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Enhancement in Thermoelectric Figure of Merit in Nanostructured Bi 2 Te 3 with Semimetal Nanoinclusions
Author(s) -
Sumithra S.,
Takas Nathan J.,
Misra Dinesh K.,
Nolting Westly M.,
Poudeu P.F.P.,
Stokes Kevin L.
Publication year - 2011
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201100338
Subject(s) - materials science , semimetal , seebeck coefficient , bismuth , thermoelectric effect , thermal conductivity , figure of merit , condensed matter physics , nanoparticle , thermoelectric materials , nanotechnology , band gap , optoelectronics , composite material , thermodynamics , metallurgy , physics
The effect of Bi (semimetal) nanoinclusions in nanostructured Bi 2 Te 3 matrices is investigated. Bismuth nanoparticles synthesized by a low temperature solvothermal method are incorporated into Bi 2 Te 3 matrix phases, synthesized by planetary ball milling. High density pellets of the Bi nanoparticle/Bi 2 Te 3 nanocomposites are created by hot pressing the powders at 200 °C and 100 MPa. The effect of different volume fractions (0–7%) of Bi semimetal nanoparticles on the Seebeck coefficient, electrical conductivity, thermal conductivity and carrier concentration is reported. Our results show that the incorporation of semimetal nanoparticles results in a reduction in the lattice thermal conductivity in all the samples. A significant enhancement in power factor is observed for Bi nanoparticle volume fraction of 5% and 7%. We show that it is possible to reduce the lattice thermal conductivity and increase the power factor resulting in an increase in figure of merit by a factor of 2 (from ZT = 0.2 to 0.4). Seebeck coefficient and electrical conductivity as a function of carrier concentration data are consistent with the electron filtering effect, where low‐energy electrons are preferentially scattered by the barrier potentials set up at the semimetal nanoparticle/semiconductor interfaces.