scholarly journals Highly Porous Thermoelectric Nanocomposites with Low Thermal Conductivity and High Figure of Merit from Large-Scale Solution-Synthesized Bi2 Te2.5 Se0.5 Hollow Nanostructures

2017 ◽  
Vol 129 (13) ◽  
pp. 3600-3605 ◽  
Author(s):  
Biao Xu ◽  
Tianli Feng ◽  
Matthias T. Agne ◽  
Lin Zhou ◽  
Xiulin Ruan ◽  
...  
2018 ◽  
Vol 47 (44) ◽  
pp. 15957-15966 ◽  
Author(s):  
Tingting Chen ◽  
Hongchao Wang ◽  
Wenbin Su ◽  
Fahad Mehmood ◽  
Teng Wang ◽  
...  

High zTs of Pb1−xBixTe alloys rapidly synthesized at low temperature in this study are comparable to those from conventional melting synthesis.


2016 ◽  
Vol 4 (24) ◽  
pp. 5806-5813 ◽  
Author(s):  
Lin Li ◽  
Yuan Liu ◽  
Jiyan Dai ◽  
Aijun Hong ◽  
Min Zeng ◽  
...  

A good thermoelectric material usually has a high power factor and low thermal conductivity for high figure of merit (ZT), and is also environmentally friendly and economical.


2018 ◽  
Vol 6 (21) ◽  
pp. 10048-10056 ◽  
Author(s):  
Wenke He ◽  
Dongyang Wang ◽  
Jin-Feng Dong ◽  
Yang Qiu ◽  
Liangwei Fu ◽  
...  

Enhanced electrical transport properties and low thermal conductivity lead to high figure of merit (ZT) over the whole temperature range in Na-doped SnS crystals.


2019 ◽  
Author(s):  
Prashun Gorai ◽  
Robert McKinney ◽  
Nancy Haegel ◽  
Andriy Zakutayev ◽  
Vladan Stevanovic

Power electronics (PE) are used to control and convert electrical energy in a wide range of applications from consumer products to large-scale industrial equipment. While Si-based power devices account for the vast majority of the market, wide band gap semiconductors such as SiC, GaN, and Ga2O3 are starting to gain ground. However, these emerging materials face challenges due to either non-negligible defect densities, or high synthesis and processing costs, or poor thermal properties. Here, we report on a broad computational survey aimed to identify promising materials for future power electronic devices beyond SiC, GaN, and Ga2O3. We consider 863 oxides, sulfides, nitrides, carbides, silicides, and borides that are reported in the crystallographic database and exhibit finite calculated band gaps. We utilize ab initio methods in conjunction with models for intrinsic carrier mobility, and critical breakdown field to compute the widely used Baliga figure of merit. We also compute the lattice thermal conductivity as a screening parameter. In addition to correctly identifying known PE materials, our survey has revealed a number of promising candidates exhibiting the desirable combination of high figure of merit and high lattice thermal conductivity, which we propose for further experimental investigations.


2016 ◽  
Vol 99 (11) ◽  
pp. 3512-3515 ◽  
Author(s):  
Wen-Long Huo ◽  
Xiao-Yan Zhang ◽  
Yu-Gu Chen ◽  
Yu-Ju Lu ◽  
Wen-Ting Liu ◽  
...  

Author(s):  
Jean-Numa Gillet ◽  
Sebastian Volz

The design of thermoelectric materials led to extensive research on superlattices with a low thermal conductivity. Indeed, the thermoelectric figure of merit ZT varies with the inverse of the thermal conductivity but is directly proportional to the power factor. Unfortunately, as nanowires, superlattices cancel heat conduction in only one main direction. Moreover they often show dislocations owing to lattice mismatches, which reduces their electrical conductivity and avoids a ZT larger than unity. Self-assembly is a major epitaxial technology to design ultradense arrays of germanium quantum dots (QDs) in silicon for many promising electronic and photonic applications as quantum computing. Accurate positioning of the self-assembled QD can now be achieved with few dislocations. We theoretically demonstrate that high-density three-dimensional (3-D) arrays of self-assembled Ge QDs, with a size of only some nanometers, in a Si matrix can also show an ultra-low thermal conductivity in the three spatial directions. This property can be considered to design new CMOS-compatible thermoelectric devices. To obtain a realistic and computationally-manageable model of these nanomaterials, we simulate their thermal behavior with atomic-scale 3-D phononic crystals. A phononic-crystal period (supercell) consists of diamond-like Si cells. At each supercell center, we substitute Si atoms by Ge atoms to form a box-like nanoparticle. Since this phononic crystal is periodic, we compute its phonon dispersion curves by classical lattice dynamics. Non-periodicities can be introduced with statistical distributions. From the flat dispersion curves, we obtain very small group velocities; this reduces the thermal conductivity in our phononic crystal compared to bulk Si. However, owing to the wave-particle duality at very small scales in quantum mechanics, another reduction arises from multiple scattering of the particle-like phonons in nanoparticle clusters. At room temperature, the thermal conductivity in an example phononic crystal can be reduced by a factor of at least 165 compared to bulk Si or below 0.95 W/mK. This value, which is lower than the classical Einstein limit of single crystalline Si, is an upper limit of the thermal conductivity since we use an incoherent-scattering approach for the nanoparticles. Because of its very low thermal conductivity, we hope to obtain a much larger ZT than unity in our atomic-scale 3-D phononic crystal. Indeed, this silicon-based nanomaterial is crystalline with a power factor that can be optimized by doping using CMOS-compatible processes. Future research on the phononic-crystal electrical conductivity has to be performed in order to compute the full ZT with a good accuracy.


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