Quaternary Cu₂ZnSnSe₄ alloys have attracted more attentions as promising thermoelectric materials due to their instinct low thermal conductivity. Herein, Cu₂ZnSnSe₄ and Cu₂ZnSn_0.98Pb_0.02Se_4−xTe_x (x = 0.005, 0.010, 0.015, 0.020, 0.025, 0.030) alloys are successfully synthesized by melting, annealing, and hot pressing. All samples show main kesterite structure with slight Cu_0.656Te_0.344 impurity phases, high relative densities, and homogeneous element distribution. A higher power factor of 678.3 μW K⁻²m⁻¹ is achieved at 673 K for Cu₂ZnSn_0.98Pb_0.02Se_3.975Te_0.025 alloy, which is due to the reduction of the electrical resistivity. Meanwhile, the lattice thermal conductivity is slightly increased because the lattice structure is more symmetrical with Te‐doped samples. Combining the increased point defects, the minimum lattice thermal conductivity of 1.5 Wm⁻¹ K⁻¹ is achieved at 673 K. As the comprehensive result, the maximum figure of merit zT of 0.24 has been obtained at 673 K for Cu₂ZnSn_0.98Pb_0.02Se_3.975Te_0.025 alloy, which is about 24% higher than that of the Cu₂ZnSnSe₄.

中文翻译：

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低Te浓度掺杂Cu2ZnSnSe4基四元合金的热电性能

第四季度Cu ₂ ZnSnSe ₄合金由于其本能的低导热性而作为有前途的热电材料吸引了更多关注。在此， 通过熔融，退火和热压成功地合成了Cu ₂ ZnSnSe ₄和Cu ₂ ZnSn _0.98 Pb _0.02 Se _{4- x} Te _x（x = 0.005，0.010，0.015，0.020，0.025，0.030 ）合金。所有样品均显示出主要的方石英结构，具有少量的Cu _0.656 Te _0.344杂质相，较高的相对密度和均匀的元素分布。更高的功率因数678.3μWK ^-2对于Cu ₂ ZnSn _0.98 Pb _0.02 Se _3.975 Te _0.025合金，在673 K时达到m ^-1，这是由于电阻率的降低。同时，由于晶格结构与掺Te的样品更对称，晶格热导率略有增加。结合增加的点缺陷，在673 K时达到1.5 Wm ^-1  K ^-1的最小晶格导热率。综合结果，对于Cu ₂ ZnSn _0.98 Pb在673 K时获得的最大品质因数zT为0.24 _0.02硒_3.975Te _0.025合金，比Cu ₂ ZnSnSe ₄高约24％。