Interlayer Incorporation of A-Elements into MXenes Via Selective Etching of A' from MA'A″C MAX Phases.

MXenes are a large family of two-dimensional materials with a general formula MXT, where M is a transition metal, X = C and/or N, and T represents surface functional groups. MXenes are synthesized by etching A-elements from layered MAX phases with a composition of MAX. As over 20 different chemical elements were shown to form A-layers in various MAX phases, we propose that they can provide an abundant source of very diverse MXene-based materials.

High-yield fabrication of electromechanical devices based on suspended TiCT MXene monolayers.

MXenes, two-dimensional transition metal carbides, nitrides, and carbonitrides, are known for their exceptional electronic and mechanical properties. Yet, the experimental efforts toward the realization of MXene-based nanoelectromechanical systems (NEMS) combining electrical and mechanical functionalities of MXenes at the nanoscale remain very limited. Here, we demonstrate a high-yield fabrication of the electromechanical devices based on individual suspended monolayer MXene flakes.

Negative photoresponse in TiCT MXene monolayers.

Two-dimensional transition metal carbides, nitrides, and carbonitrides, collectively known as MXenes, are finding numerous applications in many different areas, including optoelectronics and photonics, but there is limited information about their intrinsic photoresponse. In this study, we investigated the visible and near-infrared range photoresponse of TiCT , the most popular MXene material to date. The electrical measurements were performed on devices based on individual monolayer TiCT MXene flakes, which were characterized by a variety of microscopic and spectroscopic methods.

Nanotoxicity of ZrS Probed in a Bioluminescence Test on Bacteria: The Effect of Evolving HS.

Materials from a large family of transition metal trichalcogenides (TMTCs) attract considerable attention because of their potential applications in electronics, optoelectronics and energy storage, but information on their toxicity is lacking. In this study, we investigated the toxicity of ZrS, a prominent TMTC material, toward photoluminescent bacteria in a bioluminescence test. We found that freshly prepared ZrS suspensions in physiological saline solution with concentrations as high as 1 g/L did not exhibit any toxic effects on the bacteria.

Highly Selective Gas Sensors Based on Graphene Nanoribbons Grown by Chemical Vapor Deposition.

Despite the recent advances in bottom-up synthesis of different kinds of atomically precise graphene nanoribbons (GNRs) with very diverse physical properties, the translation of these GNRs into electronic devices remains challenging. Among other factors, the electronic characterization of GNRs is hampered by their complex synthesis that often requires custom-made organic precursors and the need for their transfer to dielectric substrates compatible with the conventional device fabrication procedures. In this paper, we demonstrate that uniform electrically conductive GNR films can be grown on arbitrary high-temperature-resistant substrates, such as metals, Si/SiO, or silica glasses, by a simple chemical vapor deposition (CVD) approach based on thermal decomposition of commercially available perylenetetracarboxylic dianhydride molecules.

Medium-Dependent Antibacterial Properties and Bacterial Filtration Ability of Reduced Graphene Oxide.

Toxicity of reduced graphene oxide (rGO) has been a topic of multiple studies and was shown to depend on a variety of characteristics of rGO and biological objects of interest. In this paper, we demonstrate that when studying the same dispersions of rGO and fluorescent () bacteria, the outcome of nanotoxicity experiments also depends on the type of culture medium. We show that rGO inhibits the growth of bacteria in a nutrition medium but shows little effect on the behavior of in a physiological saline solution.

Nanodomain Engineering for Programmable Ferroelectric Devices.

We introduce a concept of programmable ferroelectric devices composed of two-dimensional (2D) and ferroelectric (FE) materials. It enables precise modulation of the in-plane conductivity of a 2D channel material through nanoengineering FE domains with out-of-plane polarization. The functionality of these new devices has been demonstrated using field-effect transistors (FETs) fabricated with monolayer molybdenum disulfide (MoS) channels on the Pb(Zr,Ti)O substrates.

Quasi-1D TiS Nanoribbons: Mechanical Exfoliation and Thickness-Dependent Raman Spectroscopy.

Quasi-one-dimensional (quasi-1D) materials enjoy growing interest due to their unusual physical properties and promise for miniature electronic devices. However, the mechanical exfoliation of quasi-1D materials into thin flakes and nanoribbons received considerably less attention from researchers than the exfoliation of conventional layered crystals. In this study, we investigated the micromechanical exfoliation of representative quasi-1D crystals, TiS whiskers, and demonstrate that they typically split into narrow nanoribbons with very smooth, straight edges and clear signatures of 1D TiS chains.

Chemical vapor deposition and characterization of two-dimensional molybdenum dioxide (MoO) nanoplatelets.

We report on the chemical vapor deposition synthesis of MoO nanoplatelets by sublimation of MoO and its reduction in a hydrogen atmosphere at 750 °C. When grown on Si/SiO substrates, the platelets primarily assume a rhomboidal shape and have thicknesses ranging from several to tens of nm. The morphology of MoO crystals was found to depend on the chemical nature of substrates.