T. L. Makarova

Bio: T. L. Makarova is an academic researcher from Russian Academy of Sciences. The author has contributed to research in topics: Fullerene & Silicon. The author has an hindex of 6, co-authored 18 publications receiving 289 citations. Previous affiliations of T. L. Makarova include Umeå University & Lappeenranta University of Technology.

Magnetic properties of carbon structures

Abstract: Magnetic properties of the main allotropic modifications of carbon (diamond, graphite, nanographite, nanotubes, and fullerenes) are described. Properties of nanocarbon are considered from the standpoint of the interrelation between structural imperfection and magnetic ordering. Experimental data on high-temperature ferromagnetism in carbon structures and some theoretical models of magnetic carbon are reported.

Electrical and optical properties of pristine and polymerized fullerenes

Abstract: The band structure, optical, photoelectric and transport properties of solids composed of fullerene molecules linked by van der Waals bonds or forming polymers are considered. Particular attention is concentrated on different polymerization mechanisms.

Light-induced transformation of C 60 films in the presence and absence of oxygen

Abstract: The composition and structure of C60 fullerite films prepared by discrete evaporation in quasiclosed volume, as well as their changes induced by laser irradiation, have been studied by ellipsometry and Rutherford backscattering. The starting film has a 150-A thick stable top layer and a carbon to oxygen ratio of 10:1. Exposure of a film both to vacuum and to air results in formation of an insoluble photo-transformed phase, but in the second case the change in the refractive index implies the appearance of compounds with oxygen. The material does not undergo complete polymerization, although all structural changes cease at an irradiation dose of 104 photons per fullerene molecule. Treatment of the polymerized phase with organic solvents produces a porous structure, with the voids totaling 48% in the case of exposure in vacuum, and 30% when exposed in air.

Doping of fullerite with molecular oxygen at low temperature and pressure

Abstract: Two methods are described for doping of fullerite C60 with molecular oxygen at a pressure of ∼104 Pa and at temperature 20–30 °C. It was found by mass spectrometry using oxygen 18O as dopant that a portion of molecular oxygen absorbed by the pre-decontaminated fullerite (first method) is removed as CO and CO2 at the heating temperature ≤200 °C. Doping during fullerite precipitation from the liquid phase (second method) makes it possible to prepare samples with the oxygen content ≥1.2 at.%. The fullerite doped with oxygen to this level is diamagnetic. The paramagnetic properties of an O2 molecule disappear when O2 is incorporated into the fullerene lattice. This is interpreted on the basis of quantum chemical calculations as a sequence of equilibrium formation of the adduct C60O2. Calculations showed that the subsequent chemical transformation of C60O2 resulting in the O-O bond cleavage is energetically favorable, enabling prerequisites for the formation of products of incomplete (CO) and deep (CO2) oxidation of fullerene under mild conditions.

Composition and porosity of multicomponent structures: porous silicon as a three-component system

Abstract: It is shown for the system porous silicon (por-Si)-silicon (Si) that effective nondestructive investigation of the interfacial morphology of layered semiconductor systems and of the composition of multicomponent layers by ellipsometry and Rutherford backscattering is possible. Both methods were used to determine the percentage composition of the main components of por-Si: crystal silicon, silicon oxide, and voids (porosity). It is shown that por-Si obtained by pulse-anodization contains a substantial quantity of silicon oxide. It is also shown that spectral ellipsometry can be used to determine the specific ratio of individual layers or components of multilayer and multicomponent systems (provided that the spectral dispersion of the optical constants of these components is known).

Broad family of carbon nanoallotropes: classification, chemistry, and applications of fullerenes, carbon dots, nanotubes, graphene, nanodiamonds, and combined superstructures.

Abstract: and Applications of Fullerenes, Carbon Dots, Nanotubes, Graphene, Nanodiamonds, and Combined Superstructures Vasilios Georgakilas,† Jason A. Perman,‡ Jiri Tucek,‡ and Radek Zboril*,‡ †Material Science Department, University of Patras, 26504 Rio Patras, Greece ‡Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University in Olomouc, 17 listopadu 1192/12, 771 46 Olomouc, Czech Republic

Hierarchical Nanocomposites Derived from Nanocarbons and Layered Double Hydroxides - Properties, Synthesis, and Applications

Abstract: The combination of one-dimensional and two-dimensional building blocks leads to the formation of hierarchical composites that can take full advantages of each kind of material, which is an effective way for the preparation of multifunctional materials with extraordinary properties. Among various building blocks, nanocarbons (e.g., carbon nanotubes and graphene) and layered double hydroxides (LDHs) are two of the most powerful materials that have been widely used in human life. This Feature Article presents a state-of-the-art review of hierarchical nanocomposites derived from nanocarbons and LDHs. The properties of nanocarbons, LDHs, as well as the combined nanocomposites, are described first. Then, efficient and effective fabrication methods for the hierarchical nanocomposites, including the reassembly of nanocarbons and LDHs, formation of LDHs on nanocarbons, and formation of nanocarbons on LDHs, are presented. The as-obtained nanocomposites derived form nanocarbons and LDHs exhibited excellent performance as multifunctional materials for their promising applications in energy storage, nanocomposites, catalysis, environmental protection, and drug delivery. The fabrication of LDH/carbon nanocomposites provides a novel method for the development of novel multifunctional nanocomposites based on the existing nanomaterials. However, knowledge of their assembly mechanism, robust and precise route for LDH/nanocarbon hybrid with well designed structure, and the relationship between structure, properties, and applications are still inadequate. A multidisciplinary approach from the scope of materials, physics, chemistry, engineering, and other application areas, is highly required for the development of this advanced functional composite materials.

On the chemical nature of graphene edges: origin of stability and potential for magnetism in carbon materials.

Abstract: Heretofore disconnected experimental observations are combined with a theoretical study to develop a model of the chemical composition of the edges of graphene sheets in both flat and curved sp2-hybridized carbon materials. It is proposed that under ambient conditions a significant fraction of the oxygen-free edge sites are neither H-terminated nor unadulterated σ free radicals, as universally assumed. The zigzag sites are carbene-like, with the triplet ground state being most common. The armchair sites are carbyne-like, with the singlet ground state being most common. This proposal is not only consistent with the key electronic properties and surface (re)activity behavior of carbons, but it can also explain the recently documented and heretofore puzzling ferromagnetic properties of some impurity-free carbon materials.

Graphene NanoFlakes with Large Spin

Abstract: We investigate, using benzenoid graph theory and first-principles calculations, the magnetic properties of arbitrarily shaped finite graphene fragments to which we refer as graphene nanoflakes (GNFs). We demonstrate that the spin of a GNF depends on its shape due to topological frustration of the π-bonds. For example, a zigzag-edged triangular GNF has a nonzero net spin, resembling an artificial ferrimagnetic atom, with the spin value scaling with its linear size. In general, the principle of topological frustration can be used to introduce large net spin and interesting spin distributions in graphene. These results suggest an avenue to nanoscale spintronics through the sculpting of graphene fragments.