Compound semiconductors derived from ZnS (zincblende and wurtzite) with tetrahedral framework structures have functions for various applications. Examples of such materials include Cu–S‐based materials with zincblende‐derivative structures, which have attracted attention as thermoelectric (TE) materials over the past decade. This study illuminates superior TE performance in polycrystalline samples of enargite Cu₃P_1−x Ge_x S₄ with a wurtzite‐derivative structure. The substitution of Ge for P dopes holes into the top of the valence band composed of Cu‐3d and S‐3p, whereby its multiband characteristic leads to a high TE power factor. Furthermore, a reduction in the grain size to 50–300 nm can effectively decrease phonon mean free paths, leading to low thermal conductivity. These features result in a dimensionless TE figure of merit ZT of 0.5 at 673 K for the x = 0.2 sample. Environmentally benign and low‐cost characteristics of the constituent elements of Cu₃PS₄, as well as its high‐performance thermoelectricity, make it a promising candidate for large‐scale TE applications. Furthermore, this finding extends the development field of Cu–S‐based TE materials to those with wurtzite‐derivative structures.

中文翻译：

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Enargite Cu3PS4：具有纤锌矿衍生物结构的基于Cu-S的热电材料

具有四面体骨架结构的源自ZnS的化合物半导体（锌闪锌矿和纤锌矿）具有多种应用功能。这种材料的例子包括具有闪锌矿型衍生物结构的基于Cu-S的材料，在过去的十年中，这些材料作为热电（TE）材料引起了人们的关注。这项研究阐明了在辉铝矿Cu ₃ P _{1− x} Ge _x S _4的多晶样品中优异的TE性能。具有纤锌矿衍生物结构。用Ge代替P掺杂空穴到由Cu-3d和S-3p组成的价带的顶部，从而其多频带特性导致较高的TE功率因数。此外，将晶粒尺寸减小到50-300 nm可以有效地减少声子平均自由程，从而导致低热导率。对于x = 0.2的样品，这些特征导致在673 K时无量纲的TE品质因数ZT为0.5 。Cu ₃ PS ₄组成元素的环境友好和低成本特征以及其高性能的热电特性，使其成为大规模TE应用的有希望的候选者。此外，这一发现将Cu-S基TE材料的开发领域扩展到具有纤锌矿衍生结构的材料。