Evolvement of microstructure and lattice thermal conductivity in Na doped PbTe-PbS pseudo−binary system

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• 作者：Meijie YinAuthor Vitae ; Di WuAuthor Vitae ; Jiaqing He ; ^{hejq@sustc.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Thermoelectrics ; Nano-structuring ; Precipitates ; Thermal conductivity
• 刊名：Journal of Materiomics
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：2
• 期：2
• 页码：150-157
• 全文大小：1730 K

文摘

PbTe–PbS pseudo−binary is a renowned thermoelectric system largely due to its phase separation driven low thermal conductivity. To understand the thermal conductivity evolvement as well as its correlation with microstructural features (especially the nano-scale precipitates), systematic transmission electron microscope studies were performed in this work on a series of PbTe–PbS samples with gradually varying PbS or Na content. We confirmed the co-existence of two groups of precipitates in these samples, i.e. INPs (incipient nano-precipitates) ∼5 nm and PbS-rich ones ranging from 10 to a few hundreds of nano-meters. We also studied their individual size and concentration evolvement with varying PbS and Na. The effect of evolving microstructures on phonon transport was discussed and understood in a modified Callaway model, which conclusively led to the conclusion that significant impedance on heat conduction could only be realized in the case of nano-precipitates with a proper size and number density distribution.