PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2023
·Vol. 25
·期 8
·6288-6294
·
IF 3.3
Xiaotong Zhang,Dawei Jiang,Yonghao Han,Yang Gao
To reveal the pressure effects on BiOX semiconductors, we performed in-situ Raman spectroscopy and electrical transport measurements on BiOI up to 26.1 GPa and 19.2 GPa. BiOI showed good structural stability, while the electron conduction characteristics maintained dominance throughout the pressure range. The influence of grain boundary conduction disappeared at pressures above 9.2 GPa. With pressure elevation, the pressure-induced lattice fragmentation and grain refinement introduced a large number of relevant levels in the energy gap and resulted in a significant increase in the conductivity of BiOI under compression. The conductivity increased by 106 at 19.2 GPa from the initial value and maintained an increase of 102 after depressurization until ambient conditions were attained. At the same time, the space charge polarization of the crystal interface layer became weaker with pressure elevation resulting in a decrease in the relative permittivity of BiOI. The calculation results of the complex permittivity showed that the frequency of orientation polarization response decreases with pressure elevation, and the complex permittivity becomes constant in the high-frequency region. Our work proves that pressure could significantly increase the carrier concentration and mobility, thus effectively improving the conductivity of BiOX semiconductors.
研究领域:
材料科学
·
凝聚态物理
✓ 已验证
DOI
PubMed
高影响因子
ADVANCED MATERIALS
·
2023
·Vol. 35
·期 16
·2208800
·
IF 29.4
Tianyang Wang,Xuan Luo,Jingjing Gao,Zhongzhu Jiang,Wei Wang,Xingcai Yang,Nan Zhou,Xiaoguang Zhu,Lei Zhang,Wenjian Lu,Wenhai Song,Hongyan Lv,Yuping Sun
Weyl semimetal T d -MoTe 2 has recently attracted much attention due to its intriguing electronic properties and potential applications in spintronics. Here, Fe-intercalated T d -Fe x MoTe 2 single crystals (0 < x < 0.15 ) are grown successfully. The electrical and thermoelectric transport results consistently demonstrate that the phase transition temperature T S is gradually suppressed with increasing x . Theoretical calculation suggests that the increased energy of the T d phase, enhanced transition barrier, and more occupied bands in 1T′ phase is responsible for the suppression in T S . In addition, a ρ α –ln T behavior induced by Kondo effect is observed with x ≥ 0.08, due to the coupling between conduction carriers and the local magnetic moments of intercalated Fe atoms. For T d -Fe 0.15 MoTe 2 , a spin-glass transition occurs at ≈10 K. The calculated band structure of T d -Fe 0.25 MoTe 2 shows that two flat bands exist near the Fermi level, which are mainly contributed by the d yz and d x 2 − y 2 ${{\rm{d}}_{{x^2} - {y^2}}}$ orbitals of the Fe atoms. Finally, the electronic phase diagram of T d -Fe x MoTe 2 is established for the first time. This work provides a new route to control the structural instability and explore exotic electronic states for transition-metal dichalcogenides.
研究领域:
凝聚态物理
·
材料科学
·
量子材料
·
自旋电子学
·
电子输运
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2023
·Vol. 52
·期 14
·4398-4406
·
IF 4
Hongyuan Song,Bin Liu,Jinhua Zeng,Guangpeng Huo,Liangwei Chen,Jianlu Wang,Lan Yu
The transition metal oxide (TMO) SrCoO3−δ family with rich structural diversity has been widely studied in the phase transition and energy application fields. We report the multiple-phase structure evolution, phase transitions during sintering, and electrical transport of A-site doped Sr4−xYxCo4O12−δ (x = 0–1.0) ceramics. Sr6Co5O15 (x = 0) adopts a hexagonal structure (H), Sr4−xYxCo4O12−δ (x = 0.2–0.4) ceramics adopts a cubic perovskite (CP) structure, and Sr4−xYxCo4O10.5+δ′ (x = 0.8–1.0) ceramics adopts an ordered-tetragonal (OT) structure; moreover, their phase transitions during the sintering processing of samples are systematically investigated. Combining the thermal analysis and X-ray diffraction results, the exothermic peak and weight gain of Sr3YCo4O10.5 (x = 1.0, T) at 1042 °C are considered to correspond to an ordered phase transition (T → OT) occurring. Finally, a systematic phase schema of the Sr4−xYxCo4O12−δ (x = 0–1.0) state dependence on the Y content and sintering temperature is obtained. The high-energy Y–O bond stabilizes the high-temperature CP structure (x = 0.2–0.4) and induces a structural evolution from the CP to OT structure (x = 0.8–1.0). In addition, all Sr4−xYxCo4O12−δ (x = 0–1.0) ceramics show semiconductive electrical transport behavior. Sr6Co5O15 (H) with a one-dimensional chain structure has the highest resistivity, while Sr3.8Y0.2Co4O12−δ (CP) with a three-dimensional corner-sharing structure exhibits the lowest resistivity, and Sr4−xYxCo4O12−δ (x = 0.2–1.0) ceramics show an increasing tendency in resistivity due to the hole carrier Co4+ converting to Co3+. We studied multiple-phase evolution and ordered phase transition in Sr4−xYxCo4O12−δ (x = 0–1.0) ceramics through Y–O bonding.
研究领域:
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2023
·Vol. 34
·期 13
·1096
·
IF 2.8
Gu Wen,Liu Bingguo,Li Shunzi,Hu Baofu,Xu Jian,Wang Jian,Du Baoli
Cu 2 SnS 3 (CTS), as a potential thermoelectric (TE) material, the electrical and thermal transport properties are heavily determined by its original phase structure and the following phase evolution upon heating. Unlike previous studies that induced CTS phase transition by doping, this study used mechanical alloying powder as the precursor and successfully prepared phase-pure cubic (c-) and monoclinic (m-) CTS samples, as well as two-phase mixed samples with different percentage composition of c-CTS and m-CTS, by simply adjusting the hot pressing temperature. Firstly, phase structures of hot-pressed specimens were determined and confirmed by XRD refinement, SEM, TEM, and Raman spectroscopy. Secondly, thermodynamic property was analysis by DSC analysis, and phase evolution was detailed by analyzing specimens quenched at various temperatures. Then, the electrical and thermal transport properties were measured up to 500 °C, and were correlated with phase evolution analyzed above. Benefiting from cationic disorder, a maximum zT of 0.42 at 500 °C was achieved in c-CTS samples hot-pressed at 575 °C. The phase evolution of CTS was comprehensively investigated by using high-quality samples. The results indicate that phase transition is the potential mechanism for the doping effect in most studies, providing some guidance for improving the performance of environmentally friendly TE sulfides.
研究领域:
材料科学
·
凝聚态物理
·
无机化学
·
能源材料
·
热电转换
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Shaohai Wu,Chengyan Liu,Zhengsen Wu,Lei Miao,Jie Gao,Xiaokai Hu,Junliang Chen,Yanyan Zheng,Xiuxia Wang,Chengjin Shen,Hengquan Yang,Xiaoyuan Zhou
SnSe 2 is regarded as an attractive thermoelectric material for its structural and chemical analogy to SnSe that is claimed with the highest ZT in single crystal. In this study, the pure and Cl-doped SnSe 2 polycrystals (3%, 6%, 9% and 12% molar Cl content) were fabricated in four steps that are hydrothermal synthesis , heating purification, diffusion doping, and spark plasma sintering . The phase structure, lamellar morphology and crystallite orientation were studied for the synthesized SnSe 2 powder and the sintered pellets. The structural evolution was traced from the SnSe 2 hexagonal plates of powders to the (001) oriented grains in pellets. The Cl doping into SnSe 2 was verified by phase composition, lattice parameter , element distribution, and chemical valance. The doped Cl increased both the carrier concentration and the mobility. The anisotropic thermoelectric properties of SnSe 2 bulk materials were investigated as functions of temperature from 50 °C to 300 °C and the doping amount, respectively. The Seebeck coefficient was less anisotropic than the electrical and thermal conduction . The grain orientation influenced the anisotropy of the electrical and thermal conductivity at a similar ratio. The power factors were less dependent on temperature with an optimum in-plane 1.06 mW m −1 K −2 and out-of-plane 0.41 mW m −1 K −2 . The highest ZT s of 0.3 were attained at 300 °C in both directions.
研究领域:
材料科学
·
热电材料
✓ 已验证
产品关联
DOI
高影响因子
ACTA MATERIALIA
·
2018
·
IF 6.036
Xin Liang,Lei Shen
Grain boundary plays an important role in energy carrier transport. By choosing ZnO as a model system of technological importance, and by measuring the thermal and electrical transport properties of ZnO polycrystals with a wide range of grain boundary spacing, we determine the interfacial thermal (Kapitza) resistance of the ZnO grain boundary R k = 4.0 ± 0.7 × 10 − 9 m 2 K W −1 , which is relatively independent of grain size . The effective electron potential barrier height and the depletion width of the grain boundary generally increase with spacing, but they collapse below ∼100 nm and become almost invariant above ∼1 μm. When the grain boundary is locally modified by nanometer-thick ZnS thin film , the Kapitza resistance increases by more than three times, up to about 12.9 × 10 − 9 m 2 K W −1 , and the depletion region expands more than twice. The charge carrier concentration is influenced by the effective potential barrier height due to the grain boundary energy filtering effect whereas the electron mobility is related to the depletion width. Our investigations demonstrate the significance of grain boundary characteristics for interfacial and effective bulk transport properties. The findings and the approach are broadly important for polycrystalline materials of which the functional performance can be adjusted via grain boundary engineering.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
RARE METALS
·
2017
·Vol. 37
·期 4
·333-342
·
IF 1.189
Feng Dan,Chen Yue-Xing,Fu Liang-Wei,Li Ju,He Jia-Qing
Earth-abundant IV–VI semiconductor SnSe is regarded as a promising thermoelectric material due to its intrinsic low thermal conductivity. In this report, the highly textured SnSe/Ag 2 Se composites were first designed by solid solution method followed by spark plasma sintering (SPS) and their thermoelectric properties in two directions were investigated, and then, the performance of composites was further optimized with an additional ball milling. The coexistence of SnSe and Ag 2 Se phases is clearly confirmed by energy-dispersive X-ray spectroscopy (EDX) in transmission electron microscopy (TEM). After ball milling, the size of SnSe grains as well as the incorporated Ag 2 Se particles reduces effectively, which synergistically optimizes the electrical and thermal transport properties at high temperature range. As a result, a maximum ZT of ~ 0.74 at 773 K for SnSe + 1.0%Ag 2 Se in the direction vertical to the pressing direction is achieved. Composite engineering with additional ball milling is thus proved to be an efficient way to improve the thermoelectric properties of SnSe, and this strategy could be applicable to other thermoelectric systems. Graphical
研究领域:
材料科学
·
热电材料
·
半导体物理
·
纳米结构工程
·
能源材料
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2021
·Vol. 23
·期 29
·5045-5052
·
IF 3.545
Shulong Zhang,Mingtao Li,Yilun Yang,Chengchun Zhao,Mingzhu He,Yin Hang,Yifei Fang
CeSb2 is a homologue of rare-earth diantimonides. This work reports a systematic study of a series of high-quality single crystals of CeSb2 grown by a self-flux method, which is a heavy fermion Kondo metal with intricate magnetic transitions. We have grown four types of crystals with different initial material ratios in order to investigate the effect of growth conditions on the quality of the as-grown crystals. The phase purity, morphology and composition of the synthesized samples were studied with X-ray diffraction, scanning electron microscopy, electron-probe microanalysis, and Raman-scattering spectroscopy to evaluate their quality. It is found that an inappropriate raw material ratio will lead to the inhomogeneity and poor crystallinity of the as-grown crystal. In addition, the electrical transport properties of the as-grown crystals were measured, from which the residual resistivity ratios were extracted to further examine the homogeneity and crystalline quality. Furthermore, the magnetoresistance properties of CeSb2 were observed. Through a systematic study on CeSb2, the most suitable starting ratio for the growth of CeSb2 was obtained, which might serve as a guide for the growth of other light rare-earth diantimonides.
研究领域:
材料科学
·
凝聚态物理
·
晶体生长
·
磁性材料
·
强关联电子体系
✓ 已验证
DOI
高影响因子
RARE METALS
·
2017
·Vol. 37
·期 4
·343-350
·
IF 1.189
Qin Bing-Chao,Xiao Yu,Zhou Yi-Ming,Zhao Li-Dong
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) 0.5 , 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. Graphical
研究领域:
材料科学
·
凝聚态物理
·
功能材料
·
热电转换
·
半导体物理
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Yafei Liu,Mingsheng Ma,Pengjun Zhao,Qing Zhao,Zhilong Fu,Donglin He,Aimin Chang,Bo Zhang
CeNbO 4+δ ceramics have attracted extensive research interest because of their unique mixed ion-electron transport characteristics and interesting structure-functional characteristics caused by the difference in oxygen ion content. Although the change of oxygen ion content brings rich redox properties, it also causes serious crystal transformation and abnormal electrical transport properties. In order to obtain stable structure and excellent electrical transport properties, the directional regulation of the oxygen ion content has been realized through introducing Al 2 O 3 and high temperature aging. After 600 h of aging at 1073 K, the prepared composite ceramics not only obtain a stable structure without crystal transformation, but also show good negative temperature coefficient (NTC) thermistor characteristics in the temperature range of 473 K–1273 K, in which the linear fitting maximum Pearson's r of the relationship between ln ρ and 1000/ T can reach 99.97%. The proposed method provides a new thought for the design and application of high-temperature electronic ceramics .
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
·
2018
·Vol. 215
·期 11
·1700905
·
IF 1.795
Shuping Deng,Decong Li,Liping Zheng,Yu Tang,Zhong Chen,Luqi Sun,Wenting Liu,Lanxian Shen,Shukang Deng
In this work, the effect of Cd and Sn atoms partly substitution for Zn on among crystal growth, thermal stability, mechanical, and electrical transport property in β-Zn 4 Sb 3 is reported. In a series of samples prepared from the atomic ratios of Zn:Sb:Cd:Sn = 4.4:3: x :3 ( x = 0.2, 0.4, 0.6, and 0.8). Carrier concentration of all samples varies from 4.52 × 10 19 to 6.42 × 10 19 cm −3 as carrier mobility changes from 58.27 to 67.93 cm 2 V −1 s −1 at room temperature. As a result, electrical transport properties of the samples are optimized by Cd Sn co-doped. The experimental density of all the samples varies from 6.26 × 10 3 to 6.34 × 10 3 kg m −3 consistent with the theoretical value. The weight loss and melting point of the sample are determined to discuss thermal stability in the heating process in air, indicating that the single crystals β-Zn 4 Sb 3 possess an excellent thermal stability and it is practical importance in the TE application at high temperature. Consequently, the maximal power factor of 1.70 × 10 −3 W m −1 K −2 is achieved at 540 K for the sample with initial Cd content x = 0.2, which is enhanced by 40% compared with the single-doping system in β-Zn 4 Sb 3 .
研究领域:
材料科学
·
热电材料
·
固体物理
·
无机化学
·
功能材料
✓ 已验证
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2023
·Vol. 25
·期 29
·19606-19611
·
IF 3.3
Xiaotong Zhang,Yang Gao,Zhenfang Xing,Di Peng,Yonghao Han
In this work, we prepared a BiOBr powder sample by the coprecipitation method for in situ high-pressure AC impedance spectroscopy tests, in situ high-pressure Raman measurements and in situ high-pressure X-ray diffraction experiments to explore its structural properties and electrical transport processes under compression. Two pressure-driven isostructural phase transitions, T–T′ and T′–T′′ (T – tetragonal, T′ – tetragonal 1 and T′′ – tetragonal 2), were discovered at around 10.0 and 15.0 GPa, respectively. The pressure-induced changes in the crystal structure and electrical transport of BiOBr can provide a reference for explaining the mechanism of the isostructural phase transition of other similar compounds after compression.
研究领域:
材料科学
·
固体物理
·
凝聚态物理
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）