Condensed Matter National Laboratory

2016:
8. "Bubble generation in liquid rope coiling"
Hossein Hosseini, Ali Farnudi, Mouhammad Hossein Khatami, Mehdi Habibi
RCS Advances, doi: 10.1039/C6RA23012A
7. "Graphene Oxide-Based Composite Materials "
Mohsen Moazzami Gudarzi, Seyed Hamed Aboutalebi, Farhad Sharif
A book chapter in Graphene Oxide: Fundamentals and Applications(ISBN: 978-1-119-06940-9), 314-363
Google books
6. "Superflexibility of graphene oxide"
Philippe Poulin, Rouhollah Jalili, Wilfrid Neri, Frédéric Nallet, Thibaut Divoux, Annie Colin, Seyed Hamed Aboutalebi, Gordon Wallace, and Cécile Zakri
PNAS, doi: 10.1073/pnas.1605121113
Abstract: Graphene oxide (GO), the main precursor of graphene-based materials made by solution processing, is known to be very stiff. Indeed, it has a Young’s modulus comparable to steel, on the order of 300 GPa. Despite its very high stiffness, we show here that GO is superflexible. We quantitatively measure the GO bending rigidity by characterizing the flattening of thermal undulations in response to shear forces in solution. Characterizations are performed by the combination of synchrotron X-ray diffraction at small angles and in situ rheology (rheo-SAXS) experiments using the high X-ray flux of a synchrotron source. The bending modulus is found to be 1 kT, which is about two orders of magnitude lower than the bending rigidity of neat graphene. This superflexibility compares with the fluidity of self-assembled liquid bilayers. This behavior is discussed by considering the mechanisms at play in bending and stretching deformations of atomic monolayers. The superflexibility of GO is a unique feature to develop bendable electronics after reduction, films, coatings, and fibers. This unique combination of properties of GO allows for flexibility in processing and fabrication coupled with a robustness in the fabricated structure.
5. "Processable 2D materials beyond graphene: MoS2 liquid crystals and fibres"
Rouhollah Jalili, Sima Aminorroaya-Yamini, Tania M. Benedetti, Seyed Hamed Aboutalebi, Yunfeng Chao, Gordon G. Wallace and David L. Officer
Nanoscale, 2016,8, 16862-16867 DOI: 10.1039/C6NR03681C
Abstract: Herein, we show properly engineered MoS2 crystals can readily form liquid crystalline dispersions in water making them ideal candidates for large-scale manufacturing processes. The guideline provided here can serve as the basis to develop practical protocols to address the long-standing goal of large-scale manufacturing of 2D materials.
4. "Specular Andreev reflection in thin films of topological insulators"
Leyla Majidi and Reza Asgari
Physical Review B 93, 195404 (2016)
Abstract: We theoretically reveal the possibility of specular Andreev reflection in a thin film topological insulator normal-superconductor (N/S) junction in the presence of a gate electric field. The probability of specular Andreev reflection increases with the electric field, and electron-hole conversion with unit efficiency happens in a wide experimentally accessible range of the electric field. We show that perfect specular Andreev reflection can occur for all angles of incidence with a particular excitation energy value. In addition, we find that the thermal conductance of the structure displays exponential dependence on the temperature. Our results reveal the potential of the proposed topological insulator thin-film-based N/S structure for the realization of intraband specular Andreev reflection.

3. "High-Performance Multifunctional Graphene-PLGA Fibers: Toward Biomimetic and Conducting 3D Scaffolds"
Dorna Esrafilzade, Rouhollah Jalili, Elise M. Stewart, Seyed H. Aboutalebi, Joselito M. Razal, Simon E. Moulton, and Gordon G. Wallace
Advanced Functional Materials, DOI: 10.1002/adfm.201505304
Abstract: The development of electrically conducting fibers based on known cytocompatible materials is of interest to those engaged in tissue regeneration using electrical stimulation. Herein, it is demonstrated that with the aid of rheological insights, optimized formulations of graphene containing spinnable poly(lactic-co-glycolic acid) (PLGA) dopes can be made possible. This helps extend the general understanding of the mechanics involved in order to deliberately translate the intrinsic superior electrical and mechanical properties of solution-processed graphene into the design process and practical fiber architectural engineering. The as-produced fibers are found to exhibit excellent electrical conductivity and electrochemical performance, good mechanical properties, and cellular affinity. At the highest loading of graphene (24.3 wt%), the conductivity of as-prepared fibers is as high as 150 S m−1 (more than two orders of magnitude higher than the highest conductivity achieved for any type of nanocarbon-PLGA composite fibers) reported previously. Moreover, the Young's modulus and tensile strength of the base fiber are enhanced 647- and 59-folds, respectively, through the addition of graphene.

2. "Liquid-Crystal-Mediated Self-Assembly of Porous α-Fe2O3 Nanorods on PEDOT:PSS-Functionalized Graphene as a Flexible Ternary Architecture for Capacitive Energy Storage"
Md. Monirul Islam, Dean Cardillo, Taslima Akhter, Seyed Hamed Aboutalebi, Hua Kun Liu, Konstantin Konstantinov and Shi Xue Dou
Particle & Particle Systems Characterization, DOI: DOI: 10.1002/ppsc.201500150
Abstract: High-performance, lightweight, and flexible energy-storage devices such as supercapacitors, batteries, fuel cells, and solar cells are promising energy sources for wearable devices, artificial electronic skins, distributed sensors, and various portable devices. To transform such potentials into reality, the major challenge is to design and develop advanced multicomponent electrode materials with interconnected networks, satisfactory mechanical flexibility, and excellent electrochemical properties. Herein, we have successfully engineered a high-quality flexible electrode, rGO/PEDOT:PSS/porous HNR, by a liquid-crystal-mediated soft self-assembly approach. The feasibility of the nanorod preparation and the low-temperature, dispersant-free fabrication of ternary components in the uniform layered structure offered a great opportunity for creating a high-performance novel hybrid composite electrode material in a flexible arrangement. The hybrid 3D architecture of α-Fe2O3 nanorods on PEDOT:PSS-functionalized rGO layers demonstrates strong synergistic effects, leading to very high specific capacitance of 875 F g−1, as well as outstanding volumetric specific capacitance of 868 F cm−3 (at 5 mV s−1), and promising energy density of 118 W h kg−1 at 0.5 A g−1.

1. "Electric-field-driven Mott metal-insulator transition in correlated thin films: An inhomogeneous dynamical mean-field theory approach"
P. Bakalov, D. Nasr Esfahani, L. Covaci, F. M. Peeters, J. Tempere, and J.-P. Locquet
Phys. Rev. B 93, 165112
Abstract: Simulations are carried out based on the dynamical mean-field theory (DMFT) in order to investigate the properties of correlated thin films for various values of the chemical potential, temperature, interaction strength, and applied transverse electric field. Application of a sufficiently strong field to a thin film at half filling leads to the appearance of conducting regions near the surfaces of the film, whereas in doped slabs the application of a field leads to a conductivity enhancement on one side of the film and a gradual transition to the insulating state on the opposite side. In addition to the inhomogeneous DMFT, a local density approximation (LDA) is considered in which the particle density n, quasiparticle residue Z, and spectral weight at the Fermi level A(ω = 0) of each layer are approximated by a homogeneous bulk environment. A systematic comparison between the two approaches reveals that the less expensive LDA results are in good agreement with the DMFT approach, except close to the metal-to-insulator transition points and in the layers immediately at the film surfaces. LDA values for n are overall more reliable than those for Z and A(ω = 0). The hysteretic behavior (memory effect) characteristic of the bulk doping driven Mott transition persists in the slab.

2015:
1. H. Rostami, A.G. Moghaddam and R. Asgari
Spin relaxation and Kondo effect in monolayers of transition metal dichalcogenides


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