Reactivity of lithium-containing amorphous carbon (a-C) films

Töwe, Matthias; Reinke, Petra; Oelhafen, P.

doi:10.1016/s0022-3115(00)00432-3

Cited by 6 publications

(2 citation statements)

References 15 publications

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“…observed binding energy shifts, for a more detailed analysis both shifts of the Fermi level and chemical shifts must be considered, which are related to changes in the effective charge on individual atoms and other electronic and relaxation effects. 16 Our results are in accord with the previous study on chemically doped SWCNTs (by Li) where the binding energy shift toward higher energies after the doping was examined. 17 Our observations are further evidence of sample doping, and they demonstrate the stability of doped samples because the analysis was done ex situ.…”

Section: Resultssupporting

confidence: 93%

“…Therefore, the binding energies of the core-level electrons, which are measured against the Fermi level, are shifted either to higher values (n-doping) or to lower values (p-doping). Although the above-mentioned simple model explains the observed binding energy shifts, for a more detailed analysis both shifts of the Fermi level and chemical shifts must be considered, which are related to changes in the effective charge on individual atoms and other electronic and relaxation effects …”

Section: Resultsmentioning

confidence: 99%

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Chemical States of Electrochemically Doped Single Wall Carbon Nanotubes As Probed by Raman Spectroelectrochemistry and ex Situ X-ray Photoelectron Spectroscopy

et al. 2008

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X-ray photoelectron spectroscopy (XPS) was combined with Raman spectroelectrochemistry to study the electrochemically doped states of single wall carbon nanotube (SWCNT) bundles. The ex situ measurements indicated a significant drop of doping level as compared to in situ measurements. However, after this initial decrease of the doping level, the electronic structure of SWCNT bundles was found to be stable. The XPS elemental analysis indicated that electrolyte ions penetrate into the nanotube bundles. Furthermore, for the n-doped (electrochemically reduced) sample, an increase of the relative surface concentration of different C−O groups was observed, which was caused by electrochemical reduction of ClO4 − ions. Comparison of the ex situ Raman and XP spectra showed that an electrode potential shift of 1 V corresponds to the Fermi level shift of ca. 0.5 eV.

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Section: Resultssupporting

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Chemical States of Electrochemically Doped Single Wall Carbon Nanotubes As Probed by Raman Spectroelectrochemistry and ex Situ X-ray Photoelectron Spectroscopy

et al. 2008

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Effect of annealing and lithium substitution on conductivity in nickel–cobalt oxide spinel films

Owings

Holloway

Windisch

2005

Surface & Interface Analysis

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Mixed transition-metal oxide spinels exhibit high electrical conductivity and enhanced infrared transmissivity resulting from the presence of small polarons in the NiCo 2 O 4 lattice. Polarons are formed as a result of judicious choice of component metal cations and attendant resident cation charge states. Substitution of lithium for cobalt (Ni 1+x Co 2−x−z Li z O 4 ) while maintaining the spinel stoichiometry and controlled post-deposition annealing was found to influence measured conductivity in both solutionand sputter-deposited thin films. For lithium concentrations < 10% an improvement in conductivity was observed, depending upon whether the oxide film was deposited from solution (large increase) or sputter deposited (small increase). However, higher lithium concentrations degraded conductivity. Both XPS and SIMS analyses of films with high lithium concentrations (z > 0.3) revealed that lithium was concentrated near the film surface and the formation of carbonate was detected by XPS and Fourier transform infrared data. Results indicate that additions of lithium to transition-metal spinel oxides can lead to increased conductivity by increased polaron formation. However, in high concentration, lithium is an interstitial that diffuses to the surface to form compounds that degrade electrical conductivity.

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