Improved Figure of Merit of Cu2SnSe3 via Band Structure Modification and Energy-Dependent Carrier Scattering
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2020-04-14 |
| Journal | ACS Applied Materials & Interfaces |
| Authors | Hongwei Ming, Chen Zhu, Xiaoying Qin, Jian Zhang, Di Li |
| Institutions | Nanjing University of Science and Technology, University of Science and Technology of China |
| Citations | 34 |
Abstract
Section titled āAbstractāAs an ecofriendly thermoelectric material with intrinsic low thermal conductivity, ternary diamond-like Cu<sub>2</sub>SnSe<sub>3</sub> (CSS) has attracted much attention. Nevertheless, its figure of merit, ZT, is limited by its small thermopower (<i>S</i>) and power factor (PF). Here, we show that an increase in thermopower by 63% and a carrier-mobility rise of 81% at 300 K can be simultaneously achieved through 5% substitution of Fe for Sn due to both enhancement of electronic density of states and degeneracy of multiple valence band maxima, which lead to high PF = 10.3 Ī¼WĀ·cm<sup>-1</sup>Ā·K<sup>-2</sup> at 823 K for Fe-doped CSS (CSFS). Besides, an ultrahigh PF of 14.8 Ī¼WĀ·cm<sup>-1</sup>Ā·K<sup>-2</sup> (at 773 K) and 45% reduction of lattice thermal conductivity (at 823 K) are realized for CSFS-based composites with 0.125 wt % of MgO nanoinclusions, owing to further enhancement of <i>S</i> via energy-dependent scattering and strong phonon scattering by the embedded nanoparticles. Consequently, a maximum ZT = 1 at 823 K is reached for the CSFS/<i>f</i> MgO composite samples with <i>f</i> = 0.125 wt %, which is around 2.5 times larger than that of the CSS compound.