Monolayer and bilayer polyaniline C3N: two-dimensional semiconductors with high thermal conductivity

Nanoscale ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 4301-4310 ◽  
Author(s):  
Yang Hong ◽  
Jingchao Zhang ◽  
Xiao Cheng Zeng

Lateral and flexural thermal transport processes in monolayer and bilayer C3N are systematically investigated using MD simulation.

2005 ◽  
Author(s):  
Zhanrong Zhong ◽  
Xinwei Wang

In this work, thermal transport in nanocrystalline materials is studied using large-scale equilibrium molecular dynamics (MD) simulation. Nanocrystalline materials with different grain sizes are studied to explore how and to what extent the size of nanograins affects the thermal conductivity and specific heat. Substantial thermal conductivity reduction is observed and the reduction is stronger for nanocrystalline materials with smaller grains. On the other hand, the specific heat of nanocrystalline materials shows little change with the grain size. The simulation results are compared with the thermal transport in individual nanograins based on MD simulation. Further discussions are provided to explain the fundamental physics behind the observed thermal phenomena in this work.


Recent advancement of two dimensional MXene nanomaterial offers promise in gases and biosensor areas owing to its large surface area, high thermal conductivity, remarkable safety and excellent catalytic activity traits. The current chapter aimed to review the fundamental and technological aspects of MXenes, including myriad synthesis techniques and structural as well as electronic characteristics of these compounds. The features elucidated in the subsequent sections, examined by both theoretical and experimental approaches and potentialities of MXenes in the gas removal and biosensor applications. Several challenges and exciting future opportunities of this research platform are lastly summarized.


Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 285 ◽  
Author(s):  
Yi Yang ◽  
Dan Zhong ◽  
Yilun Liu ◽  
Donghui Meng ◽  
Lina Wang ◽  
...  

As a derivative material of graphene, graphene oxide films hold great promise in thermal management devices. Based on the theory of Fourier formula, we deduce the analytical formula of the thermal conductivity of graphene oxide films. The interlaminar thermal property of graphene oxide films is studied using molecular dynamics simulation. The effect of vacancy defect on the thermal conductance of the interface is considered. The interfacial heat transfer efficiency of graphene oxide films strengthens with the increasing ratio of the vacancy defect. Based on the theoretical model and simulation results, we put forward an optimization model of the graphene oxide film. The optimal structure has the minimum overlap length and the maximum thermal conductivity. An estimated optimal overlap length for the GO (graphene-oxide) films with degree of oxidation 10% and density of vacancy defect 2% is 0.33 μm. Our results can provide effective guidance to the rationally designed defective microstructures on engineering thermal transport processes.


2020 ◽  
Vol 8 (10) ◽  
pp. 3520-3526 ◽  
Author(s):  
Guangzhao Qin ◽  
Huimin Wang ◽  
Lichuan Zhang ◽  
Zhenzhen Qin ◽  
Ming Hu

The thermal conductivity of monolayer CrI3 is enlarged more than two orders of magnitude by the spin–lattice coupling, which would be large enough for its applications in nanoelectronics and magnetic storage.


Author(s):  
Yan Wang ◽  
Xiulin Ruan

Thermal transport processes in graphene nanoribbons (GNRs) within and beyond the linear response regime has been studied using classical molecular dynamics simulations. Zigzag-edged GNRs have higher thermal conductivities than armchair-edged ones, and the difference diminishes with increasing width. Analysis on the cross-sectional distribution of heat flux reveals that edge atoms cannot transport thermal energy as efficiently as interior ones. Edge localization of phonon modes reduces thermal transport through edge carbon atoms, especially on armchair edges, which results in a lower thermal conductivity. Isotope (13C) doping can reduce the thermal conductivity of GNRs by 30%–40% by an addition of only ∼20% isotope atoms. The significant reduction in thermal conductivity is partially attributed to phonon localization induced by isotope defects, which is confirmed by phonon mode participation ratio analysis. We also demonstrate that a GNR asymmetric in edge chirality or mass density can generate considerable thermal rectification, which is essential for developing GNR-based thermal management devices.


2005 ◽  
Vol 128 (4) ◽  
pp. 397-404 ◽  
Author(s):  
A. D. Sommers ◽  
A. M. Jacobi

The fin efficiency of a high-thermal-conductivity substrate coated with a low-thermal-conductivity layer is considered, and an analytical solution is presented and compared to alternative approaches for calculating fin efficiency. This model is appropriate for frost formation on a round-tube-and-fin metallic heat exchanger, and the problem can be cast as conduction in a composite two-dimensional circular cylinder on a one-dimensional radial fin. The analytical solution gives rise to an eigenvalue problem with an unusual orthogonality condition. A one-term approximation to this new analytical solution provides fin efficiency calculations of engineering accuracy for a range of conditions, including most frosted-coated metal fins. The series solution and the one-term approximation are of sufficient generality to be useful for other cases of a low-thermal-conductivity coating on a high-thermal-conductivity substrate.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aravind Krishnamoorthy ◽  
Nitish Baradwaj ◽  
Aiichiro Nakano ◽  
Rajiv K. Kalia ◽  
Priya Vashishta

AbstractEngineering thermal transport in two dimensional materials, alloys and heterostructures is critical for the design of next-generation flexible optoelectronic and energy harvesting devices. Direct experimental characterization of lattice thermal conductivity in these ultra-thin systems is challenging and the impact of dopant atoms and hetero-phase interfaces, introduced unintentionally during synthesis or as part of deliberate material design, on thermal transport properties is not understood. Here, we use non-equilibrium molecular dynamics simulations to calculate lattice thermal conductivity of $${\mathrm {(Mo|W)Se_2}}$$ ( Mo | W ) Se 2 monolayer crystals including $${\mathrm {Mo}}_{1-x}{\mathrm {W}}_x{\mathrm {Se_2}}$$ Mo 1 - x W x Se 2 alloys with substitutional point defects, periodic $${\mathrm {MoSe_2}|\mathrm {WSe_2}}$$ MoSe 2 | WSe 2 heterostructures with characteristic length scales and scale-free fractal $${\mathrm {MoSe_2}}|{\mathrm {WSe_2}}$$ MoSe 2 | WSe 2 heterostructures. Each of these features has a distinct effect on phonon propagation in the crystal, which can be used to design fractal and periodic alloy structures with highly tunable thermal conductivities. This control over lattice thermal conductivity will enable applications ranging from thermal barriers to thermoelectrics.


Author(s):  
Ravi Prasher

Nanofluids have attracted tremendous attention lately due to their promise as high thermal conductivity liquid and also due the inability of researchers all across the world in explaining the enhancement in the thermal conductivity. Various models and physics have been proposed and some of them have been quite successful in explaining the data, however none of the models in the literature take colloidal chemistry into account. Experimental data, however have shown dependence of thermal conductivity on pH and surface chemistry. In this paper we introduce a model which captures all the anomalies reported in the data 1) Effect of pH 2) effect of aging i.e. time 3) maxima in the thermal conductivity with respect to the diameter of the nanoparticles 4) increase and decrease in the ratio of the thermal conductivity of the nanofluids and the base fluids with increasing temperature. The model is based on the combination of aggregation kinetics with the physics of thermal transport.


2021 ◽  
Vol 32 (13) ◽  
pp. 135401
Author(s):  
Huimin Wang ◽  
Donghai Wei ◽  
Junfei Duan ◽  
Zhenzhen Qin ◽  
Guangzhao Qin ◽  
...  

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