It has been found that the doped Ga has a distinct role in PbTe and PbSe compounds though they possess the same crystal structure. Therefore, to understand how the thermoelectric performance evolves in the Ga-doped PbTe_1-xSe_x solid solution is crucial. Herein, we report that a maximum ZT value of 1.57 at 721 K and a high average ZT value of 1.13 in the temperature range of 300–843 K are attained for Pb_0.98Ga_0.02Te_0.96Se_0.04 compound. The experimental studies show that doping Ga into PbTe introduces a shallow level impurity state Ga³⁺ and a deep level associated with the Ga ⁺ state simultaneously. Interestingly, upon Se-alloying all of the Ga ⁺ are oxidized into Ga³⁺ at low temperatures, which increases the room-temperature carrier concentration from 1.16 × 10¹⁹ cm⁻³ to 2.17 × 10¹⁹ cm⁻³. This leads to an improved power factor of 3.04 mW m⁻¹ K⁻² for Pb_0.98Ga_0.02Te_0.96Se_0.04 sample at 482 K. Additionally, Se-alloying further enhances the point defect phonon scattering and lowers the lattice thermal conductivity to 0.46 W m⁻¹ K⁻¹ for Pb_0.98Ga_0.02Te_0.96Se_0.04 sample at 690 K. As a result, the ZT value is increased by about 112% compared with the maximum ZT of 0.74 for pristine PbTe. This work provides a new avenue for tuning the doping behavior of cation site dopant via alloying on anion site to further improve the ZT value in thermoelectric materials.

已经发现掺杂的Ga在PbTe和PbSe化合物中具有不同的作用，尽管它们具有相同的晶体结构。因此，了解 Ga 掺杂 PbTe _1-x Se _x固溶体的热电性能如何演变至关重要。在此，我们报道了Pb _0.98 Ga _0.02 Te _0.96 Se _0.04化合物在 721 K 时的最大ZT值为 1.57，在300-843 K 的温度范围内达到了 1.13的高平均ZT值。实验研究表明，将 Ga 掺杂到 PbTe 中会引入一个浅能级杂质态 Ga ³⁺和一个与 Ga  ^{+相关的深能级。} 同时状态。有趣的是，在硒合金化后，所有的Ga  ⁺在低温下 被氧化成Ga ³⁺，这将室温载流子浓度从1.16 × 10 ¹⁹  cm ^-3增加到2.17 × 10 ¹⁹  cm ^-3。这导致Pb _0.98 Ga _0.02 Te _0.96 Se _{0.04样品在 482 K 时的功率因数提高到 3.04 mW m} ^-1  K ^-2。此外，Se 合金化进一步增强了点缺陷声子散射并将晶格热导率降低到 0.46 W m ^-1  K ^-1对于 Pb_0.98 Ga _0.02 Te _0.96 Se _0.04样品在 690 K。结果，与原始 PbTe的最大ZT值 0.74 相比， ZT值增加了约 112% 。这项工作为通过在阴离子位上合金化来调整阳离子位掺杂剂的掺杂行为以进一步提高热电材料中的ZT值提供了一条新途径。