High-throughput computational materials design is an emerging area in materials science,which is based on the fast evaluation of physical-related properties.The lattice thermal conductivity(κ)is a key property of mat...High-throughput computational materials design is an emerging area in materials science,which is based on the fast evaluation of physical-related properties.The lattice thermal conductivity(κ)is a key property of materials for enormous implications.However,the high-throughput evaluation ofκremains a challenge due to the large resources costs and time-consuming procedures.In this paper,we propose a concise strategy to efficiently accelerate the evaluation process of obtaining accurate and convergedκ.The strategy is in the framework of phonon Boltzmann transport equation(BTE)coupled with first-principles calculations.Based on the analysis of harmonic interatomic force constants(IFCs),the large enough cutoff radius(r^(cutoff)),a critical parameter involved in calculating the anharmonic IFCs,can be directly determined to get satisfactory results.Moreover,we find a simple way to largely(~10 times)accelerate the computations by fast reconstructing the anharmonic IFCs in the convergence test ofκwith respect to the rcutof,which finally confirms the chosen r^(cutoff) is appropriate.Two-dimensional graphene and phosphorene along with bulk SnSe are presented to validate our approach,and the long-debate divergence problem of thermal conductivity in low-dimensional systems is studied.The quantitative strategy proposed herein can be a good candidate for fast evaluating the reliableκand thus provides useful tool for high-throughput materials screening and design with targeted thermal transport properties.展开更多
With the rapid development of various fields,including aerospace,industrial measurement and control,and medical monitoring,the need to quantify flow velocity measurements is increasing.It is difficult for traditional ...With the rapid development of various fields,including aerospace,industrial measurement and control,and medical monitoring,the need to quantify flow velocity measurements is increasing.It is difficult for traditional flow velocity sensors to fulfill accuracy requirements for velocity measurements due to their small ranges,susceptibility to environmental impacts,and instability.Herein,to optimize sensor performance,a flexible microelectromechanical system(MEMS)thermal flow sensor is proposed that combines the working principles of thermal loss and thermal temperature difference and utilizes a flexible cavity substrate made of a low-thermal-conductivity polyimide/SiO_(2)(PI/SiO_(2))composite porous film to broaden the measurement range and improve the sensitivity.The measurement results show that the maximum measurable flow velocity can reach 30 m/s with a resolution of 5.4mm/s.The average sensitivities of the sensor are 59.49 mV/(m s−1)in the medium-to-low wind velocity range of 0–2 m/s and 467.31 mV/(m s^(−1))in the wind velocity range of 2–30 m/s.The sensor proposed in this work can enable new applications of flexible flow sensors and wearable devices.展开更多
Negative Poisson’s ratio(NPR)in auxetic materials is of great interest due to the typically enhanced mechanical properties,which enables plenty of novel applications.In this paper,by employing first-principles calcul...Negative Poisson’s ratio(NPR)in auxetic materials is of great interest due to the typically enhanced mechanical properties,which enables plenty of novel applications.In this paper,by employing first-principles calculations,we report the emergence of NPR in a class of two-dimensional honeycomb structures(graphene,silicene,h-BN,h-GaN,h-SiC,and h-BAs),which are distinct from all other known auxetic materials.They share the same mechanism for the emerged NPR despite the different chemical composition,which lies in the increased bond angle(θ).However,the increase of θ is quite intriguing and anomalous,which cannot be explained in the traditional point of view of the geometry structure and mechanical response,for example,in the framework of classical molecular dynamics simulations based on empirical potential.展开更多
Phosphorene, a two-dimensional （2D） elemen- tal semiconductor with a high carrier mobility and intrinsic direct band gap, possesses fascinating chemical and physical properties distinctively different from other 2D ...Phosphorene, a two-dimensional （2D） elemen- tal semiconductor with a high carrier mobility and intrinsic direct band gap, possesses fascinating chemical and physical properties distinctively different from other 2D materials. Its rapidly growing applications in nano-/opto- electronics and thermoelectrics call for fundamental understanding of the thermal transport properties. Con- sidering the fact that there have been so many studies on the thermal transport in phosphorene, it is on emerging demand to have a review on the progress of previous studies and give an outlook on future work. In this mini- review, the unique thermal transport properties of phos- phorene induced by the hinge-like structure are examined. There exists a huge deviation in the reported thermal conductivity of phosphorene in literature. Besides, the mechanism underlying the deviation is discussed by reviewing the effect of different functionals and cutoff distance in calculating the thermal transport properties of phosphorene. It is found that the van der Waals （vdW） interactions play a key role in the formation of resonant bonding, which leads to long-ranged interactions. Taking into account of the vdW interactions and including the long-ranged interactions caused by the resonant bonding with large cutoff distance are important for getting the accurate and converged thermal conductivity of phosphor- ene. Moreover, a fundamental insight into the thermal transport is provided based on the review of resonant bonding in phosphorene. This mini-review summarizes theprogress of the thermal transport in phosphorene and gives an outlook on future horizons, which would benefit the design of phosphorene based nano-electronics.展开更多
The high-performance,wide-range tunable thermal switches play a significant role in the thermal management,high-power-density intelligent devices,energy systems,etc.However,traditional thermal switch components,such a...The high-performance,wide-range tunable thermal switches play a significant role in the thermal management,high-power-density intelligent devices,energy systems,etc.However,traditional thermal switch components,such as thermal diodes,suffer from poor stability,small adjustability,low time efficiency,and difficult implementation.Herein,we propose the superior electric-controlled thermal switch(ECTS)based on Janus monolayer MoSSe.The high-effective and asymmetric regulation of the thermal conductivity driven by electric field demonstrates a wide-range adjustable thermal switch ratio,where the peak value reaches 2.09 under the electric field of 0.04 VÅ^(−1).The underlying mechanism is revealed by electronic structures that the interactions between electrons and phonons are renormalized due to the electric field driving charge density redistribution,which ultimately modulates the phonon anharmonicity.The high-efficiency adjustable ECTS component is expected to provide new inspiration for next-generation thermal management and information processing.展开更多
Polymer composites as thermal interface materials have been widely used in modern electronic equipment.In this work,we report a novel method to prepare highly through-plane thermally conductive silicone rubber(SR)comp...Polymer composites as thermal interface materials have been widely used in modern electronic equipment.In this work,we report a novel method to prepare highly through-plane thermally conductive silicone rubber(SR)composites with vertically aligned silicon carbide fibers(VA-SiCFs)entangled by SiC nanowires(SiCNWs)networks.First,a series of carbon fibers(CFs)skeletons were fabricated in sequence of coating poor thermally conductive polyacrylonitrile-based CFs with polydopamine,icetemplated assembly,and freeze-drying processes.Furthermore,VA-SiCFs networks,i.e.,long-range continuous SiCFs-SiCNWs networks,based on the prepared CFs skeletons,were in-situ obtained via template-assisted chemical vapor deposition method.The thermal conductivity enhancement mechanism of VA-SiCFs networks on its SR composites was also intensively studied by finite element simulation,based on the first principles investigation of SiC,and Foygel’s theory.The in-situ grown VA-SiCFs networks possess high intrinsic thermal conductivity without the thermal interface between fillers,acting as the high-efficiency through-plane long-range continuous thermal conduction path,in which the SiCNWs were the in-plane“thermal spreader”.The VA-SiCFs/SR composites reached a high through-plane thermal conductivity,2.13 W/(m·K),at the filler loading of 15 vol.%,which is 868.2%,and 249.2%higher than that of pure SR sample,and random-CFs@polydopamine(PDA)/SR composites at the same content,respectively.The VA-SiCFs/SR composites also exhibited good electrical insulation performance and excellent dimensional stability,which guaranteed the stable interfacial heat transfer of high-power density electronic devices.展开更多
基金This work is supported by the Deutsche Forschungsgemeinschaft(DFG)(Project number:HU 2269/2-1).
文摘High-throughput computational materials design is an emerging area in materials science,which is based on the fast evaluation of physical-related properties.The lattice thermal conductivity(κ)is a key property of materials for enormous implications.However,the high-throughput evaluation ofκremains a challenge due to the large resources costs and time-consuming procedures.In this paper,we propose a concise strategy to efficiently accelerate the evaluation process of obtaining accurate and convergedκ.The strategy is in the framework of phonon Boltzmann transport equation(BTE)coupled with first-principles calculations.Based on the analysis of harmonic interatomic force constants(IFCs),the large enough cutoff radius(r^(cutoff)),a critical parameter involved in calculating the anharmonic IFCs,can be directly determined to get satisfactory results.Moreover,we find a simple way to largely(~10 times)accelerate the computations by fast reconstructing the anharmonic IFCs in the convergence test ofκwith respect to the rcutof,which finally confirms the chosen r^(cutoff) is appropriate.Two-dimensional graphene and phosphorene along with bulk SnSe are presented to validate our approach,and the long-debate divergence problem of thermal conductivity in low-dimensional systems is studied.The quantitative strategy proposed herein can be a good candidate for fast evaluating the reliableκand thus provides useful tool for high-throughput materials screening and design with targeted thermal transport properties.
基金supported by the National Key Research&Development(R&D)Program of China(grant number 2023YFF0720800)the Shaanxi 2023 Natural Science Basic Research Plan(grant number 2023-JC-QN-0489)+1 种基金the National Natural Science Foundation of China(grant number 52175548)the Free Exploration and Innovation-Teacher Program of Basic Scientific Research Business Expenses of Xi’an Jiaotong University(grant number xzy012023054).
文摘With the rapid development of various fields,including aerospace,industrial measurement and control,and medical monitoring,the need to quantify flow velocity measurements is increasing.It is difficult for traditional flow velocity sensors to fulfill accuracy requirements for velocity measurements due to their small ranges,susceptibility to environmental impacts,and instability.Herein,to optimize sensor performance,a flexible microelectromechanical system(MEMS)thermal flow sensor is proposed that combines the working principles of thermal loss and thermal temperature difference and utilizes a flexible cavity substrate made of a low-thermal-conductivity polyimide/SiO_(2)(PI/SiO_(2))composite porous film to broaden the measurement range and improve the sensitivity.The measurement results show that the maximum measurable flow velocity can reach 30 m/s with a resolution of 5.4mm/s.The average sensitivities of the sensor are 59.49 mV/(m s−1)in the medium-to-low wind velocity range of 0–2 m/s and 467.31 mV/(m s^(−1))in the wind velocity range of 2–30 m/s.The sensor proposed in this work can enable new applications of flexible flow sensors and wearable devices.
基金G.Q.is supported by the Fundamental Research Funds for the Central Universities(Grant No.531118010471)Z.Q.is supported by the National Natural Science Foundation of China(Grant Nos.11904324,11847158)the China Postdoctoral Science Foundation(2018M642774).
文摘Negative Poisson’s ratio(NPR)in auxetic materials is of great interest due to the typically enhanced mechanical properties,which enables plenty of novel applications.In this paper,by employing first-principles calculations,we report the emergence of NPR in a class of two-dimensional honeycomb structures(graphene,silicene,h-BN,h-GaN,h-SiC,and h-BAs),which are distinct from all other known auxetic materials.They share the same mechanism for the emerged NPR despite the different chemical composition,which lies in the increased bond angle(θ).However,the increase of θ is quite intriguing and anomalous,which cannot be explained in the traditional point of view of the geometry structure and mechanical response,for example,in the framework of classical molecular dynamics simulations based on empirical potential.
文摘Phosphorene, a two-dimensional （2D） elemen- tal semiconductor with a high carrier mobility and intrinsic direct band gap, possesses fascinating chemical and physical properties distinctively different from other 2D materials. Its rapidly growing applications in nano-/opto- electronics and thermoelectrics call for fundamental understanding of the thermal transport properties. Con- sidering the fact that there have been so many studies on the thermal transport in phosphorene, it is on emerging demand to have a review on the progress of previous studies and give an outlook on future work. In this mini- review, the unique thermal transport properties of phos- phorene induced by the hinge-like structure are examined. There exists a huge deviation in the reported thermal conductivity of phosphorene in literature. Besides, the mechanism underlying the deviation is discussed by reviewing the effect of different functionals and cutoff distance in calculating the thermal transport properties of phosphorene. It is found that the van der Waals （vdW） interactions play a key role in the formation of resonant bonding, which leads to long-ranged interactions. Taking into account of the vdW interactions and including the long-ranged interactions caused by the resonant bonding with large cutoff distance are important for getting the accurate and converged thermal conductivity of phosphor- ene. Moreover, a fundamental insight into the thermal transport is provided based on the review of resonant bonding in phosphorene. This mini-review summarizes theprogress of the thermal transport in phosphorene and gives an outlook on future horizons, which would benefit the design of phosphorene based nano-electronics.
基金This work is supported by the National Natural Science Foundation of China(Grant Nos.52006057,51906097,11904324,12274374)the Fundamental Research Funds for the Central Universities(Grant Nos.531119200237 and 541109010001)+1 种基金the State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body at Hunan University(Grant No.52175013)the Natural Science Foundation of Henan Province of China(Grant No.222300420551).
文摘The high-performance,wide-range tunable thermal switches play a significant role in the thermal management,high-power-density intelligent devices,energy systems,etc.However,traditional thermal switch components,such as thermal diodes,suffer from poor stability,small adjustability,low time efficiency,and difficult implementation.Herein,we propose the superior electric-controlled thermal switch(ECTS)based on Janus monolayer MoSSe.The high-effective and asymmetric regulation of the thermal conductivity driven by electric field demonstrates a wide-range adjustable thermal switch ratio,where the peak value reaches 2.09 under the electric field of 0.04 VÅ^(−1).The underlying mechanism is revealed by electronic structures that the interactions between electrons and phonons are renormalized due to the electric field driving charge density redistribution,which ultimately modulates the phonon anharmonicity.The high-efficiency adjustable ECTS component is expected to provide new inspiration for next-generation thermal management and information processing.
基金The authors gratefully acknowledge the financial support of this work by the National Natural Science Foundation of China(Nos.21978240,52003219,and 52006057)Youth project of basic research program of Natural Science in Shaanxi Province(No.2020JQ-179)+5 种基金the Fundamental Research Funds for the Central Universities(Nos.3102018AX004,3102017jc01001,and 531119200237)Shenzhen Xuni University Lab Construction Funding(No.YFJGJS1.0,20191024213117281)Guangdong Province Key Field R&D Project(No.2020B010178001)the student innovation fund of Northwestern Polytechnical University(No.202110699234)the Open Testing Foundation of the Analytical&Testing Center of Northwestern Polytechnical University(No.2020T020)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(No.CX2022072).
文摘Polymer composites as thermal interface materials have been widely used in modern electronic equipment.In this work,we report a novel method to prepare highly through-plane thermally conductive silicone rubber(SR)composites with vertically aligned silicon carbide fibers(VA-SiCFs)entangled by SiC nanowires(SiCNWs)networks.First,a series of carbon fibers(CFs)skeletons were fabricated in sequence of coating poor thermally conductive polyacrylonitrile-based CFs with polydopamine,icetemplated assembly,and freeze-drying processes.Furthermore,VA-SiCFs networks,i.e.,long-range continuous SiCFs-SiCNWs networks,based on the prepared CFs skeletons,were in-situ obtained via template-assisted chemical vapor deposition method.The thermal conductivity enhancement mechanism of VA-SiCFs networks on its SR composites was also intensively studied by finite element simulation,based on the first principles investigation of SiC,and Foygel’s theory.The in-situ grown VA-SiCFs networks possess high intrinsic thermal conductivity without the thermal interface between fillers,acting as the high-efficiency through-plane long-range continuous thermal conduction path,in which the SiCNWs were the in-plane“thermal spreader”.The VA-SiCFs/SR composites reached a high through-plane thermal conductivity,2.13 W/(m·K),at the filler loading of 15 vol.%,which is 868.2%,and 249.2%higher than that of pure SR sample,and random-CFs@polydopamine(PDA)/SR composites at the same content,respectively.The VA-SiCFs/SR composites also exhibited good electrical insulation performance and excellent dimensional stability,which guaranteed the stable interfacial heat transfer of high-power density electronic devices.
