Thermoelectric properties of the bismuth oxychalcogenides Bi2SO2, Bi2SeO2 and Bi2TeO2
Thermoelectric properties of the bismuth oxychalcogenides Bi2SO2, Bi2SeO2 and Bi2TeO2
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DOI：
10.1088/2515-7655/ad2afd
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发表时间：
2024-04-01
影响因子：
6.9
通讯作者：
Skelton，J. M.
中科院分区：
文献类型：
--
作者：
Flitcroft，J. M.;Althubiani，A.;Skelton，J. M.
对铋氧硫族化合物Bi 2ChO 2（Ch= S，Se，Te）的热电性质进行了详细的理论研究.电输运建模使用半经典玻尔兹曼输运理论与电子结构的混合密度泛函理论，包括一个近似模型的电子寿命。晶格热导率计算使用第一原理声子计算与明确的非谐性治疗，产生微观洞察如何部分取代铋硫属化物中的硫属元素的影响声子输运。我们发现预测的输运性质和一个有利的取消误差，允许近定量预测的热电优值ZT之间的非常好的协议。我们的计算表明，最近的实验n-掺杂的Bi 2 SeO 2已经取得了接近最大的ZT可能在散装材料，而最大的报道ZT Bi 2 TeO 2可以提高六倍，通过优化载流子浓度。我们还预测，对于Bi 2SO 2和Bi 2SeO 2，重p型掺杂可以获得更大的ZT> 2.5，与基准热电SnSe竞争。这项研究表明，这种建模方法研究热电的预测能力，并强调了几种途径，提高性能的Bi 2 ChO 2。
We present a detailed theoretical study of the thermoelectric properties of the bismuth oxychalcogenides Bi 2 ChO 2 (Ch= S, Se, Te). The electrical transport is modelled using semi-classical Boltzmann transport theory with electronic structures from hybrid density-functional theory, including an approximate model for the electron lifetimes. The lattice thermal conductivity is calculated using first-principles phonon calculations with an explicit treatment of anharmonicity, yielding microscopic insight into how partial replacement of the chalcogen in the bismuth chalcogenides impacts the phonon transport. We find very good agreement between the predicted transport properties and a favourable cancellation of errors that allows for near-quantitative predictions of the thermoelectric figure of merit ZT. Our calculations suggest recent experiments on n-doped Bi 2 SeO 2 have achieved close to the largest ZT possible in bulk materials, whereas the largest reported ZT for Bi 2 TeO 2 could be improved sixfold by optimising the carrier concentration. We also predict that much larger ZT> 2.5, competitive with the benchmark thermoelectric SnSe, could be obtained for Bi 2 SO 2 and Bi 2 SeO 2 with heavy p-type doping. This study demonstrates the predictive power of this modelling approach for studying thermoelectrics and highlights several avenues for improving the performance of the Bi 2 ChO 2.