Semi-metallic polymers
Semi-metallic polymers
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DOI：
10.1038/nmat3824
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发表时间：
2014-02-01
期刊：
影响因子：
41.2
通讯作者：
Crispin, Xavier
中科院分区：
文献类型：
--
作者：
Bubnova, Olga;Khan, Zia Ullah;Crispin, Xavier
聚合物是轻质、柔性、可溶液加工的材料，对于低成本印刷电子产品以及大规模生产和大面积应用是有希望的。以前的研究表明，它们可以具有绝缘，半导体或金属特性;在这里，我们报告聚合物也可以是半金属的。以铋、石墨和碲化物合金为例的半金属在费米能级处没有能带隙和非常低的态密度。此外，与金属相比，它们通常具有更高的塞贝克系数和更低的热导率，因此适合于热电应用。我们测量各种聚（3，4-乙撑二氧噻吩）样品的热电性能，并观察到显着增加塞贝克系数时，通过分子组织的导电性增强。这引发了从费米玻璃到半金属的转变。高Seebeck值，室温下的金属导电性和不存在不成对电子自旋使得聚合物半金属对热电和自旋电子学具有吸引力。
Polymers are lightweight, flexible, solution-processable materials that are promising for low-cost printed electronics as well as for mass-produced and large-area applications. Previous studies demonstrated that they can possess insulating, semiconducting or metallic properties; here we report that polymers can also be semi-metallic. Semi-metals, exemplified by bismuth, graphite and telluride alloys, have no energy bandgap and a very low density of states at the Fermi level. Furthermore, they typically have a higher Seebeck coefficient and lower thermal conductivities compared with metals, thus being suitable for thermoelectric applications. We measure the thermoelectric properties of various poly( 3,4-ethylenedioxythiophene) samples, and observe a marked increase in the Seebeck coefficient when the electrical conductivity is enhanced through molecular organization. This initiates the transition from a Fermi glass to a semi-metal. The high Seebeck value, the metallic conductivity at room temperature and the absence of unpaired electron spins makes polymer semi-metals attractive for thermoelectrics and spintronics.