For n-type PbTe based compounds with relatively low optimal concentration (10¹⁹ cm⁻³), the accompanied structural defects play pivotal role on the charge transport upon doping with alien valent atoms. Herein, we report that Oxygen has huge influence on the defect evolution and thermoelectric properties in n-type PbTe for the first time. A boosted thermoelectric figure of merit ZT of ∼1.12 at 673 K and a ZT_ave of 0.84 in the range of 300–873 K are achieved for vacuum sintered Bi-doped PbTe with the powders ground under the protection of Ar. This is in sharp contrast with the same Bi-doped PbTe material sintered with the powders ground in the air, which reaches a ZT_ave of 0.52. This distinct thermoelectric properties in Bi-doped PbTe compounds are strongly correlated to Bi dopant, the vacancy defects ($V_{Pb}^{″}$ and $V_{Te}^{\cdot \cdot }$) induced during the fracturing process, and oxygen in the air. The coexistence of Bi dopant and oxygen lowers the formation energy of Pb vacancies and induces large number of O–Bi related Pb vacancies in the structure, yielding an acceptor-like effect. Such negatively charged Pb vacancies in the structure exert a strong long-range coulombic repulsion force on the electrons, leading to a low doping efficiency, a low carrier mobility (200 cm² V⁻¹ s⁻¹), and inferior electronic properties. Whereas, the protection provided by Ar effectively avoids the contamination by oxygen and prevents the formation of O–Bi related Pb vacancies, which appears remarkably effective in enhancing the electronic transport. A high carrier mobility of 1300 cm² V⁻¹ s⁻¹ is attained in slightly doped Pb_0·9995Bi_0·0005Te sample and this contributes to an ultra-high power factor of 40 μW cm⁻¹ K⁻² for the Pb_0·9995Bi_0·0005Te sample at room temperature. The high PF_ave exceeds 25 μW cm⁻¹ K⁻² in the range of 300–723 K. The work provides a new insight into the formation mechanism of structural defects and a new avenue for suppressing the cation vacancies, resulting in higher performance of n-type PbTe-based compounds.

对于具有相对较低最佳浓度（10 ¹⁹  cm ^{-3 ）的}n型PbTe基化合物，伴随的结构缺陷在掺杂外来价原子时对电荷传输起关键作用。在此，我们首次报道了氧对n型 PbTe 中的缺陷演化和热电性质具有巨大影响。对于在 Ar 保护下研磨粉末的真空烧结 Bi 掺杂 PbTe，在 673 K 时提高的热电品质因数ZT在 673 K 下约为 1.12，在300-873 K 范围内的ZT _{ave为 0.84。}这与用在空气中研磨的粉末烧结的相同 Bi 掺杂 PbTe 材料形成鲜明对比，后者达到ZT_均值为 0.52。Bi掺杂的PbTe化合物中这种独特的热电特性与Bi掺杂剂密切相关，空位缺陷（${五}_{磷b}^{”}$和${五}_{吨e}^{\cdot \cdot }$) 在压裂过程中诱发，以及空气中的氧气。Bi掺杂剂和氧的共存降低了Pb空位的形成能，并在结构中诱导了大量与O-Bi相关的Pb空位，产生了类受体效应。结构中的这种带负电的Pb空位对电子施加强大的长程库仑排斥力，导致掺杂效率低、载流子迁移率低（200 cm ²  V ^-1  s ^-1）和较差的电子性能。然而，Ar提供的保护有效地避免了氧的污染并防止了与O-Bi相关的Pb空位的形成，这在增强电子传输方面似乎非常有效。1300 cm ^{2的高载流子迁移率} V ^-1  s ^-1在轻微掺杂的 Pb _0·9995 Bi _0·0005 Te 样品中获得，这有助于Pb 0· ₉₉₉₅ Bi 0· _{0005的 40 μW cm} ^-1  K ^-2的超高功率因数室温下的样品。高PF _ave在 300-723 K 范围内超过 25 μW cm ^-1  K ^-2。这项工作为结构缺陷的形成机制提供了新的见解，并为抑制阳离子空位提供了新的途径，从而提高了n型 PbTe 基化合物。