Nanocomposites of chitosan and graphene oxide are prepared by simple self-assembly of both components in aqueous media. It is observed that graphene oxide is dispersed on a molecular scale in the chitosan matrix and some interactions occur between chitosan matrix and graphene oxide sheets. These are responsible for efficient load transfer between the nanofiller graphene and chitosan matrix. Compared with the pure chitosan, the tensile strength, and Young's modulus of the graphene-based materials are significantly improved by about 122 and 64%, respectively, with incorporation of 1 wt % graphene oxide. At the same time, the elongation at the break point increases remarkably. The experimental results indicate that graphene oxide sheets prefer to disperse well within the nanocomposites.

High-throughput screening and optimization experiments are critical to a number of fields, including chemistry and structural and molecular biology. The separation of these two steps may introduce false negatives and a time delay between initial screening and subsequent optimization. Although a hybrid method combining both steps may address these problems, miniaturization is required to minimize sample consumption. This article reports a ''hybrid'' droplet-based microfluidic approach that combines the steps of screening and optimization into one simple experiment and uses nanoliter-sized plugs to minimize sample consumption. Many distinct reagents were sequentially introduced as Ϸ140-nl plugs into a microfluidic device and combined with a substrate and a diluting buffer. Tests were conducted in Ϸ10-nl plugs containing different concentrations of a reagent. Methods were developed to form plugs of controlled concentrations, index concentrations, and incubate thousands of plugs inexpensively and without evaporation. To validate the hybrid method and demonstrate its applicability to challenging problems, crystallization of model membrane proteins and handling of solutions of detergents and viscous precipitants were demonstrated. By using 10 l of protein solution, Ϸ1,300 crystallization trials were set up within 20 min by one researcher. This method was compatible with growth, manipulation, and extraction of high-quality crystals of membrane proteins, demonstrated by obtaining high-resolution diffraction images and solving a crystal structure. This robust method requires inexpensive equipment and supplies, should be especially suitable for use in individual laboratories, and could find applications in a number of areas that require chemical, biochemical, and biological screening and optimization.droplets ͉ plugs ͉ protein structure ͉ high-throughput ͉ miniaturization T his work reports a ''hybrid'' microfluidic approach that uses nanoliter plugs to perform screening and optimization simultaneously in the same experiment. To validate this method using a challenging problem, we demonstrate its compatibility with crystallization of membrane proteins. Small-scale screening and optimization experiments are important for biological assays, chemical screening, and protein crystallization (1-3). Screening and optimization are usually carried out sequentially. In the case of protein crystallization, random sparse matrix screening initially identifies the precipitants that may lead to crystallization. Subsequent gradient optimization establishes concentrations of these precipitants that lead to diffractionquality crystals (4). Combining screening and optimization steps into a single hybrid experiment would eliminate the need to wait for the outcome of the initial screen before carrying out subsequent optimizations. Furthermore, a hybrid experiment would reduce the false negatives (5) associated with screens performed at a single concentration. The hybrid experiment could also be more conclusive, because a single batch of the s...

The synthesis of high-quality In2Se3 nanowire arrays via thermal evaporation method and the photoconductive characteristics of In2Se3 individual nanowires are first investigated. The electrical characterization of a single In2Se3 nanowire verifies an intrinsic n-type semiconductor behavior. These single-crystalline In2Se3 nanowires are then assembled in visible-light sensors which demonstrate a fast, reversible, and stable response. The high photosensitivity and quick photoresponse are attributed to the superior single-crystal quality and large surface-to-volume ratio resulting in fewer recombination barriers in nanostructures. These excellent performances clearly demonstrate the possibility of using In2Se3 nanowires in next-generation sensors and detectors for commercial, military, and space applications.

A method is presented for the scalable preparation of high-quality graphdiyne nanotubes and ultrathin graphdiyne nanosheets (average thickness: ca. 1.9 nm) using Cu nanowires as a catalyst. For the storage of Li ions, the graphdiyne nanostructures show a high capacity of 1388 mAh g and high rate performance (870 mA h g at 10 A g , and 449.8 mA h g at 20 A g ) with robust stability, demonstrating outstanding overall potential for its applications.

Emerging classes of 2D noble-transition-metal dichalcogenides (NTMDs) stand out for their unique structure and novel physical properties in recent years. With the nearly full occupation of the d orbitals, 2D NTMDs are expected to be more attractive due to the unique interlayer vibrational behaviors and largely tunable electronic structures compared to most transition metal dichalcogenide semiconductors. The novel properties of 2D NTMDs have stimulated various applications in electronics, optoelectronics, catalysis, and sensors. Here, the latest development of 2D NTMDs are reviewed from the perspective of structure characterization, preparation, and application. Based on the recent research, the conclusions and outlook for these rising 2D NTMDs are presented.Very recently, group-10 noble TMDs (NTMDs) have been reintroduced as new 2D materials, displaying many fascinating properties including widely tunable bandgap, moderate carrier mobility, anisotropy, and ultrahigh air stability. [34][35][36][37] Unlike most common TMDs with less d-electrons, the d orbitals of NTMDs are nearly fully occupied, and the corresponding p z orbital of interlayer chalcogen atoms are highly hybridized, leading to strong layer-dependent properties and interlayer interactions. [36,38] For example, it has been predicted that PtS 2 holds a layerdependent bandgap from 0.25 to 1.6 eV, [36] bridging the gap between graphene and most TMDs that with large gap. Besides, the calculated mobility based on PtS 2 , PtSe 2 , and PdSe 2 field effect transistors (FETs) is as high as ≈200 cm 2 V −1 s −1 , [36,37,39] larger than most other TMDs. Moreover, NTMDs possess high air stability, and the performance of the PtSe 2 FET remains nearly unchanged after 5 months air exposure. [37] Specially, PdS 2 and PdSe 2 hold novel puckered pentagonal structure and thus exhibit very interesting anisotropic properties, [39,40] which may bring even more physics and applications. Additionally, PtTe 2 and PdTe 2 are type-II Dirac fermions, making them great platform for investigating novel transport related to topological phase transition and chiral anomaly. [41,42] Nowadays, the 2D NTMDs is becoming increasingly fascinating in the 2D materials research.In this review, we highlight a comprehensive report of the recent research progress in 2D NTMDs such as PtS 2 , PtSe 2 , PdS 2 , PdSe 2 , PtTe 2 , and PdTe 2 . In order to understand the internal relation between structural characteristics and physical properties, this review begins with a brief summary of the structure of 2D NTMDs and their transitions. Then, some recent progress on their preparation methods, including mechanical exfoliation of the bulk materials, chemical vapor deposition (CVD), molecular beam epitaxy (MBE), is reviewed along with the performance of the resulting 2D NTMDs as high-performance candidate for field effect transistors, photodetectors, catalysis, and sensors. Finally, this review is concluded with the existing challenges and a future perspective for these rising 2D NTMDs. Structure of 2D NTM...

Two-dimensional molecular crystals, consisting of zero-dimensional molecules, are very appealing due to their novel physical properties. However, they are mostly limited to organic molecules. The synthesis of inorganic version of two-dimensional molecular crystals is still a challenge due to the difficulties in controlling the crystal phase and growth plane. Here, we design a passivator-assisted vapor deposition method for the growth of two-dimensional Sb2O3 inorganic molecular crystals as thin as monolayer. The passivator can prevent the heterophase nucleation and suppress the growth of low-energy planes, and enable the molecule-by-molecule lateral growth along high-energy planes. Using Raman spectroscopy and in situ transmission electron microscopy, we show that the insulating α-phase of Sb2O3 flakes can be transformed into semiconducting β-phase under heat and electron-beam irradiation. Our findings can be extended to the controlled growth of other two-dimensional inorganic molecular crystals and open up opportunities for potential molecular electronic devices.

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Multielemental systems enable the use of multiple degrees of freedom for control of physical properties by means of stoichiometric variation. This has attracted extremely high interest in the field of 2D optoelectronics in recent years. Here, for the first time, multilayer 2D ternary Ta2NiSe5 flakes are successfully fabricated using a mechanical exfoliation method from chemical vapor transport synthesized high quality bulk and the optoelectronic properties are systematically investigated. Importantly, a high responsivity of 17.21 A W−1 and high external quantum efficiency of 2645% are recorded from an as‐fabricated photodetector at room temperature in air; this is superior to most other 2D materials‐based photodetectors that have been reported. More intriguingly, a usual sublinear and an unusual superlinear light‐intensity‐dependent photocurrent are observed under air and vacuum, respectively. These excellent and special properties make multilayer ternary Ta2NiSe5 a highly competitive candidate for future infrared optoelectronic applications and an interesting platform for photophysics studies.