Materials Today Physics
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2023
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IF 11.5
Lin Chen,Mingyu Hu,Jing Feng
Thermal transport management is of great significance for materials such as thermal barrier coatings , photovoltaics , and thermoelectrics . In particular, tremendous efforts have been made to tailor phonon thermal transport to improve performance. This work elucidated origins of low thermal conductivity of ferroelastic (Sm 1-X Yb X )TaO 4 solid solutions from defect-dominated phonon scattering processes. We estimated the influences of point defects (misfits in atomic weight and ionic radius , and oxygen vacancies), ferroelastic domains, and the Umklapp process on thermal transports via the corresponding phonon relaxation time ( τ ). The phonon relaxation time caused by point defects ( τ D ), ferroelastic domains ( τ F ), and the Umklapp process ( τ U ) exhibited a trend of τ D − 1 > τ U − 1 > τ F − 1 , indicating that point defects dominated the thermal transports. The effects of ferroelastic domains on thermal conductivity were estimated according to domain widths and space mismatches between neighboring domains. The approximately parallel relationship between the neighboring domains was beneficial for reducing ferroelastic t - m transition energy. Furthermore, a model was developed to derive the high-temperature thermal conductivity, and the contributions of radiative thermal conductivity were separated from the total thermal conductivity. The analysis of thermal transports can be used in other materials to estimate the contributions of different thermal transport mechanisms to the total thermal conductivity at both low and high temperatures, and to effectively tailor thermal transports according to specific applications.
研究领域:
材料科学
·
物理学
✓ 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
ACTA MATERIALIA
·
2025
·
IF 9.3
Hongyao Zhang,Haotian Gao,Tianxiang Jiang,Qiang Feng,Huili Liu,Tongsuo Lu,Beibei Xu,Wujie Qiu,He Lin,Kunpeng Zhao
Understanding and engineering thermal transport in complex structures is essential for the development of materials with ultralow lattice thermal conductivity . In this study, we examine the unusual thermal transport behavior of Mg 2 Sn-based high-entropy materials, using a combination of pair distribution function (PDF) analysis, first-principles calculations, and theoretical modeling. Our findings demonstrate that the crystalline high-entropy materials exhibit glass-like thermal transports, characterized by an exceptionally low lattice thermal conductivity that increases monotonically with increasing temperature across the entire measured range, devoid of the characteristic peaks typical of crystalline materials. This unique behavior is attributed to the large atomic displacement parameter (ADP) of Mg atoms, which causes the Einstein oscillators to significantly reduce lattice thermal conductivity , complemented by the strong scattering of phonons by the nanoscale chemical fluctuations and a dense concentration of point defects within the high-entropy structure. These insights deepen our understanding of thermal transport in complex-structured materials, such as Mg 2 Sn-related compounds, and offer a foundation for designing new materials with tailored thermal conductivities for advanced thermal management and thermoelectric applications.
研究领域:
材料科学
·
凝聚态物理
·
热电材料
·
固体化学
·
热输运
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2025
·
IF 12.1
Jianliang Li,Jing Li,Weili Liu,Conghui Tan,Meiqi An,Shuai Yang,Yanan Bao,Han Bao,Huayi Tang,Yingmin Luo,Yurui Fang,Jiao Xu,Yiming Yang
Thermal transport at the microscopic level is intuitively considered as a fast and random process. However, here the formation of significant microscale thermal inhomogeneity in single nanowires (NWs) of halide perovskites is reported, where the temperature gradient can be further converted to a compositional gradient via bandgap engineering. Upon employing a heat source or heat sink in the setup, arrays of composition-graded NWs are fabricated by anion-exchange with halogen-containing vapor. Quantitative analysis from multiple spatial-resolved scanning probe characterizations suggests that the exchange reaction occurs globally with a monotonically decreased rate along individual NWs, and the corresponding thermal simulation reveals a prominent temperature gradient up to 3.6 °C µm −1 in the axial direction. The large thermal inhomogeneity is attributed to the ultra-low thermal conductivity of perovskites combined with reduced nanowire (NW) diameter. In addition, the gradient NWs exhibit excellent optoelectronic features suitable for further integration into functional devices. This work provides guidelines for the composition manipulation of perovskites through phononic engineering, extending their applications in ultracompact microspectrometers, spectral imaging sensors, and other miniaturized optoelectronic devices.
研究领域:
材料科学
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纳米技术
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光电子学
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热输运
·
钙钛矿材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
·
2025
·
IF 5.8
Tonghao Wu,Danming Zhong,Shaoxing Qu
The thermal conductivity of polymeric materials is greatly influenced by the morphology of the internal molecular networks. Specifically, the irreversible alteration of molecular networks through external stress or damage changes the thermal conductivity of polymers. However, the intricate relationship between molecular network alteration and changes in thermal conductivity under large deformations remains elusive. To elucidate and quantify the variation of thermal conductivity in hydrogels as a result of the damage of polymer networks , it is necessary to construct a physically-based model. In this work, taking the PAAm-PAAm double-network hydrogel as a model material, we utilized uniaxial tension to precisely modulate the damage levels of materials. Notably, experimental observations revealed a decrease in hydrogel's thermal conductivity concurrent with progressive structural damage. It was assumed that the inter-molecular heat transfer pathways were reduced due to damage of cross-linkers within the networks. Then a percolation model utilizing square site structures for capturing heat transfer pathways’ influence on overall thermal conductivity was constructed. This work deepens our fundamental understanding of the interaction between damage-induced network alteration and the evolution of thermal conductivity. Moreover, the constructed model enables the prediction of changes in the thermal conductivity of hydrogels through simple mechanical testing.
研究领域:
材料科学
·
聚合物物理
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热输运
·
软物质力学
✓ 已验证
产品关联
DOI
高影响因子
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