Effects of Potassium on the Supramolecular Structure and Electronic Properties of Eumelanin Thin Films

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• 作者：Patrizia Borghetti ; Andrea Goldoni ; Carla Castellarin-Cudia ; Loredana Casalis ; Fabian Herberg ; Luca Floreano ; Albano Cossaro ; Alberto Verdini ; Ralph Gebauer ; Prasenjit Ghosh ; Luigi Sangaletti
• 刊名：Langmuir
• 出版年：2010
• 出版时间：December 21, 2010
• 年：2010
• 卷：26
• 期：24
• 页码：19007-19013
• 全文大小：995K
• 年卷期：v.26,no.24(December 21, 2010)
• ISSN：1520-5827

文摘

The role of potassium in the formation of synthetic eumelanin aggregates is investigated by atomic force microscopy and soft-X-ray spectroscopy. Control over the thin film granularity is achieved by using K salts, in both drop casting and electrodeposition of eumelanin thin films. Further control over orientation is made possible by a suitable choice of the substrate: evidence of self-assembly is found for thin films deposited on gold. Finally, it is shown that the potassium content affects not only the samples morphology, but also the low-lying states in the valence band, where a transfer of spectral weight across the HOMO−LUMO gap is observed, disclosing possible applications of this multifunctional biomacromolecule.