NMR evidence for the metallic nature of highly conducting polyaniline

Journal Article · Sun Jan 15 00:00:00 EST 1995 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.51.1541· OSTI ID:6880181

Kolbert, A C ^[1]; Caldarelli, S ^[2]; Thier, K F ^[1]; Sariciftci, N S ^[3]; Cao, Y ^[4]; Heeger, A J ^[3]

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1. Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States) Department of Chemistry, University of California, Berkeley, California 94720 (United States)
2. Section de Chimie, University of Lausanne, CH-1005 Lausanne (Switzerland)
3. Institute for Polymers and Organic Solids, University of California, Santa Barbara, California 93106 (United States)
4. 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), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 51:3; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
AMINES
ANILINE
AROMATICS
CAMPHOR
CARBON 13
CARBON ISOTOPES
CORRELATIONS
ELECTRON CORRELATION
ELECTRONIC STRUCTURE
EVEN-ODD NUCLEI
ISOTOPES
KETONES
LIGHT NUCLEI
NMR SPECTRA
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
ORGANIC SULFUR COMPOUNDS
POLYMERS
RELAXATION
SPECTRA
SPIN-LATTICE RELAXATION
STABLE ISOTOPES
SULFONIC ACIDS
TEMPERATURE DEPENDENCE
TERPENES