Phase separation and interface effect in pseudo-quaternary composites of Ag Bi0.5Sb1.5−Te3−
| Autor: | Jong-Soo Rhyee, Ohmyoung Kwon, Bong Seo Kim, R. Lydia, Jaywan Chung, Chan Chieh Lin, Yoo Jang Song, Su Dong Park |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
Phonon scattering Annealing (metallurgy) Mechanical Engineering Metals and Alloys Sintering 02 engineering and technology Conductivity 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Mechanics of Materials Thermoelectric effect Materials Chemistry Grain boundary Composite material 0210 nano-technology Anisotropy Eutectic system |
| Zdroj: | Journal of Alloys and Compounds. 708:1018-1025 |
| ISSN: | 0925-8388 |
| Popis: | We investigated anisotropic thermoelectric properties of p-type AgxBi0.5Sb1.5−xTe3−x ( x = 0.0, 0.1, 0.2 and 0.3) compounds, prepared by melting and hot press sintering. During hot press sintering and annealing process, the eutectoid decomposition of Ag2Te from (Bi,Sb)2Te3 matrix induces intrinsic thermoelectric composites Ag2+δTe/(Bi,Sb)2Te3. The phase separation increases the phonon scattering which lowered the lattice thermal conductivity. We also found the metallic interfacial layer in a grain boundary from the measurements of conducting atomic force microscopy (AFM) and scanning Seebeck- and scanning thermal-microscopy (SThM). Here we argue that the interfacial conductivity attributes to the increase of power factor due to increase of mobility. Thereby, the phase separation of Ag2Te from the (Bi,Sb)2Te3 matrix gives rise to the enhanced thermoelectric properties at mild-temperature range, resulting in the enhancement of dimensionless thermoelectric figure-of-merit Z T value of 1.02 at 567 K for x = 0.1 along the vertical direction. |
| Databáze: | OpenAIRE |
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