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Estimation of the potential performance in p-type SnSe crystals through evaluating weighted mobility and effective mass

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Journal of Materiomics 2020年第4期6卷 671-676页

作者： Bingchao Qin Wenke He li-dong zhao School of Materials Science and Engineering Beihang UniversityBeijing100191China

It has been proved that the thermoelectric performance of p-type SnSe crystals can be optimized through enhancing carrier *** calculations of electronic band structure elucidate that this approach can be interpreted by including multiple valence *** better estimate the potential performance,we proposed the transport properties for p-type SnSe crystals and analyzed the weighted mobility from the experimental *** weighted mobility approaches~600 cm^(2)V1s1 when the carrier concentration is as high as~6.31019 cm*** with obtained lattice thermal conductivity,through rising carrier concentration,the quality factor B possesses significant improvements of~235%and 138%at 300 K and 773 K,*** comparing weighted mobility and Hall mobility,two effective mass values~0.9 me and 1.8 me can be derived using carrier *** is expected that the ZT~1.0 at 300K and ZT~2.9 at 773 K can be obtained when the carrier concentration of~8.01019 cm3 and the effective mass~1.8 me were *** work provides an alternative way to comprehend the performance optimization in thermoelectric community.

关键词： Thermoelectric p-type SnSe crystals Weighted mobility Quality factor Effective mass

High thermoelectric figure of merit ZT>1 in SnS polycrystals

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Journal of Materiomics 2020年第1期6卷 77-85页

作者： Asfandiyar Bowen Cai li-dong zhao Jing-Feng li State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China School of Materials Science and Engineering Beihang UniversityBeijing100191China

Eco-friendly tin sulfide(SnS)has attracted increasing attention in the thermoelectric community because of its elemental abundance and analogous crystal structure to SnSe as a new thermoelectric ***,so far no high dimensionless thermoelectric figure of merit ZT>1 was reported in SnS *** work found an effective strategy for enhancing the thermoelectric performance of ptype polycrystalline SnS by Ag doping and vacancy engineering,leading to three orders of magnitude increase in carrier concentration and optimized effective mass and carrier *** a result of the enhanced electrical conductivity,three times higher power factor ~3.85 μW/cm K^(2) at 877 K is realized in Sn_(0.995)Ag_(0.005)S ***,nanostructuring with Ag nano-precipitates were formed in the Agdoped SnS ***,with introducing Sn vacancies in the crystal structure of Sn_(0.995-vac)Ag_(0.005)S,the power factor further enhanced to~4.25 μW/cm K^(2).In addition to the low-frequency phonons scattering by Ag nano-precipitates,dislocations strengthens the scattering of mid-frequency phonon,leading to an ultralow lattice thermal conductivity <0.5 W/m K above 800 K and a record high ZT up to 1.1 at 877 K in Sn_(0.99)Ag_(0.005)S polycrystals.

关键词： Thermoelectric tin sulfide Spark plasma sintering Nanoprecipitation Dislocation

Predicting the Potential Performance in P-Type SnS Crystals via Utilizing the Weighted Mobility and Quality Factor

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Chinese Physics Letters 2020年第8期37卷 88-93页

作者： Wenke He Bingchao Qin li-dong zhao Affiliations School of Materials Science and Engineering Beihang UniversityBeijing 100191China

The figure of merit ZT is the direct embodiment of thermoelectric performance for a given ***,as an indicator of performance improvement,the only ZT value is not good enough to identify its outstanding inherent properties,which are highly sought in thermoelectric ***,we utilize one powerful parameter to reveal the outstanding properties of a given *** weighted mobility is used to estimate the carrier transports of p-type SnS crystals,including the differences in doping level,carrier scattering and electronic band *** analyze the difference in carrier scattering mechanism for different crystal forms with the same doping level,then evaluate and confirm the temperature-dependent evolution of electronic band structures in ***,we calculate the quality factor B based on the weighted mobility,and establish the relationship between ZT and B to further predict the potential performance in p-type SnS crystals with low cost and earth abundance,which can be realized through taking advantage of the inherent material property,thus improving B factor to achieve optimal thermoelectric level.

关键词： scattering doping utilize

Thermoelectric transport properties of Pb-Sn-Te-Se system

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Rare Metals 2018年第4期37卷 343-350页

作者： Bing-Chao Qin Yu Xiao Yi-Ming Zhou li-dong zhao School of Materials Science and Engineering Beihang University Beijing 100191 China

IV-VI compounds are considered as promising thermoelectric materials, and high thermoelectric performance was achieved in IV-VI solid solutions. In this work, the thermoelectric properties of Pb-Sn-Te-Se-based solid solutions were systematically investigated. Among these solid solutions, it is found that a figure of merit （ZT） peak value of 1.0 at 873 K can be obtained in （PbTe）0.5（SnTe）o.5, on account of the combination of superior electrical properties in SnTe and low thermal conductivity in PbTe. Furthermore, we investigated and summarized the thermoelectric transport properties and proposed the thermoelectric performance maps for the IV- VI solid solutions in Pb-Sn-Te-Se system. This comprehensive investigation on Pb-Sn-Te-Se-based solid solutions can effectively guide and scan thermoelectric performance for a given unknown composition and enhance the thermoelectric properties in IV-VI compounds.

关键词： Thermoelectric materials Electricalconductivity Thermal conductivity Pb-Sn-Te-Se system Solid solutions

Realizing high thermoelectric properties in p-type polycrystalline SnSe by inducing DOS distortion

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Rare Metals 2021年第10期40卷 2819-2828页

作者： Yu-Ping Wang Bing-Chao Qin dong-Yang Wang Tao Hong Xiang Gao li-dong zhao School of Materials Science and Engineering Beihang UniversityBeijing 100191China Center for High Pressure Science and Technology Advanced Research(HPSTAR) Beijing 100094China

SnSe crystals have been discovered as one of the most efficient thermoelectric materials due to their remarkable thermal and electrical transports. But the polycrystalline SnSe possesses much lower performance especially for the low carrier mobility and electrical conductivity. We firstly attempted to explain and verify the difference in the electrical conductivity as a function of temperature between p-type crystalline and polycrystalline SnSe by considering the grain boundary effects in the polycrystalline samples. On the basis of 2% Na doping to optimize the carrier concentration, the carrier mobility is improved by further introducing In, leading to enhanced carrier mobility from 3 to 9 cm2·V^(-1)·s^(-1) in polycrystalline SnSe. Moreover, In doping introduces extra resonant levels in SnSe, which increases the density of states near Fermi level and leads to an enhanced band effective mass. Large Seebeck coefficient of ~205 l V·K^(-1) at 300 K and maximum power factor of ~7.5 l W·cm^(-1)·K^(-2) at 773 K can be obtained in the Sn_(0.975)Na_(0.02)In_(0.005) Se sample,leading to a competitively high dimensionless figure of merit(ZT) value exceeding 1.1 at 773 K.

关键词： Thermoelectric p-type polycrystalline SnSe Carrier mobility Resonant effect Band effective mass

类施主效应调控与高择优取向织构提升n型Bi_(2)(Te,Se)_(3)材料热电性能

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Science Bulletin 2024年第11期69卷 1728-1737页

作者：李奕辰白树林文熠赵哲王磊刘世博郑俊卿王斯琦刘姗高德政刘东锐朱英才曹茜高翔谢鸿耀赵立东 School of Materials Science and Engineering Beihang UniversityBeijing 100191China Tianmushan Laboratory Hangzhou 311115China Huabei Cooling Device Co.LTD. Langfang 065400China Center for High Pressure Science and Technology Advanced Research(HPSTAR) Beijing 100094China

Thermoelectric materials have a wide range of application because they can be directly used in refrigeration and power generation. And the Bi_(2)Te_(3) stand out because of its excellent thermoelectric performance and are used in commercial thermoelectric devices. However, n-type Bi_(2)Te_(3) has seriously hindered the development of Bi_(2)Te_(3)-based thermoelectric devices due to its weak mechanical properties and inferior thermoelectric performance. Therefore, it is urgent to develop a high-performance n-type Bi_(2)Te_(3) polycrystalline. In this work, we employed interstitial Cu and the hot deformation process to optimize the thermoelectric properties of Bi_(2)Te_(2.7)Se_(0.3), and a high-performance thermoelectric module was fabricated based on this material. Our combined theoretical and experimental effort indicates that the interstitial Cu reduce the defect density in the matrix and suppresses the donor-like effect, leading to a lattice plainification effect in the material. In addition, the two-step hot deformation process significantly improves the preferred orientation of the material and boosts the mobility. As a result, a maximum ZT of 1.27 at 373 K and a remarkable high ZT_(ave) of 1.22 across the temperature range of 300–425 K are obtained. The thermoelectric generator(TEG, 7-pair) and thermoelectric cooling(TEC, 127-pair) modules were fabricated with our n-type textured Cu_(0.01)Bi_(2)Te_(2.7)Se_(0.3) coupled with commercial p-type Bi_(2)Te_(3). The TEC module demonstrates superior cooling efficiency compared with the commercial Bi_(2)Te_(3) device, achieving a ΔT of 65 and 83.4 K when the hot end temperature at 300 and 350 K, respectively. In addition, the TEG module attains an impressive conversion efficiency of 6.5% at a ΔT of 225 K, which is almost the highest value among the reported Bi_(2)Te_(3)-based TEG modules.

关键词： Bi_(2)Te_(3) Texture engineering TEC TEG Donor-like effect

Anisotropic thermoelectric transport properties in polycrystalline SnSe_(2)

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Chinese Physics B 2021年第6期30卷 476-483页

作者： Caiyun li Wenke He dongyang Wang li-dong zhao School of Materials Science and Engineering Beihang UniversityBeijing 100191China

It is reported that SnSe_(2) consisting of the same elements as SnSe, is a new promising thermoelectric material with advantageous layered structure. In this work, the thermoelectric performance of polycrystalline SnSe_(2) is improved through introducing SnSe phase and electron doping(Cl doped in Se sites). The anisotropic transport properties of SnSe_(2) are investigated. A great reduction of the thermal conductivity is achieved in SnSe_(2) through introducing SnSe phase, which mainly results from the strong SnSe_(2)–SnSe inter-phase scattering. Then the carrier concentration is optimized via Cl doping, leading to a great enhancement of the electrical transport properties, thus an extraordinary power factor of ^5.12 μW·cm^(-1)·K^(-2) is achieved along the direction parallel to the spark plasma sintering(SPS) pressure direction( P). Through the comprehensive consideration on the anisotropic thermoelectric transport properties, an enhanced figure of merit ZT is attained and reaches to ^ 0.6 at 773 K in SnSe_(2)-2% SnSe after 5% Cl doping along the P direction, which is much higher than ^ 0.13 and ^ 0.09 obtained in SnSe_(2)-2% SnSe and pristine SnSe_(2) samples, respectively.

关键词： thermoelectric SnSe_(2) anisotropic structure Cl-doping

Homologous layered InFeO3(ZnO)m:new promising abradable seal coating materials

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Rare Metals 2018年第2期37卷 79-94页

作者： Wei-Wei Qu Xiao-Xuan Zhang Bi-Fei Yuan li-dong zhao School of Materials Science and Engineering BeihangUniversityBeijing 100191China China National Petroleum Corporation Greatwall Drilling Company Beijing 100101China

As promising abradable seal coating materials used in high temperature range, the homologous layered InFeO3（ZnO）m （m = 1, 2, 3...20） have attracted great attention. In this short review, we summary the research progress in InFeO3（ZnO）m that were developed in our group. We first introduced a series of conventional abradable seal coating materials as a research motivation. Second, the phase composition and crystal structures of lnFeO3（ZnO）m system were presented. Then, their thermophysical properties, as the most important part, were introduced in detail. At last, the mechanical properties such as hardness, friction coefficient, erosion wear resistance of InFeO3（ZnO）m system were also described. Our summary indicates that InFeO3（ZnO）m sys- tems are promising abradable seal coating materials.

关键词： Abradable seal coating InFeO3(ZnO)m Thermal conductivity Thermal expansion coefficient Mechanical properties

Postoperative recovery from posterior communicating aneurysm complicated by oculomotor palsy

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Chinese Medical Journal 2008年第12期121卷 1065-1067页

作者： YANG Ming-qi WANG Shuo zhao Yuan-li ZHANG dong zhao Ji-zong Department of Neurosurgery Beijing Tiantan Hospital Capital Medical University Beijing 100050 China

Background Oculomotor palsy is a common complication in patients with posterior communicating aneurysm. This study was conducted to investigate the postoperative recovery of patients with posterior communicating aneurysm complicated with oculomotor palsy and to analyze the factors influencing length of recovery.Methods From 2000 to 2006, 148 patients with posterior communicating aneurysm were treated at our hospital, with 74 of them having concurrent unilateral oculomotor palsy. All of the patients underwent craniotomy after the diagnosis by means of whole-brain digital subtraction angiography （DSA）. The patients were divided into two groups for observation of postoperative recovery during the follow-up period. Patients in group A were treated with simple pedicle clipping of the aneurysm while patients in group B were treated with pedicle clipping of the aneurysm and decompression of the oculomotor nerve.Results Of the 40 patients in group A, 20 underwent surgery within 14 days and completely recovered from oculomotor palsy in 10-40 days. Fourteen patients underwent surgery within 14-30 days, of whom 12 completely recovered within 30-90 days and 2 cases recovered incompletely. The remaining six patients underwent surgery after more than 30 days; of these, four patients recovered completely and two recovered incompletely. Of the 34 cases in group B, 15 underwent surgery within 14 days and completely recovered from oculomotor palsy in 10-40 days. Sixteen patients underwent surgery in 14-30 days, of whom 14 completely recovered in 30-90 days and 2 recovered incompletely. The remaining three patients underwent surgery after more than 30 days, of whom two patients recovered completely and one recovered incompletely.Conclusions Early diagnosis and surgical treatment of patients with unilateral oculomotor palsy induced by posterior communicating aneurysm are important to full postoperative recovery of the oculomotor nerve. No correlation was found, however, between d

关键词： oculomotor palsy cerebral angiography intracranial aneurysm