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JournalISSN: 0379-6779

Synthetic Metals 

About: Synthetic Metals is an academic journal. The journal publishes majorly in the area(s): Polyaniline & Conductive polymer. It has an ISSN identifier of 0379-6779. Over the lifetime, 18336 publication(s) have been published receiving 363572 citation(s).
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Journal ArticleDOI
Hiromichi Kataura1, Y. Kumazawa1, Y. Maniwa1, Ikurou Umezu2  +3 moreInstitutions (2)
01 Jun 1999-Synthetic Metals
Abstract: Four kinds of single-wall carbon nanotubes (SWNTs) with different diameter distribution have been synthesized and optical absorption spectra have been measured. Three large absorption bands due to the optical transitions between spike-like density of states, characteristics of SWNTs, were observed from infrared to visible region. Comparing with the calculated energy band, it has been concluded that the first and the second lowest absorption bands are due to the optical transitions between spikes in semiconductor phases and the third one is due to that in metallic phases. Absorption Peaks sensitively shifted to higher energy side with decreasing tube diameters as the band calculation predicted. Resonance Raman spectra were also measured using various laser lines. When the excitation is in an energy region corresponding to the absorption band of metallic phase, spectra have shown Breit-Wigner-Fano line shape, which is a sign of metallic phase. Using these results, we can easily characterize SWNTs from the optical absorption spectra without Raman measurements and transmission electron microscope observations.

2,168 citations

Journal ArticleDOI
J. C. Chiang1, Alan G. MacDiarmid1Institutions (1)
01 Jan 1986-Synthetic Metals
Abstract: The emeraldine base form of polyaniline, which consists of equal numbers of reduced [(C6H4)N(H)(C6H4)N(H)] and oxidized [(C6H4)N(C6H4)N] repeat units, is doped to the metallic conducting regime by aqueous 1 M HCl. The product is believed to consist of equal numbers of the reduced repeat units and the diprotonated oxidized repeat units, The resulting material appears to have significant π delocalization in the polymer backbone. The doping is of a type not hitherto observed in a conducting polymer. It results in the formation of an environmentally stable nitrogen base salt rather than of a carbonium ion as in conventional oxidative p-doping of a polymer. Unlike all other conducting polymers, its conductivity depends on two variables, namely the degree of oxidation and the degree of protonation of the material. Various relationships between conductivity, pH of the acid dopant solutions, percentage doping and pKa of the protonated emeraldine salt are described and discussed.

1,740 citations

Journal ArticleDOI
15 Feb 1997-Synthetic Metals
Abstract: Present polymeric microelectronic devices are typically unipolar devices, based on p-type semiconducting polymers. Bipolar devices stable under ambient conditions are desirable, but have not yet been reported due to a lack of stable n-type doped conducting polymers. Starting from the standard redox potentials of, especially, water and oxygen, stability requirements on electrode potentials of n-type doped conducting polymers are derived. The predictions are then compared with experimental data on stability of conducting polymers. A good agreement is obtained. An electrode potential of about 0 to + 0.5 V (SCE) is required for stable n-type doped polymers, similar to the requirement on the electrode potential for stable undoped p-type polymers. Consequences for bipolar devices are analysed. Huge overpotentials for the redox reaction with wet oxygen are required in order to realize thermodynamically stable bipolar devices from known doped p-type and n-type conducting polymers. Finally, possible solutions, accepting thermodynamic instability, are discussed.

1,267 citations

Journal ArticleDOI
15 Jun 1992-Synthetic Metals
Abstract: By using a suitably functionalized protonic acid to protonate polyaniline, the counter ion can induce processibility of the resulting PANI complex. Our results demonstrate the feasibility of processing, in the conducting form , polyaniline and a variety of polyblends made from polyaniline. The resulting conducting polymer materials can be melt-processed or processed from solution to enable the fabrication of thin films, sheets, fibers, transparent conductive films, bulk parts, etc. These materials exhibit relatively high levels of electrical conductivity at low volume fractions of the polyaniline complex, while maintaining excellent mechanical properties, essentially equivalent to those of the host bulk polymer.

1,245 citations

Journal ArticleDOI
01 Feb 1987-Synthetic Metals
Abstract: The analytically pure base form of polyaniline, , corresponding to the emeraldine oxidation state is converted from an insulator (σ 10 −10 S/cm) to a metal (σ 5 S/cm) by treatment with 1M aqueous HCl to form the corresponding salt, emeraldine hydrochloride, . This involves a new type of doping of a conducting polymer in that the number of electrons associated with the polymer undergoes no change during the protonic acid doping process. The metallic emeraldine hydrochloride is believed to be a delocalized poly(semiquinone radical cation) having a polaron conduction band, with most of the positive charge residing on the nitrogen atoms. It exhibits a finite density of states at the Fermi energy.

1,233 citations

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No. of papers from the Journal in previous years

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Journal's top 5 most impactful authors

Richard H. Friend

198 papers, 5.8K citations

Alan G. MacDiarmid

100 papers, 10.8K citations

Serge Lefrant

93 papers, 1.8K citations

Alan J. Heeger

88 papers, 5.8K citations

Tokio Yamabe

69 papers, 1.1K citations