High Thermoelectric Performance of AgSb<sub>1-<i>x</i></sub>Pb<sub><i>x</i></sub>Se<sub>2</sub> Prepared by Fast Nonequilibrium Synthesis.

TitleHigh Thermoelectric Performance of AgSb1-xPbxSe2 Prepared by Fast Nonequilibrium Synthesis.
Publication TypeJournal Article
Year of Publication2020
AuthorsX Tan, J Ding, H Luo, O Delaire, J Yang, Z Zhou, J-L Lan, Y-H Lin, and C-W Nan
JournalAcs Applied Materials & Interfaces
Start Page41333
Pagination41333 - 41341
Date Published09/2020

AgSbSe<sub>2</sub> is a typical member of cubic I-V-VI<sub>2</sub> semiconductors, which are known for their extremely low lattice thermal conductivity (κ<sub>l</sub>). However, the low electrical conductivity of AgSbSe<sub>2</sub>, below ∼10 S cm<sup>-1</sup> at room temperature, has hindered its thermoelectric performance. In this work, single-phase AgSbSe<sub>2</sub> bulk samples with much higher electrical conductivity were synthesized via self-propagating high-temperature synthesis (SHS) combined with spark plasma sintering (SPS) for the first time. Pb doping through the nonequilibrium process further increases the electrical conductivity to >100 S cm<sup>-1</sup>. Furthermore, continuously increased effective mass <i>m</i><sub>d</sub><sup>*</sup> can be achieved upon Pb doping because of the multiple degenerate valence bands of AgSbSe<sub>2</sub> and the energy-filtering effect induced by <i>in situ</i>-formed nanodots. The simultaneous enhancement of both the electrical conductivity and Seebeck coefficient contributes to an unprecedentedly high average power factor of 6.75 μW cm<sup>-1</sup> K<sup>-2</sup>. Meanwhile, the introduced dense grain boundaries and point defects enhance the phonon scattering and consequently suppress κ<sub>l</sub>, yielding a high <i>ZT</i> value of 1.2 at 723 K in AgSb<sub>0.94</sub>Pb<sub>0.06</sub>Se<sub>2</sub>. This study opens a new avenue for rapid, low-cost, large-scale production of AgSbSe<sub>2</sub>-based materials and demonstrates that Pb-doped AgSbSe<sub>2</sub> prepared via the SHS-SPS method is a promising candidate for thermoelectric applications.

Short TitleAcs Applied Materials & Interfaces