We report a method for carrier concentration tuning in the thermoelectric thiospinel Cu₂CoTi₃S₈, which exhibits an n-type metallic character and a high power factor. An oxidative Cu extraction treatment produced Cu defects, resulting in Cu_2−xCoTi₃S₈ up to x = 0.62. The electron carrier concentration was effectively reduced by this treatment, leading to the decrease in power factor, whereas the electronic contribution to the thermal conductivity was suppressed. As a result, the dimensionless figure of merit ZT remained unchanged as 0.2 at 670 K in the whole range of x ≤ 0.62. The oxidative Cu extraction described in this paper offers an opportunity to tune the electron carrier concentration for Cu-containing thermoelectric materials.

我们报告了一种在热电硫代吡啶₂ CuTi ₃ S _8中调节载流子浓度的方法，该方法表现出n型金属特性和高功率因数。氧化的铜提取处理产生了Cu缺陷，导致Cu _{2- x} CoTi ₃ S ₈高达x = 0.62。通过该处理有效地降低了电子载流子浓度，导致功率因数降低，而电子对热导率的贡献被抑制。结果，在x的整个范围内，ZT的无量纲品质因数ZT在670 K时保持不变，为0.2。≤0.62。本文所述的氧化铜提取工艺为调节含铜热电材料的电子载流子浓度提供了机会。