NMR evidence for the metallic nature of highly conducting polyaniline
- Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States) Department of Chemistry, University of California, Berkeley, California 94720 (United States)
- Section de Chimie, University of Lausanne, CH-1005 Lausanne (Switzerland)
- Institute for Polymers and Organic Solids, University of California, Santa Barbara, California 93106 (United States)
- UNIAX Corporation, 5375 Overpass Road, Santa Barbara, California 93111 (United States)
Polyaniline doped with camphor sulphonic acid (PANI-CSA) has been shown to yield a material that, after casting from solution in [ital meta]-cresol, exhibits a temperature-independent magnetic susceptibility [Y. Cao, P. Smith, and A. J. Heeger, Synth. Met. 48, 91 (1992); N. S. Sariciftici, A. J. Heeger, and Y. Cao, Phys. Rev. B 49, 5988 (1994)]. We report recent [sup 13]C NMR experiments on uniformly [sup 13]C-enriched PANI-CSA in which the [sup 13]C spin-lattice relaxation rates are shown to obey a modified Korringa relation for relaxation via the hyperfine coupling to conduction electrons. This observation of Korringa relaxation in polyaniline provides strong evidence for a metallic state in this material. An estimate is made of the Korringa enhancement factor that provides a measure of the degree of electron-electron correlations present. Two-dimensional spin-exchange experiments are also reported, which show that the [sup 13]C NMR signal results from a heterogeneity in the sample over at least a 30-A distance scale. These results are discussed in terms of the spatial extent of the doping-induced defect.
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6880181
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Vol. 51:3; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON 13
NMR SPECTRA
ORGANIC POLYMERS
ELECTRONIC STRUCTURE
ANILINE
CAMPHOR
ELECTRON CORRELATION
SPIN-LATTICE RELAXATION
SULFONIC ACIDS
TEMPERATURE DEPENDENCE
AMINES
AROMATICS
CARBON ISOTOPES
CORRELATIONS
EVEN-ODD NUCLEI
ISOTOPES
KETONES
LIGHT NUCLEI
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
POLYMERS
RELAXATION
SPECTRA
STABLE ISOTOPES
TERPENES
360606* - Other Materials- Physical Properties- (1992-)