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In this paper, we demonstrate the significant impact of the solution flow and electrical field on the homogeneity of large-scale ZnO nanorod electrodeposition from an aqueous solution containing zinc nitrate and ammonium nitrate, primarily based on the X-ray fluorescence results. The homogeneity can be enhanced by adjusting the counter electrode size and solution flow rate. We have successfully produced relatively uniform nanorod arrays on an 8 × 10 cm2 i-ZnO-coated fluorine-doped tin oxide (FTO) substrate using a compact counter electrode and a vertical stirring setup. The as-grown nanorods exhibit similar surface morphologies and dominant, intense, almost uniform near-band-edge emissions in different regions of the sample. Additionally, the surface reflectance is significantly reduced after depositing the ZnO nanorods, achieving a moth-eye effect through subwavelength structuring. This effect of the nanorod array structure indicates that it can improve the utilization efficiency of light reception or emission in various optoelectronic devices and products. The large-scale preparation of ZnO nanorods is more practical to apply and has an extremely broad application value. Based on the research results, it is feasible to prepare large-scale ZnO nanorods suitable for antireflective coatings and commercial applications by optimizing the electrodeposition conditions. [ABSTRACT FROM AUTHOR]

With the unique properties and superior performance, ZnO/ZnS core shell nanostructures have been applied in many photoelectric devices. Varied growth methods can synthesize ZnO/ZnS core shell samples, which exhibit different crystal and optical properties, and have the positive or negative effect on performance of related devices. To investigate the growth and properties, ZnO/ZnS core shell nanowires were grown through surface sulfurization. X-ray diffraction and scanning electron microscopy measurements indicated surface sulfurization degree can affect crystal quality. In addition, photoluminescence results exhibited that ZnO/ZnS heterojunction emission properties were dependent on shell layers quality. By increasing the amount of surface powder, it would improve shell layers’ crystal quality. And with optimal surface sulfurization degree, the vacancies and interstitial atoms defects can be restrained, which may improve photo-generated carriers separation efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flower-like C-ZnO microspheres assembly from nanoneedles were prepared using carbon spheres as templates. • C-ZnO nanoneedle is single crystal with exposed nonpolar {1010} facets. • Doping ZnO with C results in the production of oxygen vacancies. • Flower-like C-ZnO microspheres exhibited high photoreactivity and excellent stability towards MO degradation. In this work, carbon spheres (CSs) derived from glucose by simple eco-friendly process were used to create a multiphase environment for precipitation reaction to obtain flower-like C-doped ZnO (C-ZnO) nanoneedles assembly. It was found that the presence of carbon spheres can affect the crystal orientation and morphology of ZnO. When the additive amount of carbon spheres was 13 wt%, one-dimensional (1D) needle-like single crystal C-doped ZnO were obtained, which exposed with higher proportion of nonpolar {1010} facets (51%) than that of pristine ZnO (46%), and C-Zn and C-O-Zn bonds were formed. Compared with pristine ZnO prepared by direct precipitation method (ZnO-DPM) without carbon spheres, carbon doped ZnO exhibited higher light absorption ability and smaller band gap width due to the formation of surface defects. The photocatalytic degradation rate of methyl orange over 13 %C-ZnO was 99.98% for 3 h under the irradiation of UV lamp (15 W), almost 1.3 times higher than that of pristine ZnO-DPM. Even after repeating use for 3 times, the degradation rate of methyl orange can be kept as high as 99%. The present study offers a new preparation method for high photoreactive ZnO with exposed nonpolar {1010} facets by precipitation reaction. [ABSTRACT FROM AUTHOR]

Without any catalysts-assisted, homobranched ZnO nano/microstructure had been synthesized via a simple low temperature water bath method. Such nano/microstructure which consists of shuttle-like nano/microrod backbone was surrounded by six radial oriented branches. The length of the shuttle-like ZnO nano/microrods is about 5–10 μm. The diameter of the single shuttle-like nano/microrods is 1–2.5 μm at the stem and 10–50 nm at the tip while the branches size from top to bottom is 10–50 nm to 0.5–1 μm. A strong ultraviolet emission and weak deep level emission reflect the high optical quality. In addition, a detailed discussion regarding the probable growth mechanism is presented in this work. [ABSTRACT FROM PUBLISHER]

The γ-methacryloxypropyltrimethoxysilane (γ-MPS) has been employed to make hydrophilic surface of ZnO nanostructures into hydrophobic or superhydrophobic surface. Such chemical process, which binds ZnO nanostructures and organic silane together, makes the combination of organic and inorganic materials more durable and stable. Furthermore, modification of different morphologies of ZnO nanostructures has an exceptional wide field of application. Modification of ZnO nanostructures using silane coupling agent γ-MPS can produce the hydrophobic surface of ZnO, and moreover it is expected to further synthesize of many hydrophobic organic-inorganic composite materials. POLYM. COMPOS., 35:1204-1211, 2014. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Abstract: The sensing properties of ZnO nanorods which were immobilized with CA15.3 antibody (anti-CA15.3) for CA15.3 detection were studied by using quartz crystal microbalance (QCM) sensors in this work. ZnO nanorods were synthesized at 90°C by wet chemical route which was used to grow the ZnO nanorods directly on the QCM. The sensors were constructed by binding anti-CA15.3 on ZnO nanorods surface using 3-aminopropyltrietoxy silane (APTES) and glutaraldehyde and were used for CA15.3 detection. The morphology of ZnO nanorods was examined by scanning electron microscopy (SEM). The SEM results indicated the grown ZnO nanorods were well-aligned and the diameter was around 100nm. These QCM sensors showed high sensitivity (25.34±0.67Hz/scale (1U/mL)) and good linearity (0.99) in the concentration range of CA15.3 from 0.5 to 26U/mL by the experiment. The response time of these sensors were observed less than 10s with good reproducibility and stability. All the results indicated that one-dimensional ZnO nanostructure is a good material for biosensor application. [Copyright &y& Elsevier]

As a kind of semiconductor material, the morphology of zinc oxide directly affects its physical properties. By adjusting the ratio of the reaction source and the rate of the incoming gas flow, we obtained one-dimensional nanowire and two-dimensional nanoflag-like functional gradient material (FGM) using chemical vapor deposition (CVD) method. Compared with the one-dimensional nanowires, the growth of the two-dimensional ZnO FGM not only c-oriented, but other directions are also appeared. Photoluminescence results show that the FGM has a higher visible/UV emission intensity ratio than the nanowires for several orders of magnitudes. Meanwhile, the growth mechanism of these nanostructures were discussed in details. [ABSTRACT FROM AUTHOR]

Mg-doped ZnO nanorods were prepared by electrochemical deposition method in aqueous solution. To test the sample, the results show that the sample presents a rod-like shape with hexagonal cross sections and typical morphology of wurtzite ZnO, and (002) diffraction peak of Mg-doped ZnO nanorods move to large-angle direction in XRD. The peak of Mg element has appeared in EDS. XPS shows that there is Mg-O binding in the sample. PL spectrums of the samples are observed at room temperature, the UV emission of Mg-doped ZnO presents blue shift compared with undoped ZnO, absorption spectrum shows that band gap of Mg-doped ZnO is larger. We can reach the conclusion that the Zn2+ions are successfully substituted by Mg2+ions in the ZnO lattice. In addition, photocatalysis property of Mg-doped ZnO nanorods is investigated. It is found that the degradation efficiency of methyl orange raise twice by Mg-doped ZnO nanorods in comparison to undoped ZnO nanorods. The result indicates that the photocatalysis activity of ZnO nanorods can enhance after Mg2+ions are doped into ZnO lattice. [ABSTRACT FROM AUTHOR]

Phosphorus doped ZnO nanoparticles have been synthesized by simple thermal decomposition. By adjusting the concentration of reaction sources, different doping concentrations nanoparticals were obtained and kept wurtzite structure. The EDX and XPS results confirmed P incorporated in ZnO lattice and formed PZn-2VZn complex acceptor. In low temperature PL spectra and temperature dependent PL spectra, the emission peak located at 3.350 eV, 3.310 eV and 3.241 eV could be observed which were attributed to A0X, FA and DAP. Then, the increasing of P-doping concentrations would cause the energy of acceptor bound exciton became lower, and enhance the intensity of FA emission. [ABSTRACT FROM AUTHOR]

Abstract: Pd2+-doped ZnO nanotetrapods were prepared and studied for the humidity detection application. The humidity sensors developed were featured by combination of a quartz crystal microbalance (QCM) as a transducer and Pd2+-doped ZnO nanotetrapods as a sensing element. The ZnO nanotetrapods were synthesized by evaporating highly pure zinc pellets (99.999%) at 900°C in air and PdCl2 was doped on by traditional solution mixing process. Then the mixed solution distributed onto the electrode surfaces of the quartz crystal at room temperature. Pd2+-doped ZnO nanotetrapods were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results indicated that the response of the sensors varied with the different dosage PdCl2. Linear regression algorithm was used for evincing the highly linear behavior of the Pd2+-doped ZnO nanotetrapods sensor. In this humidity sensing system, the Pd2+-doped ZnO nanotetrapods sensing material coated on the gold electrode of QCM showed good sensitivity (∼74.24324Hz/%RH (relative humidity)), reproducibility, linearity (R 2 =−0.98834), short response and recovery time (less than 5s). [Copyright &y& Elsevier]

As a typical wide bandgap semiconductor, ZnO has received a great deal of attention from researchers because of its strong physicochemical characteristics. During the past few years, great progress has been made in the optoelectronic applications of ZnO, particularly in the photocatalysis and photodetection fields. To enable further improvements in the material's optoelectronic performance, construction of a variety of ZnO-based composite structures will be essential. In this paper, we review recent progress in the growth of different ZnO–graphene nanocomposite structures. The related band structures and photocatalysis and photoresponse properties of these nanocomposites are discussed. Additionally, specific examples of the materials are included to provide an insight into the common general physical properties and carrier transport characteristics involved in these unique nanocomposite structures. Finally, further directions for the development of ZnO–graphene nanocomposite materials are forecasted. [ABSTRACT FROM AUTHOR]

High transparency and low resistivity aluminum-doped zinc oxide (AZO) films were prepared by atomic layer deposition. The AZO films show a transparency of about 80% in the near-infrared (NIR) region and a resistivity of the order of 10−3 Ω cm. Organic small molecule NIR-photodetectors (NIR-PDs) with AZO as the anode have been demonstrated for the first time with lead phthalocyanine (PbPc) and C60 as the donor and acceptor, respectively. The optimized NIR-PD exhibited an external quantum efficiency of 6.2% at 760 nm. This result indicated that AZO can be used as the anode for high efficiency NIR-PDs. [ABSTRACT FROM AUTHOR]

Abstract: Zinc oxide (ZnO) nanofibers were synthesized by atom layer deposition (ALD) using polyvinylpyrrolidone (PVP) fibers as template. It was found that the morphologies of ZnO nanofibers were the same as PVP nanofibers. By annealing treatment, the different morphologies of ZnO nanofibers could be formed with the decomposition of PVP nanofibers which were characterized by means of transmission electron microscopy (TEM) and room temperature Raman spectra. The crystal and the optical properties can be also improved. The photocatalytic activities of the as-growth ZnO samples were evaluated in the photocatalytic degradations of aqueous solutions of methyl orange at room temperature. ZnO nanofibers showed higher photocatalytic activity due to more surface-to-volume ratio. [Copyright &y& Elsevier]

A vanadium dioxide (VO 2 ) thin film was fabricated on a ZnO doped with Al (AZO) conductive glass by magnetron sputtering at room temperature followed by annealing under air atmosphere. The microstructures and optical properties of the thin film were studied. The results showed that the VO 2 /AZO composite film was poly-crystalline and the AZO layer did not change the preferred growth orientation of VO 2 . Compared to the VO 2 film fabricated on soda-lime glass substrate through the same process and condition, the phase transition temperature of the VO 2 /AZO composite film was decreased by about 25 °C, thermal hysteresis width narrowed to 6 °C, the visible light transmittance was over 50%, the infrared transmittances before and after phase transition were 21% and 55%, respectively at 1500 nm. [ABSTRACT FROM AUTHOR]

The tube-brush-like ZnO nanostructures were synthesized by hydrothermal method using electrospinning polyvinylpyrrolidone (PVP) nanofibers as templates. The photocatalytic activity of as-grown samples was investigated by photo-degradation of Rhodamine B (RhB). The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV/visible absorption spectroscopy (UV–vis) and photoluminescence (PL) spectroscopy. It was found that the morphologies of the prepared ZnO were tube-brush-like nanostructures. With the grown time increasing, the crystal and the optical properties were improved. In the photocatalytic experiment, the tube-brush-like ZnO nanostructures photocatalytic activity was enhanced the degradation of RhB was up to 98% after 2 h of irradiation. The tube-brush-like ZnO nanostructures showed higher photocatalytic activity because of the special surface morphology. [ABSTRACT FROM AUTHOR]

Abstract: By cadmium allowing of zinc oxide, a phosphor-free single-chip white light emission diode based on n-ZnCdO/p-GaN heterostructure has been realized. The white light electroluminescence was produced by the superposition of two intense emission bands, a blue band and a yellow band. The origins of the blue band was contributed by both GaN and ZnCdO, while the yellow band was from the recombination of the holes and the electrons in the interface of GaN and ZnCdO. [Copyright &y& Elsevier]

Abstract: Vertically aligned ZnO nanowires (NWs) can be reconstructed on large scales by a solvent-evaporation-induced method. The morphologies of the nanowires are regulated by changing the concentration of the solution. Possible mechanism, which the compressive residual stresses and wires/wires self-attraction can be responsible for the surface reconstruction, is addressed. Furthermore, we compare the structural properties of ZnO nanowires before and after reconstructed. [ABSTRACT FROM AUTHOR]

Abstract: The authors demonstrated high spectrum selectivity hybrid ultraviolet (UV) photodetector (PD) by using electrodeposited ZnO nanorods and poly-N-vinylcarbazole as the electron acceptor and donor, respectively. The photoresponse of the PD showed a narrow band centered at 364nm with a full width at half maximum of only 26nm, which was attributed to the absorption of ZnO nanorods. An ultraviolet–visible rejection ratio (R364/R400nm) of three orders of magnitude was also obtained at −5V bias. Those results provided a simple route to fabricate low-cost high spectrum selectivity hybrid visible-blind UV-PDs. [Copyright &y& Elsevier]

Abstract: The vertically aligned ZnO nanowire arrays prepared by vapor transport process can be assembled into complex micropatterns under capillary force. The deflection of the flexible ceramic nanowire is closely related to the liquid tension coefficient, mechanical and structural properties of the ZnO nanowires. The bended nanowires are adhesive together because the solid adhesion energy is sufficient to withstand the restoring elastic force of the deformed nanowires. The size of the bundling pattern can be controlled by varying the aspect ratio of the nanowire. The deflection of the ZnO nanostructure composed of a nanowire and a base is multifarious. [Copyright &y& Elsevier]

Abstract: Aligned Sb-doped ZnO nanocolumns were synthesized by a simple hydrothermal method. Based on the analyses of the X-ray diffraction and photoluminescence result, it could be confirmed that the Sb has successfully doped in the ZnO crystal lattices to form an accepter energy level. At 85K, the recombination of the acceptor-bound exciton was predominant in PL spectrum, which was attributed to the transition of the (SbZn –2VZn) complex bound exciton. The acceptor binding energy had been calculated to be 123meV. [Copyright &y& Elsevier]