Electromechanically Responsive Liquid Crystal Elastomer Nanocomposites for Active Cell Culture.

Liquid crystal elastomers (LCEs) are unique among shape-responsive materials in that they exhibit large and reversible shape changes and can respond to a variety of stimuli. However, only a handful of studies have explored LCEs for biomedical applications. Here, we demonstrate that LCE nanocomposites (LCE-NCs) exhibit a fast and reversible electromechanical response and can be employed as dynamic substrates for cell culture.

Role of Atomic Layer Functionalization in Building Scalable Bottom-Up Assembly of Ultra-Low Density Multifunctional Three-Dimensional Nanostructures.

Building three-dimensional (3D) structures from their constituent zero-, one-, and two-dimensional nanoscale building blocks in a bottom-up assembly is considered the holey grail of nanotechnology. However, fabricating such 3D nanostructures at ambient conditions still remains a challenge. Here, we demonstrate an easily scalable facile method to fabricate 3D nanostructures made up of entirely zero-dimensional silicon dioxide (SiO) nanoparticles.

A metal-free electrocatalyst for carbon dioxide reduction to multi-carbon hydrocarbons and oxygenates.

Electroreduction of carbon dioxide into higher-energy liquid fuels and chemicals is a promising but challenging renewable energy conversion technology. Among the electrocatalysts screened so far for carbon dioxide reduction, which includes metals, alloys, organometallics, layered materials and carbon nanostructures, only copper exhibits selectivity towards formation of hydrocarbons and multi-carbon oxygenates at fairly high efficiencies, whereas most others favour production of carbon monoxide or formate. Here we report that nanometre-size N-doped graphene quantum dots (NGQDs) catalyse the electrochemical reduction of carbon dioxide into multi-carbon hydrocarbons and oxygenates at high Faradaic efficiencies, high current densities and low overpotentials.

Brittle Fracture of 2D MoSe.

An in situ quantitative tensile testing platform is developed to enable the uniform in-plane loading of a freestanding membrane of 2D materials inside a scanning electron microscope. The in situ tensile testing reveals the brittle fracture of large-area MoSe crystals and measures their fracture strength for the first time.

All-Carbon Ultrafast Supercapacitor by Integrating Multidimensional Nanocarbons.

Ultrafast and high capacity all-carbon supercapacitors with 3D porous aerogel electrode are realized by combining carbon nanostructures of various dimensionalities, including 0D carbon onions, 1D carbon nanotubes, and 2D graphene oxide. The synergistic effects from the different forms of nanocarbons render this hybrid outstanding capacitance with excellent stability, even at ultrafast charge-discharge rates.

Imaging the motion of electrons across semiconductor heterojunctions.

Technological progress since the late twentieth century has centred on semiconductor devices, such as transistors, diodes and solar cells. At the heart of these devices is the internal motion of electrons through semiconductor materials due to applied electric fields or by the excitation of photocarriers. Imaging the motion of these electrons would provide unprecedented insight into this important phenomenon, but requires high spatial and temporal resolution.

High temperature electrical energy storage: advances, challenges, and frontiers.

With the ongoing global effort to reduce greenhouse gas emission and dependence on oil, electrical energy storage (EES) devices such as Li-ion batteries and supercapacitors have become ubiquitous. Today, EES devices are entering the broader energy use arena and playing key roles in energy storage, transfer, and delivery within, for example, electric vehicles, large-scale grid storage, and sensors located in harsh environmental conditions, where performance at temperatures greater than 25 °C are required. The safety and high temperature durability are as critical or more so than other essential characteristics (e.

Multifunctional CuTe Nanocubes Mediated Combination Therapy for Multi-Drug Resistant MDA MB 453.

Hypermethylated cancer populations are hard to treat due to their enhanced chemo-resistance, characterized by aberrant methylated DNA subunits. Herein, we report on invoking response from such a cancer lineage to chemotherapy utilizing multifunctional copper telluride (CuTe) nanocubes (NCs) as photothermal and photodynamic agents, leading to significant anticancer activity. The NCs additionally possessed photoacoustic and X-ray contrast imaging abilities that could serve in image-guided therapeutic studies.

3D Porous Graphene by Low-Temperature Plasma Welding for Bone Implants.

3D scaffolds of graphene, possessing ultra-low density, macroporous microstructure, and high yield strength and stiffness can be developed by a novel plasma welding process. The bonding between adjacent graphene sheets is investigated by molecular dynamics simulations. The high degree of biocompatibility along with high porosity and good mechanical properties makes graphene an ideal material for use as body implants.

Nanoscale-Barrier Formation Induced by Low-Dose Electron-Beam Exposure in Ultrathin MoS Transistors.

Utilizing an innovative combination of scanning-probe and spectroscopic techniques, supported by first-principles calculations, we demonstrate how electron-beam exposure of field-effect transistors, implemented from ultrathin molybdenum disulfide (MoS), may cause nanoscale structural modifications that in turn significantly modify the electrical operation of these devices. Quite surprisingly, these modifications are induced by even the relatively low electron doses used in conventional electron-beam lithography, which are found to induce compressive strain in the atomically thin MoS. Likely arising from sulfur-vacancy formation in the exposed regions, the strain gives rise to a local widening of the MoS bandgap, an idea that is supported both by our experiment and by the results of first-principles calculations.

Thermally Assisted Nonvolatile Memory in Monolayer MoS Transistors.

We demonstrate a novel form of thermally-assisted hysteresis in the transfer curves of monolayer MoS FETs, characterized by the appearance of a large gate-voltage window and distinct current levels that differ by a factor of ∼10. The hysteresis emerges for temperatures in excess of 400 K and, from studies in which the gate-voltage sweep parameters are varied, appears to be related to charge injection into the SiO gate dielectric. The thermally-assisted memory is strongly suppressed in equivalent measurements performed on bilayer transistors, suggesting that weak screening in the monolayer system plays a vital role in generating its strongly sensitive response to the charge-injection process.

Blue photoluminescent carbon nanodots from limeade.

Carbon-based photoluminescent nanodot has currently been one of the promising materials for various applications. The remaining challenges are the carbon sources and the simple synthetic processes that enhance the quantum yield, photostability and biocompatibility of the nanodots. In this work, the synthesis of blue photoluminescent carbon nanodots from limeade via a single-step hydrothermal carbonization process is presented.

Bifunctional Luminomagnetic Rare-Earth Nanorods for High-Contrast Bioimaging Nanoprobes.

Nanoparticles exhibiting both magnetic and luminescent properties are need of the hour for many biological applications. A single compound exhibiting this combination of properties is uncommon. Herein, we report a strategy to synthesize a bifunctional luminomagnetic Gd2-xEuxO3 (x = 0.

Ballistic Fracturing of Carbon Nanotubes.

Advanced materials with multifunctional capabilities and high resistance to hypervelocity impact are of great interest to the designers of aerospace structures. Carbon nanotubes (CNTs) with their lightweight and high strength properties are alternative to metals and/or metallic alloys conventionally used in aerospace applications. Here we report a detailed study on the ballistic fracturing of CNTs for different velocity ranges.

In Situ Synthesis of Metal Nanoparticle Embedded Hybrid Soft Nanomaterials.

The allure of integrating the tunable properties of soft nanomaterials with the unique optical and electronic properties of metal nanoparticles has led to the development of organic-inorganic hybrid nanomaterials. A promising method for the synthesis of such organic-inorganic hybrid nanomaterials is afforded by the in situ generation of metal nanoparticles within a host organic template. Due to their tunable surface morphology and porosity, soft organic materials such as gels, liquid crystals, and polymers that are derived from various synthetic or natural compounds can act as templates for the synthesis of metal nanoparticles of different shapes and sizes.

Synthesis of ultralow density 3D graphene-CNT foams using a two-step method.

Here, we report a highly scalable two-step method to produce graphene foams with ordered carbon nanotube reinforcements. In our approach, we first used solution assembly methods to obtain graphene oxide foam. Next, we employed chemical vapor deposition to simultaneously grow carbon nanotubes and thermally reduce the 3D graphene oxide scaffold.

Ultrafast formation of interlayer hot excitons in atomically thin MoS2/WS2 heterostructures.

Van der Waals heterostructures composed of two-dimensional transition-metal dichalcogenides layers have recently emerged as a new family of materials, with great potential for atomically thin opto-electronic and photovoltaic applications. It is puzzling, however, that the photocurrent is yielded so efficiently in these structures, despite the apparent momentum mismatch between the intralayer/interlayer excitons during the charge transfer, as well as the tightly bound nature of the excitons in 2D geometry. Using the energy-state-resolved ultrafast visible/infrared microspectroscopy, we herein obtain unambiguous experimental evidence of the charge transfer intermediate state with excess energy, during the transition from an intralayer exciton to an interlayer exciton at the interface of a WS2/MoS2 heterostructure, and free carriers moving across the interface much faster than recombining into the intralayer excitons.

Room-temperature ferroelectricity in CuInP2S6 ultrathin flakes.

Two-dimensional (2D) materials have emerged as promising candidates for various optoelectronic applications based on their diverse electronic properties, ranging from insulating to superconducting. However, cooperative phenomena such as ferroelectricity in the 2D limit have not been well explored. Here, we report room-temperature ferroelectricity in 2D CuInP2S6 (CIPS) with a transition temperature of ∼320 K.

Solid-Vapor Reaction Growth of Transition-Metal Dichalcogenide Monolayers.

Two-dimensional (2D) layered semiconducting transition-metal dichalcogenides (TMDCs) are promising candidates for next-generation ultrathin, flexible, and transparent electronics. Chemical vapor deposition (CVD) is a promising method for their controllable, scalable synthesis but the growth mechanism is poorly understood. Herein, we present systematic studies to understand the CVD growth mechanism of monolayer MoSe2 , showing reaction pathways for growth from solid and vapor precursors.

Insight into In Situ Amphiphilic Functionalization of Few-Layered Transition Metal Dichalcogenide Nanosheets.

A facile route toward functionalized amphiphilic layered transition-metal dichalcogenide nanosheets through in situ polymerization of polystyrene-polyacrylamide copolymers is established. The attachment of copolymers greatly affects their dispersibility in different kinds of solvents. Surface-tension components, polarity, and coordination effects of the copolymer are found to be the main factors affecting the dispersibility.

Fabrication and Experimental Analysis of Axially Oriented Nanofibers.

A novel design of a laboratory built axially rotating collector (ARC) having capability to align electrospun nanofibers have been described. A detailed morphological comparison of such nanofibers orientation and their geometry is done using scanning electron microscopy (SEM). For comparison various polymeric solutions were electrospun on conventional static collector as well as ARC.

High hardness in the biocompatible intermetallic compound β-Ti3Au.

The search for new hard materials is often challenging, but strongly motivated by the vast application potential such materials hold. Ti3Au exhibits high hardness values (about four times those of pure Ti and most steel alloys), reduced coefficient of friction and wear rates, and biocompatibility, all of which are optimal traits for orthopedic, dental, and prosthetic applications. In addition, the ability of this compound to adhere to ceramic parts can reduce both the weight and the cost of medical components.

High-efficiency two-dimensional Ruddlesden-Popper perovskite solar cells.

Three-dimensional organic-inorganic perovskites have emerged as one of the most promising thin-film solar cell materials owing to their remarkable photophysical properties, which have led to power conversion efficiencies exceeding 20 per cent, with the prospect of further improvements towards the Shockley-Queisser limit for a single‐junction solar cell (33.5 per cent). Besides efficiency, another critical factor for photovoltaics and other optoelectronic applications is environmental stability and photostability under operating conditions.

Controlled synthesis and comparison of NiCo2S4/graphene/2D TMD ternary nanocomposites for high-performance supercapacitors.

Novel ternary electrode materials based on graphene, NiCo2S4, and transition metal dichalcogenides (TMDs) were designed and fabricated with the intention of exploiting synergistic effects conducive to supercapacitive energy storage. Compared to NiCo2S4-g-MoSe2, the NiCo2S4-g-MoS2 electrode exhibited higher specific capacitance, enhanced rate capability (1002 F g(-1) even at 5 A g(-1), 6.01 F cm(-2) at a current density of 25 mA cm(-2)) and cycling stability (94.

Interphase Induced Dynamic Self-Stiffening in Graphene-Based Polydimethylsiloxane Nanocomposites.

The ability to rearrange microstructures and self-stiffen in response to dynamic external mechanical stimuli is critical for biological tissues to adapt to the environment. While for most synthetic materials, subjecting to repeated mechanical stress lower than their yield point would lead to structural failure. Here, it is reported that the graphene-based polydimethylsiloxane (PDMS) nanocomposite, a chemically and physically cross-linked system, exhibits an increase in the storage modulus under low-frequency, low-amplitude dynamic compressive loading.