Recent findings about ultrahigh thermoelectric performance in SnSe single crystals have stimulated related research on this simple binary compound, which is focused mostly on its polycrystalline counterparts, and particularly on electrical property enhancement by effective doping. This work systematically investigated the thermoelectric properties of polycrystalline SnSe doped with three alkali metals (Li, Na, and K). It is found that Na has the best doping efficiency, leading to an increase in hole concentration from 3.2 × 10(17) to 4.4 × 10(19) cm(-3) at room temperature, accompanied by a drop in Seebeck coefficient from 480 to 142 μV/K. An equivalent single parabolic band model was found adequate to capture the variation tendency of Seebeck coefficient with doping levels within a wide range. A mixed scattering of carriers by acoustic phonons and grain boundaries is suitable for numerically understanding the temperature-dependence of carrier mobility. A maximum ZT of ∼0.8 was achieved in 1% Na- or K-doped SnSe at 800 K. Possible strategies to improve the mobility and ZT of polycrystals were also proposed.
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http://dx.doi.org/10.1021/jacs.6b04181 | DOI Listing |
ACS Appl Mater Interfaces
December 2024
Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China.
SnSe materials have attracted extensive attention in thermoelectrics due to their low thermal conductivity. Nevertheless, the thermoelectric properties of n-type polycrystalline SnSe are still low, and metallic Sn distributed in the SnSe materials would affect the repeatability of thermoelectric performance. Herein, the thermoelectric properties of n-type polycrystalline SnSe-based composites are highly enhanced by heterogeneous Cu doping.
View Article and Find Full Text PDFACS Appl Mater Interfaces
October 2024
College of Materials, Shanghai Dianji University, Shanghai 201306, China.
Small
December 2024
Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
Materials (Basel)
June 2024
Faculty of Materials Science and Ceramics, AGH University of Krakow, al. A. Mickiewicza 30, 30-059 Krakow, Poland.
In recent years, solution processes have gained considerable traction as a cost-effective and scalable method to produce high-performance thermoelectric materials. The process entails a series of critical steps: synthesis, purification, thermal treatments, and consolidation, each playing a pivotal role in determining performance, stability, and reproducibility. We have noticed a need for more comprehensive details for each of the described steps in most published works.
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