Characterization and Electrochemical Properties of Oxygenated Amorphous Carbon (a-C) Films

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Characterization and Electrochemical Properties of Oxygenated Amorphous Carbon (a-C) Films. / Palomäki, Tommi; Wester, Niklas; Johansson, Leena-Sisko; Laitinen, Mikko; Jiang, Hua; Arstila, Kai; Sajavaara, Timo; Han, Jeon G.; Koskinen, Jari; Laurila, Tomi.

julkaisussa: Electrochimica Acta, Vuosikerta 220, 01.12.2016, s. 137-145.

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Palomäki, Tommi ; Wester, Niklas ; Johansson, Leena-Sisko ; Laitinen, Mikko ; Jiang, Hua ; Arstila, Kai ; Sajavaara, Timo ; Han, Jeon G. ; Koskinen, Jari ; Laurila, Tomi. / Characterization and Electrochemical Properties of Oxygenated Amorphous Carbon (a-C) Films. Julkaisussa: Electrochimica Acta. 2016 ; Vuosikerta 220. Sivut 137-145.

Bibtex - Lataa

@article{90985e274b49452c8c178cc95cd72fa8,
title = "Characterization and Electrochemical Properties of Oxygenated Amorphous Carbon (a-C) Films",
abstract = "Amorphous carbon (a-C) films with varying oxygen content were deposited by closed-field unbalanced magnetron sputtering with the aim to understand the effect of oxygen on the structural and physical properties of the films and subsequently correlate these changes with electrochemical properties. The a-C films were characterized by transmission electron microscopy, helium-ion microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and time-of-flight elastic recoil detection analysis. The electrochemical properties were studied by electrochemical impedance spectroscopy and cyclic voltammetry with several redox systems (Ru(NH3)62+/3+, Fe(CN)64−/3−, dopamine and ascorbic acid). The results indicated that the carbon films are amorphous with an ID/IG ratio near 2.6. The oxygen content of the films seemed to saturate at around 11 at. {\%}, whereas the amount of surface oxygen functional groups increased steadily with increasing oxygen inflow during deposition. O/C ratio increased from 0.09 to 0.19. A significant increase in film resistivity was observed with increasing oxygen content. Lightly oxygenated a-C films showed a low charge transfer resistance (Rct) and reversible electron transfer for Ru(NH3)62+/3+ whereas both Rct and ΔEp increased considerably for heavily oxygenated films. The inner sphere redox systems were significantly affected by the surface oxygen functional groups with dopamine and ascorbic acid showing a linear increase in ΔEp and Epa, respectively, with increasing oxygen content. Fe(CN)64−/3− did not show a clear trend but was still clearly affected by the increase in oxygen content. The double layer capacitance was about 1 μF/cm2 for all the oxygenated a-C films.",
keywords = "oxygenated amorphous carbon, electron transfer, cyclic voltammetry, electrochemical impedance spectroscopy, unbalanced magnetron sputtering",
author = "Tommi Palom{\"a}ki and Niklas Wester and Leena-Sisko Johansson and Mikko Laitinen and Hua Jiang and Kai Arstila and Timo Sajavaara and Han, {Jeon G.} and Jari Koskinen and Tomi Laurila",
year = "2016",
month = "12",
day = "1",
doi = "10.1016/j.electacta.2016.10.063",
language = "English",
volume = "220",
pages = "137--145",
journal = "Electrochimica Acta",
issn = "0013-4686",

}

RIS - Lataa

TY - JOUR

T1 - Characterization and Electrochemical Properties of Oxygenated Amorphous Carbon (a-C) Films

AU - Palomäki, Tommi

AU - Wester, Niklas

AU - Johansson, Leena-Sisko

AU - Laitinen, Mikko

AU - Jiang, Hua

AU - Arstila, Kai

AU - Sajavaara, Timo

AU - Han, Jeon G.

AU - Koskinen, Jari

AU - Laurila, Tomi

PY - 2016/12/1

Y1 - 2016/12/1

N2 - Amorphous carbon (a-C) films with varying oxygen content were deposited by closed-field unbalanced magnetron sputtering with the aim to understand the effect of oxygen on the structural and physical properties of the films and subsequently correlate these changes with electrochemical properties. The a-C films were characterized by transmission electron microscopy, helium-ion microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and time-of-flight elastic recoil detection analysis. The electrochemical properties were studied by electrochemical impedance spectroscopy and cyclic voltammetry with several redox systems (Ru(NH3)62+/3+, Fe(CN)64−/3−, dopamine and ascorbic acid). The results indicated that the carbon films are amorphous with an ID/IG ratio near 2.6. The oxygen content of the films seemed to saturate at around 11 at. %, whereas the amount of surface oxygen functional groups increased steadily with increasing oxygen inflow during deposition. O/C ratio increased from 0.09 to 0.19. A significant increase in film resistivity was observed with increasing oxygen content. Lightly oxygenated a-C films showed a low charge transfer resistance (Rct) and reversible electron transfer for Ru(NH3)62+/3+ whereas both Rct and ΔEp increased considerably for heavily oxygenated films. The inner sphere redox systems were significantly affected by the surface oxygen functional groups with dopamine and ascorbic acid showing a linear increase in ΔEp and Epa, respectively, with increasing oxygen content. Fe(CN)64−/3− did not show a clear trend but was still clearly affected by the increase in oxygen content. The double layer capacitance was about 1 μF/cm2 for all the oxygenated a-C films.

AB - Amorphous carbon (a-C) films with varying oxygen content were deposited by closed-field unbalanced magnetron sputtering with the aim to understand the effect of oxygen on the structural and physical properties of the films and subsequently correlate these changes with electrochemical properties. The a-C films were characterized by transmission electron microscopy, helium-ion microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and time-of-flight elastic recoil detection analysis. The electrochemical properties were studied by electrochemical impedance spectroscopy and cyclic voltammetry with several redox systems (Ru(NH3)62+/3+, Fe(CN)64−/3−, dopamine and ascorbic acid). The results indicated that the carbon films are amorphous with an ID/IG ratio near 2.6. The oxygen content of the films seemed to saturate at around 11 at. %, whereas the amount of surface oxygen functional groups increased steadily with increasing oxygen inflow during deposition. O/C ratio increased from 0.09 to 0.19. A significant increase in film resistivity was observed with increasing oxygen content. Lightly oxygenated a-C films showed a low charge transfer resistance (Rct) and reversible electron transfer for Ru(NH3)62+/3+ whereas both Rct and ΔEp increased considerably for heavily oxygenated films. The inner sphere redox systems were significantly affected by the surface oxygen functional groups with dopamine and ascorbic acid showing a linear increase in ΔEp and Epa, respectively, with increasing oxygen content. Fe(CN)64−/3− did not show a clear trend but was still clearly affected by the increase in oxygen content. The double layer capacitance was about 1 μF/cm2 for all the oxygenated a-C films.

KW - oxygenated amorphous carbon

KW - electron transfer

KW - cyclic voltammetry

KW - electrochemical impedance spectroscopy

KW - unbalanced magnetron sputtering

U2 - 10.1016/j.electacta.2016.10.063

DO - 10.1016/j.electacta.2016.10.063

M3 - Article

VL - 220

SP - 137

EP - 145

JO - Electrochimica Acta

JF - Electrochimica Acta

SN - 0013-4686

ER -

ID: 8926355