Temperature-dependent phonon lifetimes and thermal conductivity of silicon by inelastic neutron scattering and 
<i>ab initio</i>
 calculations

Kim, Dennis; Hellman, Olle; Shulumba, Nina; Saunders, Claire; Lin, Jiao; Smith, Harold L.; Herriman, Jane E.; Niedziela, Jennifer L.; Abernathy, D. L.; Li, C. W.; Fultz, B.

doi:10.1103/physrevb.102.174311

Cited by 22 publications

(15 citation statements)

References 57 publications

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“…Third, 1600 cm −1 is >5kT, but this mode contributes strongly to σ 2 . The Boltzmann factor is considered in equation 3, which implies that the higher energy peaks are important because of mixing with lower energy phonons, [58,59] . Recently, this has been demonstrated in rubrene.…”

Section: Mode Analysismentioning

confidence: 99%

Catching the Killer: Dynamic Disorder Design Rules for Small‐Molecule Organic Semiconductors

Dettmann

Cavalcante

Magdaleno

et al. 2023

Adv Funct Materials

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Small‐molecule organic semiconductors are promising materials for applications ranging from solar cells to medical sensors. Their nearly infinite design space means that, in theory, it is possible to tailor the material to the exact specifications of a particular application. In reality; however, design rules to improve mobility (μ) remain elusive because of the complex calculations required to understand its limiters. Transient localization theory posits that charge carriers are slowed down by the collective phonon motions, called dynamic disorder, which localize charge carriers temporarily. Traditionally, a mode‐by‐mode analysis is performed to try and identify “killer” modes. Herein, the flaws are demonstrated with this analysis and present a streamlined simulation workflow that simplifies simulation of dynamic disorder and enables engineering of new molecular structures based on phonon dynamics. This workflow is combined with a novel visualization technique that enables per‐atom insights into how μ is limited. This workflow is applied and analyzed to a series of ‐acenes and a series of BTBT‐based molecules. Then design rules are identified in each series that identify possible ways to improve the μ beyond current experimental limits using phonon engineering.

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Section: Mode Analysismentioning

confidence: 99%

Catching the Killer: Dynamic Disorder Design Rules for Small‐Molecule Organic Semiconductors

Dettmann

Cavalcante

Magdaleno

et al. 2023

Adv Funct Materials

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“…It can be seen from Figure 3g that the thermal conductivity of SiNW would reduce 61% under a shear strain of 0.26% estimated from the MD simulation result, which is slightly less steep than our measurement. The strains would also induce changes in the grain defect 47,48 and the phonon lifetime, 49,50 resulting in the thermal conductivity reduction. Therefore, we further investigated the crystal structure change of SiNW during its bending process by in situ high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy.…”

Section: Origin Of the Remarkable Thermal Conductivitymentioning

confidence: 99%

Remarkable Thermal Conductivity Reduction of Silicon Nanowires during the Bending Process

Huang,

Zhang,

Fan

et al. 2023

ACS Appl. Mater. Interfaces

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The one-dimensional geometry of silicon nanowire helps to overcome the rigid and brittle nature of bulk silicon and enables it to withstand substantial bending stresses. This provides exciting opportunities for the development of flexible electronics. The bending strain introduces atomic displacement in the lattice structure, which inherently has a significant impact on the thermal conductivity. The strain-dependent thermal conductivity of silicon nanowire is crucial to the thermal management and performance of flexible electronic devices. However, in situ thermal conductivity measurement of bending silicon nanowires remains challenging and unreported due to the varying thermal contact resistances between the sample and sensor/heat sink. In this study, the Raman spectroscopy-assisted steady state thermal conductivity measurement method is coupled with a micromanipulation system to successively monitor the thermal conductivity variation of silicon nanowires during the bending process. The result shows that the thermal conductivity of silicon nanowires steeply decreases 55−78% owing to the strain-induced structural deformation during bending. Furthermore, the proposed in situ thermal conductivity measurement method can also be extended to other nanomaterials.

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“…19,[224][225][226][227] Recently, the phonon lifetime was measured over the entire Brillouin zone in bulk silicon using neutron scattering. 228 The chosen technique to model phonon interactions depends largely on the frequency range of interest. One way to visualize the various frequency regimes is as a function of material thickness (e.g., see eqn (1) for layered materials), as different decay processes dominate at different material thicknesses.…”

Section: Pump-probementioning

confidence: 99%

Excitation and detection of acoustic phonons in nanoscale systems

Sachat

Cespedes

et al. 2022

Nanoscale

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Temperature-dependent phonon lifetimes and thermal conductivity of silicon by inelastic neutron scattering and ab initio calculations

Cited by 22 publications

References 57 publications

Catching the Killer: Dynamic Disorder Design Rules for Small‐Molecule Organic Semiconductors

Catching the Killer: Dynamic Disorder Design Rules for Small‐Molecule Organic Semiconductors

Remarkable Thermal Conductivity Reduction of Silicon Nanowires during the Bending Process

Excitation and detection of acoustic phonons in nanoscale systems

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