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1.
Yu Liao Wenting Liu Weiping Jia Bo Wang Ling Chen Ke Huang Matthew J. Montgomery Jun Qian Song Lv Lisa D. Pfefferle 《Advanced Electronic Materials》2021,7(9):2100468
The efficiency of thermoelectric (TE) materials depends on an interplay between various material properties, and strategies for co-optimizing these properties will be necessary for implementing these materials in the future. In this work, bismuth sulfide (Bi2S3) and acid treated multiwalled carbon nanotube (f-MWNT) composites are fabricated by wet chemical synthesis at room temperature. Bi2S3 is intimately anchored onto the surface of the f-MWNT to form a coaxial nanostructure. The power factor of the composite is enhanced relative to both the pure Bi2S3 and MWNTs, due to a large enhancement of the electrical conductivity. The enhanced conductivity is attributed to restructuring of the bismuth (Bi) and oxygen (O) bonding environments when Bi2S3 is chemically interfaced with the f-MWNTs, suggestive of the formation of a strongly coupled complex via Bi O/Bi S bonds. Strong-coupling is further supported by scanning transmission electron microscopy, Raman, and diffuse reflectance spectroscopy, which reveal fast charge-transfer between the Bi2S3 and MWNT when interfaced together. These results support material compositing as a potential strategy for engineering enhanced TE materials. 相似文献
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Mona Zebarjadi Keivan Esfarjani Ali Shakouri Zhixi Bian Je-Hyeong Bahk Gehong Zeng John Bowers Hong Lu Joshua Zide Art Gossard 《Journal of Electronic Materials》2009,38(7):954-959
Recent experimental results have shown that adding nanoparticles inside a bulk material can enhance the thermoelectric performance
by reducing the thermal conductivity and increasing the Seebeck coefficient. In this paper we investigate electron scattering
from nanoparticles using different models. We compare the results of the Born approximation to that of the partial-wave method
for a single nanoparticle scattering. The partial-wave method is more accurate for particle sizes in the 1 nm to 5 nm range
where the point scattering approximation is not valid. The two methods can have different predictions for the thermoelectric
properties such as the electrical conductivity and the Seebeck coefficient. To include a random distribution of nanoparticles,
we consider an effective medium for the electron scattering using the coherent potential approximation. We compare various
theoretical results with the experimental data obtained with ErAs nanoparticles in an InGaAlAs matrix. Reasonably good agreement
is found between the measured and theoretical electrical conductivity and Seebeck data in the 300 K to 850 K temperature range. 相似文献
3.
Hua-Lu Zhuang Jun Pei Bowen Cai Jinfeng Dong Haihua Hu Fu-Hua Sun Yu Pan Gerald Jeffrey Snyder Jing-Feng Li 《Advanced functional materials》2021,31(15):2009681
The widespread application of thermoelectric (TE) technology demands high-performance materials, which has stimulated unceasing efforts devoted to the performance enhancement of Bi2Te3-based commercialized thermoelectric materials. This study highlights the importance of the synthesis process for high-performance achievement and demonstrates that the enhancement of the thermoelectric performance of (Bi,Sb)2Te3 can be achieved by applying cyclic spark plasma sintering to BixSb2–xTe3-Te above its eutectic temperature. This facile process results in a unique microstructure characterized by the growth of grains and plentiful nanostructures. The enlarged grains lead to high charge carrier mobility that boosts the power factor. The abundant dislocations originating from the plastic deformation during cyclic liquid phase sintering and the pinning effect by the Sb-rich nano-precipitates result in low lattice thermal conductivity. Therefore, a high ZT value of over 1.46 is achieved, which is 50% higher than conventionally spark-plasma-sintered (Bi,Sb)2Te3. The proposed cyclic spark plasma liquid phase sintering process for TE performance enhancement is validated by the representative (Bi,Sb)2Te3 thermoelectric alloy and is applicable for other telluride-based materials. 相似文献
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Yu‐Jia Zeng Dan Wu Xuan‐Hao Cao Wu‐Xing Zhou Li‐Ming Tang Ke‐Qiu Chen 《Advanced functional materials》2020,30(8)
The demands for waste heat energy recovery from industrial production, solar energy, and electronic devices have resulted in increasing attention being focused on thermoelectric materials. Over the past two decades, significant progress is achieved in inorganic thermoelectric materials. In addition, with the proliferation of wireless mobile devices, economical, efficient, lightweight, and bio‐friendly organic thermoelectric (OTE) materials have gradually become promising candidates for thermoelectric devices used in room‐temperature environments. With the development of experimental measurement techniques, the manufacturing for nanoscale thermoelectric devices has become possible. A large number of studies have demonstrated the excellent performance of nanoscale thermoelectric devices, and further improvement of their thermoelectric conversion efficiency is expected to have a significant impact on global energy consumption. Here, the development of experimental measurement methods, theoretical models, and performance modulation for nanoscale OTE materials are summarized. Suggestions and prospects for the future development of these devices are also provided. 相似文献
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Sung-Do Kwon Byeong-kwon Ju Seok-Jin Yoon Jin-Sang Kim 《Journal of Electronic Materials》2009,38(7):920-924
Bismuth–antimony–telluride based thin film materials were grown by metal organic vapor phase deposition (MOCVD). A planar-type
thermoelectric device was fabricated with p-type Bi0.4Sb1.6Te3 and n-type Bi2Te3 thin films. The generator consisted of 20 pairs of p-type and n-type legs. We demonstrated complex structures of different conduction types of thermoelectric elements on the same substrate
using two separate deposition runs of p-type and n-type thermoelectric materials. To demonstrate power generation, we heated one side of the sample with a heating block and
measured the voltage output. An estimated power of 1.3 μW was obtained for the temperature difference of 45 K. We provide a promising procedure for fabricating thin film thermoelectric
generators by using MOCVD grown thermoelectric materials that may have a nanostructure with high thermoelectric properties. 相似文献
7.
Improved Thermoelectric Performance of Silver Nanoparticles‐Dispersed Bi2Te3 Composites Deriving from Hierarchical Two‐Phased Heterostructure 
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下载免费PDF全文 Qihao Zhang Xin Ai Lianjun Wang Yanxia Chang Wei Luo Wan Jiang Lidong Chen 《Advanced functional materials》2015,25(6):966-976
A practical and feasible bottom‐up chemistry approach is demonstrated to dramatically enhance thermoelectric properties of the Bi2Te3 matrix by means of exotically introducing silver nanoparticles (AgNPs) for constructing thermoelectric composites with the hierarchical two‐phased heterostructure. By regulating the content of AgNPs and fine‐tuning the architecture of nanostructured thermoelectric materials, more heat‐carrying phonons covering the broad phonon mean free path distribution range can be scattered. The results show that the uniformly dispersed AgNPs not only effectively suppress the growth of Bi2Te3 grains, but also introduce nanoscale precipitates and form new interfaces with the Bi2Te3 matrix, resulting in a hierarchical two‐phased heterostructure, which causes intense scattering of phonons with multiscale mean free paths, and therefore significantly reduce the lattice thermal conductivity. Meanwhile, the improved power factor is maintained due to low‐energy electron filtering and excellent electrical transport property of Ag itself. Consequently, the maximum ZT is amazingly found to be enhanced by 304% arising from the hierarchical heterostructure when the AgNPs content reaches 2.0 vol%. This study offers an easily scalable and low‐cost route to construct a wide range of multiscale hierarchically heterostructured bulk composites with significant enhancement of thermoelectric performance. 相似文献
8.
Jian Yang;Haolin Ye;Xiangzhao Zhang;Xin Miao;Xiubo Yang;Lin Xie;Zhongqi Shi;Shaoping Chen;Chongjian Zhou;Guanjun Qiao;Matthias Wuttig;Li Wang;Guiwu Liu;Yuan Yu; 《Advanced functional materials》2024,34(11):2306961
Bismuth sulfide (Bi2S3) is a promising thermoelectric material with earth-abundant, low-cost, and environment-friendly constituents. However, it shows poor thermoelectric performance due to its extremely low electrical conductivity derived from the low electron concentration. Here, a high-performance Bi2S3-based material is reported to benefit from the Fermi level tuning by Ag and Cl co-doping and defect engineering by introducing dense low-angle grain boundaries. Both Ag and Cl act as donors in Bi2S3, upshifting the Fermi level. This increases the electron concentration without degrading the electron mobility, thereby obtaining improved electrical conductivity. The electron localization function (ELF) contour map indicates that interstitial Ag causes electron delocalization, showing higher electron mobility in Bi2S3. More importantly, dense low-angle grain boundaries block phonon propagation, yielding an ultralow lattice thermal conductivity of 0.30 W m−1 K−1. Consequently, a record ZT value of ≈0.9 at 676 K is achieved in the Bi2Ag0.01S3-0.5%BiCl3 sample. 相似文献
9.
《Advanced Electronic Materials》2018,4(7)
For developing the high‐density and high‐speed nonvolatile memory storage, the photoassisted electric field modulation of resistive switching in ferroelectric heterostructures is studied. Highly strained epitaxial BiFeO3 heterostructures are fabricated on LaAlO3 substrates by magnetron sputtering. The electric field‐modulated wide range multilevel resistance and switchable photovoltaic effects are observed in these heterostructures. It is found that the electric field‐modulated interfacial barrier can be further affected by the photogenerated excitons. Therefore, a co‐modulation of light illumination and electric field on the resistive switching behavior is demonstrated, which generates four nonvolatile resistance states. 相似文献
10.
Jeffrey L. Blackburn Stephen D. Kang Michael J. Roos Brenna Norton‐Baker Elisa M. Miller Andrew J. Ferguson 《Advanced Electronic Materials》2019,5(11)
Doped networks of semiconducting single‐walled carbon nanotubes (s‐SWCNTs) have recently demonstrated high thermoelectric (TE) power factors and figures of merit. Efforts to further improve the TE performance of s‐SWCNT networks hinge upon deeper understanding of the mechanisms underlying charge transport. This study explores the dependence of conductivity, thermopower, and resulting TE power factor on carrier density and temperature in s‐SWCNT networks. Careful control of charge‐carrier density illustrates a distinct transition between transport that is limited by energetic barriers between nanotube bundles to an “intrinsic” regime where these barriers are small enough to reveal the intrinsic transport mechanism of the nanotubes. Transport is activated in the s‐SWCNT networks, although a critical survey of the literature demonstrates that the activation energies in s‐SWCNT networks are appreciably smaller than typical semiconducting polymers. At high conductivity, transport behavior is consistent with deformation potential scattering. The analysis demonstrates that mitigation of the “extrinsic” limitations to transport (e.g., inter‐nanotube junctions), and the concomitant reduction of conductivity activation energies, can lead to at least a doubling of the TE power factor. Further comparison to prototypical semiconducting polymers demonstrates that this strategy likely represents a general design principle for improving the TE performance of organic materials. 相似文献
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Developing high‐performance thermoelectric materials is one of the crucial aspects for direct thermal‐to‐electric energy conversion. Herein, atomic scale point defect engineering is introduced as a new strategy to simultaneously optimize the electrical properties and lattice thermal conductivity of thermoelectric materials, and (Bi,Sb)2(Te,Se)3 thermoelectric solid solutions are selected as a paradigm to demonstrate the applicability of this new approach. Intrinsic point defects play an important role in enhancing the thermoelectric properties. Antisite defects and donor‐like effects are engineered in this system by tuning the formation energy of point defects and hot deformation. As a result, a record value of the figure of merit ZT of ≈1.2 at 445 K is obtained for n‐type polycrystalline Bi2Te2.3Se0.7 alloys, and a high ZT value of ≈1.3 at 380 K is achieved for p‐type polycrystalline Bi0.3Sb1.7Te3 alloys, both values being higher than those of commercial zone‐melted ingots. These results demonstrate the promise of point defect engineering as a new strategy to optimize thermoelectric properties. 相似文献
12.
Ian T. Witting Thomas C. Chasapis Francesco Ricci Matthew Peters Nicholas A. Heinz Geoffroy Hautier G. Jeffrey Snyder 《Advanced Electronic Materials》2019,5(6)
Bismuth telluride is the working material for most Peltier cooling devices and thermoelectric generators. This is because Bi2Te3 (or more precisely its alloys with Sb2Te3 for p‐type and Bi2Se3 for n‐type material) has the highest thermoelectric figure of merit, zT, of any material around room temperature. Since thermoelectric technology will be greatly enhanced by improving Bi2Te3 or finding a superior material, this review aims to identify and quantify the key material properties that make Bi2Te3 such a good thermoelectric. The large zT can be traced to the high band degeneracy, low effective mass, high carrier mobility, and relatively low lattice thermal conductivity, which all contribute to its remarkably high thermoelectric quality factor. Using literature data augmented with newer results, these material parameters are quantified, giving clear insight into the tailoring of the electronic band structure of Bi2Te3 by alloying, or reducing thermal conductivity by nanostructuring. For example, this analysis clearly shows that the minority carrier excitation across the small bandgap significantly limits the thermoelectric performance of Bi2Te3, even at room temperature, showing that larger bandgap alloys are needed for higher temperature operation. Such effective material parameters can also be used for benchmarking future improvements in Bi2Te3 or new replacement materials. 相似文献
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A stacked thermoelectric generator on a flexible polymer sheet is investigated that can utilize a low-cost high throughput roll-to-roll process, employing a metal–insulator–semiconductor structure of <100 nm thick Cu and bismuth telluride films with a ≈1 µm thick acrylate insulating coating. Thermoelectric strips can be stacked and connected in the out-of-plane direction, which significantly decreases the size required in the substrate plane and also gives rise to the opportunity for greatly extending power output by stacking thousands of layers. A smooth surface of stacked layers is confirmed due to the nature of the acrylate layer. Room-temperature sputtering can produce good quality/crystalline films, indicated by X-ray diffraction and transmission electron microscope. Both experimental and simulation results observe a small temperature gradient across the stack from the bottom heat source to the top free surface. A stacked thermoelectric generator shows comparable performance to an in-plane device, and most notably, the stacked architecture allows a higher power output without increasing the dimension of the device in the substrate plane, while the thickness is increased within only a µm range. Cyclic buckling fatigue tests suggest that the performance of stacked functional strips can be protected under deformation within the acrylate matrix. 相似文献
16.
Jiong Yang Huanming Li Ting Wu Wenqing Zhang Lidong Chen Jihui Yang 《Advanced functional materials》2008,18(19):2880-2888
A theoretical evaluation of the thermoelectric‐related electrical transport properties of 36 half‐Heusler (HH) compounds, selected from more than 100 HHs, is carried out in this paper. The electronic structures and electrical transport properties are studied using ab initio calculations and the Boltzmann transport equation under the constant relaxation time approximation for charge carriers. The electronic structure results predict the band gaps of these HH compounds, and show that many HHs are narrow‐band‐gap semiconductors and, therefore, are potentially good thermoelectric materials. The dependence of Seebeck coefficient, electrical conductivity, and power factor on the Fermi level is investigated. Maximum power factors and the corresponding optimal p‐ or n‐type doping levels, related to the thermoelectric performance of materials, are calculated for all HH compounds investigated, which certainly provide guidance to experimental work. The estimated optimal doping levels and Seebeck coefficients show reasonable agreement with the measured results for some HH systems. A few HHs are recommended to be potentially good thermoelectric materials based on our calculations. 相似文献
17.
Shaoxiong Xie Qian Xu Qiang Chen Jianguo Zhu Qingyuan Wang 《Advanced functional materials》2024,34(18):2312645
Bismuth titanate (BIT) is widely known as one of the most prospective lead-free ferroelectric and piezoelectric materials in advanced high-temperature sensing applications. Despite significant advances in developing BIT ferroelectrics, it still faces major scientific and engineering challenges in realizing super-high performance to meet next-generation high-sensitivity and light-weight applications. Here, a novel ferroelectric domain-engineered BIT ceramic system is conceived that exhibits super-high piezoelectric coefficient (d33 = 38.5 pC N−1) and inverse piezoelectric coefficient (d33* = 46.7 pm V−1) at low electric field as well as excellent fatigue resistance (stable up to 107 cycles). The results reveal that the introduction of high-density layered (001)-type 180° domain walls with flexible polarization rotation features and the formation of small-size multi-domain states with low energy barriers are mainly responsible for the excellent electrical performance. To the best of knowledge, it is the first time to reveal such intriguing domain structures in BIT ceramics in detail, especially from the atomic-scale perspective by using atomic number (Z)-contrast imaging in combination with atomic-resolution polarization mapping. It is believed that this breakthrough conduces to comprehensively understand structural features of ferroelectric domains in BIT ceramics, and also opens a window for future developments of super-high performance in bismuth layer-structured ferroelectrics via domain engineering. 相似文献
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Enhancement of thermopower is achieved by doping the narrow‐band semiconductor Ag6.52Sb6.52Ge36.96Te50 (acronym TAGS‐85), one of the best p‐type thermoelectric materials, with 1 or 2% of the rare earth dysprosium (Dy). Evidence for the incorporation of Dy into the lattice is provided by X‐ray diffraction and increased orientation‐dependent local fields detected by 125Te NMR spectroscopy. Since Dy has a stable electronic configuration, the enhancement cannot be attributed to 4f‐electron states formed near the Fermi level. It is likely that the enhancement is due to a small reduction in the carrier concentration, detected by 125Te NMR spectroscopy, but mostly due to energy filtering of the carriers by potential barriers formed in the lattice by Dy, which has large both atomic size and localized magnetic moment. The interplay between the thermopower, the electrical resistivity, and the thermal conductivity of TAGS‐85 doped with Dy results in an enhancement of the power factor (PF) and the thermoelectric figure of merit (ZT) at 730 K, from PF = 28 μW cm?1 K?2 and ZT ≤ 1.3 in TAGS‐85 to PF = 35 μW cm?1 K?2 and ZT ≥ 1.5 in TAGS‐85 doped with 1 or 2% Dy for Ge. This makes TAGS‐85 doped with Dy a promising material for thermoelectric power generation. 相似文献
20.
The notion of a locally resonant metamaterial—widely applied to light and sound—has recently been introduced to heat, whereby the thermal conductivity is reduced primarily by intrinsic localized atomic vibrations rather than scattering mechanisms. This article reviews and analyzes this new emerging concept, termed nanophononic metamaterial (NPM), and contrasts it with the competing concept of a nanophononic crystal (NPC) in which thermal conductivity reduction is realized primarily via nanoscale Bragg scattering. Both the NPM and NPC core mechanisms require the presence of a sufficient level of wave behavior, which is possible when there is a relatively wide distribution of the phonon mean free path (MFP). Silicon serves as a perfect material to form NPMs and NPCs given its relatively large average phonon MFP. This offers a unique opportunity considering silicon's abundance and mature fabrication technology. It is shown in this comparative study that while both the NPM and NPC nanosystems may be rendered to serve as extreme insulators of heat, an NPM may do so without excessive reduction in the minimum feature size–which is key to keeping the electrical properties intact. This trait makes a silicon‐based NPM poised to serve as a low‐cost thermoelectric material with exceptional performance. 相似文献