期刊
ACS APPLIED MATERIALS & INTERFACES
卷 11, 期 24, 页码 21645-21654出版社
AMER CHEMICAL SOC
DOI: 10.1021/acsami.9b08108
关键词
thermoelectrics; polycrystalline SnSe; n-type; nanostructure; dual-doping
资金
- Nanomaterial Technology Development Program through the National Research Foundation of Korea (NRF) - Ministry of Science and ICT [NRF-2017M3A7B4049274]
- NRF Grant - Korean Government (MSIP) [NRF-2015R1A5A1036133]
- National Research Foundation of Korea [2017M3A7B4049274, 2015R1A5A1036133, IBS-R006-D1-2019-A00] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
Despite extensive studies on emerging thermoelectric material SnSe, its n-type form is largely underdeveloped mainly due to the difficulty in stabilizing the carrier concentration at the optimal level. Here, we dually introduce Cl and PbSe to induce n-type conduction in intrinsic p-type SnSe. PbSe alloying enhances the power factor and suppresses lattice thermal conductivity at the same time, giving a highest thermoelectric figure of merit ZT of 1.2 at 823 K for n-type polycrystalline SnSe materials. The best composition is Sn0.90Pb0.15Se0.95Cl0.05. Samples prepared by the solid-state reaction show a high maximum ZT (ZT(max)) similar to 1.1 and similar to 0.8 parallel and perpendicular to the press direction of spark plasma sintering, respectively. Remarkably, post-ball milling and annealing processes considerably reduce structural anisotropy, thereby leading to a ZT(max)similar to 1.2 along both the directions. Hence, the direction giving a ZT(max) is controllable for this system using the specialized preparation methods for specimens. Spherical aberration-corrected scanning transmission electron microscopic analyses reveal the presence of heavily dense edge dislocations and strain fields, not observed in the p-type counterparts, which contribute to decreasing lattice thermal conductivity. Our theoretical calculations employing a Callaway-Debye model support the experimental results for thermal transport and microscopic structures.
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