1. Semi-metallic polymers.
- Author
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Bubnova, Olga, Khan, Zia Ullah, Wang, Hui, Braun, Slawomir, Evans, Drew R., Fabretto, Manrico, Hojati-Talemi, Pejman, Dagnelund, Daniel, Arlin, Jean-Baptiste, Geerts, Yves H., Desbief, Simon, Breiby, Dag W., Andreasen, Jens W., Lazzaroni, Roberto, Chen, Weimin M., Zozoulenko, Igor, Fahlman, Mats, Murphy, Peter J., Berggren, Magnus, and Crispin, Xavier
- Subjects
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POLYMERS , *METALLIC composites , *LIGHTWEIGHT materials , *SEMICONDUCTORS , *TELLURIDES , *TRANSITION metals , *SPINTRONICS - Abstract
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. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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