Local nanostructures enhanced the thermoelectric performance of n-PbTe
| Autor: | Jiayong Li, Qingyu Yan, Lingxue Chen, Minggang Xia, Bo Xiang, Xian Yi Tan, Yucheng Wu, Qi Zhang, Jian Yan, Jiaqin Liu |
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| Přispěvatelé: | School of Materials Science and Engineering |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Electron mobility
Materials science Phonon scattering Renewable Energy Sustainability and the Environment business.industry Spark plasma sintering Thermal Conductivity 02 engineering and technology General Chemistry 021001 nanoscience & nanotechnology Thermoelectric materials Grain growth Materials::Functional materials [Engineering] Thermoelectric effect Nano Optoelectronics Carrier Concentration General Materials Science Grain boundary 0210 nano-technology business |
| ISSN: | 5167-2065 |
| Popis: | Microstructure controlling and carrier concentration engineering are effective approaches to optimize thermal transport and electrical properties in thermoelectric materials. Hereby, we have developed a facile strategy to reduce the lattice thermal conductivity separately by creating locally nanostructured PbTe with controlled size in micro-sized PbTe frame. This is realized by using building blocks of PbTe nanocubes and PbTe@C:Ag nanoparticles with carbon shell as diffusion barrier to prevent grain growth during spark plasma sintering (SPS), while uncoated PbTe nanocubes grow to the micro-sized frame. The locally nano-structured PbTe/PbTe@C:Ag successfully integrates multiple defects that involve Ag based nano-precipitates, nano/micro-sized grain boundaries/interfaces, pores and other defects. They collectively scatter phonons in low-middle frequencies to reduce lattice thermal conductivity significantly in low-temperature range. In addition, Ag exhibits dynamic doping behavior due to more interstitial Ag in PbTe lattice at elevated temperature. This could further enhance the high-frequency phonons scattering and suppress bipolar effect in high-temperature range, leading to an ultralow lattice thermal conductivity of 0.39 W m-1 K-1 at 723 K. On the other hand, the micro-sized PbTe frame with Ag nanoparticles at boundaries maintains relatively high carrier mobility. Further considering the higher carrier concentration due to Ag dynamic doping at elevated temperature, a high power factor of 20.4 μW cm-1 K-2 has been achieved at 723 K. Consequently, a peak figure of merit of 1.65 was achieved at 723K in PbTe/7%PbTe@C:Ag. Our strategy shows superiority in constructing desired nano-, microstructures and tuneable carrier concentration of PbTe towards high thermoelectric performance. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Submitted/Accepted version The authors acknowledge the nancial support of the National Natural Science Foundation of China (grant No. 51672065, 21503065, and 11774278) and the General Financial Grant from the China Postdoctoral Science Foundation (Grant No. 2015M571924). The authors thank the staff in the Analytical and Testing Centre of HFUT for their assistance in the materials characterization. The authors also acknowledge Singapore MOE AcRF Tier 2 under Grant No. 2018-T2-1-010, Singapore A*STAR Pharos Program SERC 1527200022, and the support from FACTs of Nanyang Technological University for sample analysis. |
| Databáze: | OpenAIRE |
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