Discovery of novel topological orders of condensed matters is of a significant interest in bothfundamental and applied physics due to the associated quantum conductance behaviors and unique symmetry-protected backscattering-immune propagation against defects, which inspired similar fantastic effects in classical waves system, leading to the revolution of the manipulation of wave propagation. To date, however, only few theoretical models were proposed to realize acoustic topological states. Here, we theoretically and experimentally demonstrate a two dimensional acoustic topological insulators with acoustic analogue of quantum spin Hall Effect. Due to the band inversion mechanism near the double Dirac cones, acoustic one-way pseudospin dependent

Two‐variant stripe domains in BiFeO3 films on miscut (001) SrTiO3 substrates exhibit square‐like, complete ferroelectric switching with low leakage current. Both the preferential distortion of BiFeO3 unit cells and the persistent step‐flow growth induced by the substrate anisotropy are the origins of the formation of the two‐variant stripe domains in (001) BiFeO3 films.

We report on studies of field-effect transistor (FET) and transparent thin-film transistor (TFT) devices based on lightly Ta-doped SnO2 nano-wires. The nanowire-based devices exhibit uniform characteristics with average field-effect mobilities exceeding 100 cm2/V x s. Prototype nano-wire-based TFT (NW-TFT) devices on glass substrates showed excellent optical transparency and transistor performance in terms of transconductance, bias voltage range, and on/off ratio. High on-currents and field-effect mobilities were obtained from the NW-TFT devices even at low nanowire coverage. The SnO2 nanowire-based TFT approach offers a number of desirable properties such as low growth cost, high electron mobility, and optical transparency and low operation voltage, and may lead to large-scale applications of transparent electronics on diverse substrates.

We report the growth and characterization of single-crystalline Sn-doped In 2 O 3 (ITO) and Mo-doped In 2 O 3 (IMO) nanowires. Epitaxial growth of vertically aligned ITO nanowire arrays was achieved on ITO/yttria-stabilized zirconia (YSZ) substrates. Optical transmittance and electrical transport measurements show that these nanowires are high-performance transparent metallic conductors with transmittance of ∼85% in the visible range, resistivities as low as 6.29 × 10 -5 Ω·cm and failure-current densities as high as 3.1 × 10 7 A/cm 2 . Such nanowires will be suitable in a wide range of applications including organic light-emitting devices, solar cells, and field emitters. In addition, we demonstrate the growth of branched nanowire structures in which semiconducting In 2 O 3 nanowire arrays with variable densities were grown epitaxially on metallic ITO nanowire backbones.One-dimensional (1D) nanostructures such as nanowires, nanorods, and nanobelts have become the focus of intensive investigation in the past decade as potential building blocks for nanoscale devices and sensors. 1-5 Along with group IV and III-V materials, metal oxide (including In 2 O 3 , SnO 2 and ZnO) nanowires have been widely studied due to their excellent electrical and optical properties and ease of fabrication. [6][7][8] In these studies the metal oxide nanowires are typically not intentionally doped, and the carriers are normally generated by structural defects such as oxygen deficiencies. As a result, the devices behave as wide band gap semiconductors whose performance is influenced by the surrounding environment. 8 On the other hand, intentional doping can greatly modify the device properties and yield new device applications. One such example is tin-doped indium oxide (ITO), in which metal-like behavior is achieved when In 2 O 3 is degenerately doped by Sn. Due to its high conductivity and high transmittance in the visible spectral region, 9 ITO has become by far the most important transparent conducting oxide material, and ITO films have found applications in various optoelectronic devices such as flatpanel displays, solar cells, and light-emitting diodes. [10][11][12] The ability to obtain highly transparent and highly conducting ITO nanowires may potentially further enhance the performance of such devices due to the increased effective device area using nanowire electrodes. Furthermore, similar to NiSi and TaSi 2 nanowires, 13,14 the highly conducting ITO nanowires may also be used as interconnects in integrated nanocsale devices.The growth of ITO nanowires/nanorods has been reported by several groups since the first study on In 2 O 3 nanobelts in 2001. [15][16][17][18][19][20][21] However, detailed electrical characterizations have not been reported, and it is not clear whether these ITO nanowire/nanorods have the desired electrical properties. For example, the only reported resistivity value is ∼0.4 Ω‚cm, 18 which is several orders higher than that can be obtained in commercially available ITO films 9 and clearly too high ...

Up-regulated PD-L1 expression in NSCLC is related to the degree of tumor cell differentiation and TNM stage. PD-L1 status may be a new predictor of prognosis for patients with NSCLC.

Recently, three-dimensional (3D) halide perovskites were considered as Xray detection materials because of their high mobility, carrier lifetime, and absorption of Xray radiation. However, their detection sensitivity and instability at extreme conditions and environments still require optimization. In our present research work, we report using onedimensional (1D) inorganic halide perovskite CsPbI 3 crystals for stable X-ray detection. Remarkably, an X-ray detector made of CsPbI 3 has a high sensitivity of 2.37 mC•Gy −1 • cm −2 , which is an order of magnitude greater than that of detectors using 3D halide perovskites reported previously. The high-sensitivity X-ray detection of CsPbI 3 crystals is attributed to their high resistivity of 7.4 × 10 9 Ω•cm and large carrier mobility−lifetime product of 3.63 × 10 −3 cm 2 •V −1 . Our investigation demonstrates the quite promising applications of X-ray detectors made of the low-dimensional perovskite crystals.

The intrinsic poor thermal stability of layered LiNi x Co y Mn 1−x−y O 2 (NCM) cathodes and the exothermic side reactions triggered by the associated oxygen release are the main safety threats for their large-scale implantation. In the NCM family, it is widely accepted that Ni is the stability troublemaker, while Mn has long been considered as a structure stabilizer, whereas the role of Co remains elusive. Here, via Co/Mn exchange in a Ni-rich LiNi 0.83 Co 0.11 Mn 0.06 O 2 cathode, we demonstrate that the chemical and structural stability of the deep delithiated NCM cathodes are significantly dominated by Co rather than the widely reported Mn. Operando synchrotron X-ray characterization coupling with in situ mass spectrometry reveal that the Co 4+ reduces prior to the reduction of Ni 4+ and could thus prolong the Ni migration by occupying the tetrahedra sites and, hence, postpone the oxygen release and thermal failure. In contrast, the Mn itself is stable, but barely stabilizes the Ni 4+ . Our results highlight the importance of evaluating the intrinsic role of compositional tuning on the Ni-rich/Cofree layered oxide cathode materials to guarantee the safe operation of high-energy Li-ion batteries.

Silicon, one of the most promising candidates as lithium-ion battery anode, has attracted much attention due to its high theoretical capacity, abundant existence, and mature infrastructure. Recently, Si nanostructures-based lithium-ion battery anode, with sophisticated structure designs and process development, has made significant progress. However, low cost and scalable processes to produce these Si nanostructures remained as a challenge, which limits the widespread applications. Herein, we demonstrate that Si nanoparticles with controlled size can be massively produced directly from low grade Si sources through a scalable high energy mechanical milling process. In addition, we systematically studied Si nanoparticles produced from two major low grade Si sources, metallurgical silicon (∼99 wt % Si, $1/kg) and ferrosilicon (∼83 wt % Si, $0.6/kg). It is found that nanoparticles produced from ferrosilicon sources contain FeSi2, which can serve as a buffer layer to alleviate the mechanical fractures of volume expansion, whereas nanoparticles from metallurgical Si sources have higher capacity and better kinetic properties because of higher purity and better electronic transport properties. Ferrosilicon nanoparticles and metallurgical Si nanoparticles demonstrate over 100 stable deep cycling after carbon coating with the reversible capacities of 1360 mAh g(-1) and 1205 mAh g(-1), respectively. Therefore, our approach provides a new strategy for cost-effective, energy-efficient, large scale synthesis of functional Si electrode materials.