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Wu N, Liu Y, Wang S, Xing Z, Tang G. Thermal Rectification in Graphene-Boron Nitride Nanotube Hybrid Structures: An Independent Control Mechanism for Forward and Backward Heat Flux. ACS APPLIED MATERIALS & INTERFACES 2024; 16:42660-42673. [PMID: 39078264 DOI: 10.1021/acsami.4c09390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
The weak van der Waals interactions in the out-of-plane direction result in markedly low thermal conductivity in one-dimensional (1D) and two-dimensional (2D) materials, which substantially restricts their applications. Developing three-dimensional (3D) columnar hybrid structures, featuring high thermal conductivity both within and beyond the plane, effectively addresses this challenge. This study investigated a 3D hybrid structure composed of graphene and boron nitride nanotubes (GR-BNNTs) using non-equilibrium molecular dynamics simulations. This approach allowed the examination of the formation mechanisms and key factors influencing thermal rectification (TR) in these materials. Our findings reveal a novel mechanism for independently regulating forward and backward heat fluxes in GR-BNNTs. By manipulating the thermal properties of the BNNTs and the graphene layer, the TR ratio can be controlled flexibly. Additionally, we identify specific strategies for independently adjusting the heat flux, such as altering the intercolumn distance of BNNTs, which impacts the backward flux merely, while applying strain to affect the forward flux merely. This research introduces a novel concept of independent regulation of forward and backward heat fluxes, providing significant insights into phonon thermal transport in 3D hybrid structures.
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Affiliation(s)
- Ning Wu
- Department of Power Engineering, School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Yingguang Liu
- Department of Power Engineering, School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
- Hebei Key Laboratory of Low Carbon and High Efficiency Power Generation Technology, North China Electric Power University, Baoding 071003, China
| | - Shuo Wang
- Department of Power Engineering, School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Zhibo Xing
- Department of Power Engineering, School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Guihua Tang
- MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
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2
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Wang YS, Nijjar P, Zhou X, Bondar DI, Prezhdo OV. Combining Lindblad Master Equation and Surface Hopping to Evolve Distributions of Quantum Particles. J Phys Chem B 2020; 124:4326-4337. [DOI: 10.1021/acs.jpcb.0c03030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yi-Siang Wang
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Parmeet Nijjar
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Xin Zhou
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
- College of Environment and Chemical Engineering, Dalian University, Dalian 116622, P. R. China
| | - Denys I. Bondar
- Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, United States
| | - Oleg V. Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
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3
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Li Y, Zhu Y, Jiang G, Cano ZP, Yang J, Wang J, Liu J, Chen X, Chen Z. Boosting the Heat Dissipation Performance of Graphene/Polyimide Flexible Carbon Film via Enhanced Through-Plane Conductivity of 3D Hybridized Structure. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1903315. [PMID: 31999051 DOI: 10.1002/smll.201903315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 12/27/2019] [Indexed: 06/10/2023]
Abstract
The development of materials with efficient heat dissipation capability has become essential for next-generation integrated electronics and flexible smart devices. Here, a 3D hybridized carbon film with graphene nanowrinkles and microhinge structures by a simple solution dip-coating technique using graphene oxide (GO) on polyimide (PI) skeletons, followed by high-temperature annealing, is constructed. Such a design provides this graphitized GO/PI (g-GO/PI) film with superflexibility and ultrahigh thermal conductivity in the through-plane (150 ± 7 W m-1 K-1 ) and in-plane (1428 ± 64 W m-1 K-1 ) directions. Its superior thermal management capability compared with aluminum foil is also revealed by proving its benefit as a thermal interface material. More importantly, by coupling the hypermetallic thermal conductivity in two directions, a novel type of carbon film origami heat sink is proposed and demonstrated, outperforming copper foil in terms of heat extraction and heat transfer for high-power devices. The hypermetallic heat dissipation performance of g-GO/PI carbon film not only shows its promising application as an emerging thermal management material, but also provides a facile and feasible route for the design of next-generation heat dissipation components for high-power flexible smart devices.
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Affiliation(s)
- Yanhua Li
- College of Materials Science and Engineering, Hunan University, Changsha, 410082, P. R. China
- College of Materials and Chemistry Engineering, Hunan Institute of Technology, Hengyang, 421002, P. R. China
| | - Yanfei Zhu
- College of Materials Science and Engineering, Hunan University, Changsha, 410082, P. R. China
- Department of Chemical Engineering, Waterloo Institute for Nanotechnology, Waterloo Institute for Sustainable Energy, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| | - Gaopeng Jiang
- Department of Chemical Engineering, Waterloo Institute for Nanotechnology, Waterloo Institute for Sustainable Energy, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| | - Zachary P Cano
- Department of Chemical Engineering, Waterloo Institute for Nanotechnology, Waterloo Institute for Sustainable Energy, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| | - Jun Yang
- Zhuzhou Times New Material Technology Co., LTD, Zhuzhou, 412007, P. R. China
| | - Jin Wang
- Zhuzhou Times New Material Technology Co., LTD, Zhuzhou, 412007, P. R. China
| | - Jilei Liu
- College of Materials Science and Engineering, Hunan University, Changsha, 410082, P. R. China
| | - Xiaohua Chen
- College of Materials Science and Engineering, Hunan University, Changsha, 410082, P. R. China
| | - Zhongwei Chen
- Department of Chemical Engineering, Waterloo Institute for Nanotechnology, Waterloo Institute for Sustainable Energy, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
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Hundi P, Shahsavari R. Deep Learning to Speed up the Development of Structure-Property Relations For Hexagonal Boron Nitride and Graphene. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1900656. [PMID: 30968576 DOI: 10.1002/smll.201900656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 03/13/2019] [Indexed: 06/09/2023]
Abstract
Structure-property maps play a key role in accelerated materials discovery. The current norm for developing these maps includes computationally expensive physics-based simulations. Here, the capabilities of deep learning agents are explored such as convolutional neural networks (CNNs) and multilayer perceptrons (MLPs) to predict structure-property relations and reduce dependence on simulations. This study contains simulated hexagonal boron nitride (h-BN) microstructures damaged by various levels of radiation and temperature, with the objective to predict their residual strengths from the final atomic positions. By developing low dimensional physical descriptors to statistically describe the defects, these results show that purpose-specific microstructure representation can help in achieving a good prediction accuracy at low computational cost. Furthermore, the adaptability of the trained deep learning agents is explored to predict structure-property maps of other 2D materials using transfer learning. It is shown that in order to achieve good predictions accuracy (≈95% R2 ), an agent that is training for the first time ("learning from scratch") requires 23-45% of simulated data, whereas an agent adapting to a different material ("transfer learning") requires only about 10% or less. This suggests that transfer learning is a potential game changer in material discovery and characterization approaches.
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Affiliation(s)
- Prabhas Hundi
- Department of Civil and Environmental Engineering, Rice University, Houston, TX, 77005, USA
| | - Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, Rice University, Houston, TX, 77005, USA
- C-Crete Technologies LLC, Stafford, TX, 77477, USA
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Shahsavari R. Intercalated Hexagonal Boron Nitride/Silicates as Bilayer Multifunctional Ceramics. ACS APPLIED MATERIALS & INTERFACES 2018; 10:2203-2209. [PMID: 29308874 DOI: 10.1021/acsami.7b15377] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
By performing an extensive 150+ first-principles calculations, this work demonstrates how the exotic properties of emerging 2D hBN nanosheets (e.g., ultrahigh surface area, high mechanical and thermal tolerance) can be coupled strategically (via exfoliation and geometrical compatibility) with the lamellar nanostructure of calcium-silicate crystals to introduce "reinforcement" at the basal plane of materials, i.e., the smallest possible scale. Probing mechanical properties show significant enhancement in strength, toughest, stiffness and strain, providing key guidelines to intercalate a suite of emerging 2D materials in ceramics for the bottom-up design and fabrication of ultrahigh performance and multifunctional ceramic composites.
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Affiliation(s)
- Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, Department of Material Science and NanoEngineering, and Smalley Institute for Nanoscale Science and Technology Rice University , Houston, Texas 77005, United States
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6
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Zhou X, Jankowska J, Li L, Giri A, Hopkins PE, Prezhdo OV. Strong Influence of Ti Adhesion Layer on Electron-Phonon Relaxation in Thin Gold Films: Ab Initio Nonadiabatic Molecular Dynamics. ACS APPLIED MATERIALS & INTERFACES 2017; 9:43343-43351. [PMID: 29135220 DOI: 10.1021/acsami.7b12535] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Electron-phonon relaxation in thin metal films is an important consideration for many ultrasmall devices and ultrafast applications. Recent time-resolved experiments demonstrate a significant, more than a factor of five, increase in the electron-phonon coupling and acceleration in the electron-phonon relaxation rate when a narrow Ti adhesion layer is introduced between an Au film and a nonmetal substrate. Using nonadiabatic molecular dynamics combined with real-time time-dependent density functional theory, we identify the reasons that give rise to this strong effect. First, the Ti layer greatly enhances the density of states (DOS) in the energy region starting at 1 eV below the Fermi level and extending several electronvolts above it. Second, Ti atoms are four times lighter than Au atoms and therefore generate larger nonadiabatic (NA) electron-phonon coupling. Because the transition rates depend on coupling and DOS, both the factors accelerate the dynamics. Showing good agreement with the experiments, the time-domain atomistic simulations provide a detailed mechanistic understanding of the electron-phonon relaxation dynamics in thin gold films and related nanomaterials.
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Affiliation(s)
- Xin Zhou
- College of Environment and Chemical Engineering, Dalian University , Dalian 116622, P. R. China
| | - Joanna Jankowska
- Institute of Physics, Polish Academy of Sciences , 02-668 Warsaw, Poland
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Sakhavand N, Shahsavari R. Asymmetric Junctions Boost in-Plane Thermal Transport in Pillared Graphene. ACS APPLIED MATERIALS & INTERFACES 2017; 9:39122-39126. [PMID: 29095592 DOI: 10.1021/acsami.7b16162] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Hybrid 3D nanoarchitectures by covalent connection of 1D and 2D nanomaterials are currently in high demands to overcome the intrinsic anisotropy of the parent materials. This letter reports the junction configuration-mediated thermal transport properties of Pillared Graphene (PGN) using reverse nonequilibrium molecular dynamics simulations. The asymmetric junctions can offer ∼20% improved in-plane thermal transport in PGN, unlike the intuition that their wrinkled graphene sheets cause phonon scattering. This asymmetric trait, which entails lower phonon scattering provides a new degree of freedom to boost thermal properties of PGN and potentially other hybrid nanostructures.
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Affiliation(s)
- Navid Sakhavand
- Department of Civil and Environmental Engineering, ‡Department of Material Science and NanoEngineering, and §Smalley Institute for Nanoscale Science and Technology, Rice University , Houston, Texas 77005, United States
| | - Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, ‡Department of Material Science and NanoEngineering, and §Smalley Institute for Nanoscale Science and Technology, Rice University , Houston, Texas 77005, United States
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Hwang SH, Miller JB, Shahsavari R. Biomimetic, Strong, Tough, and Self-Healing Composites Using Universal Sealant-Loaded, Porous Building Blocks. ACS APPLIED MATERIALS & INTERFACES 2017; 9:37055-37063. [PMID: 28991434 DOI: 10.1021/acsami.7b12532] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Many natural materials, such as nacre and dentin, exhibit multifunctional mechanical properties via structural interplay between compliant and stiff constituents arranged in a particular architecture. Herein, we present, for the first time, the bottom-up synthesis and design of strong, tough, and self-healing composite using simple but universal spherical building blocks. Our composite system is composed of calcium silicate porous nanoparticles with unprecedented monodispersity over particle size, particle shape, and pore size, which facilitate effective loading and unloading with organic sealants, resulting in 258% and 307% increases in the indentation hardness and elastic modulus of the compacted composite. Furthermore, heating the damaged composite triggers the controlled release of the nanoconfined sealant into the surrounding area, enabling moderate recovery in strength and toughness. This work paves the path towards fabricating a novel class of biomimetic composites using low-cost spherical building blocks, potentially impacting bone-tissue engineering, insulation, refractory and constructions materials, and ceramic matrix composites.
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Shayeganfar F, Beheshtiyan J, Neek-Amal M, Shahsavari R. Electro- and opto-mutable properties of MgO nanoclusters adsorbed on mono- and double-layer graphene. NANOSCALE 2017; 9:4205-4218. [PMID: 28290570 DOI: 10.1039/c6nr08586e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Inspired by recent experiments, the trapping of molecules in 2D materials has gained increasing attention due to the unique ability of the molecules to modulate the electronic and optical properties of 2D materials, which calls for fundamental understanding and predictive design strategies. Herein, we focus on mono- and double-layer graphene encapsulating various MgO clusters and explore their diverse electronic and optical properties using a number of high-level first-principles calculations. By correlating the stability of adsorption, geometry, charge transfer, band structures, optical absorption spectrum, and the van der Waals pressure, our results decode various synergies in electro- and opto-mutable properties of MgO/graphene systems. We found that 2D-MgO flakes on graphene layers exhibit surface polarization effects - in contrast to their isolated neutral flakes - and show a significant charge transfer from graphene to n-doped flakes, breaking the symmetry of graphene layers. We obtained a van der Waals pressure of ∼0.7 (0.9) GPa on bilayer graphene encapsulating MgO nanoclusters, which matches extremely well with experiment. While there is one quantum emission in the visible light region for a single MgO flake, a wide range of visible light is accessible for MgO on mono- and double-layer graphene. Overall, these findings provide new physical insights and design strategies to modulate 2D materials with several applications in optoelectronics while significantly broadening the spectrum of strategies for fabricating new hybrid 2D heterostructures by encapsulating external molecules.
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Affiliation(s)
- Farzaneh Shayeganfar
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA. and Institute for Advanced Technologies, Shahid Rajaee Teacher Training University, 16875-163, Lavizan, Tehran, Iran
| | - Javad Beheshtiyan
- Institute for Advanced Technologies, Shahid Rajaee Teacher Training University, 16875-163, Lavizan, Tehran, Iran and Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
| | - Mehdi Neek-Amal
- Institute for Advanced Technologies, Shahid Rajaee Teacher Training University, 16875-163, Lavizan, Tehran, Iran and Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
| | - Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA. and Department of Material Science and NanoEngineering, Rice University, Houston, TX 77005, USA and Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, TX 77005, USA
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Tao L, Theruvakkattil Sreenivasan S, Shahsavari R. Interlaced, Nanostructured Interface with Graphene Buffer Layer Reduces Thermal Boundary Resistance in Nano/Microelectronic Systems. ACS APPLIED MATERIALS & INTERFACES 2017; 9:989-998. [PMID: 28073276 DOI: 10.1021/acsami.6b09482] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Improving heat transfer in hybrid nano/microelectronic systems is a challenge, mainly due to the high thermal boundary resistance (TBR) across the interface. Herein, we focus on gallium nitride (GaN)/diamond interface-as a model system with various high power, high temperature, and optoelectronic applications-and perform extensive reverse nonequilibrium molecular dynamics simulations, decoding the interplay between the pillar length, size, shape, hierarchy, density, arrangement, system size, and the interfacial heat transfer mechanisms to substantially reduce TBR in GaN-on-diamond devices. We found that changing the conventional planar interface to nanoengineered, interlaced architecture with optimal geometry results in >80% reduction in TBR. Moreover, introduction of conformal graphene buffer layer further reduces the TBR by ∼33%. Our findings demonstrate that the enhanced generation of intermediate frequency phonons activates the dominant group velocities, resulting in reduced TBR. This work has important implications on experimental studies, opening up a new space for engineering hybrid nano/microelectronics.
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Affiliation(s)
- Lei Tao
- Department of Civil and Environmental Engineering, Rice University , Houston, Texas 77005, United States
| | | | - Rouzbeh Shahsavari
- Smalley Institute for Nanoscale Science and Technology, Rice University , Houston, Texas 77005, United States
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11
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Shayeganfar F, Shahsavari R. Oxygen- and Lithium-Doped Hybrid Boron-Nitride/Carbon Networks for Hydrogen Storage. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:13313-13321. [PMID: 27771958 DOI: 10.1021/acs.langmuir.6b02997] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Hydrogen storage capacities have been studied on newly designed three-dimensional pillared boron nitride (PBN) and pillared graphene boron nitride (PGBN). We propose these novel materials based on the covalent connection of BNNTs and graphene sheets, which enhance the surface and free volume for storage within the nanomaterial and increase the gravimetric and volumetric hydrogen uptake capacities. Density functional theory and molecular dynamics simulations show that these lithium- and oxygen-doped pillared structures have improved gravimetric and volumetric hydrogen capacities at room temperature, with values on the order of 9.1-11.6 wt % and 40-60 g/L. Our findings demonstrate that the gravimetric uptake of oxygen- and lithium-doped PBN and PGBN has significantly enhanced the hydrogen sorption and desorption. Calculations for O-doped PGBN yield gravimetric hydrogen uptake capacities greater than 11.6 wt % at room temperature. This increased value is attributed to the pillared morphology, which improves the mechanical properties and increases porosity, as well as the high binding energy between oxygen and GBN. Our results suggest that hybrid carbon/BNNT nanostructures are an excellent candidate for hydrogen storage, owing to the combination of the electron mobility of graphene and the polarized nature of BN at heterojunctions, which enhances the uptake capacity, providing ample opportunities to further tune this hybrid material for efficient hydrogen storage.
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Affiliation(s)
- Farzaneh Shayeganfar
- Institute for Advanced Technologies, Shahid Rajaee Teacher Training University , 16875-163 Lavizan, Tehran, Iran
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12
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Mahdavian L. DFT Study to Reduce TCDD by B12N12 Nano-Cage: A Comparison of Calculating Spectroscopic Properties with NMR and NBO. Polycycl Aromat Compd 2016. [DOI: 10.1080/10406638.2016.1238399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Affiliation(s)
- Leila Mahdavian
- Department of Chemistry, Doroud Branch, Islamic Azad University, Doroud, Iran
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Jungwirth NR, Calderon B, Ji Y, Spencer MG, Flatté ME, Fuchs GD. Temperature Dependence of Wavelength Selectable Zero-Phonon Emission from Single Defects in Hexagonal Boron Nitride. NANO LETTERS 2016; 16:6052-6057. [PMID: 27580074 DOI: 10.1021/acs.nanolett.6b01987] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We investigate the distribution and temperature-dependent optical properties of sharp, zero-phonon emission from defect-based single photon sources in multilayer hexagonal boron nitride (h-BN) flakes. We observe sharp emission lines from optically active defects distributed across an energy range that exceeds 500 meV. Spectrally resolved photon-correlation measurements verify single photon emission, even when multiple emission lines are simultaneously excited within the same h-BN flake. We also present a detailed study of the temperature-dependent line width, spectral energy shift, and intensity for two different zero-phonon lines centered at 575 and 682 nm, which reveals a nearly identical temperature dependence despite a large difference in transition energy. Our temperature-dependent results are well described by a lattice vibration model that considers piezoelectric coupling to in-plane phonons. Finally, polarization spectroscopy measurements suggest that whereas the 575 nm emission line is directly excited by 532 nm excitation, the 682 nm line is excited indirectly.
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Affiliation(s)
| | - Brian Calderon
- Cornell University , Ithaca, New York 14853, United States
| | - Yanxin Ji
- Cornell University , Ithaca, New York 14853, United States
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14
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Feng C, Ni H, Chen J, Yang W. Facile Method to Fabricate Highly Thermally Conductive Graphite/PP Composite with Network Structures. ACS APPLIED MATERIALS & INTERFACES 2016; 8:19732-8. [PMID: 27391206 DOI: 10.1021/acsami.6b03723] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Thermally conductive polymer composites have aroused significant academic and industrial interest for several decades. Herein, we report a novel fabrication method of graphite/polypropylene (PP) composites with high thermal conductivity in which graphite flakes construct a continuous thermally conductive network. The thermal conductivity coefficient of the graphite/PP composites is markedly improved to be 5.4 W/mK at a graphite loading of 21.2 vol %. Such a great improvement of the thermal conductivity is ascribed to the occurrence of orientations of crystalline graphite flakes with large particles around PP resin particles and the formation of a perfect thermally conductive network. The model of Hashin-Shtrikman (HS) is adopted to interpret the outstanding thermally conductive property of the graphite/PP composites. This work provides a guideline for the easy fabrication of thermally conductive composites with network structures.
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Affiliation(s)
- Changping Feng
- College of Polymer Science and Engineering and ‡State Key Laboratory of Polymer Materials Engineering, Sichuan University , Chengdu 610065, Sichuan, China
| | - Haiying Ni
- College of Polymer Science and Engineering and ‡State Key Laboratory of Polymer Materials Engineering, Sichuan University , Chengdu 610065, Sichuan, China
| | - Jun Chen
- College of Polymer Science and Engineering and ‡State Key Laboratory of Polymer Materials Engineering, Sichuan University , Chengdu 610065, Sichuan, China
| | - Wei Yang
- College of Polymer Science and Engineering and ‡State Key Laboratory of Polymer Materials Engineering, Sichuan University , Chengdu 610065, Sichuan, China
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15
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Belosludov RV, Rhoda HM, Zhdanov RK, Belosludov VR, Kawazoe Y, Nemykin VN. Conceptual design of tetraazaporphyrin- and subtetraazaporphyrin-based functional nanocarbon materials: electronic structures, topologies, optical properties, and methane storage capacities. Phys Chem Chem Phys 2016; 18:13503-18. [PMID: 27128697 DOI: 10.1039/c5cp07552a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A large variety of conceptual three- and fourfold tetraazaporphyrin- and subtetraazaporphyrin-based functional 3D nanocage and nanobarrel structures have been proposed on the basis of in silico design. The designed structures differ in their sizes, topology, porosity, and conjugation properties. The stability of nanocages of Oh symmetry and nanobarrels of D4h symmetry was revealed on the basis of DFT and MD calculations, whereas their optical properties were assessed using a TDDFT approach and a long-range corrected LC-wPBE exchange-correlation functional. It was shown that the electronic structures and vertical excitation energies of the functional nanocage and nanobarrel structures could be easily tuned via their size, topology, and the presence of bridging sp(3) carbon atoms. TDDFT calculations suggest significantly lower excitation energies in fully conjugated nanocages and nanobarrels compared with systems with bridging sp(3) carbon fragments. Based on DFT and TDDFT calculations, the optical properties of the new materials can rival those of known quantum dots and are superior to those of monomeric phthalocyanines and their analogues. The methane gas adsorption properties of the new nanostructures and nanotubes generated by conversion from nanobarrels were studied using an MD simulation approach. The ability to store large quantities of methane (106-216 cm(3) (STP) cm(-3)) was observed in all cases with several compounds being close to or exceeding the DOE target of 180 cm(3) (STP) cm(-3) for material-based methane storage at a pressure of 3.5 MPa and room temperature.
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Affiliation(s)
- Rodion V Belosludov
- Institute for Materials Research, Tohoku University, Sendai, 980-85577, Japan.
| | - Hannah M Rhoda
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, USA.
| | - Ravil K Zhdanov
- Nikolaev Institute of Inorganic Chemistry, SB RAS, Lavrentiev 3, Novosibirsk 630090, Russia
| | - Vladimir R Belosludov
- Nikolaev Institute of Inorganic Chemistry, SB RAS, Lavrentiev 3, Novosibirsk 630090, Russia
| | - Yoshiyuki Kawazoe
- New Industry Creation Hatchery Center, Tohoku University, 6-6-4 Aoba, Aramaki, Sendai 980-8579, Japan
| | - Victor N Nemykin
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, USA.
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