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Action spectroscopies use a readout created by the action of light on the molecules or material rather than optical absorption. Ultrafast 2D photocurrent and 2D fluorescence spectroscopies are two such action spectroscopies. Despite their utility, multidimensional action spectroscopies suffer from a background created by incoherent population mixing. These backgrounds appear when the action of one molecule impacts that of another, creating a signal that mimics a fourth-order population response but is really just the convolution of two linear responses. The background created by incoherent mixing is often much larger than the desired foreground signals. In this paper, we describe the physical mechanisms that give rise to the incoherent signals, drawing Feynman paths for each. There are three variations of incoherent signals, differing by their pulse ordering. They all have the same phase dependence as the desired fourth-order population signals and so cannot be removed by standard phase cycling, but they do differ in their polarization responses and dephasing times. We propose, and implement, a spectrometer design that eliminates the background signals for isotropically oriented samples, leaving only the desired fourth-order 2D action spectra. Our spectrometer utilizes a TWINS interferometer and a pulse shaper interferometer, each driven with a different white-light source so that the pulse pairs within each interferometer are phase stable, but not between the two. The lack of phase stability between the two interferometers eliminates two of the three incoherent responses. The third incoherent response is eliminated with the polarization scheme ⟨0, π/2, π/4, π/4⟩. Our spectrometer also enables both 2D photocurrent and 2D white-light spectra to be collected simultaneously, thereby enabling a direct comparison between action and optical detection under identical conditions and at the exact same position on the sample. Using this spectrometer and photovoltaic devices made from thin films of semiconducting carbon nanotubes, we demonstrate 2D photocurrent spectra free of incoherent background. [ABSTRACT FROM AUTHOR]

N-type carbon nanotubes (CNTs)-based field-effect transistors (FETs) have huge potential applications in low-power consumption tunnel FETs. However, the low-work function metal electrodes can achieve n-type CNTs, but they are easily oxidized due to poor environmental stability. Therefore, based on first-principles calculations, we proposed halide perovskite nanowires Cs4MX5 (M = Pb, Sn; X = Cl, Br, I) inner filling to achieve n-type single-walled CNTs (SWCNTs). The results indicated that all the perovskite nanowires located at the center of the SWCNTs possess high stability. Moreover, the diameter of SWCNTs is a crucial factor affecting the inner filling of perovskite nanowires with an optimal diameter of about 1.4 nm. Furthermore, all the perovskite nanowires Cs4MX5 are excellent electron donors, and the largest charge transfer is up to 1.72 e/nm for Cs4SnI5. Their interaction mechanism reveals that the low work function and the large internal bandgap are two important factors for cubic-phase nanowires to realize the n-type CNTs. Our findings provide some candidate materials and a feasible way to achieve n-type CNTs for applying CNTs-based FETs. [ABSTRACT FROM AUTHOR]

An investigation into second-harmonic generation from magnetized anharmonic carbon nanotubes (CNTs) mounted on a silica substrate is conducted using a Gaussian laser pulse with modulated amplitude. An intense amplitude-modulated laser pulse incident on the array of CNTs displaces their electrons generating a restoration force. This restoration force is the nonlinear function of displacement of electrons, which ensures the anharmonic behavior of CNTs. Using the paraxial ray approximation, the nonlinear interaction of the incident pulse with CNTs is expressed in terms of a wave equation derived using the perturbative technique. The nonlinear current at second-harmonic frequency arises due to the perturbation of the electron density of CNTs by the ponderomotive force exerted on them by an incident pulse. Numerical outcomes validate the enhanced efficiency of the generated harmonic when considering the phenomenon of self-focusing. With the substantial optical nonlinearities of an anharmonic CNT structure, the plasmon resonance is broadened and high efficiency in generating harmonics is attained. It is seen that the augmenting of the amplitude-modulated parameter of the pulse and the external magnetic field strength enhances system nonlinearity, resulting in increased amplitude of generated second harmonics. Additionally, the effect of the heating rate of CNTs on the efficiency of the generated harmonic is also discussed. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) have potential applications in separation membranes and nanofluidic devices. It is well known that the behavior of water molecules confined in CNTs is affected by surface functional groups and external electric fields, leading to structural changes. The understanding of these structural changes of water within various CNTs is crucial, particularly in the context of material separation. While there have been many investigations into the effects of individual specific functional groups, a comprehensive understanding of the effect of these functional groups and the electric fields they generate on water molecules remains elusive. In this study, we investigate the properties of water molecules in tip-charged CNTs of (8,8), (10,10), and (12,12) chiral vectors with positive charges at one tip and negative charges at the other tip. Abstraction of ionized functional groups as tip charges enables a comprehensive understanding that is independent of individual functional groups. The symmetrically arranged tip-charges spontaneously generate a strong and symmetric electric field in the CNTs. However, the strength and directionality of the electric field are non-uniform and complex. In the interiors of (8,8) and (10,10) tip-charged CNTs, helical and square structures, which have disturbances caused by the non-uniformity of the electric field, are observed. The properties of the water molecules differed significantly in the center of the CNTs and near positive and negative charges, despite the electric field symmetry. In (12,12) tip-charged CNTs with 12 charges, a local ring structure is observed in the vicinity of negative charges but not in the vicinity of positive charges. It is concluded that the water structures in tip-charged CNTs have different characteristics from those in plain CNTs under a uniform electric field. [ABSTRACT FROM AUTHOR]

The conductivity type is one of the most fundamental transport properties of semiconductors, which is usually identified by fabricating the field-effect transistor, the Hall-effect device, etc. However, it is challenging to obtain an Ohmic contact if the sample is down to nanometer-scale because of the small size and intrinsic heterogeneity. Noncontact dielectric force microscopy (DFM) can identify the conductivity type of the sample by applying a DC gate voltage to the tip, which is effective in tuning the accumulation or depletion of charge carriers. Here, we further developed a dual-modulation DFM, which simplified the conductivity type identification from multiple scan times under different DC gate voltages to a single scan under an AC gate voltage. Taking single-walled carbon nanotubes as testing samples, the semiconducting-type sample exhibits a more significant charge carrier accumulation/depletion under each half-period of the AC gate voltage than the metallic-type sample due to the stronger rectification effect. The charge carrier accumulation or depletion of the p-type sample is opposite to that of the n-type sample at the same half-period of the AC gate voltage because of the reversed charge carrier type. [ABSTRACT FROM AUTHOR]

Nanoscale semiconductors with isolated spin impurities have been touted as promising materials for their potential use at the intersection of quantum, spin, and information technologies. Electron paramagnetic resonance (EPR) studies of spins in semiconducting carbon nanotubes have overwhelmingly focused on spins more strongly localized by sp3-type lattice defects. However, the creation of such impurities is irreversible and requires specific reactions to generate them. Shallow charge impurities, on the other hand, are more readily and widely produced by simple redox chemistry, but have not yet been investigated for their spin properties. Here, we use EPR to study p-doped (6,5) semiconducting single-wall carbon nanotubes (s-SWNTs) and elucidate the role of impurity–impurity interactions in conjunction with exchange and correlation effects for the spin behavior of this material. A quantitative comparison of the EPR signals with phenomenological modeling combined with configuration interaction electronic structure calculations of impurity pairs shows that orbital overlap, combined with exchange and correlation effects, causes the EPR signal to disappear due to spin entanglement for doping levels corresponding to impurity spacings of 14 nm (at 30 K). This transition is predicted to shift to higher doping levels with increasing temperature and to lower levels with increasing screening, providing an opportunity for improved spin control in doped s-SWNTs. [ABSTRACT FROM AUTHOR]

We outline a surface scattering kernel for rarefied gas flows through ideally ordered nanomaterials, such as high aspect ratio carbon nanotubes. The derived model allows for a comparison of the tangential momentum accommodation coefficient, and, hence, the total effective friction, for different species of gases as a function of the particle diameter. This surface kernel is incorporated with a Fokker–Planck model as an approximation to transport of a rarefied gas through ideally ordered carbon nanotubes. The results of this analysis predict that H 2 experiences higher friction in such systems in comparison with larger molecules such as C H 4 . The results are proposed as a potential explanation of the reduced gas transport of hydrogen gas in nanoporous systems. [ABSTRACT FROM AUTHOR]

Alkali metal doping of multi-walled carbon nanotubes is of great interest, both fundamentally to explore the effect of dopants on quasi-one-dimensional electrical systems and for energy applications such as alkali metal storage. We present an investigation with complementary photoemission and Raman spectroscopies, fully carried out in an ultra-high vacuum, to unveil the electronic and vibrational response of a forest of highly aligned multi-walled carbon nanotubes by in situ potassium doping. The charge donation by the alkali adatoms induces a plasmon mode, and the density of states undergoes an energy shift consistent with electron donation and band filling of the multi-walled carbon nanotube band structure. The π-states in the valence band and the Raman peaks unveil an evolution that can be ascribed to charge donation and partially to a tensile strain exerted by the K adatoms on the carbon lattice. All these effects are thermally reversible, fostering these materials as a potential system for electronic charge harvesting. [ABSTRACT FROM AUTHOR]

We observed a modification of transition pathways in polarized resonance Raman spectroscopy during tip-enhanced Raman spectroscopy (TERS) analysis of metallic carbon nanotubes (CNTs). At a spatial resolution reaching up to the sub-nanometer regime, the signal intensity of the typical D-band is observed to be even higher than the intensity of the G-band all over the probed CNTs in TERS imaging. The measured D-band is attributed to the non-vertical transitions of electrons in k-space that are facilitated by highly confined near-field light at the tip–sample junction of our scanning tunneling microscope based TERS system. The D-band signal was observed even when the CNTs were excited by light polarized perpendicular to the tube axis that corresponds to electronic excitations between different cutting line numbers of a CNT. By combining the electron pathways brought about by both the near-field light and its polarization, we found a unique optical transition of electrons of CNTs in near-field Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Dimensions and molecular structures play pivotal roles in the principle of heat conduction. The dimensional characteristics of a solution within nanoscale systems depend on the degrees of confinement. However, the influence of such variations on heat transfer remains inadequately understood. Here, we perform quasi-one-dimensional non-equilibrium molecular dynamics simulations to calculate the thermal conductivity of water molecules confined in carbon nanotubes. The structure of water molecules is determined depending on the nanotube radius, forming a single-file, a single-layer, and a double-layer structure, corresponding to an increasing radius order. We reveal that the thermal conductivity of liquid water has a sublinear dependency on nanotube length exclusively when water molecules form a single file. A stronger confinement leads to behavioral and structural characteristics closely resembling a one-dimensional nature. Moreover, single-layer-structured water molecules exhibit enhanced thermal conductivity. We elucidate that this is due to the increase in the local water density and the absence of transitions to another layer, which typically occurs in systems with double-layer water structures within relatively large radius nanotubes. [ABSTRACT FROM AUTHOR]

Understanding and further regulating the degradation of mandrel materials is a key aspect of target fabrication in inertial confinement fusion (ICF). Here, a quasi-one-dimensional confinement model is developed using a series of single-walled carbon nanotubes with varying diameters (Dm), and the degradation of poly-α-methylstyrene (PAMS) as a typical mandrel material is investigated under such confined conditions by using the combined method of quantum mechanics and molecular mechanics. In comparison to the isolated system, the calculations show that confinement can decrease or increase the energy barriers of PAMS degradation, which directly depends on Dm. Following which a clear exponential relationship between the degradation rate of PAMS and its own density is derived, indicating that the density of PAMS can be used to regulate mandrel degradation. This work highlights the important effects of confinement on degradation and provides a valuable reference for further development of polymer degradation technologies in ICF target fabrication and other fields. [ABSTRACT FROM AUTHOR]

In a recent work, we have briefly introduced a new structural index for water that, unlike previous indicators, was devised specifically for generic contexts beyond bulk conditions, making it suitable for hydration and nanoconfinement settings. In this work, we shall study this metric in detail, demonstrating its ability to reveal the existence of a fine-tuned interplay between the local structure and energetics in liquid water. This molecular principle enables the establishment of an extended hydrogen bond network, while simultaneously allowing for the existence of network defects by compensating for uncoordinated sites. By studying different water models and different temperatures encompassing both the normal liquid and the supercooled regime, this molecular mechanism will be shown to underlie the two-state behavior of bulk water. In addition, by studying functionalized self-assembled monolayers and diverse graphene-like surfaces, we shall show that this principle is also operative at hydration and nanoconfinement conditions, thus generalizing the validity of the two-liquid scenario of water to these contexts. This approach will allow us to define conditions for wettability, providing an accurate measure of hydrophobicity and a reliable predictor of filling and drying transitions. Hence, it might open the possibility of elucidating the active role of water in the broad fields of biophysics and materials science. As a preliminary step, we shall study the hydration structure and hydrophilicity of graphene-like systems (parallel graphene sheets and carbon nanotubes) as a function of the confinement dimensionality. [ABSTRACT FROM AUTHOR]

Due to fascinating physical properties powered by remarkable progress in chemical vapor deposition of high-quality epilayers, diamond thin films attract great attention for fabrication of nitrogen-vacancy-based solid-state spin systems capable of operating in ambient conditions. To date, diamond heteroepitaxy via bias-enhanced nucleation is an unavoidable method for reliable wafer-scale film manufacturing. In this work, we analyze the coalescence phenomena in nitrogen doped, heteroepitaxial diamond epilayers, with a particular focus on their specific role in the annihilation of macroscopic crystal irregularities such as grain boundaries, non-oriented grains, and twinned segments. Here, we also report on the growth mechanism for the "primary" crystal orientation along with a predominant formation of two different types of boundaries highlighting the {011}-type as a main source of the crystal lattice irregularities. [ABSTRACT FROM AUTHOR]

Many researchers observed enhanced water flow through carbon nanotubes (CNTs) and attributed the reason to large slips. Even after taking significant slip effects into account, there remain unaddressed observations of significant improvements in flow rates. As CNTS are deformable, we represent nanotubes with a deformable-wall using a linear pressure–area relationship. We assume lubrication assumption, and using the properties of nanoconfined water, we derive the model for deformable-nanotubes. We validated our derived model in its limiting cases with the previously reported results in the literature. We compare the predictions by our deformable-wall and rigid-wall model with the experimental results and the MD-simulation predictions by multiple literature studies. Many studies were well-predicted by the rigid-wall model with slips. However, we find that there are many studies with high porosity and thin wall tubes, where elasticity or deformability of the tube is essential in modeling, which is well-predicted by our deformable-wall model with slips. In our study, we focus on investigating the impact of two key factors: the deformability, and the slip length on the flow rate. We find that the flow rate inside the tube increases as the deformability increases or the thickness T and elastic modulus E of the tube-wall decrease). We also find that the flow rate in deformable tubes scales as m ˙ deformable ∼ 1 / α 0 for (Δ p / α A o ) ≪ 1 , m ˙ deformable ∼ 1 / α for (Δ p / α A o ) ∼ O (10 − 1) and m ˙ deformable ∼ α 2 for (Δ p / α A o ) ∼ O (1). Further, for a given deformability, the percentage change in flow rate in the smaller diameter of the tube is much larger than the larger diameter. As the tube diameter decreases for the given pressure, Δ m ˙ / m ˙ increases. We find that for rigid-tube, the flow rate varies m ˙ rigid ∼ Δ p , whereas for the deformable-tubes, the flow rate scales as m ˙ deformable ∼ Δ p 2 for (Δ p / α A o ) ∼ O (10 − 1) , and finally to m ˙ deformable ∼ Δ p 3 for (Δ p / α A o ) ∼ O (1). We further find that slip also significantly increases flow rate, but, deformability has more substantial effect. [ABSTRACT FROM AUTHOR]

Hybrid spin-mechanical systems offer a promising platform for advancing quantum science and technology. However, practical implementation of applications within these hybrid quantum systems demands the seamless integration of supplementary physical components. In this context, we present a proposal for a multi-mode spin-mechanical setup, featuring the utilization of three-mode coupling nanomechanical carbon nanotube (CNT) resonators. These resonators interact with each other via a phase-dependent phonon-exchange mechanism, which is coupled to the same nitrogen vacancy (NV) centers in diamond. Based on the modulation of the phonon–phonon coupling phase and leveraging the triple Fano-like resonance phenomenon, a tripling of electromagnetically induced transparency (EIT) becomes achievable within the system. This tripling is accompanied by swift dispersion, leading to a subtle advancement or delay in outcomes. The phenomenon of triple Fano-like resonance, alongside the resulting triple EIT, engenders noteworthy slow-to-fast and fast-to-slow light effects, which is theoretically demonstrated in CNT resonators, with both identical and distinct frequencies. The findings underscore that CNT resonators with varying frequencies can evoke a more pronounced transition in the slow–fast–slow and fast–slow–fast light effects. This study lays the foundation for the application of phonon-mediated optical information storage and processing. [ABSTRACT FROM AUTHOR]

It is a known and experimentally verified fact that the flow of pressure-driven nanoconfined fluids cannot be accurately described by the Navier–Stokes (NS) equations with non-slip boundary conditions, and the measured volumetric flow rates are much higher than those predicted by macroscopical continuum models. In particular, the flow enhancement factors (the ratio between the flow rates directly measured by experiments or simulations and those predicted by the non-slip NS equation) reported by previous studies have more than five orders of magnitude differences. We showcased an anomalous phenomenon in which the flow enhancement exhibits a non-monotonic correlation with fluid pressure within the carbon nanotube with a diameter of 2 nm. Molecular dynamics simulations indicate that the inconsistency of flow behaviors is attributed to the phase transition of nanoconfined fluid induced by fluid pressures. The nanomechanical mechanisms are contributed by complex hydrogen-bonding interactions and regulated water orientations. This study suggests a method for explaining the inconsistency of flow enhancements by considering the pressure-dependent molecular structures. [ABSTRACT FROM AUTHOR]

The sluggish oxygen evolution reaction (OER) in overall electrocatalytic water splitting poses a significant challenge in hydrogen production. A series of transition metal phosphides are emerging as promising electrocatalysts, effectively modulating the charge distribution of surrounding atoms for OER. In this study, a highly efficient OER electrocatalyst (CoP-CNR-CNT) was successfully synthesized through the pyrolysis and phosphatization of a Co-doped In-based coordination polymer, specifically InOF-25. This process resulted in evenly dispersed CoP nanoparticles encapsulated in coordination polymer-derived carbon nanoribbons. The synthesized CoP-CNR-CNT demonstrated a competitive OER activity with a smaller overpotential (η10) of 295.7 mV at 10 mA cm-2 and a satisfactory long-term stability compared to the state-of-the-art RuO2 (η10 = 353.7 mV). The high OER activity and stability can be attributed to the high conductivity of the carbon network, the abundance of CoP particles, and the intricate nanostructure of nanoribbons/nanotubes. This work provides valuable insights into the rational design and facile preparation of efficient non-precious metal-based OER electrocatalysts from inorganic–organic coordination polymers, with potential applications in various energy conversion and storage systems. [ABSTRACT FROM AUTHOR]

The carbon nano-peapod is a representative structure with interlayer van der Waals (vdW) interactions, in which encapsulated fullerene molecules play a critical role in modulating the transport properties of the carbon nanotubes (CNTs). In particular, their influence on the thermal transport characteristics has been the focal point of considerable attention. In this study, we trained an accurate machine learning potential for fullerene-encapsulated CNTs based on the efficient NEP model to investigate their thermal properties. Using equilibrium molecular dynamics simulation along with the spectral decomposition method for thermal conductivity, we find that the thermal conductivity of fullerene-encapsulated CNTs is roughly 55 % lower than that of empty CNTs, aligning with experimental observations for CNT bundles with fullerene encapsulation [Kodama et al., Nat. Mater. 16, 892 (2017)]. The research suggests that weak vdW interactions between both the fullerene and CNTs, as well as between fullerene molecules themselves, hinder phonon propagation. The encapsulated fullerene contributes to an increase in phonon scattering within the CNTs, ultimately leading to a reduction in thermal conductivity. We utilized machine learning potential to investigate the structure of fullerene-encapsulated CNTs and their heat transport property. This approach provides valuable insights for performance research of complex systems featuring interlayer vdW interactions. [ABSTRACT FROM AUTHOR]

Programmable locomotion of molecules inside the carbon nanotube (CNT) has a significant role in controlling the reactions and delivery systems based on nanotubes. Using molecular dynamics (MD) simulations as well as the theoretical approach, we evaluate the oscillation of C60 inside the CNTs that are subjected to strain gradients from both sides. The molecular dynamics simulations are implemented by LAMMPS open-source software. Using this program, the van der Waals (vdW) interactions are established between C60 and nanotube, and the simulations are performed in canonical ensemble. The strain gradient applied on CNT provides the restoring force of the oscillation of C60. The potential energy of fullerene finds the minimum value at the unstrained region of CNT, which makes it the equilibrium point of oscillation. The amplitude of the oscillations is shown to be related to the thermal energy of C60. The frequency of the oscillations depends on the magnitude of the strain gradient applied on the nanotubes. At higher strain gradients of CNTs, we observe the increase in the frequency due to the increase in the restoring force acting on the fullerene molecule. We exploit the strained carbon nanotubes to control the position of C60 inside the nanotube. It has been shown that by changing the strain gradient of CNT, it is possible to steer the locomotion of C60 to different points inside the nanotube. [ABSTRACT FROM AUTHOR]

For over half a century, traditional silicon-based integrated circuits (ICs) have been the basis of computational electronics and are widely used in computers, cell phones, and other fields. With the rapid development of human society, silicon-based semiconductor technology is approaching its physical and engineering limits. Our increasing diversity of non-traditional computing needs, such as ultra-small, ultra-fast, ultra-low-power wearables, and space radiation protection, is driving the search for new electronic materials. Semiconducting single-walled carbon nanotubes (s-SWCNTs) have many excellent electrical properties, such as high carrier mobility and high ballistic transport, making them strong candidates for new semiconductor materials in the post-Moore era. Carbon-based electronic technology has been developed for over 20 years, and the fundamental issues such as the material purification of s-SWCNTs, preparation prospects of s-SWCNT-based field-effect transistors (CNT FETs), and device physics based on CNT FETs have been basically solved. However, the chiral diversity of s-SWCNTs may lead to problems such as fluctuations in the electrical performance of CNT FETs, limiting the application of s-SWCNTs in high-end ICs. Monochiral s-SWCNTs not only have excellent electrical properties but also have a controllable structure and uniformity, which are crucial for the high-end IC of CNTs. However, some problems exist in the purity and yield of monochiral s-SWCNT preparation and the optimization of monochiral CNT FETs. Therefore, the chiral sorting of CNTs is reviewed in this paper, and the progress of polymer reprocessing in chiral separation is highlighted. Then, the research progress of monochiral CNT FETs is introduced, and possible development directions are summarized and analyzed. Finally, the application prospects of chiral-enriched s-SWCNTs include challenges and future opportunities. [ABSTRACT FROM AUTHOR]

Experimental observations unambiguously reveal quasi-frictionless water flow through nanometer-scale carbon nanotubes (CNTs). Classical fluid mechanics is deemed unfit to describe this enhanced flow, and recent investigations indicated that quantum mechanics is required to interpret the extremely weak water–CNT friction. In fact, by quantum scattering, water can only release discrete energy upon excitation of electronic and phononic modes in the CNT. Here, we analyze in detail how a traveling water molecule couples to both plasmon and phonon excitations within a sub-nanometer, periodic CNT. We find that the water molecule needs to exceed a minimum speed threshold of ∼50 m/s in order to scatter against CNT electronic and vibrational modes. Below this threshold, scattering is suppressed, as in standard superfluidity mechanisms. The scattering rates, relevant for faster water molecules, are also estimated. [ABSTRACT FROM AUTHOR]

We report on the studies of conduction mechanism, direct current conductance, and 1 f -noise of cellulose nanofiber (CNF) and multiwalled carbon nanotube (MWCNT) composites. The composites were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The temperature- and voltage-dependence of the dc conductance Σ were, respectively, probed to investigate the charge transport mechanism and the electrical response of the composite. At room temperature, the increase in Σ with wt. % of MWCNT ϕ showed typical percolation behavior. The Σ − T behavior was fitted to the combination of one-dimensional variable range hopping and the fluctuation-induced tunneling, which were attributed to hopping of charge carriers through 1D MWCNTs and the tunneling of charge carriers between the bundles of MWCNTs, respectively. The non-Ohmic electrical conduction was characterized by the onset voltage V 0 (T) which scaled with Ohmic conductance Σ 0 as V 0 (T) ∼ Σ 0 (T) x T , with x T being the onset exponent increased with ϕ. A scaling description based on the data collapse method was adopted to find the parameters V 0 (T) and x T. The noise power spectrum S V (f) followed the relation S V (f) ∼ V β with two different power-laws: β 1 in the Ohmic and β 2 in the non-Ohmic region (β 1 > --> β 2). Interestingly, this change in power-laws occurs at the same V 0 (T) obtained from Σ − V curves. A simple model was proposed to explain the noise behavior after V 0 (T). It is expected that such electrical characterization of CNF-MWCNT nanopaper composite would open up their possibility of application in flexible electronic devices, intelligent networks, sensors, and actuators. [ABSTRACT FROM AUTHOR]

The unique physical properties of carbyne, a novel carbon nanostructure, have attracted considerable interest in modern nanotechnology. While carbyne synthesis has been accomplished successfully using diverse techniques, the underlying mechanisms governing the carbon monoxide-dependent catalytic synthesis of endohedral carbyne remain poorly understood. In this simulation-based study, we investigate the synthesis of endohedral carbyne from carbon and carbon monoxide radicals in the presence of a nickel catalyst inside double-walled carbon nanotubes with a (5,5)@(10,10) structure. The outcome of our investigation demonstrates that the incorporation of the carbon atom within the Nin@(5,5)@(10,10) model system initiates the formation of an elongated carbon chain. In contrast, upon the introduction of carbon monoxide radicals, the growth of the carbyne chain is inhibited as a result of the oxidation of endohedral nickel clusters by oxygen atoms after the initial steps of nucleation. Our findings align with prior theoretical, simulation, and experimental investigations, reinforcing their consistency and providing valuable insights into the synthesis of carbyne-based nanodevices that hold promising potential for future advancements in nanotechnology. [ABSTRACT FROM AUTHOR]

Developing bifunctional catalysts for overall water splitting with high activity and durability at high current density remains a challenge. In an attempt to overcome this bottleneck, in this work, unique CoNiFe-layered double hydroxide nanoflowers are in situ grown on nickel-iron (NiFe) foam through a corrosive approach and following a chemical vapor deposition process to generate nitrogen-doped carbon nanotubes at the presence of melamine (CoNiFe@NCNTs). The coupling effects between various metal species act a key role in accelerating the reaction kinetics. Moreover, the in situ formed NCNTs also favor promoting electrocatalytic activity and stability. For oxygen evolution reaction it requires low overpotentials of 330 and 341 mV in 1M KOH and 1M KOH + seawater to drive 500 mA cm−2. Moreover, water electrolysis can be operated with CoNiFe@NCNTs as both anode and cathode with small voltages of 1.95 and 1.93 V to achieve 500 mA cm−2 in 1M KOH and 1M KOH + seawater, respectively. [ABSTRACT FROM AUTHOR]

We demonstrate a high electron conductivity (>102 S/cm and up to 103 S/cm) of tungsten suboxide W18O52.4−52.9 (or equivalently WO2.91−2.94) nanotubes (2–3 nm in diameter, ∼μm long). The conductivity is measured in the temperature range of 120–300 K by a four-probe scanning tunneling microscope in ultrahigh vacuum. The nanotubes are synthesized by a low-temperature and low-cost solvothermal method. They self-assemble in bundles of hundreds of nanotubes forming nanowires (∼μm long, few tens nm wide). We observe a large anisotropy of the conductivity with a ratio (longitudinal conductivity/perpendicular conductivity) of ∼105. A large fraction of them (∼65%–95%) shows a metallic-like, thermal activation-less electron transport behavior. Few of them, with a lower conductivity from 10 to 102 S/cm, display a variable range hopping behavior. In this latter case, a hopping barrier energy of ∼0.24 eV is inferred in agreement with the calculated energy level of the oxygen vacancy below the conduction band. This result is in agreement with a relative average concentration of oxygen vacancies of ∼3%, for which a semiconductor-to-metal transition was theoretically predicted. These tungsten suboxide nanostructures are prone to a wide range of applications in nanoelectronics. [ABSTRACT FROM AUTHOR]

The electric polarizability and the spread of the total position tensors are used to characterize the metallic vs insulator nature of large (finite) systems. Finite clusters are usually treated within the open boundary condition formalism. This introduces border effects, which prevent a fast convergence to the thermodynamic limit and can be eliminated within the formalism of periodic boundary conditions. Recently, we introduced an original approach to periodic boundary conditions, named Clifford boundary conditions. It considers a finite fragment extracted from a periodic system and the modification of its topology into that of a Clifford torus. The quantity representing the position is modified in order to fulfill the system periodicity. In this work, we apply the formalism of Clifford boundary conditions to the case of carbon nanotubes, whose treatment results in a particularly simple zigzag geometry. Indeed, we demonstrate that at the Hückel level, these nanotubes, either finite or periodic, are formally equivalent to a collection of non-interacting dimerized linear chains, thus simplifying their treatment. This equivalence is used to describe some nanotube properties as the sum of the contributions of the independent chains and to identify the origin of peculiar behaviors (such as conductivity). Indeed, if the number of hexagons along the circumference is a multiple of three, a metallic behavior is found, namely a divergence of both the (per electron) polarizability and total position spread of at least one linear chain. These results are in agreement with those in the literature from tight-binding calculations. [ABSTRACT FROM AUTHOR]

This study delves into the dynamic characteristics of intelligent arches composed of metal foams, augmented with piezoelectric nanocomposite actuators. These arches are represented within the polar coordinate system, utilizing a higher-order shear and normal deformation theory that eliminates the need for shear correction factors. The structural properties exhibit thickness-dependent variations following predetermined functions. The model operates within a thermal environment and is supported by a Winkler–Pasternak elastic substrate. Hamilton's principle is employed to derive the equations governing the structure's motion. In solving these equations for a scenario with simply supported ends, Fourier series functions are employed as an analytical method. The outcomes are cross-verified against previously published studies with simpler configurations. The investigation explores the impacts of various critical parameters on the dynamic response of the structure. Findings reveal that an increase in pores within the metal foam core decreases the frequency, whereas an increase in the volume fraction of carbon nanotubes has the opposite effect. The primary objective of this study is to design and fabricate more efficient smart structures, through a comprehensive understanding and optimization of the behavior of metal foam arches when integrated with piezoelectric components. [ABSTRACT FROM AUTHOR]

Leveraging rare-earth elements as one of the eco-friendly candidates to protect alloy coatings, this study performed the europium functionalization of carbon nanotubes (Eu–CNT) for magnesium alloy protection in the 3.5% NaCl medium. The obtained composite material was characterized by various techniques to confirm its modified chemical structure. The europium ion was shown to be chelated by carbon nanotube functional groups as confirmed by infrared (IR) and Raman spectroscopies, and the polyamorphous character of CNT and europium phases was revealed by the X-ray diffraction study (XRD). The microstructure of the composite material was investigated by field emmision scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The cyclic voltammetry results showed that the composite material becomes stable after five redox cycles. The corrosion inhibition efficiency was shown to be 82% as compared to the epoxy coating. Also, the Eu–CNT composite coating acts as a mixed inhibitor, it controlled anodic as well as cathodic inhibition. Density functional theory (DFT) study results supported the experimental findings, suggesting that the Eu–CNT composite would effectively interact with various charged corrosive species in the solution phase. The findings of this study are anticipated to contribute new knowledge to design of functional coatings and energy storage materials based on rare-earth functionalized CNT. The cytotoxic effects of Eu–CNT composite material above the concentration of 150 μg mL−1 should be considered as well in further steps of its development as human exposure is inevitable. [ABSTRACT FROM AUTHOR]

A ratiometric electrochemiluminescence (ECL) aptamer-based sensing platform was fabricated for prostate-specific antigen (PSA) determination. Activated CdS nanocrystals/multi-walled carbon nanotubes (CdS/MCNTs) and luminol-Pt/PAMAM nanocomposites (L-Pt/PAMAM NCs) were synthesized and used as cathodic and anodic ECL emitters, respectively. Amino group–modified aptamers were assembled on carboxylated magnetic beads, followed by hybridization with probe DNA functionalized L-Pt/PAMAM NCs. In the presence of PSA, the aptamer would bind specifically to the target PSA, thereby releasing L-Pt/PAMAM NCs. After magnetic separation, the separated L-Pt/PAMAM NCs would hybridize with capture DNA on CdS/MCNTs coated on glassy carbon electrode. This binding would lead to a decrease in cathodic ECL signal of CdS/MCNTs, due to the efficient energy transfer from CdS/MCNTs to L-Pt/PAMAM NCs. Meanwhile, L-Pt/PAMAM brought the anodic ECL signal from luminol. With the increase of PSA concentration, the ECL emission from luminol increased and the ECL emission from CdS/MCNTs decreased. The ratio of ECL intensity of luminol at 0.55 V and CdS/MCNTs at − 1.25 V could be used to quantify the concentration of PSA. This method enables sensitive and reliable detection of PSA over a wide range from 0.05 to 200 ng mL−1, and the detection limit is 0.02 ng mL−1. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) hold great promise for rechargeable batteries. However, the synthesis of COFs with abundant active sites, excellent stability, and increased conductivity remains a challenge. Here, chemically stable fully sp2 carbon‐conjugated COFs (sp2c‐COFs) with multiple active sites are designed by the polymerization of benzo[1,2‐b:3,4‐b′:5,6‐b′′]trithiophene‐2,5,8‐tricarbaldehyde) (BTT) and s‐indacene‐1,3,5,7(2H,6H)‐tetrone (ICTO) (denoted as BTT‐ICTO). The morphology and structure of the COF are precisely regulated from "butterfly‐shaped" to "cable‐like" through an in situ controllable growth strategy, significantly promoting the exposure and utilization of active sites. When the unique "cable‐like" BTT‐ICTO@CNT is employed as lithium‐ion batteries (LIBs) cathode, it exhibits exceptional capacity (396 mAh g−1 at 0.1 A g−1 with 97.9 % active sites utilization rate), superb rate capacity (227 mAh g−1 at 5.0 A g−1), and excellent cycling performance (184 mAh g−1 over 8000 cycles at 2.0 A g−1 with 0.00365 % decay rate per cycle). The lithium storage mechanism of BTT‐ICTO is exhaustively revealed by in situ Fourier transform infrared, in situ Raman, and density functional theory calculations. This work provides in‐depth insights into fully sp2c‐COFs with multiple active sites for high‐performance LIBs. [ABSTRACT FROM AUTHOR]

Multiple-component materials with advanced microstructure are increasingly utilized in the development of microwave absorption materials. In this paper, a magnetic hollow sphere composed of Fe 3 O 4 @PS was fabricated by simply depositing Fe 3 O 4 nanoparticles onto the surface-modified PS hollow spheres through electrostatic interactions. The microwave absorption properties of Fe 3 O 4 @PS hollow spheres were studied by varying the loading capacity of Fe 3 O 4. The results show that when the Fe 3 O 4 content is 28.59 wt%, the optimal minimum reflection loss is −26.9 dB with effective absorption bandwidths (RL ≤ −10 dB) exceeding 0.3 GHz. Furthermore, the straightforward combination of the Fe 3 O 4 @PS with MWCNTs enables the enhancement of the microwave absorption up to −41.4 dB at 14.5 GHz, with an effective absorption bandwidth exceeding 5.9 GHz (12.1–18 GHz) at a thickness of 2 mm. This study is expected to provide valuable insights into the design of nanocomposites for microwave absorption applications. [ABSTRACT FROM AUTHOR]

A hybrid material consisting of an array of vertically ordered carbon nanotubes (CNTs) in porous anodic alumina was fabricated directly on oxidized Si substrates. Individual CNTs with vertical orientation were grown using the catalyst Ni nanoparticles (NPs) embedded in the pore walls of a thin template based on porous anodic alumina with a pore diameter of 40 ± 5 nm. The initial film was a two-layer Ti-Al structure on a Si/SiO 2 substrate. A vertically oriented porous structure was formed by anodizing the Al layer. Electrochemical deposition was used to form the catalyst Ni-NPs with dimensions of 30 ± 5 nm. CNTs were synthesized by high-temperature chemical vapor deposition. Scanning and transmission electron microscopy, Raman spectroscopy, and X-ray diffraction were used to analyze the surface morphology and microstructure of the composite nanostructures. The CNT length was (0.6–1.5) μm, and the CNT spacing was 110 ± 10 nm. It is expected that the resulting structure will serve as a basis for the development of CNT-based electrodes for electrochemical impedance biosensors. Electrochemical impedance spectroscopy was used for the electrochemical characterization of the fabricated CNT-based electrodes. The results showed that the CNT-based electrodes are characterized by improved electron transfer kinetics. [ABSTRACT FROM AUTHOR]

3D carbon nanotube hybrid materials containing VO2 and V2O5 evenly distributed onto vertically aligned carbon nanotubes (VACNTs) is reported. Adjustable loading of particles in controllable sizes and shapes onto the VACNTs was developed via a stepwise chemical vapour deposition (CVD) approach. Solid VO(acac)2 is chosen as vanadium source. CO2 acts as reactive gas for the pre‐functionalisation of the VACNTs. The process temperature was identified as key parameter to control the deposited vanadium oxide phase. A temperature of 550 °C results in monoclinic VO2, while 600 °C results in the deposition of V2O5 onto the VACNT support. The morphology and the amount of deposited material was found to be dependent on the reactor dimensions and the degree of functionalisation of the carbon support. An increase of the D/G ratio of the VACNT from 0.75 to 1.08 caused by a CO2 treatment step within the process led to an increase of the particle coverage from a scarce coverage without prior CO2 treatment to a dense coverage of the VACNT support after 15 min of CO2 exposure time. Size and crystallinity of the as deposited particles can be further adjusted by a controlled heat treatment after VO(acac)2 precursor deposition. [ABSTRACT FROM AUTHOR]

Natural silk nanofibers (SNF) are attractive conductive substrates due to their high aspect ratio, outstanding mechanical strength, excellent biocompatibility, and controllable degradability. However, the inherently non‐conductivity severely restricts the potential sensor application of SNF‐based aerogels. In this work, the conductive nanofibrous aerogels with low‐density achieved through freeze–drying by dispersing carbon nanotubes (CNT) into SNF suspension. The addition of CNT significantly increases the conductivity with improved mechanical properties of composite aerogels. SEM results reveal that the distinct hierarchical structure comprising micropores and nanofibrous networks within the pores is formed when CNT content reached 30%. Furthermore, increased cell viability suggested the excellent biocompatibility of SNF‐CNT‐based conductive aerogel for tissue‐engineering applications. Subsequently, the elastic water‐borne polyurethane (WPU) is incorporated to SNF‐CNT system to construct aerogel with good sensing properties. The introduction of WPU demonstrates enhanced compressive performances and an exceptionally high elastic recovery ratio of 99.8%, thereby exhibiting a stable and lossless strain‐sensing signal output at 5% strain. This study provides a feasible choice and strategy for exploring the potential application of SNF in functional aerogels. [ABSTRACT FROM AUTHOR]

Nanoparticle agglomeration refers to the spontaneous clustering of nanoparticles caused by the attractive forces. Agglomeration impacts the physical and mechanical properties of nanoparticles and their composites. Understanding and controlling nanoparticle agglomeration is crucial for optimizing various applications, from nanomedicine to nanoelectronics. In this work, we formulated a self-exciting point process model to analyse nanoparticle agglomeration based on microstructural input. The model is utilised to categorise a specific set of points within the microstructure as either independent (dispersed) or dependent (agglomerated), along with their respective probabilities. We employed this approach to study two distinct scenarios: (a) Agglomeration in experimentally generated microstructures of titanium nanoparticles, and (b) Analysing agglomeration patterns in simulated microstructures of carbon nanotube networks, generated using a stochastic microstructure model. We obtain a quantitative understanding of the connection between the sonication duration and the level of agglomeration in titanium nanoparticles. As the sonication period increases, both the agglomeration percentage and the size of the agglomerates decrease. Furthermore, our analysis of simulated carbon nanotube microstructures, including equiaxed and rope-like agglomeration, shows a close alignment between results obtained from the point process model and those generated by the stochastic microstructure model. [ABSTRACT FROM AUTHOR]

Aiming at the micrometeoroid/orbital debris (MMOD) collision problem for space structures, this paper proposes a self-sensing aluminum/aramid hybrid laminate for detection of MMOD collision event and identification of its associated damage. A co-curing method is used to fabricate the hybrid laminate while carbon nanotube (CNT) film and flexible printed circuit (FPC) are embedded in the laminate as sensing layer. By injecting tiny currents into the CNT film before and after MMOD collision and collecting the corresponding boundary voltages, electrical resistance tomography (ERT) is employed to reconstruct tomographic image of the conductivity change caused by MMOD collision and provide information about the damage. Experimental studies have conducted to perform ballistic high velocity impacts to simulate MMOD collision to three self-sensing hybrid laminates. The results have demonstrated that, the CNT film has good sensing performance, and the reconstructed image of conductivity changes can reflect the location and approximate size of the damage, validating the effectiveness of the proposed self-sensing hybrid laminate and providing a new way for space structures to detect MMOD collisions. [ABSTRACT FROM AUTHOR]

Carbon nanotube (CNT) based supercapacitors (SCs) were fabricated using magnesium phosphate (MgPO) as a redox material and recycled polypropylene (PP) as the mechanical support for the SC electrodes. Microscopy analysis indicated that the MgPO powder is composed of grains with sizes of 100–420 nm. Firstly, SCs were made with bare CNT electrodes, and these devices generated an energy density of 44.8 W h kg−1 and a maximum capacitance of 243.9 F g−1 (at 1 A g−1). Next, MgPO powder was added to the supercapacitor electrodes resulting in an increase of energy density and capacitance to 88.7 W h kg−1 and 443.8 F g−1, respectively. The CP increased even more (44%) after adding a mixture of MgPO/CuSO4 to the SC electrodes. Interestingly, the device made with MgPO/CuSO4 had the best electrochemical stability, with a capacitance retention of 92% after 500 cycles of charge–discharge. Spectroscopy analysis (XPS, UV-vis, and Raman) of the supercapacitor electrodes demonstrated the existence of the following redox species, which are useful to store charge: Mg2+/Mg0, oxygen vacancies, and P3+/P5+. The best device made with a mixture of redox powder MgPO/CuSO4 presented the highest capacitance (638.6 F g−1) because extra redox centers of Cu+/Cu2+ are found on its electrodes. Thus, combining magnesium phosphate materials and copper sulfate is a useful strategy not only to improve the electrochemical stability of carbon nanotube-based supercapacitors, but also to increase their capacitance/energy density, which are of interest for application in flexible electronics. [ABSTRACT FROM AUTHOR]

Cardiovascular disease such as myocardial infarction is one of the chief reasons for death universally. An extensive variety of natural and synthetic biodegradable polymers have been studied lately for cardiac tissue engineering applications. Cardiac tissue regeneration is a substitute approach for in situ cellular cardiomyoplasties, which is considered to renovate infarcted myocardium utilizing cells, scaffold, and growth factors. Polymer-based scaffolds including graphene and carbon nanotubes can be employed for heart tissue engineering. In this review, we consider the literature in terms of cardiac tissue engineering and discuss the most recent developments in terms of scaffold-based polymers for cardiac tissue regeneration. [ABSTRACT FROM AUTHOR]

Piezoelectric Carbon Nanotube Reinforced Functionally Graded (P-CNT-FG) structures have great application potential in aerospace for vibration control. The precise modeling technique for P-CNT-FG plates and shells is a big challenge, especially for moderate thick and thick P-CNT-FG structures. This paper develops a Finite Element (FE) model for P-CNT-FG plates and shells. The FE model is derived by Reddy's third-order shear deformation theory with consideration of various CNT distribution forms, CNT volume fractions, boundary conditions and arbitrary fiber orientations. Eight-node quadrilateral elements are developed for P-CNT-FG structures with seven mechanical degrees of freedom (DOFs) at each node. The mathematical model is first validated by a simply supported square plate, a cross-ply plate with sinusoidally distributed loading and a CNT plate with PZT layers. Afterwards, vibration and dynamic responses of P-CNT-FG plates have been presented, later the effective of parameters on static and dynamic response of P-CNT-FG smart structures are carried out by the present model. [ABSTRACT FROM AUTHOR]

[Display omitted] Despite the bright fortune of lithium-sulfur (Li-S) batteries as one of the next-generation energy storage systems owing to the ultrahigh theoretical energy density and earth-abundance of sulfur, crucial challenges including polysulfide shuttling and low sulfur content of sulfur cathodes need to be overcome before the commercial survival of sulfur cathodes. Herein, cobalt/carbon spheres embedded CNTs (Co-C-CNTs) are rationally designed as multifunctional hosts to synergistically address the drawbacks of sulfur cathodes. The host is synthesized by a facile pyrolysis using Co(OH) 2 template and followed with the controllable etching process. The hierarchical porous structure owning high pore volume and surface area can buffer the volume change, physically confine polysulfides, and provide conductive networks. Besides, partially remained metallic cobalt nanoparticles are favorable for chemical adsorption and conversion of polysulfides, as validated by density functional theory simulations. With the combination of above merits, the S@Co-C-CNTs cathodes with a high sulfur content of 80 wt% present a superior initial capacity (1568 mAh g−1 at 0.1C) with ultrahigh 93.6% active material utilization, and excellent rate performance (649 mAh g−1 at 2C), providing feasible strategies for the optimization of cathodes in metal-sulfur batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] Compared to the great achievements in enhancing thermoelectric (TE) performance, little attention is paid to the mechanical (ME) performance of polymer composites although it is a prerequisite for practical applications. However, how to improve a trade-off between TE and ME performance is a great challenge, as the increase in ME performance is always along with the decrease in TE performance and vice versa. Herein, an enhanced trade-off is realized for ionic liquid (IL)-modulated flexible poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/ single-walled carbon nanotube (SWCNT)/polycarbonate (PC) composites. It shows a maximum power factor value of 8.5 ± 2.1 μW m−1 K−2 and a strong mechanical robustness is also achieved for the composite with a fracture strength of 43.4 ± 5.4 MPa and a tensile modulus of 3.8 ± 0.4 GPa. The TE and ME performances are superior to other thermoplastics-based TE composites, and even comparable to some conducting polymers and their composites. The high electrical conductivity of PEDOT:PSS/SWCNT and their strong interfacial interaction with PC are responsible for the enhanced trade-off between ME and TE performances. This work provides a new avenue to endow polymer composites with high TE and ME performances simultaneously and will promote their versatile TE applications. [ABSTRACT FROM AUTHOR]

Double Z-scheme Bi 2 S 3 /S-CN/Bi 2 O 3 heterojunction hollow nanotubes with defective structure were synthesized and exhibited efficient photocatalytic amine oxidation owing to the synergistic of each component, hollow nanotube structure, and unique defect-transit double Z-scheme heterostructure. [Display omitted] The rational design of Z-scheme heterojunction hybrid photocatalysts is considered a promising way to achieve high photocatalytic activity. In this study, a dual Z-scheme heterojunction with bismuth sulfide (Bi 2 S 3) nanorods and bismuth oxide (Bi 2 O 3) nanoparticles anchored Sulfur-doped carbon nitride (S-CN) nanotubes (Bi 2 S 3 /S-CN/Bi 2 O 3) is designed and fabricated through the ordinal metal ion adsorption, pyrolysis, and sulfidation processes using supramolecular rods as precursor. Compared with pristine Bi 2 S 3 , Bi 2 O 3 , and CN, the dual Z-scheme tube-shaped Bi 2 S 3 /S-CN/Bi 2 O 3 catalyst exhibited a significantly improved photocatalytic activity in amine oxidation. The optimized Bi 2 S 3 /S-CN/Bi 2 O 3 nanostructure exhibits a 97.6 % benzylamine conversion and 99.4 % imine selectivity within 4 h under simulated solar light irradiation. The excellent activity of Bi 2 S 3 /S-CN/Bi 2 O 3 nanotubes can be attributed to the characteristic hollow defect band structure and efficient charge separation and transfer achieved by the dual Z-scheme charge transfer mechanism, which was systematically studied using electron spin resonance spectroscopy, Kelvin probe force microscope, and other techniques. The optimized dual Z-scheme heterojunction hybrid photocatalyst maintains the high oxidizing ability of Bi 2 S 3 and Bi 2 O 3 and the excellent reducing ability of CN, thereby significantly enhancing the photocatalytic activity. This research provides a facile and feasible synthesis strategy for designing dual Z-scheme heterojunctions with defect band structure to improve the photocatalytic activity. [ABSTRACT FROM AUTHOR]

Ruthenium (Ru)‐based catalysts are known to accelerate the slow kinetics of the alkaline hydrogen evolution reaction (HER). However, enhancing the transfer kinetics of adsorbed hydroxyl (OHad) remains challenging. Herein, a dual‐regulation strategy is presented to alleviate OH blockage on the catalyst surface, using a cluster‐level Ru electrocatalyst supported by single‐atom CoN4 generated in situ on carbon nanotubes (CNTs). Experimental and theoretical studies demonstrate that introducing oxophilic single‐atom CoN4 can mitigate the strong interaction between Ru and OHad by directly competing for OHad on the Ru surface, thereby preventing Ru site poisoning. Meanwhile, single‐atom CoN4 effectively modifies the electronic structure of Ru atomic clusters (ACs), indirectly optimizing the energy barriers for OH desorption at the Ru interface and promoting OHad release. The electronic interaction between Ru ACs and CoN4 also inhibits Ru atom migration, significantly enhancing catalytic stability. The resulting catalyst shows excellent HER activity at 10 mA cm−2 with a low overpotential of 15 mV in alkaline solution and remains stable at 200 mA cm−2 for over 1000 h. An alkaline anion‐exchange membrane water electrolyzer (AEMWE) using this catalyst can exhibit an ultralow potential (1.785 V at 1 A·cm−2) and high stability at 500 mA·cm−2. [ABSTRACT FROM AUTHOR]

Broadening the scope of functionalities that can be covalently bound to single‐walled carbon nanotubes (SWCNTs) is crucial for enhancing the versatility of this promising nanomaterial class in applied settings. Here we report the covalent linkage of triphenylphosphine oxide [Ph3P(O)] to SWCNTs, a hitherto overlooked surface functionality. We detail the synthesis and structural characterization of a new family of phosphine oxide‐functionalized diaryliodonium salts that can facilitate direct Ph3P(O) transfer and afford novel SWCNTs with tunable Ph3P(O) content (SWCNT‐P). The molecularly‐distributed and robust nature of the covalent Ph3P(O) attachment in SWCNT‐P was supported by a combination of characterization methods including Raman, infrared, UV/Vis‐NIR and X‐ray photoelectron spectroscopies coupled with thermogravimetric analysis. Electron microscopy further revealed the effectiveness of the Ph3P(O) moiety for de‐bundling SWCNTs to yield SWCNT‐P with superior dispersibility and processability. Finally, electrochemical studies established that SWCNT‐P is sensitive to the presence of Li+, Na+ and K+ wherein the Gutmann‐Beckett Lewis acidity parameters of the ions were quantitatively transduced by Ph3P(O) to electrochemical responses. This work hence presents a synthetic, structural, spectroscopic and electrochemical foundation for a new phosphorus‐enriched responsive nanomaterial platform featuring the Ph3P(O) functionality. [ABSTRACT FROM AUTHOR]

Molecular dynamics (MD) simulations are employed to assess the effects of diverse carbon nanomaterials on the thermo‐oxidative aging properties and tribological behavior of perfluoroelastomer (FFKM) in high‐temperature environments. In this study, carbon nanofillers such as graphene nanosheets (GNS), carbon nanotubes (CNTs), hydroxyl‐functionalized graphene (OH‐GNS), and hydroxyl‐functionalized carbon nanotubes (OH‐CNTs) are examined. The aging properties of composite systems are characterized by parameters like cohesive energy density and mean square displacement. The constant strain method is utilized to estimate the shear modulus and bulk modulus. Three‐layer friction structures are established to analyze the mechanism of fillers on the tribological behavior of composites by applying shear loads. According to the MD simulation results, the addition of carbon nanofillers enhances FFKM's thermo‐oxidative aging performance at 533 K, increases its bulk and shear moduli, and reduces the coefficient of friction and abrasion rate of each composite at high temperatures. Among the four nanofillers, OH‐CNTs is the most effective in terms of improving FFKM performance. Stronger dipoledipole interactions and hydrogen bonding are introduced into the system by OH‐CNTs, which improves the stability of the filler‐matrix interface and produces stronger interfacial interactions. This work offers theoretical predictions for the design and optimization of carbon nanomaterial and FFKM polymer composites. [ABSTRACT FROM AUTHOR]

In this work, a rectangular cellular microplate is taken into consideration which is embedded between two functionally graded carbon nanotube-reinforced composite layers that have the piezoelectric ability. Different patterns for the carbon nanotube dispersion are considered. Moreover, an external electrical voltage is applied to them. The displacements are described based on a higher-order shear deformation theory which is called hyperbolic theory and the size influence is captured via the modified couple stress formulations. The governing motion equations are then derived using the variational technique and Hamilton’s principle. Then, for simply supported edge conditions, a closed-form solution is provided. Next, it turns to validate the results in simpler states, and after that, the effect of the most prominent parameters on the results is investigated. It is observed that by increasing the external applied voltage to the face sheets, the frequencies are reduced. Also, the natural frequencies have a tendency to decrease as the dimensionless material length scale parameter increases. This study’s outcomes may help design and manufacture micro-/nano-electro systems, sensors and actuators, small-scale devices, and other engineering structures. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) composites with multifunctional properties and minimal filler content are increasingly in demand across various industries. However, achieving a balance between high mechanical strength, electrical conductivity, thermal conductivity, and electromagnetic interference (EMI) shielding remains challenging. In this study, a dual‐processing strategy combining Pickering emulsion templating and melt blending is presented to hybridize 1D carbon nanotubes (CNTs) and 2D graphene nanoplatelets (GNPs) within a PLA matrix. This approach successfully forms a stable dual‐filler network, ensuring uniform dispersion of the fillers. The results show that this method significantly enhances the performance of the resulting PM‐PGxCy composites (P: Pickering emulsion; M: melt blending; x and y: mass fractions of GNPs and CNTs, respectively). Specifically, the PM‐PG1.43C1.43 composite exhibits remarkable improvements in mechanical strength (56.2 MPa), electrical conductivity (43.5 S m−1), EMI shielding effectiveness (20.1 dB), and thermal conductivity (0.34 W m·K−1), outperforming composites prepared using either method alone. These findings indicate that the dual‐processing strategy effectively combines 1D and 2D fillers, facilitating superior interfacial interactions and enhancing the multifunctional properties of PLA‐based composites. This study offers a new approach to achieving high‐performance PLA composites with low filler content, offering significant potential for applications in electronics, packaging, and EMI shielding technologies. [ABSTRACT FROM AUTHOR]

In the field of VLSI technology, the miniaturization of ICs poses significant challenges to overall interconnect performance, particularly due to the rising concerns of crosstalk-induced reliability and durability issues. This work explores graphene-based randomly mixed carbon nanotube bundle (RMCB) interconnects as a viable solution for advanced reliable VLSI applications. Employing metaheuristic algorithms (Maximum Hole Degree, Particle Swarm Optimization, Stoyan and Yaskov Algorithm), this study seeks to optimize RMCB structures, maximizing carbon nanotube density within a fixed area. Notably, this study explores the effectiveness of algorithms’ performance in optimizing RMCB structures at a nano-technology node. Extensive signal integrity and reliability assessments, considering both rugged and pristine substrates, reveal that Stoyan and Yaskov (SY)-based optimization excels over PSO and MHD-based counterparts in terms of on-chip interconnect performance and reliability. The SY structure significantly dominates MHD-based (and PSO) counterparts by reducing crosstalk delay by 50% (30%), enhancing the average failure rate by 40% (37%), and improving electromigration reliability by 170% (63%). [ABSTRACT FROM AUTHOR]

This article presents the first experiments on filling single‐walled carbon nanotubes (SWCNTs) with the phosphorus sulfides P4S3 and P4S10 using the ampoule method. Transmission electron microscopy examination reveals the encapsulation of phosphorus and sulfur species inside the cavities of SWCNTs without the formation of any regular structures. X‐ray photoelectron spectroscopy observes different oxidation states of P and S atoms, depending on the P/S ratio in the initial mixture used to fill the nanotubes. The Raman signals associated with the encapsulated species are low in intensity, and the vibrational modes are shifted and broadened as compared to those in crystalline P4S3 and P4S10. The proposed models for the arrangement of sulfur and phosphorus inside SWCNTs suggest the formation of 1D amorphous glassy phosphorus sulfides with stoichiometric ratios close to those of elemental phosphorus and sulfur in the initial mixtures. [ABSTRACT FROM AUTHOR]

The surface of carbon fiber is treated with sizing agent containing hydroxylated carbon nanotubes, fullerenols, and graphene oxide, respectively. The effects of carbon nanomaterials and their structures on the surface properties of carbon fiber, the interfacial properties and the mechanical properties of carbon fiber/epoxy composites are investigated. All three types of carbon nanomaterial can improve the interfacial bonding strength and modulus, thereby enhancing the interlaminar shear strength (ILSS) of composites. Moreover, the ILSS increases with the increase of interfacial bonding strength, due to the roughness and the number of active groups. Compared with the composite without carbon nanomaterials, the interfacial bonding strength of the three nanoparticle‐modified composites increased by 14%, 5% and 4%, the modulus increased by 10%, 26%, and 9%, and the ILSS increased by 14%, 8%, and 7%, respectively. The interfacial bonding strength has a more significant impact on the ILSS than the interfacial modulus. Highlights: CNTs, graphene oxide and fullerenols regulate the surface characteristics of carbon fibers.The influence of carbon nanomaterials on the interfacial properties of composites.The relationship between the fiber surface, the interface and the composites. [ABSTRACT FROM AUTHOR]