Charging Processes in Electroactive C60/Pd Films: Effect of Solvent and Supporting Electrolyte

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• 作者：Krzysztof Winkler ; Ana de Bettencourt-Dias ; and Alan L. Balch
• 刊名：Chemistry of Materials
• 出版年：1999
• 出版时间：August 1999
• 年：1999
• 卷：11
• 期：8
• 页码：2265 - 2273
• 全文大小：116K
• 年卷期：v.11,no.8(August 1999)
• ISSN：1520-5002

文摘

The electrochemical properties of solid films deposited on an electrode surface bysimultaneous electrochemical reduction of C₆₀ and palladium(II) acetate trimer in anacetonitrile/toluene mixture have been studied using cyclic voltammetry. The electrochemicalswitching between the doped (conducting) and undoped (nonconducting) states involves bothelectron and ion transport within the film. The overall control of charge percolation throughthe C₆₀/Pd electroactive material is governed by the transport of cations. The ion transportdepends both on the nature of solvent and supporting electrolyte. The size of solvent moleculeis the major factor determining the degree of solvent swelling of the layer. In the case ofsmall solvent molecules, the C₆₀/Pd film exhibits a reversible redox behavior. For largermolecule solvents, the voltammograms show a departure from reversibility. The reductionof the layer is accompanied by changes in its morphology allowing for the solvent swellingof the film also in the case of large molecule solvents. The electrochemical response of thelayer is not affected by the anions of the supporting electrolyte. However, a strong influenceof both nature and concentration of supporting electrolyte cations on the redox properties ofthe layer is observed, since these cations are incorporated into the C₆₀/Pd layer. The redoxability in solutions containing large cations is considerably reduced. The activation of thefilm at negative potentials results in an increase of the doping level. The stability of thefilms is affected by the potential range over which they are examined. Scanning to highlynegative potentials results in the loss of redox activity due to removal of the film from theelectrode surface.