Effect of SOCl2 Treatment on Electrical and Mechanical Properties of Single-Wall Carbon Nanotube Networks

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• 作者：Urszula Dettlaff-Weglikowska ; Viera Ská ; kalová ; Ralf Graupner ; Sung Ho Jhang ; Byung Hoon Kim ; Hyun Jung Lee ; Lothar Ley ; Yung Woo Park ; Savas Berber ; David Tomá ; nek ; and Siegmar Rot
• 刊名：Journal of the American Chemical Society
• 出版年：2005
• 出版时间：April 13, 2005
• 年：2005
• 卷：127
• 期：14
• 页码：5125 - 5131
• 全文大小：298K
• 年卷期：v.127,no.14(April 13, 2005)
• ISSN：1520-5126

文摘

Chemical modification by SOCl₂ of an entangled network of purified single-wall carbon nanotubes,also known as 'bucky paper', is reported to profoundly change the electrical and mechanical properties ofthis system. Four-probe measurements indicate a conductivity increase by up to a factor of 5 at roomtemperature and an even more pronounced increase at lower temperatures. This chemical modificationalso improves the mechanical properties of SWNT networks. Whereas the pristine sample shows an overallsemiconducting character, the modified material behaves as a metal. The effect of SOCl₂ is studied interms of chemical doping of the nanotube network. We identified the microscopic origin of these changesusing SEM, XPS, NEXAFS, EDX, and Raman spectroscopy measurements and ab initio calculations. Weinterpret the SOCl₂-induced conductivity increase by p-type doping of the pristine material. This conclusionis reached by electronic structure calculations, which indicate a Fermi level shift into the valence band,and is consistent with the temperature dependence of the thermopower.