Materials Today Physics ( IF 11.5 ) Pub Date : 2021-11-17 , DOI: 10.1016/j.mtphys.2021.100571 Safdar Imam, Khasim Saheb Bayikadi, Mohammad Ubaid, V.K. Ranganayakulu, Sumangala Devi, Bhalchandra S. Pujari, Yang-Yuan Chen, Li-Chyong Chen, Kuei-Hsien Chen, Feng-Li Lin, Raman Sankar
Among the lead-free thermoelectric material, germanium telluride (GeTe) has been extensively investigated due to its high thermoelectric performance (ZT) in mid-temperature; however, high p-type carrier density (∼1021 cm−3) hinder its suitability for higher ZT. To enhance the thermoelectric performance of the environmentally favorable GeTe, we explored the Mo doping significantly optimizes the carrier concentration along with uniquely unveiled microcrystalline rods accompanying compact grain boundaries, high-density planar defects, and point defects effectuating all-frequency phonon scattering yields to lower down the thermal conductivity. Furthermore, Sb/Bi co-doping with Mo at the Ge sites predominantly reduces the carrier concentration and thermal conductivity to attain a higher ZT. The co-doping of Bi manifested a more prominent role in achieving the highest ZT of ∼2.3 at 673 K for the sample composition with Ge0.89Mo0·01Bi0.1Te. This study demonstrates an exciting hidden aspect of microstructural modification by forming highly dense microcrystalline rods through Mo doping to achieve high performance in the GeTe system.
中文翻译:
通过在 Mo 掺杂的 GeTe 基化合物中诱导的高度压实的微晶棒实现协同性能
在无铅热电材料中,碲化锗(GeTe)因其在中温下的高热电性能(ZT)而受到广泛研究;然而,高 p 型载流子密度(~10 21 cm -3) 阻碍其适用于更高的 ZT。为了提高对环境有利的 GeTe 的热电性能,我们探索了 Mo 掺杂显着优化了载流子浓度以及独特的微晶棒伴随着紧密的晶界、高密度平面缺陷和点缺陷,这些缺陷影响了全频声子散射产率以降低降低热导率。此外,Sb/Bi 在 Ge 位点与 Mo 共掺杂主要降低载流子浓度和热导率,以获得更高的 ZT。对于具有 Ge 0.89 Mo 0·01 Bi 0.1的样品组成,Bi 的共掺杂在 673 K 下实现最高 ZT 方面表现出更突出的作用特。该研究通过 Mo 掺杂形成高密度微晶棒以在 GeTe 系统中实现高性能,从而证明了微结构改性的一个令人兴奋的隐藏方面。