2014 (English)In: Nature Materials, ISSN 1476-1122, E-ISSN 1476-4660, Vol. 13, no 2, 190-194 p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
Nature Publishing Group , 2014. Vol. 13, no 2, 190-194 p.
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-104644DOI: 10.1038/nmat3824ISI: 000330182700027OAI: oai:DiVA.org:liu-104644DiVA: diva2:698183