Na próxima semana, de 25 a 27 de outubro, acontecerá a V Semana de Física dos Materiais do programa de pós-graduação FIMAT. O principal objetivo da V SEFIMAT éreunir docentes, alunos de graduação e de pós-graduação em um único ambiente acadêmico visando a divulgação e o interesse em Física de Materiais. A semana contará com defesas de qualificação dos alunos do programa e uma palestra convidada do professor Mário Sérgio de Carvalho Mazzoni, do departamento de física da UFMG, com o título: “Abordagem teórica no estudo de nanoestruturas e o...
"THE KAVLI PRIZE IN NANOSCIENCE is shared between Gerd Binnig, Former Member of IBM Zurich Research Laboratory, Switzerland, Christoph Gerber, University of Basel, Switzerland, and Calvin Quate, Stanford University, USA. They receive the prize “for the invention and realization of atomic force microscopy, a breakthrough in measurement technology and nanosculpting that continues to have a transformative impact on nanoscience and technology”.
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).
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.
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.
Despite the advanced stage of diamond thin-film technology, with applications ranging from superconductivity to biosensing, the realization of a stable and atomically thick two-dimensional diamond material, named here as diamondene, is still forthcoming. Adding to the outstanding properties of its bulk and thin-film counterparts, diamondene is predicted to be a ferromagnetic semiconductor with spin polarized bands. Here, we provide spectroscopic evidence for the formation of diamondene by performing Raman spectroscopy of double-layer graphene under high pressure. The results are explained in terms of a breakdown in the Kohn anomaly associated with the finite size of the remaining graphene sites surrounded by the diamondene matrix. Ab initio calculations and molecular dynamics simulations are employed to clarify the mechanism of diamondene formation, which requires two or more layers of graphene subjected to high pressures in the presence of specific chemical groups such as hydroxyl groups or hydrogens.