Carrier Lifetime Enhancement in a Tellurium Nanowire/PEDOT:PSS Nanocomposite by Sulfur Passivation

James N. Heyman, Ayaskanta Sahu, Nelson E. Coates, Brittany Ehraann, Jeffeiy J. Urban

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We report static and time-resolved terahertz (THz) conductivity measurements of a high- performance thermoelectric material containing tellurium nanowires in a PEDOT:PSS matrix. Composites were made with and without sulfur passivation of the nanowires surfaces. The material with sulfur linkers (TeNW/PD-S) is less conductive but has a longer carrier lifetime than the formulation without (TeNW/PD). We find real conductivities at/= ITHz of σTeNw/pd = 160 S/cm and σTeNw/PD-s = 5.1 S/cm. These values are much larger than the corresponding DC conductivities, suggesting DC conductivity is limited by structural defects. The free-carrier lifetime in the nanowires is controlled by recombination and trapping at the nanowire surfaces. We find surface recombination velocities in bare tellurium nanowires (22m/s) and TeNW/PD-S (40m/s) that are comparable to evaporated tellurium thin films. The surface recombination velocity in TeNW/PD (509m/s) is much larger, indicating a higher interface trap density.

Original languageEnglish (US)
Title of host publicationMolecular, Polymer and Hybrid Materials for Thermoelectrics
EditorsM. Kovalenko, R. Segalman, A. Carella, M. Chabinyc, J. Malen
PublisherMaterials Research Society
Pages7-12
Number of pages6
ISBN (Electronic)9781510806221
DOIs
StatePublished - 2015
Event2014 MRS Fall Meeting - Boston, United States
Duration: Nov 30 2014Dec 5 2014

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1742
ISSN (Print)0272-9172

Other

Other2014 MRS Fall Meeting
CountryUnited States
CityBoston
Period11/30/1412/5/14

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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