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Ultrahigh average ZT realized in p-type SnSe crystalline thermoelectrics through producing extrinsic vacancies
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2020-03-03 , DOI: 10.1021/jacs.0c01726
Bingchao Qin 1 , Yang Zhang 2 , Dongyang Wang 1 , Qian Zhao 1 , Bingchuan Gu 3 , Haijun Wu 2 , Hongjun Zhang 3 , Bangjiao Ye 3 , Stephen J Pennycook 2 , Li-Dong Zhao 1
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2020-03-03 , DOI: 10.1021/jacs.0c01726
Bingchao Qin 1 , Yang Zhang 2 , Dongyang Wang 1 , Qian Zhao 1 , Bingchuan Gu 3 , Haijun Wu 2 , Hongjun Zhang 3 , Bangjiao Ye 3 , Stephen J Pennycook 2 , Li-Dong Zhao 1
Affiliation
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Crystalline SnSe has been revealed as an efficient thermoelectric candidate with outstanding performance. Herein, record-high performance can be realized in p-type SnSe crystals through simply introducing small amount of SnSe2, as a kind of extrinsic defect dopant. This excellent performance mainly arises from the largely enhanced power factor by increasing the hole carrier concentration from ~ 4.0 × 1019 to ~ 6.55 × 1019 cm-3, which was surprisingly promoted by introducing extrinsic SnSe2 even though pristine SnSe2 is n-type conductor. The optimized carrier concentration promotes Fermi level deeper and activates more valence bands, leading to an extremely-high power factor ~ 54 μWcm-1K-2 at 300 K through enlarging band effective mass and Seebeck coefficient. Along with the greatly decreased thermal conductivity due to phonon scattering by Sn vacancies and SnSe2 microdomains, maximum ZT values ~ 0.9 to 2.2 at 300 - 773 K and record-high average ZT > 1.7 are achieved in Na doped SnSe crystals with 2% extrinsic SnSe2. This work provides a new strategy for optimizing thermoelectric performance through introducing defect dopants, which might be well implemented in other thermoelectric systems.
中文翻译:
通过产生外在空位在p型SnSe晶体热电中实现超高平均ZT
结晶 SnSe 已被证明是一种具有出色性能的高效热电候选物。在此,通过简单地引入少量 SnSe2 作为一种外在缺陷掺杂剂,可以在 p 型 SnSe 晶体中实现创纪录的高性能。这种优异的性能主要源于通过将空穴载流子浓度从 ~ 4.0 × 1019 增加到 ~ 6.55 × 1019 cm-3 大大提高了功率因数,尽管原始 SnSe2 是 n 型导体,但通过引入外在 SnSe2 令人惊讶地促进了这一点。优化的载流子浓度使费米能级更深,激活更多价带,通过扩大能带有效质量和塞贝克系数,在 300 K 下产生极高的功率因数~54 μWcm-1K-2。由于 Sn 空位和 SnSe2 微畴的声子散射导致热导率大大降低,在 300 - 773 K 时的最大 ZT 值约为 0.9 至 2.2,并且在具有 2% 外在 SnSe2 的 Na 掺杂 SnSe 晶体中实现了创纪录的平均 ZT > 1.7 . 这项工作提供了一种通过引入缺陷掺杂剂来优化热电性能的新策略,这可能在其他热电系统中得到很好的实施。
更新日期:2020-03-03
中文翻译:

通过产生外在空位在p型SnSe晶体热电中实现超高平均ZT
结晶 SnSe 已被证明是一种具有出色性能的高效热电候选物。在此,通过简单地引入少量 SnSe2 作为一种外在缺陷掺杂剂,可以在 p 型 SnSe 晶体中实现创纪录的高性能。这种优异的性能主要源于通过将空穴载流子浓度从 ~ 4.0 × 1019 增加到 ~ 6.55 × 1019 cm-3 大大提高了功率因数,尽管原始 SnSe2 是 n 型导体,但通过引入外在 SnSe2 令人惊讶地促进了这一点。优化的载流子浓度使费米能级更深,激活更多价带,通过扩大能带有效质量和塞贝克系数,在 300 K 下产生极高的功率因数~54 μWcm-1K-2。由于 Sn 空位和 SnSe2 微畴的声子散射导致热导率大大降低,在 300 - 773 K 时的最大 ZT 值约为 0.9 至 2.2,并且在具有 2% 外在 SnSe2 的 Na 掺杂 SnSe 晶体中实现了创纪录的平均 ZT > 1.7 . 这项工作提供了一种通过引入缺陷掺杂剂来优化热电性能的新策略,这可能在其他热电系统中得到很好的实施。