Role of Anions in the AuCl3-Doping of Carbon Nanotubes

详细信息    查看全文

• 作者：Soo Min Kim ; Ki Kang Kim ; Young Woo Jo ; Min Ho Park ; Seung Jin Chae ; Dinh Loc Duong ; Cheol Woong Yang ; Jing Kong ; Young Hee Lee
• 刊名：ACS Nano
• 出版年：2011
• 出版时间：February 22, 2011
• 年：2011
• 卷：5
• 期：2
• 页码：1236-1242
• 全文大小：1037K
• 年卷期：0
• ISSN：1936-086X

文摘

The doping/dedoping mechanism of carbon nanotubes (CNTs) with AuCl₃ has been investigated with regard to the roles of cations and anions. Contrary to the general belief that CNTs are p-doped through the reduction of cationic Au³⁺ to Au⁰, we observed that chlorine anions play a more important role than Au cations in doping. To estimate the effects of Cl and Au on CNTs, the CNT film was dedoped as a function of the annealing temperature (100−700 °C) under an Ar ambient and was confirmed by the sheet resistance change and the presence of a G-band in the Raman spectra. The X-ray photoelectron spectroscopy (XPS) analysis revealed that the doping level of the CNT film was strongly related to the amount of adsorbed chlorine atoms. Annealing at temperatures up to 200 °C did not change the amount of adsorbed Cl atoms on the CNTs, and the CNT film was stable under ambient conditions. Alternatively, Cl atoms started to dissociate from CNTs at 300 °C, and the stability of the film was degraded. Furthermore, the change in the amount of Cl atoms in CNTs was inversely proportional to the change in the sheet resistance. Our observations of the Cl adsorption, either directly or mediated by an Au precursor on the CNT surface, are congruent with the previous theoretical prediction.