Showing papers by "Hua Zhang published in 2012"

Graphene-based composites

Abstract: Graphene has attracted tremendous research interest in recent years, owing to its exceptional properties. The scaled-up and reliable production of graphene derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), offers a wide range of possibilities to synthesize graphene-based functional materials for various applications. This critical review presents and discusses the current development of graphene-based composites. After introduction of the synthesis methods for graphene and its derivatives as well as their properties, we focus on the description of various methods to synthesize graphene-based composites, especially those with functional polymers and inorganic nanostructures. Particular emphasis is placed on strategies for the optimization of composite properties. Lastly, the advantages of graphene-based composites in applications such as the Li-ion batteries, supercapacitors, fuel cells, photovoltaic devices, photocatalysis, as well as Raman enhancement are described (279 references).

Single-Layer MoS2 Phototransistors

Abstract: A new phototransistor based on the mechanically exfoliated single-layer MoS2 nanosheet is fabricated, and its light-induced electric properties are investigated in detail. Photocurrent generated from the phototransistor is solely determined by the illuminated optical power at a constant drain or gate voltage. The switching behavior of photocurrent generation and annihilation can be completely finished within ca. 50 ms, and it shows good stability. Especially, the single-layer MoS2 phototransistor exhibits a better photoresponsivity as compared with the graphene-based device. The unique characteristics of incident-light control, prompt photoswitching, and good photoresponsivity from the MoS2 phototransistor pave an avenue to develop the single-layer semiconducting materials for multifunctional optoelectronic device applications in the future.

Growth of Large-Area and Highly Crystalline MoS2 Thin Layers on Insulating Substrates

Abstract: The two-dimensional layer of molybdenum disulfide (MoS2) has recently attracted much interest due to its direct-gap property and potential applications in optoelectronics and energy harvesting. However, the synthetic approach to obtain high-quality and large-area MoS2 atomic thin layers is still rare. Here we report that the high-temperature annealing of a thermally decomposed ammonium thiomolybdate layer in the presence of sulfur can produce large-area MoS2 thin layers with superior electrical performance on insulating substrates. Spectroscopic and microscopic results reveal that the synthesized MoS2 sheets are highly crystalline. The electron mobility of the bottom-gate transistor devices made of the synthesized MoS2 layer is comparable with those of the micromechanically exfoliated thin sheets from MoS2 crystals. This synthetic approach is simple, scalable, and applicable to other transition metal dichalcogenides. Meanwhile, the obtained MoS2 films are transferable to arbitrary substrates, providing gr...

Imparting functionality to a metal–organic framework material by controlled nanoparticle encapsulation

Abstract: Microporous metal–organic frameworks (MOFs) that display permanent porosity show great promise for a myriad of purposes. The potential applications of MOFs can be developed further and extended by encapsulating various functional species (for example, nanoparticles) within the frameworks. However, despite increasing numbers of reports of nanoparticle/MOF composites, simultaneously to control the size, composition, dispersed nature, spatial distribution and confinement of the incorporated nanoparticles within MOF matrices remains a significant challenge. Here, we report a controlled encapsulation strategy that enables surfactant-capped nanostructured objects of various sizes, shapes and compositions to be enshrouded by a zeolitic imidazolate framework (ZIF-8). The incorporated nanoparticles are well dispersed and fully confined within the ZIF-8 crystals. This strategy also allows the controlled incorporation of multiple nanoparticles within each ZIF-8 crystallite. The as-prepared nanoparticle/ZIF-8 composites exhibit active (catalytic, magnetic and optical) properties that derive from the nanoparticles as well as molecular sieving and orientation effects that originate from the framework material.

3D Graphene–Cobalt Oxide Electrode for High-Performance Supercapacitor and Enzymeless Glucose Detection

Abstract: Using a simple hydrothermal procedure, cobalt oxide (Co3O4) nanowires were in situ synthesized on three-dimensional (3D) graphene foam grown by chemical vapor deposition. The structure and morphology of the resulting 3D graphene/Co3O4 composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. The 3D graphene/Co3O4 composite was used as the monolithic free-standing electrode for supercapacitor application and for enzymeless electrochemical detection of glucose. We demonstrate that it is capable of delivering high specific capacitance of ∼1100 F g–1 at a current density of 10 A g–1 with excellent cycling stability, and it can detect glucose with a ultrahigh sensitivity of 3.39 mA mM–1 cm–2 and a remarkable lower detection limit of <25 nM (S/N = 8.5).

Fabrication of Single‐ and Multilayer MoS2 Film‐Based Field‐Effect Transistors for Sensing NO at Room Temperature

Abstract: Single- and multilayer MoS(2) films are deposited onto Si/SiO(2) using the mechanical exfoliation technique. The films were then used for the fabrication of field-effect transistors (FETs). These FET devices can be used as gas sensors to detect nitrous oxide (NO). Although the single-layer MoS(2) device shows a rapid response after exposure to NO, the current was found to be unstable. The two-, three-, and four-layer MoS(2) devices show both stable and sensitive responses to NO down to a concentration of 0.8 ppm.

Fabrication of flexible MoS2 thin-film transistor arrays for practical gas-sensing applications.

Abstract: By combining two kinds of solution-processable two-dimensional materials, a flexible transistor array is fabricated in which MoS2 thin film is used as the active channel and reduced graphene oxide (rGO) film is used as the drain and source electrodes. The simple device configuration and the 1.5 mm-long MoS2 channel ensure highly reproducible device fabrication and operation. This flexible transistor array can be used as a highly sensitive gas sensor with excellent reproducibility. Compared to using rGO thin film as the active channel, this new gas sensor exhibits much higher sensitivity. Moreover, functionalization of the MoS2 thin film with Pt nanoparticles further increases the sensitivity by up to ∼3 times. The successful incorporation of a MoS2 thin-film into the electronic sensor promises its potential application in various electronic devices.

Graphene-Based Electrodes

Abstract: Graphene, the thinnest two dimensional carbon material, has become the subject of intensive investigation in various research fields because of its remarkable electronic, mechanical, optical and thermal properties. Graphene-based electrodes, fabricated from mechanically cleaved graphene, chemical vapor deposition (CVD) grown graphene, or massively produced graphene derivatives from bulk graphite, have been applied in a broad range of applications, such as in light emitting diodes, touch screens, field-effect transistors, solar cells, supercapacitors, batteries, and sensors. In this Review, after a short introduction to the properties and synthetic methods of graphene and its derivatives, we will discuss the importance of graphene-based electrodes, their fabrication techniques, and application areas.

Graphene-based electronic sensors

Abstract: Graphene, the archetypal two-dimensional material, is attracting increasing attention due to its unique and superior properties. The atomic thickness of the graphene sheet is extremely sensitive towards the change of local environment, making it an ideal channel material in field-effect transistors used as electronic sensors. In this minireview, we review the graphene-based electronic sensors for detection of various chemicals and biomolecules. We first introduce the different kinds of graphene materials used in the electronic sensors and how they affect the device sensing performance. Then we focus on the use of the reduced graphene oxide for the fabrication of cost-efficient, high-yield and highly reproducible sensing devices.

An Effective Method for the Fabrication of Few‐Layer‐Thick Inorganic Nanosheets

Abstract: Intercalation and exfoliation of lithium: Few-layer-thick inorganic nanosheets (BN, NbSe(2), WSe(2), Sb(2)Se(3), and Bi(2)Te(3)) have been prepared from their layered bulk precursors by using a controllable electrochemical lithium intercalation process. The lithium intercalation conditions, such as cut-off voltage and discharge current, have been systematically studied and optimized to produce high-quality BN and NbSe(2) nanosheets.

Graphene‐Based Composites

Abstract: Graphene has attracted tremendous research interest in recent years, owing to its exceptional properties. The scaled-up and reliable production of graphene derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), offers a wide range of possibilities to synthesize graphene-based functional materials for various applications. This critical review presents and discusses the current development of graphene-based composites. After introduction of the synthesis methods for graphene and its derivatives as well as their properties, we focus on the description of various methods to synthesize graphene-based composites, especially those with functional polymers and inorganic nanostructures. Particular emphasis is placed on strategies for the optimization of composite properties. Lastly, the advantages of graphene-based composites in applications such as the Li-ion batteries, supercapacitors, fuel cells, photovoltaic devices, photocatalysis, as well as Raman enhancement are described (279 references).

Seed-assisted synthesis of highly ordered TiO2@α-Fe2O3 core/shell arrays on carbon textiles for lithium-ion battery applications

Abstract: Highly ordered TiO2@α-Fe2O3 core/shell arrays on carbon textiles (TFAs) have been fabricated by a stepwise, seed-assisted, hydrothermal approach and further investigated as the anode materials for Li-ion batteries (LIBs). This composite TFA anode exhibits superior high-rate capability and outstanding cycling performance. The specific capacity of the TFAs is much higher than that of pristine carbon textiles (CTs) and TiO2 nanorod arrays on carbon textiles (TRAs), indicating a positive synergistic effect of the material and structural hybridization on the enhancement of the electrochemical properties. This composite nanostructure not only provides large interfacial area for lithium insertion/extraction but should also be beneficial in reducing the diffusion pathways for electronic and ionic transport, leading to the improved capacity retention on cycling even at high discharge–charge rates. It is worth emphasizing that the CT substrates also present many potential virtues for LIBs as flexible electronic devices owing to the stretchable, lightweight and biodegradable properties. The fabrication strategy presented here is facile, cost-effective, and scalable, which opens new avenues for the design of optimal composite electrode materials for high performance LIBs.

Preparation of MoS2‐Polyvinylpyrrolidone Nanocomposites for Flexible Nonvolatile Rewritable Memory Devices with Reduced Graphene Oxide Electrodes

Abstract: A facile method for exfoliation and dispersion of molybdenum disulfide (MoS2) with the aid of polyvinylpyrrolidone (PVP) is proposed. The resultant PVP-coated MoS2 nanosheets, i.e., MoS2-PVP nanocomposites, are well dispersed in the low-boiling ethanol solvent, facilitating their thin film preparation and the device fabrication by solution processing technique. As a proof of concept, a flexible memory diode with the configuration of reduced graphene oxide (rGO)/MoS2-PVP/Al exhibited a typical bistable electrical switching and nonvolatile rewritable memory effect with the function of flash. These experimental results prove that the electrical transition is due to the charge trapping and detrapping behavior of MoS2 in the PVP dielectric material. This study paves a way of employing two-dimensional nanomaterials as both functional materials and conducting electrodes for the future flexible data storage.

Electrochemically Reduced Single‐Layer MoS2 Nanosheets: Characterization, Properties, and Sensing Applications

Abstract: The electrochemical study of single-layer, 2D MoS₂ nanosheets reveals a reduction peak in the cyclic voltammetry in NaCl aqueous solution. The electrochemically reduced MoS₂ (rMoS₂) shows good conductivity and fast electron transfer rate in the [Fe(CN)₆]³⁻/⁴⁻ and [Ru(NH₃)₆]²⁺/³⁺ redox systems. The obtained rMoS₂ can be used for glucose detection. In addition, it can selectively detect dopamine in the presence of ascorbic acid and uric acid. This novel material, rMoS₂, is believed to be a good electrode material for electrochemical sensing applications.

A general method for the large-scale synthesis of uniform ultrathin metal sulphide nanocrystals

Abstract: Ultrathin metal sulphide nanomaterials exhibit many unique properties, and are thus attractive materials for numerous applications. However, the high-yield, large-scale synthesis of well-defined ultrathin metal sulphide nanostructures by a general and facile wet-chemical method is yet to be realized. Here we report a universal soft colloidal templating strategy for the synthesis of high-quality ultrathin metal sulphide nanocrystals, that is 3.2 nm-thick hexagonal CuS nanosheets, 1.8 nm-diameter hexagonal ZnS nanowires, 1.2 nm-diameter orthorhombic Bi(2)S(3) nanowires and 1.8 nm-diameter orthorhombic Sb(2)S(3) nanowires. As a proof of concept, the ultrathin CuS nanosheets are used to fabricate an electrode for a lithium-ion battery, which exhibits a large capacity and good cycling stability, even after 360 cycles. Furthermore, high-yield, gram-scale production of these ultrathin metal sulphide nanomaterials has been achieved (~100%, without size-sorting process). Our method could be broadly applicable for the high-yield production of novel ultrathin nanostructures with great promise for various applications.

Optical Identification of Single- and Few-Layer MoS2 Sheets

Abstract: A simple approach is developed to identify the layer number of 2D MoS₂ sheets. By using an optical imaging method combined with image analysis software, a high-contrast image of the MoS₂ sheets can be extracted from the red (R) channel of the color optical microscopy image. The value of the intensity difference in the grayscale image of the R channel between MoS₂ sheets (1-3 layers) and the SiO₂ substrate can be used to identify the layer number of the sheet.

Virologic factors associated with failure to passive-active immunoprophylaxis in infants born to HBsAg-positive mothers.

Abstract: In infants born to hepatitis B surface antigen (HBsAg)-positive mothers, failure after passive-active immunization still occurs. The role of maternal hepatitis B DNA level and other risk factors in this setting remains unclear. This study retrospectively evaluated virologic and other risk factors associated with immunoprophylaxis failure in infants born to HBsAg-positive mothers. Between January 2007 and March 2010, we reviewed the clinical and virologic tests in 869 mother-infant pairs. All infants received the identical passive-active immunization schedule after birth. The failure infants (HBsAg positive at 7-12 months of age) were compared to infants who were HBsAg negative when tested during this time period. Among 869 infants, 27 (3.1%) infants were immunoprophylaxis failures and the other 842 (96.9%) infants remained HBsAg negative. When mothers' pre-delivery HBV DNA levels were stratified to <6, 6-6.99, 7-7.99 and ≥ 8 log(10) copies/mL, the corresponding rates of immunoprophylaxis failure were 0%, 3.2% (3/95), 6.7% (19/282) and 7.6% (5/66), respectively (P < 0.001 for the trend). All failure infants were born to hepatitis B e antigen (HBeAg)-positive mothers. Multivariate logistic regression analysis identified maternal HBV DNA levels [odds ratio (OR) = 1.88, 95% confidence interval (CI): 1.07-3.30] and detectable HBV DNA in the cord blood (OR = 39.67, 95% CI: 14.22-110.64) as independent risk factors for immunoprophylaxis failure. All failure infants were born to HBeAg-positive mothers with HBV DNA levels ≥ 6 log(10) copies/mL. The presence of HBV DNA in cord blood predicted failure to passive-active immunization.

3D graphene foam as a monolithic and macroporous carbon electrode for electrochemical sensing.

Abstract: Graphene, a single-atom-thick monolayer of sp(2) carbon atoms perfectly arranged in a honeycomb lattice, is an emerging sensing material because of its extraordinary properties, such as exceptionally high specific surface area, electrical conductivity, and electrochemical potential window. In this study, we demonstrate that three-dimensional (3D), macroporous, highly conductive, and monolithic graphene foam synthesized by chemical vapor deposition represents a novel architecture for electrochemical electrodes. Being employed as an electrochemical sensor for detection of dopamine, 3D graphene electrode exhibits remarkable sensitivity (619.6 μA mM(-1) cm(-2)) and lower detection limit (25 nM at a signal-to-noise ratio of 5.6), with linear response up to ∼25 μM. And the oxidation peak of dopamine can be easily distinguished from that of uric acid - a common interferent to dopamine detection. We envision that the graphene foam provides a promising platform for the development of electrochemical sensors as well as other applications, such as energy storage and conversion.

Self-assembly of well-ordered whisker-like manganese oxide arrays on carbon fiber paper and its application as electrode material for supercapacitors

Abstract: Self-assembled well-ordered whisker-like manganese dioxide (MnO2) arrays on carbon fiber paper (MOWAs) were synthesized via a simple in situ redox replacement reaction between potassium permanganate (KMnO4) and carbon fiber paper (CFP) without any other oxidant or reductant addition. The CFP serves as not only a sacrificial reductant and converts aqueous permanganate (MnO4−) to insoluble MnO2 in this reaction, but also a substrate material and guarantees MnO2 deposition on the surface. The electrochemical properties were examined by cyclic voltammograms (CV), galvanostatic charge/discharge, and electrochemical impedance spectroscopy (EIS) in a three-electrode cell. According to the CV results, the ordered MOWAs yield high-capacitance performance with specific capacitance up to 274.1 F g−1 and excellent long cycle-life property with 95% of its specific capacitance kept after 5000 cycles at the current density of 0.1 A g−1. The high-performance hybrid composites result from a synergistic effect of large surface area and high degree of ordering of the ultrathin layer of MnO2 nanowhisker arrays, combined with the flexible CFP substrate and can offer great promise in large-scale energy storage device applications.

Nanoporous walls on macroporous foam: rational design of electrodes to push areal pseudocapacitance.

Abstract: Supercapacitors, also known as electrochemical capacitors, are considered the most promising energy storage devices owing to their high power densities and long lifespan. [ 3–5 ] The fast charge and discharge capability make supercapacitors favorable for applications in hybrid vehicles, portable electronics, and backup energy systems. [ 6–10 ] Carbonaceous materials, including carbon nanotubes and graphene, are being widely studied as alternatives to conventional graphites. [ 2 , 11–14 ] However, carbon-based materials usually show low energy density as they store charges electrostatically at their surfaces, so they have intrinsically low specifi c areal capacitance ( C a ) in the range of 10 − 40 μ F cm − 2 . Transition metal oxides/hydroxides store charges with surface faradaic (redox) reactions, which enable higher energy density compared to carbon. Metal oxides/hydroxides such as MnO 2 , NiO, Ni(OH) 2 , CoO x and their compounds have recently come into focus in the design of high-energy-density charge-storage materials. [ 15–27 ] Despite these efforts, practical energy storage applications still require higher specifi c capacitance. One way out is to design nanometer-scale electrode materials with very large surface areas and structural stability. In this context, porous nanostructures are of great interest because they can reduce ionic and electronic diffusion distance and provide large electrode/electrolyte contact area. For example, porous Ni and Au electrodes as current collectors have recently been reported, which signifi cantly improve the specifi c capacitance when covered with the pseudoactive material MnO 2 . [ 28 , 29 ] Also, nanoporous graphene electrodes with ∼ 4 nm pores drastically enhance the specifi c capacitance up to 166 F g − 1 . [ 30 ] For metal oxides,

Fabrication of graphene nanomesh by using an anodic aluminum oxide membrane as a template.

Abstract: Graphene, a one-atom-thick two-dimensional carbon sheet, has been extensively studied owing to its broad applications in nanoelectronics, [ 1 , 2 ] nanocomposites, [ 3 , 4 ] chemical sensors and biosensors, [ 5–10 ] solar cells, [ 11–13 ] and electrical and optical devices. [ 14–16 ] However, the application of graphene in fi eldeffect transistors (FETs) is limited because of its semi-metallic behavior with zero bandgap. [ 17 , 18 ] Cutting graphene sheets into nanoribbons led to bandgap opening, with current ON/OFF ratio large enough for transistor operation. [ 19–23 ] Unfortunately, FET devices based on the individual nanoribbons exhibited low driving current and conductance. [ 22 ]

Experimental evidence showing that no mitotically active female germline progenitors exist in postnatal mouse ovaries

Abstract: It has been generally accepted for more than half a century that, in most mammalian species, oocytes cannot renew themselves in postnatal or adult life, and that the number of oocytes is already fixed in fetal or neonatal ovaries. This assumption, however, has been challenged over the past decade. In this study, we have taken an endogenous genetic approach to this question and generated a multiple fluorescent Rosa26rbw/+;Ddx4-Cre germline reporter mouse model for in vivo and in vitro tracing of the development of female germline cell lineage. Through live cell imaging and de novo folliculogenesis experiments, we show that the Ddx4-expressing cells from postnatal mouse ovaries did not enter mitosis, nor did they contribute to oocytes during de novo folliculogenesis. Our results provide evidence that supports the traditional view that no postnatal follicular renewal occurs in mammals, and no mitotically active Ddx4-expressing female germline progenitors exist in postnatal mouse ovaries.

Real-time DNA detection using Pt nanoparticle-decorated reduced graphene oxide field-effect transistors.

Abstract: A large-area, continuous, few-layer reduced graphene oxide (rGO) thin film has been fabricated on a Si/SiO2 wafer using the Langmuir–Blodgett (LB) method followed by thermal reduction. After photochemical reduction of Pt nanoparticles (PtNPs) on rGO, the obtained PtNPs/rGO composite is employed as the conductive channel in a solution-gated field effect transistor (FET), which is then used for real-time detection of hybridization of single-stranded DNA (ssDNA) with high sensitivity (2.4 nM). Such a simple, but effective method for fabrication of rGO-based transistors shows great potential for mass-production of graphene-based electronic biosensors.

Hollow core–shell nanostructure supercapacitor electrodes: gap matters

Abstract: Hollow core–shell nanorods with a nanogap are designed and constructed with the assistance of atomic layer deposition (ALD) for energy storage applications. As a demonstration, CoO nanorods and NiO nanowalls are enclosed by a TiO2 nanotube shell, forming the “wire in tube” and “wall in box” structures, respectively. A thin sacrificial layer of Al2O3 is deposited by ALD and removed eventually, forming a nanogap between the CoO core (or the NiO nanowall) and the TiO2 shell. When they are tested as supercapacitor electrodes, an evident difference between the solid core–shell nanostructure and hollow ones can be found; for example, the hollow structure shows ∼2 to 4 times the capacitance compared to the solid wires. The electrochemical properties are also superior compared to the bare nanorods without the nanotube shell. The enhancement is ascribed to the conformal hollow design which provides enlarged specific surface areas and a shorter ion transport path. It is prospected that such a positive nanogap effect may also exist in other electrochemical cell electrodes such as lithium ion batteries and fuel cells.

Growth of Large-Area and Highly Crystalline MoS2 Thin Layers on Insulating Substrates

Abstract: The two-dimensional layer of molybdenum disulfide (MoS2) has recently attracted much interest due to its direct-gap property and potential applications in optoelectronics and energy harvesting. However, the synthetic approach to obtain high quality and large-area MoS2 atomic thin layers is still rare. Here we report that the high temperature annealing of a thermally decomposed ammonium thiomolybdate layer in the presence of sulfur can produce large-area MoS2 thin layers with superior electrical performance on insulating substrates. Spectroscopic and microscopic results reveal that the synthesized MoS2 sheets are highly crystalline. The electron mobility of the bottom-gate transistor devices made of the synthesized MoS2 layer is comparable with those of the micromechanically exfoliated thin sheets from MoS2 crystals. This synthetic approach is simple, scalable and applicable to other transition metal dichalcogenides. Meanwhile, the obtained MoS2 films are transferable to arbitrary substrates, providing great opportunities to make layered composites by stacking various atomically thin layers.

Flexible carbon nanotube papers with improved thermoelectric properties

Abstract: Although theoretical calculations indicate that the thermoelectric figure of merit, ZT, of carbon nanotubes (CNTs) could reach >2, the experimentally reported ZT values of CNTs are typically in the range of 10−3–10−2, which is not attractive for thermal energy conversion applications. In this work, we report the preparation of flexible CNT bulky paper for thermoelectric applications. The ZT values of the CNT bulky papers could be significantly enhanced by Ar plasma treatment, i.e. increasing it from 0.01 for pristine CNTs to 0.4 for Ar-plasma treated CNTs. The improved thermoelectric properties were mainly due to the greatly increased Seebeck coefficients and a reduction in the thermal conductivities, although the electrical conductivities also decreased. Such an improvement makes the plasma treated CNT bulky papers promising as a new type of thermoelectric material for certain niche applications as they are easily processed, mechanically flexible and durable, and chemically stable.

Controlled synthesis of carbon-coated cobalt sulfide nanostructures in oil phase with enhanced li storage performances.

Abstract: A novel solvothermal process was developed for the synthesis of carbon-coated Co9S8 nanodandelions using 1-dodecanethiol as the sulfur source and the soft template. Replacing 1-dodecanethiol with sulfur powder as the sulfur source leads to the formation of 20 nm Co9S8 nanoparticles without carbon coating. When tested as LIB anode, the C@Co9S8 dandelion delivers a specific capacity of 520 mA h g–1 at a current density of 1 A g–1 (1.8 C) during the 50th cycle, which is much higher than that of Co9S8 nanoparticles (e.g. 338 mA h g–1). Furthermore, the C@Co9S8 dandelion also exhibits excellent high C-rate performance, e.g., depicts a 10th-cycle capacity of 373 mA h g–1 at a current density of 6 A g–1 (10.9 C), which is better than that of many reported anode materials. Such synthesis approach is attractive for the preparation of sulfide anode materials with high Li storage properties.

Full solution-processed synthesis of all metal oxide-based tree-like heterostructures on fluorine-doped tin oxide for water splitting.

Abstract: Well-ordered tree-like functional heterostructures, composed of the environmentally friendly oxides ZnO, TiO(2) , and CuO, on a fluorine-doped tin oxide substrate are realized by a practical, cost-effective, solution-processable strategy. The heterostructures are demonstrated to be an efficient light-harvesting medium in a photo-electrochemical cell to split water for hydrogen-gas generation, and the developed strategy provides a highly promising, cheap, green way to fabricate multifunctional hierarchically branched structures for many potential applications.