A systematic study of the changes in the thermoelectric power (TEP) and four-probe resistance of vacuum-degassed thin films of nanotube bundles induced by the adsorption of polar alcohols and water six-membered ring molecules was presented. A strong effect on both the TEP, represented by S, and resistivity was found for methanol, ethanol, isopropanol, and butanol. For these four compounds, the TEP increased exponentially with time from the degassed value S0 ∼ -2.7 μV/K to a higher plateau after ∼ 1 hr. For methanol and ethanol, S was even driven positive, saturating at Smax ∼ +1.1 and +0.1 μV/K, respectively. Exposure to larger alcohol molecules, i.e., isopropanol and butanol, led to smaller changes in S and saturation at Smax ∼ -0.5 and -1.0 μV/K, respectively. Exposure to water vapor induced virtually no change in the TEP. S exhibited a linear relationship with ΔR/R0, consistent with the creation of a new impurity scattering channel via physisorption.
|Original language||English (US)|
|Number of pages||2|
|Journal||ACS Division of Fuel Chemistry, Preprints|
|State||Published - Sep 1 2004|
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