Department of Mechanical Engineering, The University of Hong Kong , Pokfulam Road, Hong Kong SAR, China.
Department of Materials Science, Fudan University , 220 Handan Road, Shanghai 200433, China.
ACS Appl Mater Interfaces. 2017 Aug 23;9(33):27372-27376. doi: 10.1021/acsami.7b06872. Epub 2017 Aug 8.
As a promising thermoelectric material, BiCuSeO is of great interest for energy conversion. A higher figure of merit in n-type BiCuSeO than that in the p-type was predicted from theory, suggesting a need of in-depth investigations on the doping effects. In this work, the influences of group IV elements (Si, Ge, Sn, and Pb) on the electronic structures of BiCuSeO are studied from first principles. Despite the similar electronegativities of the group IV elements, Si is found to be an n-type dopant, being distinctly different from Ge, Sn, and Pb, which exhibit typical p-type behaviors. Detailed analysis on the doping effects is performed based on a recently developed band unfolding technique. Furthermore, Si-doped BiCuSeO is shown to have a higher power factor than p-type BiCuSeO from the Boltzmann transport theory.
作为一种很有前途的热电材料，BiCuSeO 对于能量转换非常有意义。理论预测 n 型 BiCuSeO 的品质因数高于 p 型，这表明需要深入研究掺杂效应。在这项工作中，我们从第一性原理出发研究了 IV 族元素（Si、Ge、Sn 和 Pb）对 BiCuSeO 电子结构的影响。尽管 IV 族元素的电负性相似，但 Si 被发现是一种 n 型掺杂剂，与 Ge、Sn 和 Pb 明显不同，它们表现出典型的 p 型行为。我们基于最近开发的能带展开技术对掺杂效应进行了详细分析。此外，从玻尔兹曼输运理论可以看出，Si 掺杂的 BiCuSeO 的功率因子高于 p 型 BiCuSeO。
