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Controlling the crystal phase in layered transition metal dichalcogenides (TMDs) is critical for their diverse, flexible applications. However, due to the thermodynamic stability of 2H over other polymorphs, fine synthesis control over polymorphism in TMDs is challenging, restricting the entire range of characteristics associated with other polymorphs. Herein, we present a solution-based crystal phase engineering approach for layered transition metal disulphide nanosheets by modulating the reactivity of the molecular precursors. By tuning precursor–ligand chemistry, 2H, 1T′ and polytypic MoS2 and WS2 are synthesised. The flexibility to selectively modify the reactivity of S and metal precursors allowed control over the proportion of specific phases in synthesised nanosheets. The formation of 1T′ is facilitated by the highly reactive metal and S source, whereas less reactive sources lead to the formation of thermodynamically stable 2H. The electrocatalytic properties of the synthesised TMDs were examined for the oxygen reduction reaction. The polytypic MoS2 comprising a mix of 2H–1T′ displayed the most positive potential of 0.82 V (vs. RHE). The comprehensive mechanistic interpretation of the chemical transformations provided in this study will be instrumental in designing scalable solution-based pathways for phase engineering in layered transition metal dichalcogenides. Furthermore, this synthesis approach has the potential to be extended to various TMD compositions, enabling exquisite control over polymorphism in TMDs. [ABSTRACT FROM AUTHOR]

Multifunctional multinary metal chalcogenides have long been a research hotspot in the field of materials chemistry due to their rich composition, flexible structure, excellent properties and wide range of applications. However, the exploration of complex quinary chalcogenides is still challenging. In this work, for the first time, we have developed the controlled synthesis of quinary Cu3NiInSnS6 nanocrystals, realizing the selective preparation of hexagonal wurtzite and cubic zinc blende metastable phases by simply tuning the sulfur source. The phase structure analysis reveals that both metastable phases possess a disordered structure with a random distribution of metal atoms in the unit cells. The fabricated wurtzite and zinc blende-structure Cu3NiInSnS6 nanocrystals have a direct band gap of 1.82 and 1.94 eV, respectively, and both exhibit superparamagnetic behavior at low temperatures. This work is of great significance for the development of novel multifunctional materials based on metastable multinary metal chalcogenide phases. [ABSTRACT FROM AUTHOR]

Hollow polycrystalline structures and noble-metal-coating endow ternary sulfides with promising light absorption and electrical properties for solar energy conversion applications. We developed a facile one-pot solvothermal chemical route to synthesize hollow Cu3SbS4 microspheres with an opening. Additionally, four phase-pure Cu–Sb–S high-quality nanocrystals can be produced in a selectable way by the same route. The detailed evolution process and self-driven breakage mechanism have been proposed in detail. Subsequently, in situ reduction of the Ag-ion precursor was conducted and Ag clusters were uniformly deposited in the hollow spherical architecture with a nanoparticle-textured surface and interior to mitigate the oxidization of Cu3SbS4 nanoparticles. The created hollow metal-semiconductor nanocomposite opens up a favorable new situation. The nanocomposites exhibited a remarkably enhanced absorption of over 2 × 105 cm−1, covering the UV and visible regions of the electromagnetic spectrum. The electrical resistivity decreased drastically by 90% after the coating of noble metals. A reduction in the bandgap energy after the addition of Ag to Cu3SbS4 was confirmed from extrapolated optical results and theoretical calculation validation. The synthetic effect of hollow structures and nanocomposites results in the superior performance of Cu–Sb–S compounds, thus highlighting their potential applications in light absorbers and energy conversion technologies. [ABSTRACT FROM AUTHOR]

We report a systematic and scalable single-step growth of three-dimensional hierarchical ZnO/ZnS heterojunction branched nanowires (3D ZnO/ZnS h-b-NWs) on a Si substrate using MOCVD for the first time and their application as photoanodes for photoelectrochemical water splitting (PEC-WS). Vertically well-aligned main trunk ZnO nanowires (MTr-ZnO NWs) were grown on a low-temperature ZnO buffer layer, which was followed by ZnS deposition. Subsequently, hierarchically branched ZnO nanowires (h-b-ZnO NWs) were grown on the side wall of the core–shell heterostructure, which was further modified with a thin layer of ZnS for the growth of multiple ZnO NW branches. The PEC-WS results revealed that the photo-conversion efficiency achieved using MTr-ZnO NWs and 3D ZnO/ZnS h-b-NWs was 0.03% and 0.46% at 0.5 V vs. RHE, respectively, which corresponds to 16-fold enhancement. The achieved improvements can be attributed to the enhanced photoabsorption, which is directly related to the augmented surface area. In addition, ZnS plays a significant role in promoting faster photogenerated carrier transport with high efficiency and visible light absorption by type-II transition at the ZnO/ZnS interface. The novel growth approach that we followed to fabricate the photoanode opens a new avenue for the synthesis of multiple-level hierarchical heterostructures that are beneficial for PEC-WS devices. [ABSTRACT FROM AUTHOR]

Multi-morphological Ln3+ (Ln = Eu, Tb) doped SrWO4 hierarchical structures were successfully synthesized via a hydrothermal method. The phase structure, morphology and luminescence properties of the as-prepared samples were characterized by XRD, SEM, TEM, PL spectroscopy and lifetime measurements. The results indicate that the alteration of synthesis conditions has almost no effect on the phase structure, but has a prominent effect on the morphology of the obtained samples, such as the molar ratio of Sr2+ to WO42− from 1 : 3 to 6 : 1 (split spheres, dumbbell-like, rod-like, nanosheets), addition of Na3C6H5O7·2H2O from 0.1 to 0.5 g (microspheres, rice-like), addition of Na2EDTA·2H2O from 0.01 to 0.3 g (spheres, split spheres, peanut-like, drum-like, ellipsoidal morphology), and the doping concentration of Eu3+ ions from 1% to 16% (dumbbell-like, rod-like). The as-synthesized SrWO4:Ln3+ (Ln = Eu, Tb) samples with various morphologies have an identical scheelite structure and exhibit the characteristic visible emission of the dopant rare earth ions under the excitation of UV light. [ABSTRACT FROM AUTHOR]

In recent years, nanocrystals of metal sulfide materials have attracted scientific research interest for renewable energy applications due to the abundant choice of materials with easily tunable electronic, optical, physical and chemical properties. Metal sulfides are semiconducting compounds where sulfur is an anion associated with a metal cation; and the metal ions may be in mono-, bi- or multi-form. The diverse range of available metal sulfide materials offers a unique platform to construct a large number of potential materials that demonstrate exotic chemical, physical and electronic phenomena and novel functional properties and applications. To fully exploit the potential of these fascinating materials, scalable methods for the preparation of low-cost metal sulfides, heterostructures, and hybrids of high quality must be developed. This comprehensive review indicates approaches for the controlled fabrication of metal sulfides and subsequently delivers an overview of recent progress in tuning the chemical, physical, optical and nano- and micro-structural properties of metal sulfide nanocrystals using a range of material fabrication methods. For hydrogen energy production, three major approaches are discussed in detail: electrocatalytic hydrogen generation, powder photocatalytic hydrogen generation and photoelectrochemical water splitting. A variety of strategies such as structural tuning, composition control, doping, hybrid structures, heterostructures, defect control, temperature effects and porosity effects on metal sulfide nanocrystals are discussed and how they are exploited to enhance performance and develop future energy materials. From this literature survey, energy conversion currently relies on a limited range of metal sulfides and their composites, and several metal sulfides are immature in terms of their dissolution, photocorrosion and long-term durability in electrolytes during water splitting. Future research directions for innovative metal sulfides should be closely allied to energy and environmental issues, along with their advanced characterization, and developing new classes of metal sulfide materials with well-defined fabrication methods. [ABSTRACT FROM AUTHOR]

Nanostructured, multicomponent metal sulfides have recently attracted much attention as anode materials for high-performance sodium ion batteries (SIBs). Therefore, a simple strategy for constructing rationally designed multicomponent metal sulfide-based nanostructures is needed. Herein, we propose a metal–organic framework-based (MOF) strategy to construct human backbone-like CoMoS3 nanostructures with multiple voids as high-performance SIB anodes. This strategy involves conformal coating of a Co-based MOF onto the surface of MoO3 nanobelts, followed by sulfidation of the hybrids. We explore not only the optimized conditions for uniform ZIF-67 coating on the MoO3 nanobelts, but also the transformation mechanism of the MoO3@ZIF-67 hybrids into CoMoS3 nanobackbones with multiple voids. To further improve the structural stability, the nanobackbones were coated with polydopamine and then thermally treated under inert conditions, resulting in the formation of CoMoS3@N-doped carbon (NC) nanobackbones. Benefiting from their unique structural design, conductive carbon shells, and synergistic effects between multiple components, the CoMoS3@NC nanobackbones exhibit enhanced electrochemical performance when tested as anode materials for SIBs. They deliver a reversible capacity of 411 mA h g−1 for 300 cycles at a current density of 2 A g−1, and an excellent rate performance of 349 mA h g−1 at a current density of 10 A g−1. This simple strategy can be used to fabricate other multicomponent metal sulfide/carbon composites with multiple voids, which can be used for various applications. [ABSTRACT FROM AUTHOR]

CoFe2O4 hollow nanoparticles with an average diameter and shell thickness of about 9.0 nm and 3.0 nm, respectively, were grown on graphene sheets. The hybrid exhibited excellent electromagnetic wave absorption properties with all of the minimal reflection losses below −10 dB at a thickness of 1.5–5.0 mm, superior to the hybrid based on CoFe2O4 solid nanoparticles and recently reported absorbers. Our results open a novel way for fabrication of hollow nanoparticles on graphene sheets for high-performance electromagnetic wave absorbers. [ABSTRACT FROM AUTHOR]

Surface modification is an essential step in engineering high performance nickel-rich layered (NLO) cathode materials that can withstand the increasingly harsh environment encountered in lithium-ion batteries. However, most traditional technologies suffer disadvantages such as low diffusion kinetics, processing difficulties and/or compatibility issues. Here, based on the dual-Kirkendall effect, we report an efficient, self-guided way for fabricating a multifunctional NiTiO3 (NTO) nanocoating to stabilize the cathode/electrolyte interface for NLO. The NTO nanocoating can epitaxially and chemically bond to the surface framework of NLO particles and eliminate surface lithium residues by evolving into a Li–Ni–Ti–O mixed phase coating that is mainly composed of Li2−xTiO3. Taking full advantage of such a novel multifunctional NTO nanocoating, the structural degradation in NLO cathodes can be effectively suppressed, leading to excellent rate capability and cyclability. This method provides insights into novel surface chemistry that prevents high performance layered electrode materials from structural degradation. [ABSTRACT FROM AUTHOR]

Transition metal chalcogenide and pnictide nanocrystals are of interest for optoelectronic and catalytic applications. Here, we present a generalized route to the synthesis of these materials from the silylative deoxygenation of metal oxides with trimethylsilyl reagents. Specific nanophases produced in this way include Ni3S2, Ni5Se5, Ni2P, Co9S8, Co3Se4, CoP, Co2P, and heterobimetallic (Ni/Co)9S8. The resulting chalcogenide nanocrystals are hollow, likely due to differential rates of ion diffusion during the interfacial phase transformation reaction (Kirkendall-type effect). In contrast, the phosphide nanocrystals are solid, likely because they form at higher reaction temperatures. In all cases, simultaneous partial decomposition of the deoxygenating silyl reagent produces a coating of amorphous silica around the newly formed nanocrystals, which could impact their stability and recyclability. [ABSTRACT FROM AUTHOR]

The application of a thermal gradient to an aqueous electrolyte solution induces the Soret effect, and the salt migrates towards hot (thermophilic) or cold regions (thermophobic). Experimental studies of LiCl reported changes in the sign of the Soret coefficient as well as a minimum in this coefficient at specific salt concentrations and temperatures. At the minimum the thermodiffusive response of the solution is enhanced significantly. We have performed non-equilibrium molecular dynamics simulations of LiCl solutions to quantify the dependence of the sign change and minimum of the Soret coefficient with salt concentration and temperature. We find that the ion mass plays a secondary role in determining the magnitude of the Soret coefficient, while the diameter of the cation has a significant impact on the coefficient and on the observation of the minimum. Our simulations show that the ordering of water around Li+ plays a key role in determining the Soret coefficient of LiCl salts. [ABSTRACT FROM AUTHOR]

Cobalt pentlandite (Co9S8) has recently emerged as an alternative non-noble metal based electrocatalyst for the oxygen evolution reaction (OER). Co9S8 is known for its intrinsic structural and electronic properties favorable for electrocatalytic applications, but the synthesis of stoichiometrically optimal Co9S8 electrocatalysts remains challenging. Herein, a facile one-step solid phase calcination approach is presented in which Co9S8 nanoparticles (NPs) were concurrently synthesised on carbon nanosheets (CNSs). The reaction mechanism for this synthesis was systematically investigated using TG/DSC-MS analysis. Relative to other cobalt chalcogenide electrocatalysts, the as-prepared thermally stable nanocomposite (Co9S8/CNS) has better electrocatalytic performance for the OER in alkaline electrolytes, exhibiting a smaller overpotential of 294 mV at a current density of 10 mA cm−2 with a Tafel slope of 50.7 mV dec−1. Furthermore, a minimum overpotential of 267 mV with a Tafel slope of 48.2 mV dec−1 could be achieved using highly conducting multi-walled carbon nanotubes (MWCNTs) as a conducting filler in the nanocomposites. [ABSTRACT FROM AUTHOR]

Iron oxide nanocrystals (IONCs) with various geometric morphologies show excellent physical and chemical properties and have received extensive attention in recent years. The various shape-induced magnetic and electrochemical properties of the IONCs make them suitable for diverse applications. Understanding the correlation between the physicochemical properties and morphology of IONCs is a prerequisite for their widespread applications. Hence, this review focuses on current research progress regarding shape-controlled IONCs in different dimensions, and the corresponding shape-dependent magnetic, catalytic and gas-sensor properties are discussed. Furthermore, the general preparation methods, shape-guided growth mechanisms and energy conversion applications in photoelectrochemical water splitting, dye-sensitized solar cells (DSSCs) and lithium-ion batteries (LIBs) of these IONCs (α-Fe2O3, γ-Fe2O3, Fe3O4) are also discussed. Finally, the perspectives of IONCs in promising research directions are proposed. [ABSTRACT FROM AUTHOR]

The precise morphological control of the surface of inorganic nanocrystals (NCs) is critical for the understanding of the unique properties of the materials at the nanoscale and useful in a wide range of applications, such as catalysis, where the development of highly active and low-cost materials represents a landmark for the development of industrial technologies. Here we show how combining solid state chemistry and colloidal synthesis allows us to prepare exotic materials, in particular, PtAg@Pt single-crystal hollow NCs with high-index planes synthesized at room temperature by controlled corrosion of silver templates, which minimize Pt consumption and maximize surface reactivity. [ABSTRACT FROM AUTHOR]

Organo-modified Cloisite clays at varying contents were incorporated into poly(ethylene-co-vinyl acetate) (EVA) by melt blending. Nanoclay dispersion in films was first evaluated. The water transport properties were investigated by pervaporation and sorption measurements. A decrease of the water permeation flux was obtained when incorporating nanoparticles. This barrier effect is usually attributed to the increase of the diffusion pathways due to nanoclay-induced tortuosity effects. However, the diffusion coefficient was found to be dependent on water concentration, which generally reflects a plasticization effect of water. Besides, at 7 wt% of loading, an unexpected increase of water diffusivity was measured with a time-scale shift of the permeation flux. This was correlated with the formation of preferential diffusion pathways along interfacial regions due to free volumes existing between the EVA matrix and nanoclays as well as the water affinity of microfillers. As a consequence, water mass gain was found to be increased. The water-induced plasticization of sorbed water molecules was also highlighted through sorption kinetics. Eventually, some applications to these films in which water barrier behaviour is required were discussed. [ABSTRACT FROM AUTHOR]

Hollow cobalt sulfide nanoprisms obtained by a two-step, microwave-assisted synthesis within 15 min exhibit higher hydrogen evolution catalytic activity and better specific capacitance than their counterparts prepared by a traditional solvothermal method. [ABSTRACT FROM AUTHOR]

Nowadays there are several technologies used for flat panel displays (FPDs) and the development of FPDs with enhanced energy efficiency and improved display quality is strongly required. Field emission displays (FEDs) have been considered as one of the most promising next generation flat panel display technologies due to their excellent display performance and low energy consumption. For the development of FEDs, phosphors are irreplaceable components. In the past decade, the study of highly efficient low-voltage cathodoluminescent materials, namely FED phosphors, has become the focus of enhancing energy efficiency and realizing high-quality displays. This review summaries the recent progress in the chemical synthesis and improvement of novel, rare-earth and transition metal ions activated inorganic cathodoluminescent materials in powder and thin film forms. The discussion is focused on the modification of morphology, size, surface, composition and conductivity of phosphors and the corresponding effects on their cathodoluminescent properties. Special emphases are given to the selection of host and luminescent centers, the adjustment of emission colors through doping concentration optimization, energy transfer and mono- or co-doping activator ions, the improvement of chromaticity, color stability and color gamut as well as the saturation behavior and the degradation behavior of phosphors under the excitation of a low-voltage electron beam. Finally, the research prospects and future directions of FED phosphors are discussed with recommendations to facilitate the further study of new and highly efficient low-voltage cathodoluminescent materials. [ABSTRACT FROM AUTHOR]

A universal technique to synthesize hollow nanoparticles including spindle-like YVO4, urchin-like YPO4, and bowl-like NaYF4 by a sacrificial process utilizing the Y(OH)CO3 template is described. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and N2 adsorption-desorption measurements reveal that hollow nanoparticles with a controllable size are produced due to the Kirkendall phenomenon. Bright fluorescence can be obtained by doping the nanoparticles with lanthanide ions such as Eu3+, Ce3+/Tb3+, and Yb3+/Er3+. These hollow nanoparticles exhibiting bright fluorescence have potential in fluorescence-guided drug-delivery applications and this universal and effective technique can be employed to fabricate various types of hollow materials. [ABSTRACT FROM AUTHOR]

8 nm Co nanoparticles with various crystalline structures called polymorphs were produced using different synthetic procedures, such as using reverse micelles, the thermal decomposition of organometallics approach or the hot injection process. These 8 nm Co nanoparticles differing by their crystalline structures are exposed to oxygen at elevated temperature. The fcc Co polycrystalline nanoparticles produce either Co–CoO yolk–shell or CoO hollow structures whereas amorphous Co nanoparticles produce Co–CoO core–shell nanoparticles. Furthermore, single domains with either hcp or ε crystalline structure behave differently upon oxygen diffusion. Co–CoO nanoparticles were produced from the hcp phase while CoO hollow nanoparticles were the product for ε-phase Co nanocrystals. [ABSTRACT FROM AUTHOR]

A simple reflux method was developed to fabricate hollow microparticles of complex oxides. Single crystalline perovskite-type BaZrO3 hollow microspheres were synthesized in a concentrated KOH solution via Ostwald ripening. The high KOH concentration resulted in the increased supersaturation of the reactants and grain growth of primary particulates that readily agglomerated into aggregated particles. The high KOH concentration also decreased the size of the aggregated particles due to enhanced interparticle attractive forces. Heat treatment promoted the hollowing process. Refluxing a mixture in 20 mol L−1 KOH solutions in a 200 °C oil bath produced perovskite BaZrO3 hollow microspheres with an average size of 92 nm. XRD patterns demonstrated the cubic perovskite structure of the BaZrO3 hollow microspheres. HRTEM and SAED measurements disclosed the single crystalline nature of a single BaZrO3 hollow microsphere. The products showed variations in morphology, from solid to core–shell and hollow microspheres, at various reaction durations. The highly concentrated KOH solution not only led to smaller aggregated particle sizes but also afforded a high boiling temperature to accelerate the diffusion rate and promote the ripening process. Similarly, perovskite SrZrO3 and SrHfO3 hollow microparticles were also fabricated by this method. [ABSTRACT FROM AUTHOR]

Monodisperse metal nanoparticles (NPs) with high activity and selectivity are among the most important catalytic materials. However, the intrinsic process to obtain well-dispersed metal NPs with tunable high density (ranging from 1013 to 1016 m−2) and thermal stability is not yet well understood. Herein, the preparation of metal NPs with tunable areal density from layered double hydroxide (LDH) precursors in which the metal cations were pre-dispersed at an atomic scale was explored. Large quantities of mesopores induced by the Kirkendall effect were formed on the as-calcined layered double oxide (LDO) flakes. The O atoms bonded with Fe3+ cations were easy to be extracted at a temperature higher than 750 °C, which greatly increased the mobility of Fe. Consequently, coalescence of the reduced Fe atoms into large NPs enhanced the Kirkendall effect, leading to the formation of monodisperse embedded Fe NPs on the porous LDO flakes. The flake morphology of LDHs was well preserved, and the areal density of Fe NPs on the LDO flakes can be well controlled through adjusting the Fe content in the LDH precursor. With higher Fe loading, larger Fe NPs with higher areal density were available. When the areal density was increased from 0.039 to 0.55, and to 2.1 × 1015 m−2, the Fe NPs embedded on the LDO flakes exhibited good catalytic performance for the growth of entangled carbon nanotubes (CNTs), aligned CNTs, and double helical CNTs, respectively. This work provides not only new insights into the chemical evolution of monodisperse NPs from an atomic metal-dispersed precursor, but also a general route to obtain tunable NPs as heterogeneous catalysts for chemical and material production. [ABSTRACT FROM AUTHOR]

Novel 3D hierarchical flower-like Co1-xS architectures were successfully synthesized via a hydrothermal process using trisodium citrate (Na3Cit) as a chelating agent. The crystal structure and morphology of the as-prepared products were characterized and the results demonstrated that the Na3Cit could efficiently control the formation of flower-like Co1-xS hierarchitectures. A possible growth mechanism for this hierarchical flower-like Co1-xS nanostructure was proposed on the basis of a series of time-dependent experiments, and this work provides an efficient route for designing desirable micro-/nanostructures. The flower-like Co1-xS nanostructures were fabricated as anode materials of lithium ion batteries and tested in the range of 0.01 V-3.00 V. The initial discharge capacity was up to 1244 mAh g-1 at the current density of 50 mA g-1. The electrochemical measurement suggested that the flower-like Co1-xS nanostructures have high capacity and excellent cycle stability as a Li-ion battery anode. [ABSTRACT FROM AUTHOR]

In2O3–In2S3 core–shell nanostructures were prepared via a simple hydrothermal process at low temperatures. Ultraviolet photoelectron spectroscopy (UPS) shows that the In2O3–In2S3 nanorod is an inverted type I nanostructure. The energy potential in this structure would drive both the photo-generated holes and electrons towards the shell to facilitate photocatalytic H2 generation. Such inverted type-I nanostructure is firstly used for hydrogen generation. Comparing with reported indium-based photocatalysts upon UV-Vis illumination, the core–shell In2O3–In2S3 nanostructure obtained here exhibits a good H2 evolution rate of 61.4 μmol h−1 g−1. [ABSTRACT FROM AUTHOR]

This work presents a facile and general solvothermal approach to prepare hierarchical cobalt sulfides (ComSn) microflowers, which are composed of curved nanosheets. The homogeneous phases of Co9S8, Co3S4 and Co1−xS could be obtained just by adjusting the molar ratio of cobalt acetate to thiourea. The structure and morphology of the as-prepared cobalt sulfides were investigated by powder X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy (TEM) and high-resolution TEM, X-ray photoelectron spectroscopy and N2-sorption measurements. The possible growth process was discussed on the basis of time-dependent experimental results. The ComSn materials exhibited great electrocatalytic activities towards both oxygen reduction and oxygen evolution reactions, making them a kind of promising electrode materials for fuel cells and batteries. [ABSTRACT FROM AUTHOR]

Luminescent materials have found a wide variety of applications, including information displays, lighting, X-ray intensification and scintillation, and so on. Therefore, much effort has been devoted to exploring novel luminescent materials so far. In the past decade, defect-related luminescent materials have inspired intensive research efforts in their own right. This kind of luminescent material can be basically classified into silica-based materials, phosphate systems, metal oxides, BCNO phosphors, and carbon-based materials. These materials combine several favourable attributes of traditional commercially available phosphors, which are stable, efficient, and less toxic, being free of the burdens of intrinsic toxicity or elemental scarcity and the need for stringent, intricate, tedious, costly, or inefficient preparation steps. Defect-related luminescent materials can be produced inexpensively and on a large scale by many approaches, such as sol–gel process, hydro(solvo)thermal reaction, hydrolysis methods, and electrochemical methods. This review article highlights the recent advances in the chemical synthesis and luminescent properties of the defect-related materials, together with their control and tuning, and emission mechanisms (solid state physics). We also speculate on their future and discuss potential developments for their applications in lighting and biomedical fields. [ABSTRACT FROM AUTHOR]

Inorganic hollow spheres have attracted considerable interest due to their singular properties and wide range of potential applications. In this critical review, we provide a comprehensive overview of the preparation and applications of inorganic hollow spheres. We first discuss the syntheses of inorganic hollow spheres by use of polymers, inorganic nonmetals, metal-based hard templates, small-molecule emulsion, surfactant micelle-based soft-templates, and the template-free approach. For each method, a critical comment is given based on our knowledge and related research experience. We go on to discuss some important applications of inorganic hollow spheres in 0D, 2D, and 3D arrays. We conclude this review with some perspectives on the future research and development of inorganic hollow spheres (235 references). [ABSTRACT FROM AUTHOR]

Polycrystalline Co9S8nanotubes were successfully fabricated by using Co(CO3)0.35Cl0.20(OH)1.10nanorod bunches as sacrificial hard templates through a hydrothermal route. The samples were characterized by means of XRD, XPS, SEM and TEM. The Co9S8nanotubes were formed due to the nanoscale Kirkendall effect, which can be explained by the difference in diffusion rates between the cobalt source and the sulfur ion. Magnetic measurements indicate that the Co9S8nanotubes show a paramagnetic property instead of a ferromagnetic property, which can be attributed to the tiny sizes of the component nanoparticles. The electrochemical properties of the Co9S8nanotubes demonstrate that they deliver a large discharge capacity, which might find possible applications as an electrode material in lithium batteries. [ABSTRACT FROM AUTHOR]

There has been a tremendous research effort in the past few years in colloidal magnetic nanocrystals. New synthetic methods have been developed that enable a wide variety of magnetic materials to be synthesized in nanocrystal form, including ferromagnetic transition metals, intermetallics and metal oxides. These nanocrystals can be obtained with controlled size, shape and composition. Nanocrystal heterostructures, such as core/shell particles and heterodimers can be synthesized. New materials such as doped magnetic semiconductor quantum dots and nanowires have been made. The magnetic properties of these unique nanostructures have been measured and their applications in medicine, information storage and processing and sensing are being developed. This review attempts to provide a summary and a flavor for this exciting research area as it has evolved during the past few years. [ABSTRACT FROM AUTHOR]

SnO2 Nanotubes were synthesized via a one-pot redox route at room temperature, in which the Kirkendall effect is definitely responsible for the formation of hollow structures. [ABSTRACT FROM AUTHOR]