Sulfur is a promising cathode material for lithium–sulfur batteries because of its high theoretical capacity (1,675 mA h g−1); however, its low electrical conductivity and the instability of sulfur-based electrodes limit its practical application. Here we report a facile in situ method for preparing three-dimensional porous graphitic carbon composites containing sulfur nanoparticles (3D S@PGC). With this strategy, the sulfur content of the composites can be tuned to a high level (up to 90 wt%). Because of the high sulfur content, the nanoscale distribution of the sulfur particles, and the covalent bonding between the sulfur and the PGC, the developed 3D S@PGC cathodes exhibit excellent performance, with a high sulfur utilization, high specific capacity (1,382, 1,242 and 1,115 mA h g−1 at 0.5, 1 and 2 C, respectively), long cycling life (small capacity decay of 0.039% per cycle over 1,000 cycles at 2 C) and excellent rate capability at a high charge/discharge current.

In this paper, we show that well-defined, highly crystalline nanowires of a rigid rod conjugated polymer, a poly(para-phenylene ethynylene)s derivative with thioacetate end groups (TA-PPE), can be obtained by self-assembling from a dilute solution. Structural analyses demonstrate the nanowires with an orthorhombic crystal unit cell wherein the lattice parameters are a approximately = 13.63 A, b approximately = 7.62 A, and c approximately = 5.12 A; in the nanowires the backbones of TA-PPE chains are parallel to the nanowire long axis with their side chains standing on the substrate. The transport properties of the nanowires examined by organic field-effect transistors (OFETs) suggest the highest charge carrier mobility approaches 0.1 cm(2)/(V s) with an average value at approximately 10(-2) cm(2)/(V s), which is 3-4 orders higher than that of thin film transistors made by the same polymer, indicating the high performance of the one-dimensional polymer nanowire crystals. These results are particular intriguing and valuable for both examining the intrinsic properties of PPEs polymer semiconductors and advancing their potential applications in electronic devices.

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For the first time, a composite of fluorine-doped SnO 2 and reduced graphene oxide (F-SnO 2 @RGO) was synthesized using a cheap F-containing Sn source, Sn(BF 4 ) 2 , through a hydrothermal process. X-ray photoelectron spectroscopy and X-ray diffraction results identified that F was doped in the unit cells of the SnO 2 nanocrystals, instead of only on the surfaces of the nanoparticles. F doping of SnO 2 led to more uniform and higher loading of the F-SnO 2 nanoparticles on the surfaces of RGO sheets, as well as enhanced electron transportation and Li ion diffusion in the composite. As a result, the F-SnO 2 @RGO composite exhibited a remarkably high specific capacity (1277 mA h g -1 after 100 cycles), a long-term cycling stability, and excellent high-rate capacity at large charge/discharge current densities as anode material for lithium ion batteries. The outstanding performance of the F-SnO 2 @RGO composite electrode could be ascribed to the combined features of the composite electrode that dealt with both the electrode dynamics (enhanced electron transportation and Li ion diffusion due to F doping) and the electrode structure (uniform decoration of the F-SnO 2 nanoparticles on the surfaces of RGO sheets and the three-dimensional porous structures of the F-SnO 2 @RGO composite).

Oligoarenes as an alternative group of promising semiconductors in organic optoelectronics have attracted much attention. However, high‐performance and low‐cost opto‐electrical devices based on linear asymmetric oligoarenes with nano/microstructures are still rarely studied because of difficulties both in synthesis and high‐quality nano/microstructure growth. Here, a novel linear asymmetric oligoarene 6‐methyl‐anthra[2,3‐b]benzo[d]thiophene (Me‐ABT) is synthesized and its high‐quality microribbons are grown by a solution process. The solution of Me‐ABT exhibits a moderate fluorescence quantum yield of 0.34, while the microribbons show a glaucous light emission. Phototransistors based on an individual Me‐ABT microribbon prepared by a solution‐phase self‐assembly process showed a high mobility of 1.66 cm2 V−1 s−1, a large photoresponsivity of 12 000 A W−1, and a photocurrent/dark‐current ratio of 6000 even under low light power conditions (30 µW cm−2). The measured photoresponsivity of the devices is much higher than that of inorganic single‐crystal silicon thin film transistors. These studies should boost the development of the organic semiconductors with high‐quality microstructures for potential application in organic optoelectronics.

Over the past 20 years, organic field-effect transistors (OFETs) based on soluble polymers and conjugated oligomers have attracted enormous interest for the realization of organic electronic devices. 1 Pentacene as the benchmark material with a mobility beyond 1.0 cm 2 V -1 s -1 has been reported. 2 Despite the great progress in the exploration of functional organic materials for OFETs, 3 fundamental aspects of carrier transport, especially the role of solid-state packing, still remain unclear. 4 From the standpoint of bandwidth and the hopping theory of carrier conduction, a cofacial π stacking structure is expected to facilitate carrier transport. 4,5 However, most of the organic semiconductors with high mobilities have a herringbone structure which reduces the overlap. 6 On the other hand, the research work for OFETs has mainly focused on thin-film and bulk singlecrystal state. Study of micro-and nanomaterials, including fibers, ribbons, and wires, has only been recently reported because of the potential applications in integrated (opto) electronic devices due to many unique properties, such as flexibility, high photoconductivity, and nonlinear optical effects, etc. 7 Herein we present our studies of a new class of a high-performance OFET semiconductor based on perylo [1,12-b,c,d]thiophene (PET, Figure 1). The integration of a S atom into the polycyclic aromatic hydrocarbon (PAH) skeleton induces an extraordinary solid-state packing arrangement with the likelihood of double-channel superstructure, which is expected to permit effective charge transporting. Furthermore, we have grown its micrometer single-crystal wires by physical vapor transport and successfully applied them to transistors. The devices exhibit excellent performance with a high mobility up to 0.8 cm 2 V -1 s -1 .The oligothiophene and PAHs are among the most versatile and effective molecular scaffolds for organic functional materials. It is thus surprising that little effort has been devoted to exploiting sulfur heterocyclic PAHs in OFETs. We choose PET as an ideal system for investigating structure-property relationships among organic semiconductors because of its unique packing in single crystals ( Figure 1). Although its synthesis was first reported by Rogovik, 8 its electrical property is rarely studied. The crystal structure contains almost planar PET molecules stacked along the b-axis with interplanar distances of 3.47 Å, 9 in contrast to the sandwich herringbone packing of perylene crystals. Remarkably, marked S‚ ‚‚S short contacts (3.51 Å) were found between the neighboring columns related by an inversion center. The double-channel fashion is envisioned to be transformed into the facile establishment of a high-performance charge transport system.As a control result, we have first investigated the thin-film fieldeffect behavior of PET. Transistors have been fabricated on SiO 2 / Si substrate with octadecyltrichlorosilane (OTS) treatment, adopting a top-contact configuration. Only p-channel activity is observed for the device. It exhibits...

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Understanding the cellular internalization mechanism of nanoparticles is essential to study their biological fate. Especially, due to the anisotropic properties, rod-like nanoparticles have attracted growing interest for the enhanced internalization efficiency with respect to spherical nanoparticles. Here, to elucidate the effect of aspect ratio of rod-like nanoparticles on cellular uptake, tobacco mosaic virus (TMV), a typical rod-like bionanoparticle, is developed as a model. Nanorods with different aspect ratios can be obtained by ultrasound treatment and sucrose density gradient centrifugation. By incubating with epithelial and endothelial cells, we found that the rod-like bionanoparticles with various aspect ratios had different internalization pathways in different cell lines: microtubules transport in HeLa and clathrin-mediated uptake in HUVEC for TMV4 and TMV8; caveolae-mediated pathway and microtubules transport in HeLa and HUVEC for TMV17. Differently from most nanoparticles, for all the three TMV nano-rods with different aspect ratios, macropinocytosis takes no effect on the internalization in both cell types. This work provides a fundamental understanding of the influence of aspect ratio on cellular uptake decoupled from charge and material composition.