Enhanced thermoelectric performance of n-type Cu0.008Bi2Te2.7Se0.3 by band engineering

Kyu Hyoung Lee, Sang Il Kim, Hyeona Mun, Byungki Ryu, Soon Mok Choi, Hee Jung Park, Sungwoo Hwang, Sung Wng Kim

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36 Scopus citations


We herein report the significantly improved thermoelectric performance of n-type Bi2Te2.7Se0.3 polycrystalline bulks through band structure engineering achieved by Au-doping. The Seebeck coefficient can be increased for both Bi2Te2.7Se0.3 and Cu-intercalated Bi2Te2.7Se0.3 bulks by doping Au on the Bi site, either due to the addition of the resonant state or the enhancement of density of states (DOS) effective mass md∗. Theoretical calculations combined with experimental measurements showed that band engineering connected with chemical potential tuning results in higher DOS at the bottom of the conduction band and increases the md∗ from ∼0.88m0 (Bi2Te2.7Se0.3) to ∼1.06m0 (Cu0.008Bi1.99Au0.01Te2.7Se0.3). As a consequence, a peak thermoelectric figure of merit ZT ∼0.91 was obtained at 320 K for Cu0.008Bi1.99Au0.01Te2.7Se0.3, which is ∼40% and ∼25% enhancement in comparison with Bi2Te2.7Se0.3 and Cu0.008Bi2Te2.7Se0.3, respectively.

Original languageEnglish
Pages (from-to)10604-10609
Number of pages6
JournalJournal of Materials Chemistry C
Issue number40
StatePublished - 2015


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