The effect of adsorbed vapors on the electrical conductivity of Saran carbon

Dacey, J. R.; Quinn, D.F.; Gallagher, J.T.

doi:10.1016/0008-6223(66)90011-x

Cited by 12 publications

(7 citation statements)

References 7 publications

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“…It is to be noted that while the values of the conductivities relative to the room-temperature value It is suggestive to make a comparison between the room-temperature (RT) conductivity of ACF's and those of other carbon systems because systems with conductivities of about the same magnitude at RT may exhibit the same kind of conducting behavior at low temperature. A typical range of RT conductivity for phenolic ACF's is approximately 5-10 S/cm, which is comparable to that for active carbon rods, 7 Saran carbon, 13 and glassy carbon. 14 ACF's are much more conductive than evaporated carbon thin films 15 and a great deal less conductive than vapor-grown carbon fibers.…”

Section: Resultsmentioning

confidence: 69%

Raman scattering and electrical conductivity in highly disordered activated carbon fibers

et al. 1993

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Because of their unusually large specific surface area (SSA), Activated Carbon Fibers (ACF's) have a huge density of micropores and defects. The Raman scattering technique and low-temperature dc electrical conductivity measurements were used as characterization tools to study the disorder in ACF's with SSA ranging from 1000 m 2 /g to 3000 m 2 /g. Two peaks were observed in every Raman spectrum for ACF's and they could be identified with the disorder-induced peak near ~1360 cm" 1 and the Breit-Wigner-Fano peak near -1610 cm" 1 associated with the Raman-active E 2g2 mode of graphite. The graphitic nature of the ACF's is shown by the presence of a well-defined graphitic structure with L a values of 20-30 A. We observed that the Raman scattering showed more sensitivity to the precursor materials than to the SSA of the ACF's. From 4 K to room temperature, the dc electrical resistivity in ACF's is observed to follow the exp[(r o /T) 1/2 ] functional form and it can be accounted for by a charge-energy-limited tunneling conduction mechanism. Coulomb-gap conduction and n-dimensional (n =£ 3) variable-range hopping conduction models were also considered but they were found to give unphysical values for their parameters.

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Section: Resultsmentioning

confidence: 69%

Raman scattering and electrical conductivity in highly disordered activated carbon fibers

et al. 1993

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“…As shown in a B.E.T. measurement of other activated carbon materials, 1 every second atom can be a surface atom that has a dangling bond. Thus activated carbon is regarded as a good material for research on strongly disordered systems.…”

Section: Introductionmentioning

confidence: 98%

“…In the case of carbon materials, interesting phenomena that are not observed in graphitic systems have been reported in some disordered carbons, such as Saran carbon rods (in terms of their conductivity 1 ), active carbon rods (in terms of their resistivity 2 ' 3 ), evaporated carbon films (in terms of their resistivity, 4 ' 5 photoconductivity, 6 optical absorption edge, 7 adsorption, 8 ' 9 and ESR 10 ), anthracite carbon powders (in terms of their electrical properties 11 ), glassy carbons, 12 " 14 and others. 15 " 20 A series of systematic investigations on the electronic properties of various types of carbon materials have been carried out by Mrozowski.…”

Section: Introductionmentioning

confidence: 99%

Photoconductivity of activated carbon fibers

Kuriyama

Dresselhaus

1991

J. Mater. Res.

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The conductivity and photoconductivity are measured on a high-surface-area disordered carbon material, i.e., activated carbon fibers, to investigate their electronic properties. This material is a highly disordered carbon derived from a phenolic precursor, having a huge specific surface area of 1000-2000 m 2 /g. Our preliminary thermopower measurements show that the dominant carriers are holes at room temperature. The x-ray diffraction pattern reveals that the microstructure is amorphous-like with L c -10 A. The intrinsic electrical conductivity, on the order of 20 S/cm at room temperature, increases by a factor of several with increasing temperature in the range 30-290 K. In contrast, the photoconductivity in vacuum decreases with increasing temperature. The magnitude of the photoconductive signal was reduced by a factor of ten when the sample was exposed to air. The recombination kinetics changes from a monomolecular process at room temperature to a bimolecular process at low temperatures, indicative of an increase in the photocarrier density at low temperatures. The high density of localized states, which limits the motion of carriers and results in a slow recombination process, is responsible for the observed photoconductivity.

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“…This was in agreement with the results discussed by Davtyan (1961). Interestingly, other authors have reported the saturation of the resistance reading before particle saturation for other adsorbate/adsorbent systems (McIntosh et al, 1947;Dacey et al, 1966;McLintock and Orr, 1968;Merey and Cointot, 1975;Lukaszewicz and Siedlewski, 1982). Sushchev et al (1997) measured the resistance of a packed bed of activated carbon, and developed an equation to predict the e ective resistivity of an idealized bed of activated carbon grains.…”

Section: Introductionmentioning

confidence: 93%