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Despite 30‐year development of carbon nanotube (CNT) based materials, harnessing the outstanding nanoscale properties of individual CNT for macroscale applications remains challenging. High specific surface area, a crucial feature of CNTs, often suffers from the formation of tightly packed bundles with inaccessible "dead space". Herein, a novel "microwave shock" approach to open the "dead space" trapped within bundles is reported. Employing N2 ambient during microwave irradiation, CNT bundles undergo an efficient structural alteration and interfacial modification simultaneously due to the strong radiative coupling, while the graphitic structure remains undamaged. In this way, a 15‐fold increase (from 42 to 648 m2 g−1) in the interstitial surface area as well as the lithiophilic functionalization (≈1 atom% nitrogen doping) are achieved without the degradation of other properties. Furthermore, to highlight the merits of this microwave shock process, the treated CNT films are applied as a host material for the anode in a lithium metal battery and demonstrate the suppression of dendritic lithium growth and improve cycling stability. This microwave shock approach provides an efficient avenue to modify nanocarbon‐based materials for further applications. [ABSTRACT FROM AUTHOR]

A comprehensive characterization of various carbon nanotube (CNT) yarns provides insight for producing high-performance CNT yarns as well as a useful guide to select the proper yarn for a specific application. Herein we systematically investigate the correlations between the physical properties of six CNT yarns produced by three spinning methods, and their structures and the properties of the constituent CNTs. The electrical conductivity increases in all yarns regardless of the spinning method as the effective length of the constituent CNTs and the density of the yarns increase. On the other hand, the tensile strength shows a much stronger dependence on the packing density of the yarns than the CNT effective length, indicating the relative importance of the interfacial interaction. The contribution of each physical parameter to the yarn properties are quantitatively analyzed by partial least square regression. [ABSTRACT FROM AUTHOR]

Hybridizing air-stable organic-molecules with advanced III-V semiconductor quantum-dots (QDs) structures can be utilized to create a new generation of biochemical sensing devices. In order to enhance their optical performances, the active regions in these QDs structures commonly consist of multistacked dots-in-a-well (DWELL) units. The effects of grafted molecules on the performances of the QDs structures with multistacked DWELLs, however, still remain unclear. Here, we show the significant improvements in the optical properties of InAs QDs in a hybrid nanosystem obtained by grafting biocompatible diazonium salt compound (amine donor) atop InAs QDs structure. Since its interface between the QDs structure and molecular monolayer retains an uncontaminated and non-oxidized condition, the nanosystem is an ideal platform to study the intrinsic properties of charge-carrier transport inside the system. Because of the complexity of the energy-levels in the QDs structure due to the existing surface QDs and DWELLs, selective excitation wavelengths (400, 633, and 885 nm, respectively) with different photo-energies are used to exactly analyze the complete charging mechanism in these QDs. A clear view of charge-carrier transfer inside the nanosystem is revealed by employing photoluminescence technique under selective-wavelength excitations. The present work provides new quantitative evidences for exploiting inorganic QDs applications in complex biological systems. [ABSTRACT FROM AUTHOR]

Preserving the quality of carbon nanotubes (CNTs) is essential to fully utilize the characteristics in dispersions and other forms. To fabricate CNT dispersions retaining the quality, we propose to reduce CNT aggregate size distributions by viscous liquids at the initial stage from as-grown CNT powders originally possessing a wide aggregate size distribution. Higher viscosity solvents were found to highly disentangle the CNT powder and give a narrower CNT aggregate size distribution without impairing the quality. To show the advantages of these CNT dispersions, we demonstrated a 104-fold increased electrical conductivity of CNT rubber composite based on the predispersion step of CNT powder in the rubber base compound with high viscosity. Our method can afford a high quality of CNT and avoid a long, heavy dispersion, which was conventionally carried out to decrease entangled, large size CNT aggregates, furthermore, applicable for fabrication of conducting polymer composites. [ABSTRACT FROM AUTHOR]

We propose a porosimetry-based method to characterize pores formed by carbon nanotubes (CNTs) in the CNT agglomerates for designing neat CNT-based materials and composites. CNT agglomerates contain pores between individual CNTs and/or CNT bundles (micropore < 2 nm, mesopores 2-50 nm, and macropores > 50 nm). We investigated these pores structured by CNTs with different diameters and number of walls, clarifying the broader size distribution and the larger volume with increased diameters and number of walls. Further, we demonstrated that CNT agglomerate structures with different bulk density were distinguished depending on the pore sizes. Our method also revealed that CNT dispersibility in solvent correlated with the pore sizes of CNT agglomerates. By making use of these knowledge on tailorable pores for CNT agglomerates, we successfully found the correlation between electrical conductivity for CNT rubber composites and pore sizes of CNT agglomerates. Therefore, our method can distinguish diverse CNT agglomerate structures and guide pore sizes of CNT agglomerates to give high electrical conductivity of CNT rubber composites. [ABSTRACT FROM AUTHOR]

A wafer‐scale integrated energy device circuit (IEDC) consisting of electrochemically isolated microsupercapacitor cells that could be connected in parallel and in series, as well as in arbitrarily arrangements. Such an IEDC possesses the same capacitance, operational voltage, and order relaxation time constant, although it is 1/1000th‐times smaller than an equivalent Al electrolytic capacitor. [ABSTRACT FROM AUTHOR]

By using long single-walled carbon nanotubes (SWNTs)as a filler possessing the highest aspect ratio and small diameter,we mimicked the chain structure of polymers in the matrix and realizeda highly conductive elastomeric composite (30 S/cm) with an excellentmechanical durability (4500 strain cycles until failure), far superiorto any other reported conductive elastomers. This exceptional mechanicaldurability was explained by the ability of long and traversing SWNTsto deform in concert with the elastomer with minimum stress concentrationat their interfaces. The conductivity was sufficient to operate manyactive electronics components, and thus this material would be usefulfor practical stretchable electronic devices. [ABSTRACT FROM AUTHOR]

Soluble, ultra-short (length < 60 nm), carboxylated, single-walled carbon nanotubes (SWNTs) have been prepared by a scalable process. This process, predicated on oleum's (100% H2SO4 with excess SO3) ability to intercalate between individual SWNTs inside SWNT ropes, is a procedure that simultaneously cuts and functionalizes SWNTs using a mixture of sulfuric and nitric acids. The solubility of these ultrashort SWNTs (US-SWNTs) in organic solvents, superacid and water is about 2 wt %. The availability of soluble US-SWNTs could open opportunities for forming high performance composites, blends, and copolymers without inhibiting their processibility. [ABSTRACT FROM AUTHOR]

Influence of acyl end-group of oligomers on morphology of poly(p-mercaptobenzoyl)(PMB) was examined by the polymerization of S-acyl-4-mercaptobenzoic acids having the different acyl groups and their dimers in liquid paraffin at 260-300 °C. The polymerization of S-acetyl-4-mercaptobenzoic acid afforded PMB whiskers, whereas the polymerization of S-propionyl-4-mercaptobenzoic acid, S-butyryl-4-mercaptobenzoic acid and S-valeryl-4-mercaptobenzoic acid yielded PMB microspheres. The microspheres were formed by the liquid-liquid phase separation of oligomers induced by the longer acyl end-groups than acetyl group of the oligomers due to the reduction of freezing point of oligomers. In contrast to this, the polymerizations of their dimers afforded needle-like ad slab-like crystals instead of microspheres. In these polymerizations, the crystallization was induced due to the increase of the molecular weight of the phase-separated oligomers, leading to the increase of the freezing point of oligomers. The morphology of PMB could be controlled by the chemical modification of oligomer end-groups. [ABSTRACT FROM AUTHOR]

We propose tabular two-dimensional correlation spectroscopy analysis for extracting features from multifaceted characterization data, essential for understanding material properties. This method visualizes similarities and phase lags in structural parameter changes through heatmaps, combining hierarchical clustering and asynchronous correlations. We applied the proposed method to data sets of carbon nanotube (CNT) films annealed at various temperatures and revealed the complexity of their hierarchical structures, which include elements such as voids, bundles, and amorphous carbon. Our analysis addresses the challenge of attempting to understand the sequence of structural changes, especially in multifaceted characterization data where 11 structural parameters derived from eight characterization methods interact with complex behavior. The results show how phase lags (asynchronous changes from stimuli), and parameter similarities can illuminate the sequence of structural changes in materials, providing insights into phenomena such as the removal of amorphous carbon and graphitization in annealed CNTs. This approach is beneficial even with limited data and holds promise for a wide range of material analyses, demonstrating its potential in elucidating complex material behaviors and properties. [ABSTRACT FROM AUTHOR]

We present a study quantitatively demonstrating that the method of synthesis (gas phase, fixed bed, non-fixed bed) represents a determining factor in the level of crystallinity in growing single wall carbon nanotubes (SWCNTs). Using far infrared spectroscopy, the "effective length" (associated with the level of crystallinity) was estimated for CNTs grown using various synthetic methods (lab-produced and supplemented by commercially purchased SWCNTs) as a metric for crystallinity (i.e., defect density). Analysis of the observed "effective lengths" showed that the SWCNTs fell into two general groups: long and short (high and low crystallinity) synthesized by gas-phase methods and all other supported catalyst methods, respectively. Importantly, the "long" group exhibited effective lengths in the range of 700–2200 nm, which was greater than double that of the typical values representing the "short" group (110–490 nm). These results highlight the significant difference in crystallinity. We interpret that the difference in the crystallinity stemmed from stress concentration at the nanotube-catalyst interface during the growth process, which originated from various sources of mismatch in growth rates (e.g., vertically aligned array) as well as impact stress from contact with other substrates during fluidization or rotation. These results are consistent with well-accepted belief, but now are demonstrated quantitatively. [ABSTRACT FROM AUTHOR]

Kenji Hata and co‐workers present the key issues to achieve on chip integration of carbon nanotube (CNT) microsupercapacitors with a designable performance in article number 1500741. It is envisioned that this will advance the miniaturization of electronics by replacing bulky aluminum electrolytic capacitors (AECs). The back cover image shows a photograph of the sealed integrated energy device circuit (IEDC) compared to an AEC. Both possess the same operational voltage, capacitance, similar speed, but the IEDC is 1/1000th the size of the AEC. [ABSTRACT FROM AUTHOR]

• Properties of buckypapers can be seamlessly controlled by mixing. • Electrical conductivities and thermal diffusivities are correlated. • Crystallinity affects above properties only in higher ranges. Controlling the properties of materials such as electrical conductivities has become more important to satisfy the requirement for objective applications. Carbon nanotubes (CNTs) exhibit high electrical conductivities thus are potential to fabricate high performance electrically conductive materials. However, controlling these electrical conductivities into a desired range is still challenging due to the difficulty of adjusting their dispersion state. In this study, we aimed to achieve the control on electrical conductivities of CNT buckypapers, by utilizing mixed dispersions of several kinds of CNTs. This simple mixing approach realized seamless transitions of electrical conductivity between those of two sole counterparts. Moreover, we have also investigated the thermal diffusivities of obtained buckypapers, revealing an intriguing correlation between electrical conductivities and thermal diffusivities. This finding would provide profound suggestions to the applications which both electrical and thermal conductions by CNTs are employed. [ABSTRACT FROM AUTHOR]