Cariglia M, Giambò R, Perali A
. Electronic Properties of Curved Few-Layers Graphene: A Geometrical Approach
. Condensed Matter [Internet]. 2018;3 (2, ARTICLE NUMBER = 1). Publisher's VersionAbstract
We show the presence of non-relativistic Lévy-Leblond fermions in flat three- and four-layers graphene with AB stacking, extending the results obtained in Cariglia et al. 2017 for bilayer graphene. When the layer is curved we obtain a set of equations for Galilean fermions that are a variation of those of Lévy-Leblond with a well defined combination of pseudospin, and that admit Lévy-Leblond spinors as solutions in an approriate limit. The local energy of such Galilean fermions is sensitive to the intrinsic curvature of the surface. We discuss the relationship between two-dimensional pseudospin, labelling layer degrees of freedom, and the different energy bands. For Lévy-Leblond fermions, an interpretation is given in terms of massless fermions in an effective 4D spacetime, and in this case the pseudospin is related to four dimensional chirality. A non-zero energy band gap between conduction and valence electronic bands is obtained for surfaces with positive curvature.
Araujo KAS, Cury LA, Matos MJS, Fernandes TFD, Cançado LG, Neves BRA
. Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system
. Beilstein Journal of Nanotechnology. 2018;9 :963-974.
de Brito ACF, Correa RS, Pinto AA, Matos MJS, Tenorio JC, Taylor JG, Cazati T
. Synthesis, crystal structure, photophysical properties and theoretical studies of a novel bis(phenylisoxazolyl) benzene derivative
. Journal of Molecular Structure [Internet]. 2018 :-. Publisher's VersionAbstract
Abstract Isoxazoles have well established biological activities but, have been underexplored as synthetic intermediates for applications in materials science. The aims of this work are to synthesis a novel isoxazole and analyze its structural and photophysical properties for application in electronic organic materials. The novel bis (phenylisoxazolyl) benzene compound was synthesized in four steps and characterized by NMR, high resolution mass spectrometry, differential thermal analysis, infrared spectroscopy, cyclic voltammetry, ultraviolet–visible spectroscopy, fluorescence spectroscopy, \DFT\ and \TDDFT\ calculations. The molecule presented optical absorption in the ultraviolet region (from 290 nm to 330 nm), with maximum absorption length centered at 306 nm. The molar extinction coefficients (ε), fluorescence emission spectra and quantum efficiencies in chloroform and dimethylformamide solution were determined. Cyclic voltammetry analysis was carried out for estimating the \HOMO\ energy level and these properties make it desirable material for photovoltaic device applications. Finally, the excited-state properties of present compound were calculated by time-dependent density functional theory (TDDFT).
Chacham H, Barboza APM, de Oliveira AB, de Oliveira CK, Batista RJC, Neves BRA
. Universal deformation pathways and flexural hardening of nanoscale 2D-material standing folds
. Nanotechnology [Internet]. 2018;29 (9) :095704. Publisher's VersionAbstract
In the present work, we use atomic force microscopy nanomanipulation of 2D-material standing folds to investigate their mechanical deformation. Using graphene, h-BN and talc nanoscale wrinkles as testbeds, universal force–strain pathways are clearly uncovered and well-accounted for by an analytical model. Such universality further enables the investigation of each fold bending stiffness κ as a function of its characteristic height h 0 . We observe a more than tenfold increase of κ as h 0 increases in the 10–100 nm range, with power-law behaviors of κ versus h 0 with exponents larger than unity for the three materials. This implies anomalous scaling of the mechanical responses of nano-objects made from these materials.
Dias RF, da Rocha Martins J, Chacham H, de Oliveira AB, Manhabosco TM, Batista RJC
. Nanoporous Graphene and H-BN from BCN Precursors: First-Principles Calculations
. The Journal of Physical Chemistry C [Internet]. 2018;122 (7) :3856-3864. Publisher's Version
Fernandes TFD, Gadelha A, Barboza A, Paniago R, Campos LC, Guimaraes P, Assis P, Almeida Neves BR
. Robust nanofabrication of monolayer MoS2 islands with strong photoluminescence enhancement via local anodic oxidation.
2D Materials [Internet]. 2018. Publisher's VersionAbstract
Abstract In this work, we demonstrate the nanofabrication of monolayer MoS2 islands using local anodic oxidation of few-layer and bulk MoS2 flakes. The nanofabricated islands present true monolayer Raman signal and photoluminescence intensity up to two orders of magnitude larger than that of a pristine monolayer. This technique is robust enough to result in monolayer islands without the need of
meticulously fine-tuning the oxidation process, thus providing a fast and reliable way of creating monolayer regions with enhanced optical properties and with controllable size, shape, and position.