A carbon host capable of effective and uniform sulfur loading is the key for lithium-sulfur batteries (LSBs). Despite the application of porous carbon materials of various morphologies, the carbon hosts capable of uniformly impregnating highly active sulfur is still challenging. To address this issue, we demonstrate a hierarchical pore-structured CNT particle host containing spherical macropores of several hundred nanometers. The macropore CNT particles (M-CNTPs) are prepared by drying the aerosol droplets in which CNTs and polymer particles are dispersed. The spherical macropore greatly improves the penetration of sulfur into the carbon host in the melt diffusion of sulfur. In addition, the formation of macropores greatly develops the volume of the micropore between CNT strands. As a result, we uniformly impregnate 70 wt % sulfur without sulfur residue. The S-M-CNTP cathode shows a highly reversible capacity of 1343 mA h g at a current density of 0.2 C even at a high sulfur content of 70 wt %. Upon a 10-fold current density increase, a high capacity retention of 74% is observed. These cathodes have a higher sulfur content than those of conventional CNT hosts but nevertheless exhibit excellent performance. Our CNTPs and pore control technology will advance the commercialization of CNT hosts for LSBs.

A new method for the preparation of graphene has been developed via porphyrin exfoliation of graphite in NMP. The exfoliation, which follows the intercalation of organic ammonium ions, is based on the pi-pi interaction between graphene and porphyrins. The graphene sheets prepared by this method show undisturbed sp(2) carbon networks.

Poly(3‐hexylthiophene) (P3HT) hybrids with single‐walled carbon nanotubes (SWNTs) were prepared using a series of SWNTs with various defect contents on their surfaces. The hybrids were synthesized by exploiting the π–π interaction between P3HT and the SWNTs, resulting in efficient dispersion of the carbon nanotubes in the P3HT solution. UV‐visible and photoluminescence (PL) spectra showed that the carbon nanotubes quench the PL of P3HT in the hybrids, indicating that electron transfer occurs from photo‐excited P3HT to the SWNTs. This electron transfer from P3HT to carbon nanotubes was disrupted by the presence of defects on the SWNT surfaces. However, the PL lifetime of P3HT in the hybrids was found to be the same as that of pure P3HT in solution, indicating the formation of a ground‐state non‐fluorescent complex of P3HT/SWNTs.

We report a simple method for preparing transparent conductive graphene films using a chemically converted graphene (CCG) suspension that was obtained via controlled chemical reduction of exfoliated graphene oxide (GO) in the absence of dispersants. Upon thermal annealing of the CCG films, the films displayed a sheet resistance on the order of 103 Ω·◻−1 at 80% transparency (550 nm), with a bulk conductivity on the order of 102 S·cm−1. FT-IR, UV−visible, and X-ray photoelectron spectroscopy results showed that the combination of the controlled reduction of GO in suspension and thermal annealing of the CCG films efficiently restored the sp2 carbon networks of the graphene sheets, facilitating charge carrier transport in the individual CCG sheets. Furthermore, grazing-incidence X-ray diffraction results showed that the thermal annealing of the CCG films reduced the interlayer distance between the CCG sheets to a distance comparable to that in bulk graphite, facilitating charge carrier transport across the CCG sheets. Polymer solar cell devices composed of the CCG films as transparent electrodes showed power conversion efficiencies, η, of 1.01 ± 0.05%, which corresponded to half the value (2.04 ± 0.1%) of the reference devices, in which indium tin oxide-covered glass was used for the transparent electrode.

The use of carbon nanotubes (CNTs) as transparent conducting films is one of the most promising aspects of CNT-based applications due to their high electrical conductivity, transparency, and flexibility. However, despite many efforts in this field, the conductivity of carbon nanotube network films at high transmittance is still not sufficient to replace the present electrodes, indium tin oxide (ITO), due to the contact resistances and semi-conducting nanotubes of the nanotube network films. Many studies have attempted to overcome such problems by the chemical doping and hybridization of conducting guest components by various methods, including acid treatment, deposition of metal nanoparticles, and the creation of a composite of conducting polymers. This review focuses on recent advances in surface-modified carbon nanotube networks for transparent conducting film applications. Fabrication methods will be described, and the stability of carbon nanotube network films prepared by various methods will be demonstrated.

Upon the addition of silver nanowires (AgNWs), the electrical conductance of graphene film is improved. According to the film's optical birefringence, as shown by studies using liquid crystals (LCs), the improvements do not result from the chemical doping properties of the AgNWs; instead, they arise because the AgNWs facilitate connections among the domains in the graphene film. This is further supported by the film's Dirac point voltage, Raman spectra, and electrical resistance.

We investigated the electrical conductivities of double-walled carbon nanotube (DWNT) network films upon post-treatment via HNO 3 or gold ions, particularly with respect to their potential use as transparent conducting films. Post-treatment of DWNT films with HNO 3 and deposition of gold nanoparticles, respectively, resulted in a significant decrease of the electrical resistance, while the initial value of the transmittance of pristine-DWNT films was maintained. The DWNT-Au nanoparticle hybrid films exhibited the best transmittanceconductivity performance among the evaluated network films, i.e., pristine-SWNT films, pristine-DWNT films, SWNT-Au nanoparticle hybrid films, and HNO 3 -treated DWNT films. The electrical behaviors of the gold nanoparticle-coated and HNO 3 -treated DWNT films were examined by an analysis of the work functions of the DWNT films. The DWNT-Au nanoparticle hybrid films are expected to be applicable to transparent electrodes of various optoelectronic devices such as solar cells, light-emitting diodes, sensors, and fieldeffect transistors.

We examined the electrical conductivity and transmittance of six types of SWNT network films, developed for potential use in transparent conductive films, to investigate the effect of Au doping on single-walled carbon nanotube (SWNT) defects: (i) SWNT network films without Au doping (as-produced (AP-SWNTs), purified (P-SWNTs), and cut (C-SWNTs)) and (ii) Au-doped films of AP-SWNTs (Au/AP SWNTs), P-SWNTs (Au/P-SWNTs), and C-SWNTs (Au/C-SWNTs). The density of SWNT network films was varied systematically by controlling the SWNT concentration and mediating defect formation. The electrical conductivity of each SWNT film was found to be significantly enhanced upon Au doping, with a negligible loss of optical transmittance. The effects of Au doping differed depending on the type of nanotube network present: the electrical conductivity of Au/C-SWNTs was found to be similar to that of Au/AP-SWNTs for a given transmittance, whereas the conductivity of C-SWNTs is much lower than that of the AP-SWNTs prior to Au doping. Therefore, the electrical conductivity was enhanced by the hybridization of gold nanoparticles to a larger degree in the defect-containing SWNT networks than in the AP-SWNT networks. This unusual electrical behavior of SWNT network films may be attributed to an increased number of gold nanoparticles deposited onto C-SWNT surfaces, which are formed from C-SWNTs containing an abundance of carboxylic groups. These results highlight an important consideration in the fabrication of efficient transparent conducting SWNT films for applications in optoelectronic devices.