Here we find the peculiar behavior of Cu ions in the PbSe–Cu system increases its thermoelectric performance. For the electrical transport, a dynamic doping effect is achieved because more Cu ions enter into the PbSe lattice and provide extra charge carriers as the temperature increases, which guarantees an optimized carrier concentration over a wide temperature range. For the thermal transport, the presence of Cu₂Se nanoprecipitates and dislocations at a low temperature range as well as the vibration of Cu atoms around the interstitial sites of PbSe at high temperatures result in hierarchical phonon scattering and a significantly reduced lattice thermal conductivity over the whole temperature range. As a result, a peak thermoelectric material figure of merit zT of up to 1.45 and a thermoelectric device figure of merit ZT close to unity are obtained for the sample with 0.375 at% Cu. Furthermore, enhanced thermoelectric properties are also realized for the Cu-intercalated PbS, implying that the temperature-driven dynamic behavior of Cu ions in a rigid lattice can serve as a general strategy to optimize the thermoelectric performance of IV–VI compounds.

中文翻译：

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通过动态掺杂和分层声子散射提高PbSe的热电性能†

在这里，我们发现铜离子在PbSe–Cu系统中的特殊行为增加了其热电性能。对于电传输，由于更多的Cu离子进入PbSe晶格并随着温度升高而提供额外的电荷载流子，因此获得了动态掺杂效果，从而确保了在宽温度范围内优化的载流子浓度。对于热传输，在低温范围内Cu ₂ Se纳米沉淀和位错的存在，以及高温下PbSe间隙位置周围Cu原子的振动导致声子的分层散射，并且在整个过程中晶格热导率显着降低。整个温度范围。结果，热电材料的峰值品质因数zT对于含0.375 at％Cu的样品，可得到高达1.45的最大电导率和接近于1的热电器件品质因数ZT。此外，对于嵌入Cu的PbS，还实现了增强的热电特性，这意味着在刚性晶格中Cu离子的温度驱动动态行为可以作为优化IV-VI化合物热电性能的一般策略。