Overcoming the global energy crisis due to vast economic expansion with the advent of human reliance on energy-consuming labor-saving devices necessitates the demand for next-generation technologies ...in the form of cleaner energy storage devices. The technology accelerates with the pace of developing energy storage devices to meet the requirements wherever an unanticipated burst of power is indeed needed in a very short time. Supercapacitors are predicted to be future power vehicles because they promise faster charging times and do not rely on rare elements such as lithium. At the same time, they are key nanoscale device elements for high-frequency noise filtering with the capability of storing and releasing energy by electrostatic interactions between the ions in the electrolyte and the charge accumulated at the active electrode during the charge/discharge process. There have been several developments to increase the functionality of electrodes or finding a new electrolyte for higher energy density, but this field is still open to witness the developments in reliable materials-based energy technologies. Nanoscale materials have emerged as promising candidates for the electrode choice, especially in 2D sheet and folded tubular network forms. Due to their unique hierarchical architecture, excellent electrical and mechanical properties, and high specific surface area, nanotubular networks have been widely investigated as efficient electrode materials in supercapacitors, while maintaining their inherent characteristics of high power and long cycling life. In this review, we briefly present the evolution, classification, functionality, and application of supercapacitors from the viewpoint of nanostructured materials to apprehend the mechanism and construction of advanced supercapacitors for next-generation storage devices.
Overcoming the global energy crisis due to vast economic expansion with the advent of human reliance on energy-consuming labor-saving devices necessitates the demand for next-generation technologies in the form of cleaner energy storage devices.
To the league of rapidly expanding 2D materials, borophene is a recent addition. Herein, a combination of ab initio density functional theory (DFT) and nonequilibrium Green’s function (NEGF) based ...methods is used to estimate the prospects of this promising elemental 2D material for gas sensing applications. We note that the binding of target gas molecules such as CO, NO, NO2, NH3, and CO2 is quite strong on the borophene surface. Interestingly, our computed binding energies are far stronger than several other reported 2D materials like graphene, MoS2, and phosphorene. Further rationalization of stronger binding is made with the help of charge transfer analysis. The sensitivity of the borophene for these gases is also interpreted in terms of computing the vibrational spectra of the adsorbed gases on top of borophene, which show dramatic shift from their gas phase reference values. The metallic nature of borophene enables us to devise a setup considering the same substrate as electrodes. From the computation of the transmission function of system (gas + borophene), appreciable changes in the transmission functions are noted compared to pristine borophene surface. The measurements of current–voltage (I–V) characteristics unambiguously demonstrate the presence and absence of gas molecules (acting as ON and OFF states), strengthening the plausibility of a borophene based gas sensing device. As we extol the extraordinary sensitivity of borophene, we assert that this elemental 2D material is likely to attract subsequent interest.
Dilithium benzenedipropiolate was prepared and investigated as a potential negative electrode material for secondary lithium-ion batteries. In addition to the expected reduction of its carbonyls, ...this material can reduce and reversibly oxidize its unsaturated carbon–carbon bonds leading to a Li/C ratio of 1/1 and a specific capacity as high as 1363 mAh g–1: the highest ever reported for a lithium carboxylate. Density functional theory calculations suggest that the lithiation is preferential on the propiolate carbons.
The use of graphene electrodes with hydrogenated edges for solid‐state nanopore‐based DNA sequencing is proposed, and molecular dynamics simulations in conjunction with electronic transport ...calculations are performed to explore the potential merits of this idea. The results of the investigation show that, compared to the unhydrogenated system, edge‐hydrogenated graphene electrodes facilitate the temporary formation of H‐bonds with suitable atomic sites in the translocating DNA molecule. As a consequence, the average conductivity is drastically raised by about 3 orders of magnitude while exhibiting significantly reduced statistical variance. Furthermore, the effect of the distance between opposing electrodes is investigated and two regimes identified: for narrow electrode separation, the mere hindrance due to the presence of protruding hydrogen atoms in the nanopore is deemed more important, while for wider electrode separation, the formation of H‐bonds becomes the dominant effect. Based on these findings, it is concluded that hydrogenation of graphene electrode edges represents a promising approach to reduce the translocation speed of DNA through the nanopore and substantially improve the accuracy of the measurement process for whole‐genome sequencing.
DNA sequencing with graphene nano‐electrodes shows great promise because the atomically thin graphene could electrically couple to one nucleobase at a time. Through a combination of molecular dynamics simulations and electronic transport calculations, it is found that hydrogenation of the graphene edges can lead to the formation of H‐bonds with DNA, resulting in higher conductivity and less statistical signal distribution.
With the aim of improving nanopore-based DNA sequencing, we explored the effects of functionalizing the embedded gold electrodes with purine and pyrimidine molecules. Hydrogen bonds formed between ...the molecular probe and target bases stabilize the scanned DNA unit against thermal fluctuations and thus greatly reduce noise in the current signal. The results of our first-principles study indicate that this proposed scheme could allow DNA sequencing with a robust and reliable yield, producing current signals that differ by at least 1 order of magnitude for the different bases.
We present calculated interband transitions and effective masses for diamond from first principles including electron correlation effects via the GW-approximation. Our findings are in agreement with ...experiments, already the first iteration of the GW-scheme gives a direct gap at the gamma-point of 7.38 eV and a indirect gap of 5.75 eV close to experimental values. For deeper bands a quasiparticle self-consistent method is necessary to accurately reproduce the valence band width to 23.1 eV. We also obtain effective hole masses along different symmetry axes and electron conduction masses, m
l
= 1.1m
0 and m
t
= 0.22m
0
Recent significant advancements have been made in demonstrating the usage of phosphorene to detect the presence of gases leading to a new breed of gas sensor device. Based on pristine phosphorene, ...the devices can detect a small concentration of adsorbed molecules with high sensitivity at room temperature. In this work, we propose doping silicon and sulfur impurity atoms into phosphorene to drastically improve its gas sensing performance. We use a combination of density functional theory and non-equilibrium Green's function method to evaluate the sensitivity and selectivity of doped phosphorene nanosensors for four gases (NO, NO2, NH3, and CO). Both devices demonstrate a prominent distinction in conductance when the gas molecules are exposed to the sensor surface. We suggest the doped phosphorene may present advantages over the device based purely on phosphorene due to the ability to discriminate different gases controlled by types of dopants.
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•The substitutional doping of Si or S induces the metallic feature of phosphorene.•The conductance modulation originates from the change in doped concentration and position.•The chargetransfer of NO, NO2, NH3, and CO onto the device surfaces gives rise to the significant decrease in conductance.•The doped-phosphorene sensor can be promising nanosensor for detecting gas molecules with high sensitivity and selectivity.
New technologies, such as: additive, hybrid technologies based on new physical principles, machining of new (non-traditional) structures, etc., envisage new requirements for control systems. The ...tasks of controlling non-traditional processes go beyond the capability of classical open CNC systems which does not allow them to be used to solve the new range of tasks. An underlying computing platform enabling building on its base specialized CNC systems for non-traditional processes has been created. A limited and at the same time extensible set of software and hardware components that implement the new processing technologies has been defined, and a solution matrix for the subsequent synthesis of specialized CNC systems has been built. The procedure of the synthesis of specialized CNC systems is illustrated by an example of a five-axis water jet cutting machine and a machine for selective laser sintering.
The fabrication of nanopores in atomically thin graphene has recently been achieved, and translocation of DNA has been demonstrated. Taken together with an earlier proposal to use graphene nanogaps ...for the purpose of DNA sequencing, this approach can resolve the technical problem of achieving single-base resolution in electronic nucleobase detection. We have theoretically evaluated the performance of a graphene nanogap setup for the purpose of whole-genome sequencing, by employing density functional theory and the nonequilibrium Green’s function method to investigate the transverse conductance properties of nucleotides inside the gap. In particular, we determined the electrical tunneling current variation at finite bias due to changes in the nucleotides orientation and lateral position. Although the resulting tunneling current is found to fluctuate over several orders of magnitude, a distinction between the four DNA bases appears possible, thus ranking the approach promising for rapid whole-genome sequencing applications.
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