Electron delocalization enhances the thermoelectric performance of misfit layer compound(Sn_(1-x)Bi_(x)S)_(1.2)(TiS_(2))_(2)  

作　　者：Xin Zhao Xuanwei Zhao Liwei Lin Ding Ren Bo Liu Ran Ang 赵昕;赵轩为;林黎蔚;任丁;刘波;昂然(Key Laboratory of Radiation Physics and Technology,Ministry of Education,Institute of Nuclear Science and Technology,Sichuan University,Chengdu 610064,China;Institute of New Energy and Low-Carbon Technology,Sichuan University,Chengdu 610065,China)

机构地区：[1]Key Laboratory of Radiation Physics and Technology,Ministry of Education,Institute of Nuclear Science and Technology,Sichuan University,Chengdu 610064,China [2]Institute of New Energy and Low-Carbon Technology,Sichuan University,Chengdu 610065,China

出　　处：《Chinese Physics B》2022年第11期82-88,共7页中国物理B（英文版）

基　　金：financially supported by the National Key Research and Development Program of China(Grant No.2018YFA0702100);the Joint Funds of the National Natural Science Foundation of China;the Chinese Academy of Sciences’Large-Scale Scientific Facility(Grant No.U1932106);the Sichuan University Innovation Research Program of China(Grant No.2020SCUNL112)。

摘　　要：The misfit layer compound(SnS)_(1.2)(TiS_(2))_(2)is a promising low-cost thermoelectric material because of its low thermal conductivity derived from the superlattice-like structure.However,the strong covalent bonds within each constituent layer highly localize the electrons thereby it is highly challenging to optimize the power factor by doping or alloying.Here,we show that Bi doping at the Sn site markedly breaks the covalent bonds networks and highly delocalizes the electrons.This results in a high charge carrier concentration and enhanced power factor throughout the whole temperature range.It is highly remarkable that Bi doping also significantly reduces the thermal conductivity by suppressing the heat conduction carried by phonons,indicating that it independently modulates phonon and charge transport properties.These effects collectively give rise to a maximum ZT of 0.3 at 720 K.In addition,we apply the single Kane band model and the Debye–Callaway model to clarify the electron and phonon transport mechanisms in the misfit layer compound(SnS)_(1.2)(TiS_(2))_(2).

关 键 词：misfit layer sulfide electron delocalization carrier mobility chemical bond 

分 类 号：TB34[一般工业技术—材料科学与工程]