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With the emergence of stretchable/wearable devices, functions, such as sensing, energy storage/harvesting, and electrical conduction, should ideally be carried out by a single material, while retaining its ability to withstand large elastic deformations, to create compact, functionally-integrated and autonomous systems. A new class of trimodal, stretchable yarn-based transducer formed by coating commercially available Lycra® yarns with PEDOT:PSS is presented. The material developed can sense strain (first mode), and temperature (second mode) and can power itself thermoelectrically (third mode), eliminating the need for an external power-supply. The yarns were extensively characterized and obtained an ultrahigh (gauge factor ∼3.6 × 105, at 10–20% strain) and tunable (up to about 2 orders of magnitude) strain sensitivity together with a very high strain-at-break point (up to ∼1000%). These PEDOT:PSS-Lycra yarns also exhibited stable thermoelectric behavior (Seebeck coefficient of 15 μV K−1), which was exploited both for temperature sensing and self-powering (∼0.5 μW, for a 10-couple module at ΔT ∼ 95 K). The produced material has potential to be interfaced with microcontroller-based systems to create internet-enabled, internet-of-things type devices in a variety of form factors.

Hybrid organic–inorganic perovskites have generated considerable research interest in the field of optoelectronic devices. However, there have been significantly fewer reports of their thermoelectric properties despite some promising early results. In this article, we investigate the thermoelectric properties of bismuth-doped CH3NH3PbBr3 (MAPbBr3) single crystals. The high-quality Bi-doped crystals were synthesized by inverse temperature crystallization and it was found that Bi substitutes onto the B-site of the ABX3 perovskite lattice of MAPbBr3 crystals with very little distortion of the crystal structure. Bi doping does not significantly alter the thermal conductivity but dramatically enhances the electrical conductivity of MAPbBr3, increasing the charge carrier density by more than three orders of magnitude. We obtained a negative Seebeck coefficient of −378 μV K−1 for 15% (x = 0.15) Bi-doped MAPb(1−x)BixBr3 confirming n-type doping and also measured the figure of merit, ZT. This work highlights routes towards controlled substitutional doping of halide perovskites to optimise them for thermoelectric applications.

A simple wet chemical method involving only sonication in aqueous GdCl3 solution was used for surface functionalization of iron-filled multiwalled carbon nanotubes with gadolinium. Functional groups on the sidewalls produced by the sonication provide active nucleation sites for the loading of Gd3+ ions. Characterization by EPR, EELS, and HRTEM confirmed the presence of Gd3+ ions on the sidewall surface. The room temperature ferromagnetic properties of the encapsulated iron nanowire, saturation magnetization of 40 emu/g and coercivity 600 Oe, were maintained after surface functionalization. Heating functionality in an alternating applied magnetic field was quantified through the measurement of specific absorption rate: 50 W/gFe at magnetic field strength 8 kA/m and frequency of 696 kHz. These results point to candidacy for dual-functioning MRI imaging and magnetic hyperthermia structures for cancer therapy.

Boundary layer chemical vapour synthesis is a new technique that exploits random fluctuations in the viscous boundary layer between a laminar flow of pyrolysed metallocene vapour and a rough substrate to yield ferromagnetically filled radial-carbon-nanotube structures departing from a core agglomeration of spherical nanocrystals individually encapsulated by graphitic shells. The fluctuations create the thermodynamic conditions for the formation of the central agglomeration in the vapour which subsequently defines the spherically symmetric diffusion gradient that initiates the radial growth. The radial growth is driven by the supply of vapour feedstock by local diffusion gradients created by endothermic graphitic-carbon formation at the vapour-facing tips of the individual nanotubes and is halted by contact with the isothermal substrate. The radial structures are the dominant product and the reaction conditions are self-sustaining. Ferrocene pyrolysis yields three common components in the nanowire encapsulated by multiwall carbon nanotubes, Fe3C, α-Fe, and γ-Fe. Magnetic tuning in this system can be achieved through the magnetocrystalline and shape anisotropies of the encapsulated nanowire. Here we demonstrate proof that alloying of the encapsulated nanowire is an additional approach to tuning of the magnetic properties of these structures by synthesis of radial-carbon-nanotube structures with γ-FeNi encapsulated nanowires.

Self supporting nickel substrates coated with nickel nanorods having diameters distributed between 110 nm and 170 nm were electrochemically synthesised using a two-step anodisation process, using as freshly anodised nanoporous alumina membrane as template. Field emission from the nanorods was observed at a relatively low bias potential Vbias (Vbias ≤ 1 V) using scanning tunnelling microscopy; the emission current was found to be larger than that from the nickel substrate at least by a factor of 4 at Vbias = 1.0 V. Experimental results were interpreted in the modified Millikan–Lauritsen plot and values of the emission parameters were estimated using the value of the work function measured by the Kelvin probe technique.

Ultra-high molecular weight polyethylene/multi-wall carbon nanotube (UHMW-PE/MWNT) composites have been prepared by a novel approach which involves the use of a mixture of solvents during the gelation process. By combining one of the best known organic solvents for nanotubes, N,N-dimethylformamide (DMF) with xylene and use this mixed-solvent in the gelation/crystallisation process for UHMW-PE/MWNT composite fabrication, an attempt is made to improve the dispersion of carbon nanotubes in UHMW-PE. The obtained films were drawn to obtain highly oriented tapes, which were characterized in terms of electrical and mechanical properties. The conductivity of the drawn tapes is maintained at 10−4 S/m at draw ratio 30, two orders of magnitude higher than the minimum level required to provide electrostatic discharge. Although the mechanical properties are compromised by use of DMF and MWNTs, the Young’s modulus still remains at 25 GPa, in comparison with 35 GPa for pure UHMW-PE tape at draw ratio 30.

It is shown that the dominant conduction mechanism in single-wall carbon nanotube networks at room temperature is variable range hopping. Thin networks follow a variable range hopping law throughout the temperature range 4 K < T < 300 K, thick networks display variable range hopping characteristics in the range 50 K < T < 300 K, with deviation to Bloch–Gruneisen behaviour at lower temperatures. The adsorption state of these materials is shown to determine the sign of change in conductance upon subsequent exposure to oxygen. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The development of new flexible and stretchable sensors addresses the demands of upcoming application fields like internet-of-things, soft robotics, and health/structure monitoring. However, finding a reliable and robust power source to operate these devices, particularly in off-the-grid, maintenance-free applications, still poses a great challenge. The exploitation of ubiquitous temperature gradients, as the source of energy, can become a practical solution, since the recent discovery of the outstanding thermoelectric properties of a conductive polymer, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS). Unfortunately the use of PEDOT:PSS is currently constrained by its brittleness and limited processability. Herein, PEDOT:PSS is blended with a commercial elastomeric polyurethane (Lycra), to obtain tough and processable self-standing films. A remarkable strain-at-break of ≈700% is achieved for blends with 90 wt% Lycra, after ethylene glycol treatment, without affecting the Seebeck voltage. For the first time the viability of these novel blends as stretchable self-powered sensors is demonstrated.

We report here the thermally activated growth of carbon composite nanostructures on the faceted TiC(1 1 1) single crystal surface. As a result of a high temperature anneal over 2500 K complex structures are growing from well defined nucleation sites at the cusps of the faceted surface. The growth of the complex shaped nanostructures is initialized by the formation of Ti nanodroplets and is fed by the thermal decomposition of TiC. The shape of the nanostructures is determined by the minimum energy configuration of their encapsulating carbon shell.

The electronic and optical properties of nitrogen doped tetrahedral amorphous carbon (ta-C:N) are compared with those of a new form of carbon ta-C film in which nanotube regions are included (ta-C:(NT)). It is found that nanotubes in ta-C inhibit the N doping effect in ta-C and leads to a reduction in conductivity. The results point to the nanotube regions acting as electronically isolated graphitic regions in ta-C. The refractive index in ta-C:(NT) is found to have the opposite dependency on wavelength to that of ta-C. It is proposed that the refractive index can be used as a signature for the presence of nanotubes and other large graphitic regions in ta-C.

Thin film formation of graphite by chemical vapor deposition using 2-methyl-1,2′-naphthyl ketone as a starting material was carried out on Ni film substrates. On Ni films directly deposited on quartz glass, the graphite films were obtained when the Ni film thickness was above 1 000 A and above 5 000 A at 700 °C and 1 000 °C, respectively. Depositions on thinner Ni film substrates comprise amorphous carbon (a-C) or graphite tubes which was owing to the thermal coagulation of the Ni film into droplets. On the other hand, graphite film was obtained on the Ni film with thickness 10 A when a-C was inserted between the Ni film and the quartz glass. The coagulation of the Ni film is considered to be avoided by inserting a-C layer.

The study of potassium-oxygen and cesium-oxygen graphite intercalation compounds (GICs) first synthesized by the authors is presented. It is shown that these GICs are formed in reactions of graphite with alkali metal/alkali Superoxide mixtures or with alkali suboxide (in the case of cesium). Stage 1 and 2 potassium-oxygen GICs Jmterplanar distance 8.44 A), and stages 1, 2 and 5 cesium-oxygen GICs (interplanar distance 9.84 A) were isolated. X-ray diffraction, XPS, TEM electron diffraction and chemical analysis were used to characterize the content and constitution of the GICs synthesized. Metal-like temperature dependence of c -axis resistivity was obtained in the 1.5–300 K range where the resistivity values at room temperature are 0.07, 0.81, 2.6 and 0.089 Ωcm for KO stagel, KO stage 2, CsO stage 1 and CsO stage 2 compounds, respectively. All the GICs exhibit low spin susceptibility (order of 10 −7 emu/g) which suggests the absence of magnetic species O 2 − .

We have observed a new angular oscillatory magnetotransport phenomenon in the out-of-plane resistivity of stage 2 SbCl 5 -intercalated graphite. The phenomenon is similar in many respects to the one recently found in organic conductors, which is attributed to a semiclassical geometrical resonance effect inherent in a weakly corrugated cylindrical Fermi surface. Some deviations from the “standard” behavior are found.

We have observed angular dependent magnetoresistance oscillations (ADMRO) in the out-of-plane resistivity of low-stage SbCl 5 -intercalated graphite. This new phenomenon is a semi-classical geometric resonance effect inherent in quasi two-dimensional systems whose Fermi surface is weakly corrugated in the k z -direction. Typically, ADMRO is characterized by peak positions that are periodic in tan θ. The peaks in ϱ zz occur when the average of the k z -component of electron group velocity around its extended orbit is zero. Significant deviations from ‘standard’ behaviour are found. The implications for electronic structure are discussed.

Structures of carbon nanotube/ligand complexes were studied by flow linear dichroism (the differential absorption of light polarized parallel and perpendicular to the flow orientation direction) with the aim of establishing linear dichroism as a technique to study such systems. Anthracene, naphthalene, and DNA were chosen as ligands, and the potential for flow linear dichroism to probe ligands noncovalently (as well as covalently) bound to single-walled nanotubes is reported. Linear dichroism enables the determination of approximate orientations of the ligands on the carbon nanotubes.

In this work we have studied the field emission from three different types of carbon films: (i) a-C:H:N deposited using an inductively coupled rf PECVD process, where the N content in the films can be as high as 30 at%. (ii) Cathodic arc deposited tetrahedral amorphous carbon (ta-C) with embedded regions of carbon nanotube and onion structures. (iii) Unoriented carbon nanotube films on a porous substrate. These films were formed by filtering a solution of nanotubes dispersed in alcohol through the pores (0.2 um dia.) and drying.

A modified cathodic arc technique has been used to deposit carbon nitride thin films directly on n+ Si substrates. Transmission Electron Microscopy showed that clusters of fullerene-like nanoparticles are embedded in the deposited material. Field emission in vacuum from as-grown films starts at an electric field strength of 3.8 V/micron. When the films were etched in an HF:NH4F solution for ten minutes, the threshold field decreased to 2.6 V/micron. The role of the carbon nanoparticles in the field emission process and the influence of the chemical etching treatment are discussed., Comment: 22 pages, 8 figures, submitted to J. Vac. Sc. Techn. B

Corrected values for the coefficients G0 and T0 in Table 2 as well as the corrected value for the parameter T0 in Eq. (3) are given for the paper by Morgan et al. [Phys. Status Solidi A 205, No. 6, 1394–1398 (2008)]. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We propose a model for the low temperature conductivity of intercalated multiwall carbon nanotube bundles in terms of three-dimensional weak localisation, with a weakly temperature dependent inelastic scattering process, and interaction effect. At a crossover temperature T * weak localisation conditions collapse and the intrinsic conduction process is observed at T>T * .

Carbon nanotubes are a significant addition to the emerging field of nanotube biotechnology. The biocompatibility, high structural integrity, and unique electronic and mechanical properties of carbon nanotubes complement or surpass those of self-assembled lipid nanotubes, peptide nanotubes, and template-synthesised nanotubes (metals, polymers, semiconductors, and carbons). Carbon nanotubes are candidates for a range of biomolecular applications that is likely to widen considerably in the future.

A correspondence between Fermi surface parameters determined by semiclassical angular dependent magnetoresistance oscillations (ADMRO) and those by the Shubnikov-de Haas effect in stage-2 SbCl 5 -intercalated graphite is demonstrated. The wavevector underlying most robust ADMRO feature and strongest branch of the Shubnikov-de Haas spectrum is the radius of lower valence band primitive cylinder of the Blinowski-Rigaux model.

Though the presence of nanotubes in a carbon sample may be clearly detected by electron microscopy, yet it has been difficult to determine if the nanotubes in question belong to a Russian doll or scroll type. This work shows how a chemical reaction with ferric chloride or with potassium metal reveals the differences between the two types of intratube shell arrangement. Scroll nanotubes are intercalated by alien molecules which penetrate from the side of the scroll and fill the intershell spaces. The corresponding intershell spaces expansion was directly observed in this work by TEM. Russian doll nanotubes do not enter the reaction and stay intact. The reaction with scroll nanotubes is accompanied with a remarkable tube swelling which is easily observed by scanning electron microscopy. The presence of intercalated nanotubes may also be detected by X-ray diffraction and Raman spectroscopy.