides complementary information on the energy of the electronic states where charge is stored (after injection). The EVS results provide a measurement of the energy gap; from these electrochemical data, we infer Eg≃ 1.5 eV, in good agreement with that obtained by other methods. The observation of hysteresis in the electrochemical cycle, and the associated increase in the midgap optical absorption upon doping, are both indicative of the formation of states in the bandgap. The resolution available with the EVS technique allows precise determination of both the energy and number of these states. The results demonstrate that the injected charge is stored in the form of charged solitons (chemical potential Eg/π, with respect to midgap) and not a random distribution of impurity states throughout the gap, nor polaron states near the bandedge. The observation of 300 ppm charge removal precisely at midgap provides a detailed verification of Kivelson's model of charge transport via intersoliton electron hopping. Kinetics studies performed both at low and high dopant levels reveal that ionic diffusion rates under load (current carrying conditions) are two orders of magnitude faster than free ionic-diffusion rates. This anomaly is explained in terms of electric field enhancement of the ionic diffusion in (CH)x.

Original languageEnglish (US)
Pages (from-to)2847-2856
Number of pages10
JournalJournal of the Electrochemical Society
Volume131
Issue number12
DOIs
StatePublished - Dec 1984

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Polyacetylenes
Doping (additives)
Spectroscopy
Electric potential
Energy gap
Gene Conversion
Charge injection
Kinetics
Chemical potential
Electronic states
Solitons
Light absorption
Hysteresis
Charge transfer
Electric fields
Impurities
Electrons

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

Cite this

Kaufman, J. H. ; Chung, T. C. ; Heeger, A. J. / Fundamental Electrochemical Studies of Polyacetylene. In: Journal of the Electrochemical Society. 1984 ; Vol. 131, No. 12. pp. 2847-2856.
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Fundamental Electrochemical Studies of Polyacetylene. / Kaufman, J. H.; Chung, T. C.; Heeger, A. J.

In: Journal of the Electrochemical Society, Vol. 131, No. 12, 12.1984, p. 2847-2856.

Research output: Contribution to journalArticle

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