Huang Lulu, Kong Yuan, Zhang Jian, Zhu Chen, Zhang Jinhua, Li Yuanyue, Li Di, Xin Hongxing, Wang Zhaoming, Qin Xiaoying
Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, PR China.
University of Science and Technology of China, Hefei 230026, China.
ACS Appl Mater Interfaces. 2020 Mar 25;12(12):14145-14153. doi: 10.1021/acsami.0c00094. Epub 2020 Mar 10.
Thermoelectric material tetrahedrite CuSbS has attracted much attention because of its intrinsic low lattice thermal conductivity, excellent electrical transport property, and environment-friendly constituents. However, its thermoelectric figure merit, , is limited because of the low Seebeck coefficient () and power factor (PF). Hence, it is indispensable to enhance its and PF to increase its . Here, we show that when Sb deviation from its stoichiometric ratio in the CuSbS band structure is modulated, it gives rise to increased density of states and enhancement of the Seebeck coefficient. Moreover, carrier concentration is tuned by changing sulfur and copper vacancies through controlling the CuSbS phase with an atomic ratio of Sb, leading to increased electrical conductivity. In addition, as large as ∼60% reduction of lattice thermal conductivity is obtained by intensified phonon scattering using an impurity phase/element and vacancy-like defects induced by different Sb contents. As a result, a high = 0.86 is achieved at 723 K for the CuSbS sample with δ = 0.2, which is ∼50% larger than that of stoichiometric CuSbS studied here, indicating that of CuSbS can be improved through simple modulation of the Sb stoichiometric ratio.
热电材料黝铜矿CuSbS因其固有的低晶格热导率、优异的电输运性能和环保的成分而备受关注。然而，由于其低塞贝克系数（）和功率因子（PF），其热电优值受到限制。因此，提高其和PF以增加其是必不可少的。在这里，我们表明，当CuSbS能带结构中Sb偏离其化学计量比时，会导致态密度增加和塞贝克系数增强。此外，通过控制具有Sb原子比的CuSbS相来改变硫和铜空位，从而调节载流子浓度，导致电导率增加。此外，通过使用杂质相/元素和由不同Sb含量引起的类空位缺陷强化声子散射，晶格热导率降低了约60%。结果，对于δ = 0.2的CuSbS样品，在723 K时实现了高 = 0.86，比这里研究的化学计量比的CuSbS高出约50%，这表明通过简单调节Sb化学计量比可以提高CuSbS的。
