V. V. Shunaev

Phenomenon of current occurrence during the motion of a C60 fullerene on substrate-supported graphene

This paper studies the patterns of behavior of the fullerene C60 on graphene supported by an SiO2 substrate, taking into account the substrate topology and features of the electronic interaction between graphene and fullerene. It is found that the motion of the C60 molecule acquires a finite character when the substrate has a certain determined degree of curvature. We establish that such a character of motion occurs at a corrugation wavelength of 3.4 nm and wave-depth of 1.6 nm. The motion of the fullerene becomes more precise with deviations of tenths of an angstrom under an external electric field, which allows the motion of the fullerene to be manipulated along the trough. During the investigation of the electronic interaction between graphene and the C60 molecule it was found for the first time that the motion of the fullerene on graphene creates a small current that constantly changes due to the changing distance between the two objects. This physical phenomenon can be used as a physical principle for designing nanodevices.

Moving of fullerene between potential wells in the external icosahedral shell.

The results of the theoretical investigation of the behavior of fullerenes C20 and C60 inside the icosahedral external shell on example of carbon nanoclusters, C20@С240 and C60@С540, are presented in this article. The multiwell potential of interaction between fullerenes in investigated nanoclusters is calculated to reveal the regularities of moving for internal fullerene in the field of holding potential of the external shell. The possible variants of fullerenes C20 and C60 moving between the potential wells are predicted on base of topology data of the fullerenes relative positioning in nanoparticle and analysis of relief of the energy surface of interaction between fullerenes. The formulated prediction is confirmed by the data of the numerical experiment. The investigation of two‐shell fullerenes allows to conclude that the light fullerene С20 will probably jump between the potential wells already at small temperatures (139–400 K) if the external shell is slightly bigger.

Development of the terahertz emitter model based on nanopeapod in terms of biomedical applications

Model of terahertz radiation sources was developed in this work. This model based on the nanopeapod: carbon nanotube (10, 10) with incapsulated chains of the fullerene C60. Simulation of the nanoemitter action was carried out by means of the molecular-mechanical model. The length of the considered nanotube is equals to 10.3 nm, and radius of this tube is equals to 1.35 nm. It was found that to generate the radiation in terahertz range it is necessary to apply the external field with strength of 1⋅106 V / cm to our system. The moving fullerene C60 has a charge of +3е, and the nanotube has a charge of -3е. It was established that the field emission process from the surface of the nanotube is not observed in this case. The submitter model of nanoemitter works with a frequency 0.36 THz at a field strength of 1⋅106 V / cm.

Electronic properties of Bilayer Fullerene onions

ABSTRACT HOMO–LUMO gaps of the bilayer fullerene onions were investigated. For this purpose, HOMO and LUMO energies for the isolated fullerenes were calculated using the parameterization of the tight binding method with the Harrison–Goodwin modification. Then, by the consideration of the van der Waals interaction, the thermodynamical stability of possible combinations of the fullerene molecules was verified and the unstable forms were excluded. Next, the difference of the Fermi levels of the outer and inner shells was calculated by the consideration of the hybridization of the orbitals by using the geometric parameters. The results were obtained by the combination of these calculations.

New graphene technologies of manipulation with molecular objects

A new technique of manipulating with fullerene C60 over graphene on a SiO2 substrate is proposed. To stop the chaotic motion of molecules and limit its range, it is suggested to use a corrugated substrate. The study has shown that, at the corrugation wavelength of 3.4 nm and depth of 1.6 nm, the fullerene motion becomes directed with a deviation within 0.5 nm. The fullerene motion becomes even more definite, with a deviation from a straight line within tenths of an angstrom by the action of an external electric field, which allows one to manipulate the motion along the bottom of a groove. The method proposed can serve as a basis for the controlled assembly of molecules to supermolecular structures of given configurations, which can be applied in bio- and nanoelectronics.

Theoretical study of the behavior of cryptand with different ion metal inside carbon nanotube

In this paper we study the behavior of [2.2.2] cryptand with various metal ions (Na, K, Eu, Fe) inside the armchair carbon nanotube. To identify regularities of behavior for cryptand inside a nanotube we carried out a series of numerical experiments in molecular dynamics using Amber force field at different temperatures and under influence of external electric field. We have established the dependence of the oscillation frequency of the cryptand inside a carbon nanotube. On the basis of the established effect of fluctuations for cryptand inside the nanotube is predicted that such complexes can be used as miniature radiating systems.

Manipulation of fullerene molecules on graphene

Due to the increasing demand for functionalization of graphene and its application as a functional element of real electronic and / or mechanical devices, as well as due to its unique adhesive and sensory abilities the actual problem is the use of graphene as a substrate on which the assembly of supramolecular structures. Elements of such structures can be different molecules driven by external factors, and can be easily transported on graphene. These molecules primarily include miniature spheroidal fullerenes easy to navigate on the surface of graphene, in particular icosahedral C60. The aim of this work was to find an effective method of manipulation of fullerene C60 on graphene. As such method we proposed to introduce in graphene sheet structural defect of the atomic framework namely defect Stone-Wales (pentagon-heptagon pairs). Another structural defect studied in this paper is adsorbed on the Stone-Wales defect hydrogen atom. Molecular dynamics and tight binding method were applied to calculate the location of the molecule C60 on graphene sheet and its movement. To identify the regulatities of behavior of fullerene on graphene sheet we carried out a series of numerical experiments at different temperatures. In this paper we calculated the energy profile of interaction between fullerene and graphene sheet. Obtained results showed that forming on the surface of the graphene sheet defects in a certain way, one can control the trajectory of molecules on graphene.

Partitioned carbon nanotubes as perspective nanomaterial for energy conversion

The results of the theoretical and experimental investigations of the emission properties of the partitioned carbon nanotubes are presented in this paper. We have calculated ionization potential and energy gap of the energy spectrum for stable carbon partitioned carbon nanotube (15,15) of the smallest diameter by means of the tight-binding method. Also we have developed the original synthesis technique of the partitioned carbon nanostructures. This synthesis technology provides the high efficiency of the partitioned carbon nanotubes growth. As a result of calculations it was established that the emission properties of the infinite partitioned carbon nanotubes at the increasing of the distance between the bridges are better in comparison to the emission properties of the hollow nanotubes.

Prediction of the behavior for fullerene C20 inside the icosahedral outer shell of C240

In this work, we study the behavioral regularity of fullerene C20 inside the icosahedral outer shell of fullerene C240. The feature of such two-shell fullerenes is that the internal fullerene will move at low temperatures in a certain way: between the potential wells. The aim of this work is to reveal the regularities for motion of small fullerenes in nanospace of large external icosahedral fullerene, including the identification of the spatial configuration for a multi-well potential of interaction between two objects and prediction of possible movement for the internal object between potential wells. For the fullerene C20 it was found twenty potential wells in the direction of the fifth order axes for icosahedron of fullerene C240 cage, thirty towards in the direction of the middle of the ribs and twenty potential wells towards centers of the faces of the icosahedron. The prediction of possible moving for the internal object between potential wells and the regularities of this movement were made based on the relief analysis of the interaction energy surface of fullerenes. The numerical simulation of C20 motion in the field of C240 was carried out to test the prediction of movement. As results of the experiment, it was found that the fullerene C20 is easy to jump between the potential wells even at low temperatures up to 300K. Molecular dynamics simulations confirmed our conclusions about regularities of C20 movement between potential wells. Thus, one can conclude that the analysis of the topology of the energy surface of van der Waals interaction between the components of nanoparticles gives a true predictive picture of the regularities of the internal molecule behavior. Probably, the phenomenon of fullerene C20 movement in a cell of another fullerene can be used in modern technologies, such as determining a local temperature by increase of jumping velocity.

Unit coefficient of thermal conductivity of carbon nanotubes with positions of their use as a material for nano-emitters

In the process of field emission surface of carbon nanotubes is heated, that may lead to the rapid destruction of the emitter based on them. Therefore, the problems of heat reducing and the destruction of carbon nanotubes prevention are important. Experimental study of the thermal conductivity of isolated CNT is time consuming and expensive process, so it is better to use the numerical models to understand the process of heat transfer in carbon nanotubes. In this work the change of the nanotubes thermal conductivity was investigated with increasing length and diameter of the nanotubes and the number of defects Stone-Wales.