Thermal conductivity model for nanoporous thin films

Huang, Congliang; Zhao, Xinpeng; Regner, Keith T.; Yang, Ronggui

doi:10.1016/j.physe.2017.11.014

Cited by 17 publications

(7 citation statements)

References 48 publications

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“…For nanoporous materials, other characteristic lengths proposed for phonons scattered by nanostructures like nanopores within a host can be found elsewhere. [105,106,[129][130][131][132] This analytical model is validated by simulating a structure with eight Si nanoparticles uniformly distributed within equal-sized cubic Ge grains (Fig. 6).…”

Section: Grains With Embedded Nanostructuresmentioning

confidence: 99%

A Review on Phonon Transport within Polycrystalline Materials

Hao¹,

Garg²

2021

ES. Mater. Manuf.

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As one fundamental problem in materials science research, thermal transport across grain boundaries is critical to many energy-related applications. Due to the complexity of grain boundaries, the current understanding on how a grain boundary interacts with heat carriers is still in its infancy. This review summarizes the current progresses of this important topic, with its further extension to general interfaces. One focus is on major modeling and simulation techniques to predict the thermal resistance of a grain boundary. The corresponding thermal measurements of individual grain boundaries and grain-boundary thermal engineering are also discussed. A better understanding of the grain-boundary phonon transport is critical to many energy-related applications, where the concerned thermal transport within a polycrystalline material can be largely suppressed by grain boundaries.

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Section: Grains With Embedded Nanostructuresmentioning

confidence: 99%

A Review on Phonon Transport within Polycrystalline Materials

Hao¹,

Garg²

2021

ES. Mater. Manuf.

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“…C is the phononspecific heat, v is the phonon group velocity and F(φ) is the correction factor for the porosity φ. Λ eff is the effective mean free path, accounting for the phonon size effect induced by boundary scattering, which can be modified from the bulk phonon mean free path (MFP) Λ bulk based on Matthiessen's rule as Λ eff = (1/Λ bulk + 1/Λ pore ) −1 . Λ pore is the characteristic length of the porous structure 14,63,65,66 . We use the kinetic model to predict the thermal conductivities of porous graphene by taking Λ pore as interpore distance (more details can be found in Supplementary Note 5 in Supplementary Information), which is shown as the solid line in Fig.…”

Section: Crossover Of Point Defect Scattering and Boundary Scatteringmentioning

confidence: 99%

Influence of point defects and multiscale pores on the different phonon transport regimes

Han

Bao

2023

Commun Mater

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A common strategy to tailor the thermal conductivity of a material is to introduce structural features that modulate phonon scattering, such as atomic-scale defects and nano- and macro-sized pores. However, particle-like and wave-like phonon transport and scattering during a crossover in thermal transport regimes is not well understood. Here, we perform a rigorous quantitative comparison of the thermal conductivity obtained from molecular dynamics simulations and phonon Boltzmann transport equations, taking graphene as an example. We observe a generally increasing trend in thermal conductivity when the pore size increases from point defect to nanopore, due to a transition from Rayleigh scattering to geometric scattering and reduced boundary density. The thermal conductivity further converges to the diffusive limit for macropores because of the dominant effect of phonon-phonon scattering over phonon-boundary scattering. Moreover, we identify a critical interpore distance for the crossover from dependent to independent phonon-pore scattering and a critical pore size for the crossover from point defect scattering to boundary scattering. This work provides a comprehensive understanding of phonon transport in materials containing defects and pores.

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“…Extended, disordered defects such as those encountered in form of voids in nanoporous materials are much more effective in tuning the thermal conductivity, because they are also able to effectively suppress long mean free path phonons that carry a significant fraction of the heat 29,30,31,32,33,34,35,36,37,38,39,40 . Remarkably, small porosities of less than 5% are sufficient to decrease greatly the thermal conductivity, while going above 15% only results in a further, but marginal reduction.…”

Section: Impurity and Boundary Scatteringmentioning

confidence: 99%

Manipulating phonons at the nanoscale: Impurities and boundaries

Zardo

Rurali

2019

Current Opinion in Green and Sustainable Chemistry

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Efficiently controlling phonon propagation is important in many applications, ranging from the design of thermoelectric materials to thermal budget engineering. Phonon manipulation, nonetheless, has proved to be an elusive task. Here we review some basic strategies to alter vibrational modes throughout the entire phonon spectrum by means of point and extended defects, boundaries, and the design of periodic superstructures.These individual scattering mechanisms allow altering the phononic properties in specific spectral regions, while combing two or more can lead to a modification of the full-spectrum.

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Thermal conductivity model for nanoporous thin films

Cited by 17 publications

References 48 publications

A Review on Phonon Transport within Polycrystalline Materials

A Review on Phonon Transport within Polycrystalline Materials

Influence of point defects and multiscale pores on the different phonon transport regimes

Manipulating phonons at the nanoscale: Impurities and boundaries

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