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In this paper, CdMnTe nanopowders with uniform shapes were prepared through a facile hydrothermal route using 3-mercaptopropionic acid (MPA) as the stabilizer and modifier. The effects of different experimental conditions including Cd-to-MPA ratio, pH value and reaction temperature on the phase composition and formation mechanism of as-prepared nanopowders were studied. XRD results indicated as-prepared CdMnTe nanopowders were pure phase and had cubic sphalerite structure with high crystallinity. SEM and Rietveld refinement clearly showed that the powders were about 10-100 nm in size. In PL measurement, there was a strong luminescence peak in the infrared region 1.717-1.826 eV. Compared with the CdMnTe single crystal, a blue shift of about 0.109 eV indicated a wider band gap. In UV-vis spectra, the absorption peak of the sample blue shifted with the decrease of crystal size, which indicated an obvious quantum confinement effect (QCE) in nanopowders. The optimal conditions for the preparation of CdMnTe nanopowders are 180 °C for 24 h with the molar ratio 1 : 1 of Cd : MPA at pH 13. In particular, the growth kinetics and possible formation mechanism of the nanopowders were proposed.

CdMgTe crystal is a hopeful room temperature radiation detection material because of some potential advantages. The Cd0.95Mg0.05Te ingot with free of inclusion was successfully grown by a modified Bridgman method in this paper. This results was achieved by using a significant excess cadmium and in situ annealing during the growth process. The grown ingot was about 30 mm in diameter and 120 mm in length. The CdMgTe crystal had a cubic zinc-blende structure. The distribution of Mg element along growth direction was homogeneous. In the whole ingot, no inclusions were observed in IR images and as high IR transmittance as above 60% was measured. Raman scattering spectroscopy showed a good crystal quality for CdMgTe crystals. Moreover, the resistivity with 109 Ω cm order of magnitudes for the ingot could be useful for the fabrication of room temperature radiation detector.

A simple hydrothermal method was used to synthesize four kinds of electrode materials (NiSe2, MoS2, MoS2/NiSe2 composite, and CQDs/MoS2/NiSe2 composite). Structures and electrochemical performance were investigated. Among the four kinds of electrode materials, CQDs/MoS2/NiSe2 composite has excellent performance. The specific capacitance of the CQDs/MoS2/NiSe2 composite can be as high as 1540.7 F g−1 at a current density of 5 A g−1, which is higher than that of NiSe2 (830.9 F g−1), MoS2 (82.2 F g−1) and MoS2/NiSe2 composite (1289.7 F g−1). After 2000 cycles, the specific capacitance of the CQDs/MoS2/NiSe2 composite can be retained by 80.6% at 20 A g−1, indicating its good cycling stability. The experiment results show that the CQDs/MoS2/NiSe2 composite has promising electrochemical energy storage application in supercapacitors.

This work reports a molecularly imprinting polymer based on environmentally friendly and non-toxic ZnO quantum dots for the selective detection sulfadimidine. The MIP@ZnO was prepared by sol–gel method, which usedZnO quantum dots, TEOS, APTES, ammonia as signal materials, cross-linker, function monomer, and initiator, respectively. Result proved that MIP@ZnO exhibited excellent selective fluorescence quenching in the presence of sulfadimidine, good linear relationship in the range of 0–40 μmol L−1 with a correlation coefficient (R2) of 0.98547 was obtained, and the imprinting factor was 2.83. Furthermore, MIP@ZnO has been successfully applied for detection SM2 in real samples with the spiked recoveries ranging from 95.6 to 99.8% with RSD below 2.38%.

A simple fluorescence sensor for the detection of sulfadimidine (SM2) was fabricated by molecular imprinting technology. Cadmium telluride quantum dots (CdTe QDs) as the fluorescent material, 3-aminopropyltriethoxysilane (APTES) as functional monomer, sulfadimidine as template molecule and tetraethoxysilane (TEOS) as cross-linker, the CdTe QDs were embedded in silica nano-particles by reverse microemulsion method. Under optimal detection condition, response is linear in the 2–30 μmol L−1 SM2 concentration condition with the detection limit was 0.4 μmol L−1. In addition, the correlation coefficient was 0.9857 and the imprinting factor was 4.82. The fluorescent probe was successfully applied to the determination of SM2 in tap water and milk sample with the spiked recoveries ranging from 99.8 to 103.2%. It gets a good specific recognition ability and potential practical application value.

In order to improve the electrochemical properties of MoS2, an important method of reflecting synergy between different components has been proposed. And this article describes that four kinds of electrode materials were prepared using a simple hydrothermal method. Herein, a composite doping a small amount of carbon quantum dots (CQDs) can be used as an excellent electrode material. It can be found that carbon quantum dots/MoS2@ZnS composite (CQDs/MoS2@ZnS composite) possesses a higher specific capacitance of 2899.5 F g−1 than MoS2@ZnS composite (2176.1 F g−1), single MoS2 (1067.6 F g−1) and single ZnS (423.4 F g−1). Moreover, CQDs/MoS2@ZnS has excellent cycling stability, maintaining 76.1% of original capacitance after 3500 cycles. The results indicate that the CQDs/MoS2@ZnS composite electrode has potential application in supercapacitors, and the investigation also provides an important idea to improve electrochemical performance of other electrode materials through doping a small amount of CQDs.

This article shows that carbon dots (CQDs), polystyrene sphere (PS) or silica sphere (SiO2) assembled on MoS2 have been successfully synthesized as electrode materials (CQDs/MoS2, PS/MoS2 and SiO2/MoS2) for supercapacitors by a simple hydrothermal process. It can be observed that SiO2 is distributed in the periphery of the flower-like MoS2, and the special morphology has a positive effect on electrochemical performance. As expected, SiO2/MoS2 as a promising electrode material for supercapacitor, exhibiting a higher specific capacitance of 1448.53 F g−1 at a current density of 5 A g−1 and good cycle stability of 70.10% retention after 2000 cycles. This method also provides a reference for the electrode material of supercapacitors with better performance in the future.

In order to investigate the passivation effects of hydrogen, high-resistivity indium doped cadmium manganese telluride (CMT:In) single crystals were annealed in H2 atmosphere. The results indicated the concentration of Mn element and the density of Te inclusions did not change after annealing. Both the resistivity and IR transmittance increased because of the reduction of the carrier concentration. The intensity of (D0,X) peak and (D0,h) peak decreases remarkably because of the passivation of the indium donor. The donor–acceptor pair peak (DAP) peak disappeared, which was due to the dissociation of [VCd − InCd] complexes and the passivation of the impurities by hydrogen. Moreover, Dcomplex peak consisted of two peaks. The intensities of D1 peak increased and D2 peak decreased because the passivation of hydrogen on the donor and dislocation, respectively. The best condition of passivation for H2 atmosphere annealing is 573 K for 30 h.

This paper presents a novel approach of principal component analysis- (PCA-) assisted back propagation (BP) neural networks for the problem of rotor blade load prediction. 86.5 hours of real flight data were collected from many steady-state and transient flight maneuvers at different altitudes and airspeeds. Prediction of the blade loads was determined by the PCA-BP model from 16 flight parameters measured and monitored by the flight control computer already present in the helicopter. PCA was applied to reduce the dimension of the flight parameters influencing the component load and eliminate the correlation among flight parameters. Thus, obtained principal components were used as input vectors of the BP neural network. The combined PCA-BP neural network model was trained and tested by real flight data. Comparison of this model and to a BP neural network model as well as to a multiple linear regression (MLR) model was also done. The results of comparison demonstrate that the PCA-BP model has higher prediction precision with an average error of 2.46%, while 4.49% for BP and 10.20% for MLR. The results also reveal that the PCA-BP model has a shorter convergence path than the BP model. This method not only is useful in establishing the load spectra of helicopter rotor in-service where installation of strain gauges is impractical but also can reduce the cost of installation and maintenance measured by strain gauges.

Two kinds of electrode materials Ni(OH)2 and Ni(OH)2@Zn(OH)2 composite are fabricated on nickel foam. Electrochemical experiments indicate Ni(OH)2@Zn(OH)2 composite deserves further study due to high specific capacitance and good cycle stability, so that it can achieve energy storage and conversion as much as possible. When the hydrothermal time is different, the electrochemical performance of the sample is also different. Accurately, samples can obtain better electrochemical performance at 15 h, and the maximum specific capacitance of Ni(OH)2@Zn(OH)2 is 7.87 F cm−2 compared to Ni(OH)2 (0.61 F cm−2) at 5 mA cm−2. Even at 50 mA cm−2, specific capacitance is 5.24 F cm−2 and rate capability is 66.6%. Furthermore, Ni(OH)2@Zn(OH)2-15 h loses 19.8% after 1000 cycles, revealing the composite has an outstanding stable cycle. These properties also indicate Ni(OH)2@Zn(OH)2-15 h is a promising electrode material.

Sulfamethazine, one of the most widely applied feed additives, has been shown to cause negative health effects to humans. In the present work, a novel and facile fluorescence visual detection probe was established to determine sulfamethazine in milk samples with naked-eye detection. Considering the good stability, excellent optical properties, and easy synthesis, blue-emission carbon dots were used as the standard signal and red-emission CdTe quantum dots as the responsive signal for the determination of sulfamethazine. The fluorescence intensity of red-emission CdTe quantum dots was gradually quenched with increasing concentration of sulfamethazine, while the blue-emission carbon dots response remained constant. Apparent color variations were observed by naked-eye detection in the concentration range from 9.0 to 54 µmol · L−1. In addition, the presented strategy was shown to be promising to provide a rapid, facile, and sensitive method for the determination of sulfamethazine in milk samples with ...

Radiation detectors with different thickness are needed to detect gamma rays with various energies. In this paper, a post-growth annealing method was used to improve the properties of CdMnTe:In (CMT:In) crystals with different thickness for gamma-ray detectors. The results indicated that Te inclusions in CMT:In crystals with different thickness were reduced remarkably after annealing. Both the resistivity and IR transmittance of annealed CMT:In crystals with different thickness increased obviously, which suggested that the crystal quality was improved. For the detectors fabricated by annealed CMT:In slices with 1 mm, 2 mm and 5 mm thickness, the energy resolutions were enhanced about 252%, 193% and 141%, respectively. And ( μτ ) e values were enhanced about 80%, 80% and 76%, respectively. The performance of the detectors was greatly improved after annealing.

In this paper, the effects of Te inclusions on the optical and electrical properties of CdMnTe and CdMgTe crystals grown by the modified vertical Bridgman method were investigated. For CdMnTe ingot, the average size and density distribution of Te inclusions along axial direction were in the range of 12 ~ 29 μm and 1.53 × 104 cm−2 ~ 2.81 × 105 cm−2, respectively. For CdMgTe ingot, the average size and density distribution of Te inclusions were in the range of 6 ~ 20 μm and 8.17 × 103 cm−2 ~ 2.42 × 104 cm−2, respectively. The density and size of Te inclusions increased gradually from the first-to-freeze part to the last-to-freeze part for CdMnTe ingot, while that of CdMgTe ingot first decreased and then increased. For both CdMnTe and CdMgTe ingots, the resistivity, IR transmittance and FWHM of (D0, X) peak first increased and then decreased from the first-to-freeze part to the last-to-freeze part. The middle-to-freeze parts of both ingots had the best crystal quality. For both CdMnTe and CdMgTe detectors, the energy resolution and (μτ)e value were first increased and then decreased from the first-to-freeze part to the last-to-freeze part. The detectors fabricated by the middle-to-freeze parts of both crystals had the best performance and can could meet the requirements of room temperature radiation detection. PACS: 78.30.Fs; 78.55.Et; 81.40.Ef.

In this study, a novel detection method based on the technique of surface enhanced Raman scattering (SERS) was presented. Firstly, the homogeneous Ag particles were prepared and CdTe quantum dots were modified on the surface of Ag particles to synthesize the Ag/CdTe heterostructures as the SERS substrate. Then 2,6-DCP was chosen as the template molecule and combined the technique of atom transfer radical polymerization to prepare Ag/CdTe/molecular imprinted polymers (MIPs). Through characterization analysis, it was proved that the Ag/CdTe/MIPs exhibited splendid SERS properties and selectivity. Under the optimal condition, it was presented good linear relationship (R2 = 0.96) between the Raman signal (at 1596 cm−1) and the concentration of the templates, and the detection limit was determined as 10−9 mol L−1. It was envisaged that the sensitivity of SERS coupled with the selective properties of MIPs could induce a promising chemosensor for practical applications.

The authors describe a fluorescence based assay for determination of the macrolid antibiotic erythromycin (ERY). It is based in the use of fluorescent gold nanoclusters (AuNCs) coated first with silica (to obtain AuNC@SiO2) and then with a molecularly imprinted polymer (MIP). The MIP was synthesized from 3-aminopropyltriethoxysilane as the functional monomer, ERY as the template, and tetraethoxysilane as the cross-linker via a sol-gel process that leads to surface imprinting. By using this method, the strong fluorescence of AuNCs was maintained in the resultant MIPs. After optimization of the experimental conditions, the signal (measured at excitation/emission wavelengths of 396/585 nm) decreases linearly with increasing concentration of ERY in the 0.1 to 11.9 μM ERY concentration range. The limit of detection is 12 nM, and the imprinting factor is 4.0. The method was successfuly applied to the determination of ERY in spiked human urine and saliva.

With the deeply cognition of the micro domain, in biomedical, analytical chemistry, and integrated circuits manufacturing etc., there is an urgent need to develop some object which is micro-sized or able to be micro-operated. However, conventional micromanipulation systems are limited by space, accuracy and safety. In this work, a facile fabrication method is demonstrated to create three-dimensional (3D) electrostatic microstructures for microrobotics applications. The microstructures are developed using lamination of SU-8 photosensitive films and deposition of copper (Cu), which has potential for large-scale manufacturing. The simulation of the electrostatic microstructures movement was conducted; and the results showed the maximum deformation occurred in the waist; strain and stress concentrated at bottom edge of the microrobot. The microstructures were actuated moving on an electric substrate by varying the voltage. It was found that the microstructure step size is proportional to the square of voltage. When 1000 V, 50 Hz electric field was applied, the step size was 0.1 µm and average speed could achieve 300 µm/min, which shows great potential in microfluidics and microrobotics applications.

In this paper, a highly stable ratiometric fluorescence probe based on dual-emission quantum dots (QDs) was designed for the visual detection of aspirin. The probe was composed of two differently colored CdTe QDs, in which red-emitting QDs embedded in SiO2 (r-QDs@SiO2) acted as the reference signal and green-emitting QDs (g-QDs) covalently anchored on the surface of r-QDs@SiO2 served as the response signal. The fluorescence of r-QDs@SiO2 remained constant, whereas the fluorescence of g-QDs was quenched by the addition of aspirin. As a result, continuous color changes in the dual-emission fluorescence probe were observed. Under optimum conditions, the as-prepared dual-emission fluorescence probe was used for the determination of aspirin in a concentration range of 6.0–45 μmol L−1 with a detection limit of 0.20 μmol L−1. Furthermore, the present method was successfully applied in the detection of aspirin in real samples with a relatively high stability for about ten days.

In this study, a novel SERS sensor was successfully prepared by combining a molecular imprinted technique (MIT) with a SERS technique to improve the selectivity of the traditional SERS technique. Moreover, a thermo-sensitive technique was also introduced to confer stimuli-responsive properties to the materials. In a typical procedure, the Ag nanoparticles (NPs) were reduced on the surface of ZnO nanorods (NRs), and the ZnO/Ag heterostructures were used as the SERS substrates. Subsequently, a layer of thermo-sensitive imprinted polymer was coated on the surface of ZnO/Ag heterostructures to prepare the thermoresponsive ZnO/Ag/molecularly imprinted polymers (ZOA-TMIPs) by precipitation polymerization. Moreover, it was proven that the ZOA-TMIPs were regenerable and exhibited good reusability. The results proved that the materials in this study can be effectively used for residual organic dye detection in water.

A NiO@ZnO (NZO) hybrid with different reaction times was successfully synthesized by a green hydrothermal method. After comparison, it was found that hydrothermal time had a great impact on specific capacitance. As a supercapacitor electrode of NZO-12h, it exhibited the maximum reversible specific capacitance of 985.0 F/g (3.94 F/cm2) at 5 mA/cm2 and 587.5 F/g (2.35 F/cm2) at 50 mA/cm2, as well as a high retention of 74.9% capacitance after 1500 cycles at 20 mA/cm2. Furthermore, the asymmetric electrode device with ZnO-12h and activated carbon (AC) as the positive and negative electrodes was successfully assembled. In addition, the device exhibited a specific capacitance of 85.7 F/g at 0.4 A/g. Moreover, the highest energy density of 27.13 Wh kg−1 was obtained at a power density of 321.42 W kg−1. These desirable electrochemical properties demonstrate that the NZO hybrid is a promising electrode material for a supercapacitor.

This paper studies a flight load test method for helicopter blade, including the structural force of helicopter blade, strain gauge bridge modification, load calibration method and the establishment of load calibration equation in the typical maneuvers. First, blade structure of the helicopter was analyzed and the strain gauges were pasted in the load profile which were considered to be important positions to analysis the flight safe of helicopter. Second, Load calibration equations were obtained by ground calibration test, which would be used to convert the strain time curve to the load time curve. The helicopter flighted in different maneuvers, such as hovering, horizontal flight and climbing. At the same time, flight parameters were recorded, such as helicopter altitude, pitch angle, roll angle and yaw Angle. The flight parameters can be used to analysis the flight conditions. Then the blade flight load in different flight maneuvers was analyzed. The result was that the time-domain waveform was neat, good periodicity, strong regularity, no hybrid interference and jump point. It was illustrated that the blade load test flight data were accurate and reliable, which met the accuracy requirements of Engineering. The blade load data obtained through different flight maneuvers can be used to structural modification, fatigue analysis and blade design.

In this paper, a load test method of landing gear during take-off and landing of helicopter was proposed and the structure of helicopter landing gear, the modification of strain gauge bridge, the establishment of load calibration equation and the flight test of helicopter were studied. Firstly, according to the structure of helicopter landing gear, the stress analysis of landing gear was carried out, and the load position and force form of landing gear were determined during take-off and landing. Then, the measuring principle of the strain bridge was studied. According to the technical requirements, structural characteristics of the landing gear load test and the properties and principles of the strain bridge, the distribution and load measurement form of the strain bridge of the dangerous structure of the landing gear were designed. Then, studying load calibration test scheme of landing gear and carrying out load calibration test, the load calibration equation of landing gear was obtained, and the accuracy of load calibration equation was verified by comparing the expected load and actual load. Through the flight test, the landing gear load during the take-off and landing of the helicopter was obtained. Finally, the valid analysis of flight load data was carried out. The results show that the proposed method is feasible, and the flight test data of landing gear load are accurate and reliable, which can provide data support for the structure modification, fatigue analysis and the life evaluation of landing gear.

In this paper, an effective annealing method in which CdMnTe:In (CMT:In) single crystals were coated with CMT powders of the same composition was used to improve the crystal quality of CMT:In crystals. The results indicated that the density of Te inclusions decreased as the annealing time increased. The resistivity and IR transmittance of annealed CMT:In crystals were enhanced obviously. The resistivity of 120 h annealed crystal increased even two orders of magnitude. The reduction of full-width at-half-maximum (FWHM) and the increase of the intensity of X-ray rocking curve indicated an improvement of the crystal quality. PL measurements also showed the crystal quality improved after annealing. No characteristic peak of 241Am γ-ray could be observed in the detector fabricated with as-grown crystal. Remarkably, for the detector fabricated with annealed crystals, the peak of 241Am γ-ray appeared. And the energy resolution and μτ value were improved as the annealing time increased. Specially, 120 h annealed CMT:In crystal with 10.11% energy resolution and 1.20×10−3 cm2/V μτ value has the best detector performance.

The microflower-like Si/MoS2 composites were fabricated using Si quantum dots (QDs) to assist a facile hydrothermal method. The electrochemical performance of Si/MoS2 composite in symmetric and asymmetric systems was studied. Electrochemical characterization revealed that the Si/MoS2 composite electrode in a three-electrode system has a high specific capacitance of 574.4 F&middot, g&minus, 1 at 5 A&middot, 1. Furthermore, the Si/MoS2 composite electrode in a two-electrode system had the maximum energy density of 27.2 Wh&middot, kg&minus, 1 when a power density of 749.1 W&middot, 1 was achieved. Therefore, this investigation proves the Si/MoS2 composite microflower-like structure should be a promising candidate electrode material for supercapacitors.

Recently, researchers were interesting in exploring alternative materials for well-studied CdZnTe which was the key material of radiation detection. Cadmium Magnesium Telluride (Cd1-xMgxTe) crystal was regarded as promising one for room temperature X-ray and gamma-ray detectors due to some potential advantages. In this paper, two large-size Cd0.95Mg0.05Te ingots with 30 mm diameter and over 100 mm length were successfully grown by a modified vertical Bridgman method. Two modifications, including Cd excess or Te-rich condition and the accelerated crucible rotation technique (ACRT), were applied in growing process to decrease defects, enhance resistivity and homogenize component distribution. The results indicated that both ingots had a cubic zinc-blende structure. The distribution of Mg element in the ingots along axial direction was very homogeneous. The energy band gap of Cd0.95Mg0.05Te was close to Cd0.9Zn0.1Te. Low density of Te inclusions (103 cm−3 order of magnitudes) and high IR transmittance (over 60%) showed the good crystal quality. Raman scattering spectroscopy also showed a good crystal quality for Cd0.95Mg0.05Te crystals. Thus, Cd0.95Mg0.05Te crystals could be a promising radiation detector material.

Cadmium&ndash, magnesium&ndash, telluride (CdMgTe) crystal was regarded as a potential semiconductor material. In this paper, an indium-doped Cd0.95Mg0.05Te ingot with 30 mm diameter and 120 mm length grown by a modified Bridgman method with excess Te condition was developed for room temperature gamma-ray detection. Characterizations revealed that the as-grown Cd0.95Mg0.05Te crystals had a cubic zinc-blende structure and additionally Te-rich second phase existed in the crystals. From the tip to tail of the ingot, the density of Te inclusions was about 103&ndash, 105 cm&minus, 2. The crystals had a suitable band-gap range from 1.52&ndash, 1.54 eV. Both infrared (IR) transmittance and resistivity were relatively low. Photoluminescence measurement indicated that the ingot had more defects. Fortunately, after annealing, IR transmittance and the resistivity were significantly enhanced due to the elimination of Te inclusions. CdMgTe crystal after annealing showed a good crystal quality. The energy resolutions of the detector for 241Am and 137Cs gamma-ray were 12.7% and 8.6%, respectively. The mobility-lifetime product for electron was 1.66 &times, 10&minus, 3 cm2/V. Thus, this material could be used for room temperature radiation detectors.

There is growing attention and rapid development on flexible electronic devices with electronic materials and sensing technology innovations. In particular, strain sensors with high elasticity and stretchability are needed for several potential applications including human entertainment technology, human–machine interface, personal healthcare, and sports performance monitoring, etc. This article presents recent advancements in the development of polydimethylsiloxane (PDMS)-based flexible resistive strain sensors for wearable applications. First of all, the article shows that PDMS-based stretchable resistive strain sensors are successfully fabricated by different methods, such as the filtration method, printing technology, micromolding method, coating techniques, and liquid phase mixing. Next, strain sensing performances including stretchability, gauge factor, linearity, and durability are comprehensively demonstrated and compared. Finally, potential applications of PDMS-based flexible resistive strain sensors are also discussed. This review indicates that the era of wearable intelligent electronic systems has arrived.

In this paper, detector-grade CdMnTe:In (CMT:In) single crystals were annealed under Te atmosphere with various annealing times. The results indicated that the density of Te inclusions had not changed as the annealing time increased, whereas the resistivity exhibited an initial increase followed by a decrease. The conduction type was changed from weak n-type conduction in as-grown crystal to p-type conduction in 60 h annealed crystal. The lR transmittance decreased obviously as the annealing time increased. In the PL spectra, the obvious reduction of the intensity of (D degrees,X) peak and the increase of the intensity of the D-complex peak in the annealed CMT:In crystals indicated a degradation of the crystal quality. The energy resolution of the detector fabricated with 15 h annealed crystal was improved, whereas the mu tau values of the detectors fabricated with all annealed crystals were reduced. Specially, the characteristic peak of Am-241 gamma-ray could not be observed in the detectors fabricated by 60 h annealed crystals. Therefore, optimal annealing temperature and the duration are 773 K and 15 h, respectively. (C) 2015 Elsevier B.V. All rights reserved

Well-oriented ZnO nanorod arrays are successfully fabricated on different substrates. They are formed on different substrates at low temperature via a hydrothermal method, without adding any catalysts or templates. This approach is convenient and inexpensive. The morphologies of ZnO crystals could be controlled and transformed to other morphologies successfully by using different substrates. The effects of the substrates on the ZnO nanorod arrays have been systematically studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The characterizations of XRD and scanning electron microscopy (SEM) reveal that these products are pure single-crystal and the structure is uniform. The photoluminescence property has been detected by photoluminescence (PL) spectrum and Raman spectrum. Photoluminescence measurements show that each spectrum consists of the ultraviolet (UV) band and a relative broad visible light emission peak. But substrates play roles in the intensity of ultraviolet and visible light emission peak. The green emission in Raman measurement may be related to the surface states.

ZnO nanotube arrays were synthesized on zinc foil by a simple solvothermal approach. In this approach, zinc foil was used not only as a substrate but also as a zinc-ion source for the direct growth of ZnO nanotube arrays. X-ray diffraction (XRD) analysis and Scanning electron microscope (SEM) images, indicated that the structure of the ZnO nanotube arrays on the zinc foil substrate was single-crystalline with a wurtzite structure. The optical properties of the ZnO nanorod arrays were characterized by photoluminescence spectroscopies and Raman. Photoluminescence exhibited strong UV emission and a broad deep-level (visible) emission emission at with 325 nm excitation. A possible mechanism is also proposed to account for the growth of the ZnO nanotube arrays. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Well-faceted hexagonal ZnO nanotubes have been synthesized on Si substrates by a simple hydrothermal method and the subsequent aged process at relative low temperature without any catalysts or templates. The samples have been characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) measurement. XRD pattern confirmed that the as-prepared ZnO was the single-phase wurtzite structure. SEM results showed that the samples were tubular textures, with the average lengths of 3–5 μm, inner diameters of 300–350 nm. The surface-related optical properties have been investigated by photoluminescence (PL) spectrum and Raman spectrum. The PL implied that fairly high surface state density existed in ZnO nanotubes. And the green emission in Raman measurement might be related to surface states. A possible growth mechanism on the formation of crystalline ZnO nanotubes has been presented.

Well-faceted hexagonal ZnO nanorods have been synthesized by a simple hydrothermal method at relative low temperature (90°C) without any catalysts or templates. Zinc oxide (ZnO) nanorods were grown in an aqueous solution that contained Zinc chloride (ZnCl2, Aldrich, purity 98%) and ammonia (25%). Most of the ZnO nanorods show the perfect hexagonal cross section and well-faceted top and side surfaces. The diameter of ZnO nanorods decreased with the reaction time prolonging. The samples have been characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) measurement. XRD pattern confirmed that the as-prepared ZnO was the single-phase wurtzite structure formation. SEM results showed that the samples were rod textures. The surface-related optical properties have been investigated by photoluminescence (PL) spectrum and Raman spectrum. Photoluminescence measurements showed each spectrum consists of a weak band ultraviolet (UV) band and a relatively broad visible light emission peak for the samples grown at different time. It has been found that the green emission in Raman measurement may be related to surface states. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Cu and Ce co-doped ZnO powder has been carried out by sol-gel method in order to gain high performance photocatalyst. The structures, morphologies and photocatalytic properties of resultant (Zn0.97-xCu0.03CexO, x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10) have been investigated by XRD, SEM and the degradation rate of methyl orange. XRD analyses evidenced that the increase of Ce doping concentration will lead to the decrease of the crystal quality of Zn0.97-xCu0.03CexO powders. SEM indicated that the uniformity of particle size and the increase of the dispersion property of the doped sample will be beneficial to the suspension dispersion of the catalyst. At the same time, it can also promote the catalyst absorption of light and reactant molecules. Photocatalytic analysis showed the total degradation rate is close to one time function distribution with time, and the photocatalytic effect is obviously enhanced.