Bi₂Te₃ thermoelectric materials are utilized for refrigeration for decades, while their application of energy harvesting requires stable thermoelectric and mechanical performances at elevated temperatures. This work reveals that a steady zT of ≈0.85 at 200 to 300 °C can be achieved by doping small amounts of copper iodide (CuI) in Bi₂Te_2.2Se_0.8–silicon carbide (SiC) composites, where SiC nanodispersion enhances the flexural strength. It is found that CuI plays two important roles with atomic Cu/I dopants and CuI precipitates. The Cu/I dopants show a self‐tuning behavior due to increasing solubility with increasing temperatures. The increased doping concentration increases electrical conductivity at high temperatures and effectively suppresses the intrinsic excitation. In addition, a large reduction of lattice thermal conductivity is achieved due to the “in situ” CuI nanoprecipitates acting as phonon‐scattering centers. Over 60% reduction of bipolar thermal conductivity is achieved, raising the maximum useful temperature of Bi₂Te₃ for substantially higher efficiency. For module applications, the reported materials are suitable for segmentation with a conventional ingot. This leads to high device ZT values of ≈0.9–1.0 and high efficiency up to 9.2% from 300 to 573 K, which can be of great significance for power generation from waste heat.

中文翻译：

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自调谐n型Bi2（Te，Se）3 / SiC热电纳米复合材料可实现高达300°C的高性能

Bi ₂ Te ₃热电材料用于制冷已有数十年的历史，而其能量收集的应用要求在高温下具有稳定的热电和机械性能。这项工作表明，通过在Bi ₂ Te _2.2 Se _0.8中掺杂少量的碘化铜（CuI），可以在200至300°C的温度下实现稳定的zT≈0.85。–碳化硅（SiC）复合材料，其中SiC纳米分散增强了弯曲强度。发现CuI与原子Cu / I掺杂剂和CuI沉淀物起着两个重要的作用。由于温度升高，溶解度增加，Cu / I掺杂剂表现出自调谐行为。增加的掺杂浓度增加了高温下的电导率，并有效地抑制了固有的激发。此外，由于“原位” CuI纳米沉淀物起声子散射中心的作用，大大降低了晶格热导率。双极导热率降低了60％以上，从而提高了Bi ₂ Te ₃的最高使用温度以获得更高的效率。对于模块应用，所报道的材料适用于用常规铸锭进行分段。这导致设备的ZT值高至约0.9-1.0，并且在300至573 K范围内的效率高达9.2％，这对于利用余热发电非常重要。