Papers by Keyword: Fullerenes

Abstract: The behavior of С₅₆ fullerene when heated in a nitrogen atmosphere at a pressure of 10⁵ Pa was studied using computer thermodynamic modeling. The modeling consisted in a complete thermodynamic analysis of the system using the TERRA software package, which is one of the most developed and efficient ones that implements such thermodynamic calculations. Experiment temperature ranges are from 273 to 3373 К. Based on the calculated data, a graph of the carbon balance in the С₅₆-N₂ system was constructed, the ongoing physicochemical processes were described, divided into four classes: sublimation, dissociation in the gas phase, chemical reactions occurring in the gas phase, dissociation and chemical reaction in the gas phase. Temperature intervals of reactions are identified. The equilibrium constants of the reactions are calculated and described, as well as the coefficients of these constants are found using the least squares method. The temperature interval of thermal stability of the condensed C₅₆ fullerene and C₅₆ vapors is defined. This work is one of the series of works on the properties of nanoparticles, in the future it is planned to study the thermal properties of higher fullerenes. The data obtained can be used to determine the explosive and fire hazardous properties of fullerenes as a dispersed solid.

Abstract: Electrical conductance of Si(111)6×6-Tl and Si(111)β√3×√3-Bi surfaces has been monitored in the course of fullerenes deposition. It has been found that dependence of surface conductivity on the adsorbed C60 dose can be understood in terms of charge transfer induced by interaction of fullerene molecules and substrate which can be explained by the acceptor-like behavior of fullerenes. For the Si(111)6×6-Tl surface decreasing of conductance is connected with depletion of metallic bands of the Tl double layer. For the Si(111)β√3×√3-Bi surface the conductivity is almost unchanged with C60 dose, but due to the fact that C60 layer on this surface form close-packed hexagonal arrays in the layer-by-layer mode, it can be used as a template for alkali-induced ultra-thin fulleride formation.

Abstract: The physical and chemical principles of the preparation of carbon nanoparticles (fullerenes, carbon nanotubes) and their complexes, and the methods for introducing nanoparticles into metal, ceramic and polymer matrices are considered. The most important properties of some materials containing these cluster molecules are given. It is shown that the introduction of carbon nanoparticles into materials, even in small fractions (up to 1.0 wt. %), significantly in some cases, at times alters their structure, electrical and tribological properties.

Abstract: Schemes of structural classification of carbon materials which are based on the types of chemical bonds formed in materials and the number of nearest neighbors with which each atom forms covalent bonds have been proposed. The classification schemes cannot only describe the known phases, but also are the methodological basis for the prediction of new phases and nanostructures. New phases can be obtained by linking, superpositioning or cutting of precursor structures.

Abstract: The influence of fullerenes on anti-friction, anti-wear, and scoring-resistance properties of lubricants is studied.

Abstract: Nanotechnology decides the ability of human manipulation of the atoms and molecules, the goal is to master the ability to create new material and design to create the desired application products, and nanomaterials is the basis of the integration of a variety of nanotechnology. The connotation and development prospect of nanotechnology are introduced. The present status and the research emphasis in every stage of the nanomaterials are pointed out and nanomaterials are classified according to the different way. The characteristics of all kinds of nanomaterials and applications in all fields are analyzed.Key words: Nanomaterials; Nanotechnology; Fullerenes; Graphene; Carbon nanotubes

Abstract: Recently, Graphene oxide (GO), carbon nanotubes (CNTs) and fullerenes (C₆₀) have attracted enormous interests because of their extraordinary properties, and they can improve various kinds of properties of polymeric materials. The latest achievements on investigating applications and properties including mechanical properties, thermal properties, crystallization behavior and bioactivity of poly (ε-caprolactone). (PCL)/GO, PCL/CNTs and PCL/ C₆₀ nanocomposites obtained in the last five years were summarized in this paper. The relationships between the properties of nanocomposites and the loading, dispersion chemical modification of GO, CNTs and C₆₀ were also discussed.

Abstract: This paper discusses some theoretical aspects of design of ultralight metallic materials using analytical and heuristic arguments. Potential application of syntactic foams to obtain metal-matrix composites lighter than air is also analyzed. Carbon allotropes (fullerenes, colossal carbon tubes) and some non-carbon materials are considered as components of ultralight metal-matrix composites. Calculations for the size of fullerenes, number of atoms in their structure, and coating thickness required to produce ultralight composites are presented. It is concluded that 3D carbon molecules (fullerenes) and colossal carbon tubes are the most promising components to design ultralight metallic materials which can be lighter than air.

Abstract: In this paper, we have inspected the structural morphology of novel composite materials - transition metal (TM) (Ni, Ti) / fullerene (C60) thin films, prepared at room temperature (RT) or 500°C, and modified by ion-irradiation and/or thermal annealing. The hybrid films were synthesized by alternative or simultaneous deposition of the immiscible TM and C60 phases. As deposited (at RT) the hybrid systems were thermodynamically unstable and the internal stress induced lengthy phase separation. Co-deposition at 500°C resulted in the formation of a large-scale pattern structure. By high temperature annealing of the multilayer’s a new morphology could be synthesized. In addition, high-fluence ion-irradiation induces C60 fragmentation that has a strong impact on the final shaping of the resulted morphology.

Abstract: Fabrication and characterization of fullerene (C₆₀) / dibenzotetrathiafulvalene (DBTTF) solar cells were carried out. Photovoltaic and optical properties of the organic solar cells were investigated. Transmission electron microscopy, x-ray and electron diffraction confirmed that the bulk heterojunction thin films had microstructure of C₆₀ crystal phase in DBTTF amorphous phase. The photovoltaic performance of the bulk heterojunction solar cell would be originated in the extent of electron diffusion across interface around the microstructure. Photovoltaic mechanism was discussed on the basis of experimental results.