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Stability and high energy densities are essential qualities for emerging battery electrodes. Because of its high specific capacity, silicon has been considered a promising anode candidate. However, the several-fold volume changes during lithiation and delithiation leads to fractures and continuous formation of an unstable solid-electrolyte interphase (SEI) layer, resulting in rapid capacity decay. Here, we present a carbon-silicon-carbon (C@Si@C) nanotube sandwich structure that addresses the mechanical and chemical stability issues commonly associated with Si anodes. The C@Si@C nanotube array exhibits a capacity of ∼2200 mAh g(-1) (∼750 mAh cm(-3)), which significantly exceeds that of a commercial graphite anode, and a nearly constant Coulombic efficiency of ∼98% over 60 cycles. In addition, the C@Si@C nanotube array gives much better capacity and structure stability compared to the Si nanotubes without carbon coatings, the ZnO@C@Si@C nanorods, a Si thin film on Ni foam, and C@Si and Si@C nanotubes. In situ SEM during cycling shows that the tubes expand both inward and outward upon lithiation, as well as elongate, and then revert back to their initial size and shape after delithiation, suggesting stability during volume changes. The mechanical modeling indicates the overall plastic strain in a nanotube is much less than in a nanorod, which may significantly reduce low-cycle fatigue. The sandwich-structured nanotube design is quite general, and may serve as a guide for many emerging anode and cathode systems.

InGaN-based blue light-emitting diodes (LEDs), with their high efficiency and brightness, are entering the display industry. However, a significant gap remains between the expectation of highly efficient light sources and their experimental realization into tiny pixels for ultrahighdensity displays for augmented reality (AR). Herein, we report using tailored ion implantation (TIIP) to fabricate highly-efficient, electrically-driven pixelated InGaN microLEDs (μLEDs) at the mid-submicron scale (line/space of 0.5/0.5 μm), corresponding to 8500ppi (RGB). Creating a laterally confined nonradiative region around each pixel with controlled amount of mobile vacancies, TIIP pixelation materializes relatively invariant luminance, and high pixel distinctiveness, at submicron-sized pixels. Moreover, with incomparable integration capability of TIIP pixelation owing to its planar geometry, we demonstrate 2000 ppi μLED displays with monolithically integrated thin-film transistor pixel circuits, and 5000 ppi compatible core technologies. We expect that the demonstrated method will pave the way toward highperformance μLED displays for seamless AR glasses in the near future.

As potential high-performance anodes for Li-ion batteries (LIBs), hierarchical heteronanostructures consisting of TiNbO nanofibers and ultrathin MoS2 nanosheets (TNO@MS HRs) were synthesized by simple electrospinning/hydrothermal processes. With their growth mechanism revealed, the TNO@MS HRs exhibited an entangled structure both for their ionic and electronic conducting pathways, which enabled the synergetic combination of one- and two-dimensional structures to be realized. In the potential range of 0.001-3 V vs Li/Li, the TNO@MS HR-based LIBs exhibited high capacities of 872 and 740 mAh g after 42 and 200 cycles at a current density of 1 A g, respectively, and excellent rate performance of 611 mAh g at 4 A g. We believe that the fabrication route of TNO@MS HRs will find visibility for the use of anode electrodes for high capacity LIBs at low cost.

WSe 2 , etc.) and other mono-elemental materials (e.g., black phosphorus, tellurene, etc.) have generated significant interest in numerous research fields. [2][3][4][5][6] In particular, atomically thin monolayers have proven to be an ideal platform for the exploration of the unique features associating with 2D electronic systems such as ultrahigh mobility, [7] quantum phase transition, [8] indirect exciton condensation, [9] quantum oscillation, [10] and the quantum Hall effect. [11] Despite the unique merits of monolayers, multilayers, which consist of multiple conducting monolayers, may be a better candidate for most 2D layered materials because of their higher carrier mobility and larger current density compared to monolayers, with respect to applications in electronic devices. [3,6,12,13] Previous theoretical and experimental investigations have clearly demonstrated that the effective mass increases with bandgap energy as thickness reduced. [14] In addition, the adjacent surface phonon and numerous Coulomb scatterers that surround atomically thin channel materials further degrade the intrinsic carrier mobility, [15,16] implying the disadvantage of monolayer platform as a transistor.Among the various families of 2D layered materials, a multilayer rhenium disulfide (ReS 2 ) has recently garnered notable attention because of their three unique properties compared to other TMD materials; i) anisotropic in-plane transport, ii) direct bandgap, and iii) layer-independent electronic band structure. [17] The distorted octahedral (1T′) structure of ReS 2 is responsible for the anisotropic in-plane transport property. [18][19][20] The layer-independent electronic band structure with direct bandgap is linked to a decoupled vdW interaction between adjacent layers, [21] leading to a much higher interlayer resistivity of bulk ReS 2 [22] compared to that of the other TMDs [23] including MoS 2 . [24] This fact implies that few-layered ReS 2 is the potentially a superior platform for studying intrinsic carrier transport features of multilayer systems. This is because the interlayer resistivity governs the charge distribution along the channel thickness [25] and the channel access resistance, in addition to the Thomas-Fermi charge screening length.Herein, we report on the distinctive electron conduction mechanism of few-layered 1T′ ReS 2 by presenting; i) the anisotropic carrier transport, ii) modification of charge distribution Charge carrier transport in multilayer van der Waals (vdW) materials, which comprise multiple conducting layers, is well described using Thomas-Fermi charge screening (λ TF ) and interlayer resistance (R int ). When both effects occur in carrier transport, a channel centroid migrates along the c-axis according to a vertical electrostatic force, causing redistribution of the conduction centroid in a multilayer system, unlike a conventional bulk material. Thus far, numerous unique properties of vdW materials are discovered, but direct evidence for distinctive charge transport behavior in 2D layered materi...

We have fabricated fully vacuum-sealed 5 in. diagonal carbon nanotube field-emission displays of a gated structure with reliable electron emission characteristics. Single-walled carbon nanotube tips were implemented into the gate structure using self-aligned backside exposure of photosensitive carbon nanotube paste. An onset gate electrode voltage for emission was about 60 V and the luminance as high as 510 cd/m2 was exhibited under an application of 100 V and 1.5 kV to gate electrode and anode, respectively.

3D mesostructured AgCl-KCl photonic crystals emerge from colloidal templating of eutectic solidification. Solvent removal of the KCl phase results in a mesostructured AgCl inverse opal. The 3D-template-induced confinement leads to the emergence of a complex microstructure. The 3D mesostructured eutectic photonic crystals have a large stop band ranging from the near-infrared to the visible tuned by the processing.

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