標題: Nano Approach Investigation of the Conduction Mechanism in Polyaniline Nanofibers
作者: Lin, Yen-Fu
Chen, Chien-Hsiang
Xie, Wen-Jia
Yang, Sheng-Hsiung
Hsu, Chain-Shu
Lin, Minn-Tsong
Jian, Wen-Bin
電子物理學系
應用化學系
Department of Electrophysics
Department of Applied Chemistry
關鍵字: conducting polymer;one-dimensional nanostructures;polyaniline;hopping conduction;nanofiber
公開日期: 1-Feb-2011
摘要: A nanotechnological approach is applied to measurements of the electric field dependence of resistance under a high electric field while in low voltage. With this technique, the conduction mechanism on a mesoscopic scale is explored in a single, nonagglomerated nanofiber. Polyaniline nanofibers are prepared by vigorous mixing of aniline and oxidation agent ammonium persulfate in acid solution. They exhibit a uniform nanoscale morphology rather than agglomeration as that produced via conventional chemical oxidation. The as-synthesized polyaniline nanofibers are doped (dedoped) with a HCl acid (NH(3) base), and their temperature behaviors of resistances follow an exponential function with an exponent of T(-1/2). To measure the conduction mechanism in a single nanofiber, the dieiectrophoresis technique is implemented to position nanofibers on top of two electrodes with a nanogap of 100-600 nm, patterned by electron-beam lithography. After the devices are irradiated by electron beam to reduce contact resistances, their temperature behaviors and electric field dependences are unveiled. The experimental results agree well with the theoretical model of charging energy limited tunneling. Other theoretical models such as Efros-Shklovskii and Mott's one-dimensional hopping conduction are excluded after comparisons and arguments. Through fitting, the size of the conductive grain, separation distance between two grains, and charging energy per grain in a single polyaniline nanofiber are estimated to be about 4.9 nm, 2.8 nm, and 78 meV, respectively. The nanotechnological approach, where the nanogap and the dielectrophoresis technique are used for single nanofiber device fabrication, Is applied for determination of mesoscopic charge transport in a polyaniline conducting polymer.
URI: http://dx.doi.org/10.1021/nn103525b
http://hdl.handle.net/11536/25810
ISSN: 1936-0851
DOI: 10.1021/nn103525b
期刊: ACS NANO
Volume: 5
Issue: 2
起始頁: 1541
結束頁: 1548
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