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We present a design of a nanoscale inertial measurement unit or a data archive using a graphene-nanoflake (GNF) sandwiched between crossed graphene-nanoribbon (GNR) junctions. When an external force applied is below the retracting force, the inertial force exerted on the movable GNF can telescope it. Then, the self-restoring force increases as the attractive van der Waals force between the GNF and the GNRs, which enables the GNF to automatically and fully retract back into the sandwich position immediately after the externally applied force is released. When the external force exceeds the retracting force, the GNF escapes from the crossed GNR junctions, which enables the device to be used as non-volatile memory. The heterostructure of GNR/h-BN/GNR can be considered as an advanced structure in the proposed scheme.

Cadmium telluride (CdTe) nanoparticles (NPs) are known for their unique physical and chemical properties. NP synthesis via a size-controlled procedure has become an intriguing research topic because NPs exhibit novel optical and physical properties depending on their size. Their sizes and properties can vary depending on the types and concentrations of stabilizers, which are bound to the surface of the NPs and protect the NPs from aggregation. In this study, we synthesized CdTe NPs stabilized by thioglycolic acid (TGA), 1-thioglycerol (TGC), and L-cysteine (L-C). The ratio of stabilizer to Cd2+ was 1:2.4. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and photoluminescence (PL) were employed for characterization of the NPs. The average sizes of the synthesized NPs were 4.2, 4.1, and 3.7 nm for TGA, TGC, and L-C, respectively. The maximum fluorescent emission peaks of the three NP solutions were at 554.9, 551.6, and 538.3 nm for TGA, TGC, and L-C, respectively. The produced particles were crystalline in structure with a face-centered cubic (fcc) system.

Superlubric motions of graphene nanoflakes (GNFs) on graphene have opened up more applications of graphene for micromachines and nanomachines. Here, we investigate the dynamic behavior of a GNF shuttle on a graphene nanoribbon (GNR) with carbon nanotube (CNT) blocks via molecular dynamics simulations. The GNF moves on a GNR superlubrically, and the CNTs as building blocks induce bistable potential wells so that the GNF is stabilized. MD simulation results indicate that when a GNF shuttle approaches the CNTs, a potential well is created by an increase in the attractive van der Waals energy between the GNF and CNTs, and bistability at the local energy minima positions can be achieved near the CNTs. In order for the GNF shuttle to escape the local energy minima positions, a high external force must be applied to overcome the potential energy barrier. However, after the GNF shuttle escapes from one of the bistable positions, only a low external force is required to stabilize the GNF shuttle. This work explicitly demonstrates that a GNF-GNR/CNT system could be applied to alternative nonvolatile memory and high-speed mass storage by using GNR-CNT arrays.

Partially side-opened carbon nanopeapods show great potential for various applications. Here, we investigated the schematics and energetics of a nonvolatile nanomemory element, based on a C60 fullerene encapsulated in a partially opened carbon nanopeapod, using empirical interatomic interaction potential functions. Bistability of the van der Waals potential energy is achieved from the positional change of the encapsulated C60 fullerene, and the encapsulated C60 fullerene can shuttle between bistable positions, under alternatively applied force fields. Since the C60 fullerene can retain its position without recharging, the proposed system can operate as a nonvolatile memory device. These results can be useful for the understanding of new molecular machines.

Thiol-capped cadmium telluride (CdTe) nanoparticles (NPs) self-assembled into nanowires (NWs) under dark conditions, and the evolutionary process was investigated. Thiolglycolic acid (TGA) was selected as one of the stabilizers and a TGA-to-Cd ion ratio of 1.3 rather than the traditional 2.4 ratio was used. The reduced amount of the stabilizer and the oxidation of tellurium ions on CdTe NP surface under dark conditions resulted in reorganization from individual NPs into NWs consisting of multi-layers of individual NPs. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were performed to characterize the synthesized nanostructures. The NWs produced were straight and long, with lengths ranging from 500 nm to 10 μm. Photoluminescence (PL) showed that the nanostructure wavelengths were slightly blue-shifted from 546 to 539 nm. Both control of the amount of stabilizer and oxidation of Te ions acted as driving forces to form NWs. Thus, small modifications in synthesis yielded a major difference in the final nanomaterial structure. The suggested synthetic procedure provides a viable pathway for the fabrication of nanomaterials.

We have investigated the motion of a C60 molecule absorbed on sinusoidal graphene nanoflake (GNF) via molecular dynamics simulations. Since C60 deposited on sinusoidal GNF is favorable on energetic grounds, the C60 molecule moved toward one of the valleys of sinusoidal GNF without energy barrier. So no sooner the C60 molecule was deposited on the sinusoidal GNF, then the C60 molecule immediately began to move toward the valley of the sinusoidal GNF Since the position of the C60 molecule can be changed by externally applied force fields and has a binding energy of 0.754 eV in the valley of sinusoidal GNF, the sinusoidal C60/GNF can be applied to a switchable nonvolatile memory device. This work provides the probability of alternative 'bucky shuttle' memory based on the sinusoidal C60/GNF hybrid nanostructure.

This study examined the thermodynamic stability and guest gas inclusion of tetra-iso-amyl ammonium bromide (TiAAB) semiclathrates with CO2, N2, or CO2 (20%) + N2 (80%), with a primary focus on semiclathrate phase equilibria and Raman spectra. The three-phase (H-LW-V) equilibria of TiAAB semiclathrates with CO2, N2, or CO2 (20%) + N2 (80%) were measured at a stoichiometric concentration (TiAAB 3.7 mol%) using both a conventional isochoric method and a stepwise differential scanning calorimeter (DSC) method. The phase equilibria demonstrated that TiAAB (3.7 mol%) semiclathrates with CO2, N2, or CO2 (20%) + N2 (80%) were significantly stabilized compared with the corresponding CO2, N2, or CO2 (20%) + N2 (80%) gas hydrates. The enclathration of CO2 and N2 molecules in the cages of TiAAB semiclathrates was clearly confirmed via Raman spectroscopy. The experimental results indicate that TiAAB semiclathrates can incorporate CO2 and N2 into the cage lattices at elevated temperatures and lowered pressures and are potential materials for CO2 capture.

Cadmium telluride (CdTe) nanowires were successfully synthesized from individual nanoparticles via self-assembly, and the evolutionary process was investigated. The oxidation of tellurium ions in CdTe nanoparticles under dark conditions led to the assembly of straight nanowires made of several layers of individual nanoparticles. Transmission electron microscopy and scanning electron microscopy were performed to characterize the synthesized nanostructures. The length of the NWs assembled from CdTe NPs ranged from 0.5 to 30 μm. Unlike generally prepared NWs, these NWs were made from individual NPs layered on top of each other. Remarkably, the assembly of individual NPs formed bundles during the intermediate steps before they unraveled into individual NWs. Both control of the amount of stabilizer and oxidation of Te ions acted as driving forces to form NWs. Thus, small modifications in synthesis yielded a major difference in the final nanomaterial structure. The suggested synthetic procedure provides a viable pathway for the fabrication of nanomaterials.

A tunable graphene-resonator was investigated using classical molecular dynamics modeling and simulations. The fundamental resonance frequency variation of the graphene resonator was found to be very closely related to the average tension acting on both its edges. The initial stain-induced tension could be adjusted by using the mismatch between the negative thermal expansion coefficient of the graphene and the positive thermal expansion coefficient of the substrate, and the deflection-induced tension could be controlled by an electrostatic capacitive force due to the gate voltage. For very small initial axial-strains, the tunable range reached above several hundred gigahertz. As the initial axial-strain on the graphene-resonator increased, both the tunability and the tunable range decreased. The fundamental resonance frequency as a function of the calculated gate voltage was in good agreement with previous experiments. Considering the variables that affect the tension variation, this graphene-resonator is suitable for use as an ultra-sensitive accelerometer, thermo-sensor or weight scale, as well as many other types of sensor.

A tunable graphene-nanoribbon (GNR)-resonator was investigated via classical molecular dynamics simulations. Resonance frequencies increased with increasing externally applied gate-force and axial-strain, and could be tuned above several hundred GHz. Tunable resonance frequencies achieved from the gate force were higher than those achieved from the axial-strain. The operating frequencies of GNR-resonators without axial-strain or with small axial-strains were most widely tuned by the gate, and almost linearly increased with increasing mean deflection. As the axial strain increased, the tunable ranges of the GNR-resonators were exponentially decreased, although the operating frequencies increased. GNR-resonators without axial-strain could be applied to wide-range-tuners, whereas GNR-resonators with high axial-strain could be applied to high-frequency-fine-tuners.

Molecular dynamics methods are used to model the vibrational behavior of a suspended graphene-resonator that absorbs a finite mass at constant temperature. The effective molecular dynamics simulations easily estimate the fundamental frequency shifts of the suspended graphene with attached mass. The resonance frequency of the graphene-resonator can be functionalized by both the attached mass and the applied force. The results obtained from the molecular dynamics simulations were in good agreement with those of previous related experimental and theoretical works. For this graphene-based scaled nanobalance, the possible frequency-shift ranges increased with increasing applied force and with decreasing attached mass, they then reached 75–80% of the fundamental resonance frequency of a bare graphene-resonator. The mass sensitivity of the graphene-resonator reached ∼10 −24 g and a logarithmically linear relationship was found in the frequency-vs-mass curves for attached masses of 10 −21 –10 −19 g.

Superlubricity in nanoscale graphene structures has been of interest for developing graphene-based nanoelectromechanical systems, as well as for the study of basic mechanical properties. Here, we investigated the translational and rotational motions of a square graphene nanoflake with retracting motions by performing classical molecular dynamics simulations. Our results show that the kinetic energy of the translational motion was exchanged into the kinetic energy of the rotational motion. Thus, square graphene nanoflake oscillators have very low quality factors in translational motions. We discuss that square graphene nanoflakes have great potential to be a core component in nanoelectromechanical systems by detecting their motions with ultrahigh sensitivity to facilitate the development of sensor, memory, and quantum computing.

We investigated the tension and strain energy variations as a function of the axial strain in static conditions in graphene nanoribbon resonators and the resonance frequency change with tensile loading in dynamic conditions via classical molecular dynamics simulations. This theoretical study presents the application of graphene nanoribbon resonators tuned by tensile loading as ultrahigh frequency devices. The non-linear mechanical properties of the resonators were found, and for small axial strains, the mechanical properties of the graphene nanoribbon, such as strain-energy vs . axial-strain and frequency vs . strain or tension, were estimated by the classical continuum theory. The resonance frequencies increased with increasing axial strain, and such a relation could be regressed by a linearly increasing line on a log – log scale. The increasing resonance frequency due to increasing tension could be regressed by a square root function.

CdTe nanorribons were successfully synthesized from individual nanoparticle. Slow oxidation of Te(2-) in CdTe nanoparticles resulted in the assembly of ribbons consisting of several layers of individual nanocrystals. The light-controlled self-assembly of CdTe nanoparticles led to twisted ribbons with variable pitch. Transmission electron microscopy, scanning electron microscopy, and atomic force microscopy were performed to characterize the synthesized nanostructures. The suggested synthetic procedure provides a viable pathway for the fabrication of nanomaterials with helical conformations.

We investigate the nano mass transfer in an ultrahigh frequency carbon-nanotube-resonator encapsulating a nanocluster via classical molecular dynamics simulations. When the carbon-nanotube-resonator vibrated, the encapsulated copper nanocluster more rapidly approached the end of the cantilevered carbon-nanotube-resonator. Such phenomena were due to the migration of the encapsulated copper nanocluster due to the centrifugal force induced by the vibrating nanotube resonator. So the resonance frequency change could be time-dependently found. For the movable copper nanocluster in carbon nanotube resonator, the vibrational spectra when the copper nanocluster inside the carbon nanotube resonator rapidly settled at the capped edge were different from those obtained when the copper nanocluster continuously oscillated inside the carbon nanotube resonator. Such results showed that the frequency of the carbon-nanotube-resonator encapsulating the movable copper nanocluster could be adjusted by controlling the mean position of the oscillating copper nanocluster. The movable nanocluster inside a carbon-nanotube can be applied to a nanotube-based data storage media by sensing the position of the nanocluster.

We investigated the cantilevered carbon-nanotube-resonator including electromigratively movable nanoparticle via classical molecular dynamics simulations and continuum model. The change of the effective mass value, which was closely correlated with the position change of the encapsulated nanoparticle, could be regressed by a power function, the resonance frequency of the carbon-nanotube-resonator could be tuned by controlling the nanoparticle’s position, and the possible frequency-shift-ranges then reached 18–85%. The suggested device could be served as a data-storage-media for electromechanical nonvolatile-memory as well as a frequency-tuner.

We investigated a linear nanomotor based on the telescoping carbon nanotube motion induced by electromigration of an encapsulated nanoparticle. The nanoparticle motion induced by the electric current makes the inner nanotube linearly telescope or retreat. Theoretical results using a kinetic Monte Carlo method were in good agreement with previous experiments. The telescoping speed of the linear nanomotor exponentially decreased with increasing mass of the inner nanotube.

Metal nanoparticles were successfully synthesized from the self-regulated reduction of hydroxylated ionic liquids in aqueous phase without additives. A new water-phase synthesis of gold and palladium nanoparticles using N-(2-hydroxyethyl)-N-methylmorpholinium tetrafluoroborate is described. Transmission electron microscopy was performed to characterize the metal nanoparticles. The average sizes of the gold and palladium nanoparticles were 4.3 nm and 3.2 nm, respectively. Hydroxylated ionic liquids served as both reductants and protective agents, significantly simplifying the preparation of nanoparticles. The produced particles were highly crystalline in structure with a face-centered cubic (fcc) lattice. Finally, we showed preliminary results that suggest different hydroxylated ionic liquids can also be used to prepare various metal nanoparticles.

We propose an angular-velocimeter with a carbon nanotube resonator for sensing the angular velocity of a rotating body. When centrifugal force exerted by the rotation of the system causes an elongation of the carbon nanotube resonator due to the centrifugal force, the frequency spectra of centrifugal force is dependent on the angular velocity of the rotating plate, and feedback sensing is then achieved via operating frequency shift. Such a nanoelectromechanical device is investigated via molecular dynamics simulations and the classical continuum theory. The model of the classical continuum theory is in good agreement with the results obtained from the classical molecular dynamics simulations.

CdTe nanowires were synthesized from individual nanoparticles via self-assembly at a specific wavelength of light. The wavelength of 500 nm resulted in a self-assembly of nanoparticles into nanowires. Most of the produced nanowires were straight and long in shape and their length ranged from 300 nm to 20 µm. The oxidation of Te2- in CdTe nanoparticles under the visible light resulted in the assembly of nanowires consisting of several layers of individual nanoparticles. Transmission electron microscopy and scanning electron microscopy were performed to characterize the synthesized nanostructures. Energy-dispersive X-ray demonstrated the atomic percentage of nanowires. Photoluminescence showed that the wavelength of the nanostructures is slightly blue-shifted from 555 to 548 nm.

Cadmium telluride (CdTe) nanowires were successfully synthesized from individual nanoparticles and the evolutionary process was investigated. Slow oxidation of Te(2-) in CdTe nanoparticles resulted in the generation of ribbons consisting of several layers of individual nanocrystals. The length of nanowires ranged from 1 to 8 μm. The presence of unusual shapes of multiparticle assemblies, such as bouquet, dog-bone, and ribbon bunches was observed as intermediate stages. The images of nanoribbons were analysed based on transmission electron microscopy and scanning electron microscopy. The suggested synthetic procedure provides a viable pathway for the fabrication of nanomaterials with helical conformations.

One-phase synthesis of gold and platinum nanoparticles using new thiol-functionalized ionic liquids (TFILs) is described for the first time. TFILs as stabilizing agents for gold and platinum nanoparticles were designed to have thiol groups on either the cation or anion and symmetrical or unsymmetrical positions only in the cation. Transmission electron microscopy, electron diffraction, and NMR were used for the characterization of nanoparticles. The metal nanoparticles formed using TFILs are crystalline structures with face-centered cubic packing arrangements and have small sizes (the average diameters are 3.5, 3.1, and 2.0 nm for Au and 3.2, 2.2, and 2.0 nm for Pt, respectively) and uniform distributions (the standard deviations are 0.7, 0.5, and 0.1 nm for Au and 1.1, 0.2, and 0.1 for Pt, respectively). It is believed that the nanoparticle size and distribution depend on the number and position of thiol groups in the IL.

In this paper, we investigated the resonant frequencies of multi-walled carbon nanotube (MWCNT) resonators with short outertubes according to the classical molecular dynamics approach. The resonant frequencies of the MWCNT resonators with short outertubes were influenced in both the wall number and the length of the short outertubes. The resonance frequencies of MWCNTs with short outertubes could be modeled by Gaussian distribution functions. Both the bandwidth and the sensitivity increased with increasing the wall number of the outertubes. The maximum frequency increased with increasing the diameter and with increasing the wall number of the outertubes for MWCNTs. So the effects of increasing the wall number of the outertubes were very important factors for understanding the vibrational frequency changes of MWCNTs with short outertubes as well as the effect of increasing the lengths of the outertubes.

We have successfully synthesized ionic liquid (IL)-stabilized palladium (Pd) nanoparticles (NPs) by electrochemical reduction. The particle size was controlled by adjusting the current density. Transmission electron microscopic (TEM) images showed that the average diameters of the Pd NPs were 2.4, 3.2, and 3.5 nm, depending on the synthetic conditions. Particle size increased as the current density and the length of the alkyl chain in the cation decreased. X-ray diffraction of the resulting NPs indicated that the particles had a crystalline structure. Overall, the results show that NPs can be finely tuned according to the kinds of ILs employed, as well as by electrochemical reduction.

We conceptually investigated a carbon-nanotube-based tuner operated by the telescoping nanotube motion in a multi-walled carbon-nanotube induced by electromigration of an encapsulated nanoparticle. The telescoping lengths in the proposed carbon-nanotube-based tuner could be achieved from the electromigration phenomena of the nanoparticle embedded in the carbon nanotube. So the core part is the nanoparticle shuttle and a multi-walled carbon-nanotube with ultra-low interlayer friction. The tuning of this telescoping carbon-nanotube-based tuner is achieved from the electric current flow. The properties of operation were investigated via classical molecular dynamics simulations and then the parameters of the continuum model were then calibrated to fit the results of the molecular dynamics simulations. Since the effective boundary considered as the movable clamp affected the vibration of the telescoping nanotube, the calibrated Young's modulus of this work were lower than the those of the previous works. Presented tuners are controllable in a few nanometers, and their operations are robust and reliable.

The vibrational properties of various double-walled carbon nanotube resonators were investigated via a classical molecular dynamics approach. The fundamental frequencies of double-walled carbon nanotube resonators with short outer tubes were closely related to the intertube spacing and the chirality of the outer tubes. Even though the length of the outer tube was 1 nm, the vibration of the outer tube affected that of the inner tube. For nanotubes with similar intertube spacing, both maximum frequencies were similar. For their corresponding maximum frequencies, the lengths of the outer tubes of the zigzag nanotubes were slightly less than those of the armchair ones.

We investigated the characteristics of a capacitive nano-accelerometer based on a telescoping carbon nanotube by means of classical molecular dynamics simulations. The position of the telescoping nanotube was controlled by an externally applied force, and feedback sensing was based on the capacitance change. The capacitance variations, which were almost linearly proportional to the applied acceleration, were monitored within an error tolerance.