Metallic transport in polyaniline
Metallic transport in polyaniline
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DOI：
10.1038/nature04705
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发表时间：
2006-05-04
期刊：
影响因子：
64.8
通讯作者：
Lee, SH
中科院分区：
文献类型：
--
作者：
Lee, K;Cho, S;Lee, SH
尽管经过近三十年的材料开发，所谓的导电聚合物在“金属状态”下的传输特性仍然不是传统金属的典型特性（1-7）。金属导电性的标志-电阻率随温度单调下降-在低于室温的整个温度范围内都没有得到;并且也没有观察到金属典型的频率依赖性电导率，σ（Ω）。相比之下，“金属”聚合物的低温行为，在所有先前的情况下，随着温度的进一步降低，表现出电阻率的增加，这是由于电荷载流子的无序诱导的局部化（1-4）。这种无序诱导的局域化也改变了红外响应，使得sigma（omega）偏离Drude理论的预测（5-7）。在这里，我们报告经典的金属传输数据从真正的金属聚合物。对于使用自稳定分散聚合制备的聚苯胺样品（8），我们发现对于室温电导率超过1，000 S cm（-1）的样品，电阻率随着温度降低至5 K而单调降低，并且红外光谱即使在测量的最低频率下也具有传统Drude模型的特征。
Despite nearly three decades of materials development, the transport properties in the 'metallic state' of the so-called conducting polymers are still not typical of conventional metals(1-7). The hallmark of metallic resistivity-a monotonic decrease in resistivity with temperature-has not been obtained at temperatures over the full range below room temperature; and a frequency dependent conductivity, sigma(omega), typical of metals has also not been observed. In contrast, the low-temperature behaviour of 'metallic' polymers has, in all previous cases, exhibited an increase in resistivity as temperature is further decreased, as a result of disorder-induced localization of the charge carriers(1-4). This disorder-induced localization also changes the infrared response such that sigma(omega) deviates from the prediction of Drude theory(5-7). Here we report classic metallic transport data obtained from truly metallic polymers. With polyaniline samples prepared using self-stabilized dispersion polymerization(8), we find that for samples having room-temperature conductivities in excess of 1,000 S cm(-1), the resistivity decreases monotonically as the temperature is lowered down to 5 K, and that the infrared spectra are characteristic of the conventional Drude model even at the lowest frequencies measured.