Yangang Sun

Hydrophilic Flower‐Like CuS Superstructures as an Efficient 980 nm Laser‐Driven Photothermal Agent for Ablation of Cancer Cells

Photothermal ablation (PTA) therapy has attracted much interest in recent years as a minimally invasive alternative to conventional approaches, such as surgery and chemotherapy, for therapeutic intervention of specifi c biological targets. [ 1 , 2 ] In particular, near-infrared (NIR, λ = 700–1100 nm) laser-induced PTA, which converts NIR optical energy into thermal energy, has attracted increasing attention, because the NIR laser is absorbed less by biological tissues and the typical penetration depth of the NIR (such as 980 nm) light can be several centimeters in biological tissues. [ 3 , 4 ] A prerequisite for the development of the NIR laser-induced PTA is to gain access to biocompatible and effi cient photothermal coupling agents. As the well-known NIR photothermal conversion agents, gold (Au) nanostructures, including supramolecularly assembled nanoparticles, [ 5–8 ]

MnO2 ultralong nanowires with better electrical conductivity and enhanced supercapacitor performances

Single-crystal α-MnO2 ultralong nanowires (∼40 μm in length, ∼15 nm in diameter), which were synthesized by a simple polyvinylpyrrolidone (PVP) assisted hydrothermal route, exhibited a better electrical conductivity, a highest specific capacitance of 345 F g−1 at a current density of 1 A g−1 with high rate capability (54.7% at 10 A g−1) and good cycling stability.

Lightly doped single crystalline porous Si nanowires with improved optical and electrical properties

The doping level of Si is crucial for its optical and electrical properties, and only highly doped porous Si nanowires have been reported in recent studies. Herein, we demonstrate the fabrication of lightly doped single crystalline porous Si nanowire arrays through metal-assisted chemical etching from lightly doped n-type (100) Si wafers. In this process, though the etching temperature and concentration of H2O2 in the etchant have significant effects on the uniformity and density of the porosity of the Si nanowires, the forming porous Si nanowires is available without the use of H2O2 in the etchant, which is different from the previous cases of fabricating porous Si nanowires from a highly doped Si wafer. Importantly, as-fabricated lightly doped porous Si nanowire arrays possess improved optical and electrical properties: the current value range of individual porous Si nanowire is ∼3 times as large as that of an individual solid Si nanowire under the same applied voltages range, suggesting that porous Si nanowires have enhanced electrical conductivity; an intensive photoluminescence emission peak is centered at 560 nm, showing a blue-shift of 90–120 nm compared with those of highly doped Si nanowires. The results indicate that the lightly doped single crystalline porous Si nanowires may shed light on new opportunities for nanoscale optoelectronic devices, electronics, photo-catalytic substrates and sensors.

Controllable hydrothermal synthesis, growth mechanism, and properties of ZnO three-dimensional structures

A series of ZnO three-dimensional (3D) structures, including flower-like, star-like, sphere-like and sea urchin-like morphologies, have been fabricated by a hydrothermal method without any catalyst or template. The morphologies of these ZnO structures can be conveniently controlled, by selecting the reactants and controlling the experimental conditions, with excellent reproducibility, and a specific mechanism for the formation is proposed. The ZnO 3D structures have a strong emission peak at 405 nm, and several weak emission peaks at 452, 467, 493, 541 and 568 nm, and a high sensitivity and selectivity for gas sensing of ethanol.

One-step aqueous solution synthesis of Ge nanocrystals from GeO2 powders

A one-step route to the synthesis of Ge nanocrystals on a large-scale from GeO2 powders in aqueous solution at 60 °C under an ambient atmosphere is reported, which avoids toxic precursors and by-products, high temperature, and inert atmospheres.

Morphology-selective synthesis and wettability properties of well-aligned Cu2-xSe nanostructures on a copper substrate

The morphology-selective synthesis of well-aligned Cu2-xSe nanostructures including nanosheets, nanoribbons, and heterostructures on copper substrate has been achieved by a simple hydrothermal route; the micropatterned assembly of Cu2-xSe nanostructures has been realized using a copper grid to direct the growth on prescribed arbitrary patterns with unprecedented control and selectivity. The control experimental conditions, such as hydrothermal temperature and time, and concentration of NaOH have been found to be important parameters for the growth process of the Cu2-xSe nanostructures. So-called “coordination assembly” has shown to be dominant in the formation of the Cu2-xSe nanostructures, consisting of an initial nucleation and subsequent vertical growth on the copper substrate. The wettability properties of the Cu2-xSe nanostructures have been investigated, and the water contact angle from these nanostructured materials has been measured to be up to 160°, showing a superhydrophobicity. These results might provide a facile route for the preparation of novel micropatterned and high assemblies of nanostructures on other metal substrates (e.g.Al, Zn, Mg, etc.), for which a number of promising applications in microelectronic fields can be envisioned.

Prospective important semiconducting nanotubes: synthesis, properties and applications

Semiconducting nanotubes with well-controlled dimensions, compositions and crystal structures represent a new class of intriguing systems for detailed studies of structure–property relationships at the nanoscale and prospective functional applications. This article features recent research progress in the design of different synthetic routes towards important semiconducting nanotubes made of groupIV: silicon; groupIII–V: GaN, GaP, AlN, InN and InP, and groupII–VI: ZnO, ZnS, ZnSe, CdS and CdSe. The fabricated nanotubes possess desirable atomic structures, surfaces, morphologies and properties to meet the growing demands and specific requirements of new technologies.

Hydrothermal synthesis, growth mechanism, and properties of three-dimensional micro/nanoscaled hierarchical architecture films of hemimorphite zinc silicate

A simple hydrothermal route has been developed for the fabricating hemimorphite zinc silicate, Zn4Si2O7(OH)2·H2O (ZSO), 3D hierarchical architecture films deposited on the Si substrate. Individual ZSO hierarchical architectures are assembled by many well-aligned and highly ordered rod bundles. The morphologies of the rod bundles within the ZSO hierarchical superstructures can be varied with the different surfactants and Zn sources; it realizes parts or all of the assembled rod bundles transforming into a single non-hierarchical prism. A possible mechanism for the formation of the ZSO hierarchical architectures is carefully investigated. The luminescence property of the ZSO architectures was dependent on the morphologies of the rod bundles within the ZSO hierarchical superstructures; also, as-prepared ZSO hierarchical superstructure films exhibits a hydrophobic feature.

Oriented Free-Standing Ammonium Vanadium Oxide Nanobelt Membranes: Highly Selective Absorbent Materials

Highly selective, absorbent, free-standing, paper-like membranes made of ammonium vanadium oxide (NH(4)V(4)O(14)) nanobelts have been engineered by taking advantage of the nanoscaled self-assembly of architectures that display a mesh structure with an average periodic pore size of about 5 to 10 nm. The NH(4)V(4)O(14) nanobelts are synthesized by using a simple hydrothermal process, and exhibit the same orientation and assemble into bundles, each about 40 to 80 nm in width, 3 to 5 nm in thickness, and up to several millimeters in length. Importantly, the as-obtained NH(4)V(4)O(14) nanobelt membranes can highly selectively absorb a variety of organic solvents, covering both polar and non-polar solvents, for example, the absorbent capacity of glycol is 28 times as high as the initial weight of the membrane, and it can even separate organic solvents with similar polarities and absorb solid contaminants in organic solvents. These highly selective, absorbent membrane materials can be an ideal candidate for the separation and removal of pollution in industrial and environmental applications.

A controllable hydrothermal synthesis of uniform three-dimensional hierarchical microstructured ZnO films

ZnO films composed of uniform three-dimensional (3D) hierarchical microstructures on the conductive glass were synthesized by a one-step polyethylene glycol-assisted hydrothermal route with excellent reproducibility. The morphology of the ZnO hierarchical structured films was controlled by adjusting hydrothermal reaction conditions, i.e., time, temperature, reactant concentration, Zn source and surfactant. A specific growth mechanism for the ZnO hierarchical microstructured films is proposed, and the hydrothermal time is found to be a crucial role in the formation of the hierarchical structures either from the initial nucleation and growth of the primary rods or secondary/tertiary nucleation and growth on the the column facets of the primary rods. As-fabricated ZnO films show a strong photoluminescence emission peak at 435 nm, and a superhydrophobic adhesive surface with a water contact angle of 154.1° and a high contact angle hysteresis.