Nanoparticles are increasingly being recognized for their potential utility in biological applications including nanomedicine.Here,we have synthesized zinc oxide(ZnO)nanorods using zinc acetate and hexamethylenetetram...Nanoparticles are increasingly being recognized for their potential utility in biological applications including nanomedicine.Here,we have synthesized zinc oxide(ZnO)nanorods using zinc acetate and hexamethylenetetramine as precursors followed by characterizing using X-ray diffraction,fourier transform infrared spectroscopy,scanning electron microscopy and transmission electron microscopy.The growth of synthesized zinc oxide nanorods was found to be very close to its hexagonal nature,which is confirmed by X-ray diffraction.The nanorod was grown perpendicular to the long-axis and grew along the[001]direction,which is the nature of ZnO growth.The morphology of synthesized ZnO nanorods from the individual crystalline nucleus was confirmed by scanning and transmission electron microscopy.The length of the nanorod was estimated to be around 21 nm in diameter and 50 nm in length.Our toxicology studies showed that synthesized ZnO nanorods exposure on hela cells has no significant induction of oxidative stress or cell death even in higher concentration(10μg/ml).The results suggest that ZnO nanorods might be a safer nanomaterial for biological applications.展开更多
The effect of mixed oxide support on the performance of Ni/ZnO in the reactive adsorption desulfurization(RADS) reaction was investigated in a fixed bed reactor by using thiophene as the sulfur-containing compound in ...The effect of mixed oxide support on the performance of Ni/ZnO in the reactive adsorption desulfurization(RADS) reaction was investigated in a fixed bed reactor by using thiophene as the sulfur-containing compound in the model gasoline. A series of oxide supports for Ni/ZnO were synthesized by the co-precipitation method and characterized by XRD, N_2-adsorption, TPR and NH_3-TPD techniques. It was found that the desulfurization capacity of Ni/ZnO was enhanced greatly when active components were supported on the proper mixed oxide. Ni/ZnO supported on oxides exhibited much higher desulfurization efficiency and sulfur adsorption capacity than the unsupported Ni/ZnO and the synthesized Ni/ZnO-SA adsorbent exhibited the highest efficiency for thiophene removal. The higher desulfurization activity and sulfur capacity of Ni/ZnO supported on SiO_2-Al_2O_3 with small particle size, high specific surface area and large pore volume could promote the high dispersion of active metal phase and the transfer of sulfur to ZnO with lower mass transfer resistance. γ-Al_2O_3 species could weaken the interaction of active phases and SiO_2 as well as could increase greatly the amount of weak acids. Therefore, these oxides could impose a great influence on the structure and chemical properties of the catalyst.展开更多
Nano-ZnO particle （nZnOp） reinforced polyethylene glycol （PEG）/polyethylene terephthalate （PET） （nZnOp/PEG/PET） copolymeric composites with different mass fractions and molecular weights of PEG are synthesized...Nano-ZnO particle （nZnOp） reinforced polyethylene glycol （PEG）/polyethylene terephthalate （PET） （nZnOp/PEG/PET） copolymeric composites with different mass fractions and molecular weights of PEG are synthesized via in-situ polymerization. The dispersion of nZnOp in copolymer matrixes and the effects of PEG and nZnOp particles on the crystallization behavior of the composites are studied by TEM, differential scanning calorimetry（DSC）, XRD and Fourier thansform infrared spectroscopy （FTIR ）. The results reveal that nZnOp particles are dispersed in the matrixes with nano-scale, and the addition of PEG induces more homogeneous dispersion of nZnOp. Simultaneously, these nanoparticles become nucleating centers during the crystallization of the matrixes. PEG segments can improve the flexibility of the PET molecular chain, resulting in the drop of the cold crystallization temperature and the rise of the crystallization rate of the composites. Furthermore, PEG （4 000） with the mass fraction of 10% can promote the crystallization rate of the composites. The mechanical properties show that the nano-particles strengthen and toughen the PET matrix, whereas PEG weakens these improve- ments.展开更多
Reactive sputtered boron-doped zinc oxide(BZO) film was deposited from argon,hydrogen and boron gas mixture.The reactive sputtering technique provides us the flexibility of changing the boron concentration in the prod...Reactive sputtered boron-doped zinc oxide(BZO) film was deposited from argon,hydrogen and boron gas mixture.The reactive sputtering technique provides us the flexibility of changing the boron concentration in the produced films by using the same intrinsic zinc oxide target.Textured surface was obtained in the as-deposited films.The surface morphology and the opto-electronic properties of the films can be controlled by simply varying the gas concentration ratio.By varying the gas concentration ratio,the best obtained resistivity ~6.51×10^-4Ω-cm,mobility ~19.05 cm^2 V^-1 s^-1 and sheet resistance ~7.23Ω/□ were obtained.At lower wavelength of light,the response of the deposited films improves with the increase of boron in the gas mixture and the overall transmission in the wavelength region 350-1100 nm of all the films are>85 %.We also fabricated amorphous silicon(a-Si) thin film solar cell on the best obtained BZO layers.The overall efficiency of the a-Si solar cell is 8.14 %,found on optimized BZO layer.展开更多
Ordered zinc oxide （ZnO） rod arrays with very high orientation were fabricated on Si substrates by using a solution method. The substrate surfaces were functionalized by Self-Assembly Monolayers （SAMs）. In the ver...Ordered zinc oxide （ZnO） rod arrays with very high orientation were fabricated on Si substrates by using a solution method. The substrate surfaces were functionalized by Self-Assembly Monolayers （SAMs）. In the very early growth stage, the oriented ZnO crystals had already grown, which appeared to be the main reason why ZnO nanorods showed very high orientation. The un-dense and un-uniform SAMs provided a surface that was heterogeneous to ZnO nucleation. Consequently, highly oriented ZnO rods were selectively grown on the ＂coin-like＂ SAM-uncovered regions. The route developed here can provide some helpful information to control the nucleation and orientation of ZnO in aqueous solution. Also, the site-selective growth mechanisms can indicate a clue to grow patterned highly oriented ZnO nanorod arrays by the organic template.展开更多
BiOI/ZnO/rGO(reduced graphene oxide) composite photocatalyst was fabricated using a simple one-step hydrothermal process and applied to the degradation of antibiotic chloramphenicol(CAP). By tuning the Bi/Zn ratios, t...BiOI/ZnO/rGO(reduced graphene oxide) composite photocatalyst was fabricated using a simple one-step hydrothermal process and applied to the degradation of antibiotic chloramphenicol(CAP). By tuning the Bi/Zn ratios, the structure and photoelectric properties of the catalyst were investigated and characterized in terms of their morphological, structural, optical and photoelectrochemical properties. The as-synthesized composite photocatalysts are well-crystalline, uniform dispersion and exhibit good photocatalytic properties.The photocatalytic degradation rate of CAP by BiOI/ZnO/rGO composite is 8.1 times and 1.8times that of BiOI and ZnO, respectively. The photocatalytic mechanism studies revealed that the synergistic effect between rGO and BiOI/ZnO can effectively separate photogenerated electron–hole, enhance photocurrents and conductivity, and improve charge carrier densities. Moreover, BiOI/ZnO/rGO possesses good stability and reusability that the degradation efficiency remained above 80% even after 5 recycling. This study reveals that both the introduction of rGO and heterostructure construction between BiOI and ZnO play a crucial role in their photoelectrochemical and photocatalytic properties.展开更多
In the past several decades, dilute magnetic semiconductors, particularly the dilute magnetic oxides have evolved into an important branch of materials science due to their potential application in spintronic devices ...In the past several decades, dilute magnetic semiconductors, particularly the dilute magnetic oxides have evolved into an important branch of materials science due to their potential application in spintronic devices combining of properties of semiconductors and ferromagnets. In spite of a major effort devoted to the mechanism of ferromagnetism with a high Curie temperature in these materials, it still remains the most controversial research topic, especially given the unexpected do ferromagnetism in a series of undoped wide-band-gap oxides films or nanostructures. Recently, an abundance of research has shown the critical role of various defects in the origin and control of spontaneous magnetic ordering, but contradicting views from intertwined theoretical calculations and experiments require more in-depth systematic research. In our previous work, considerable efforts have been focused on two major oxides, i.e. ZnO and Zr02. This review will present a summary of current experimental status of this defect-driven ferromag- netism in dilute magnetic oxides （DMOs）.展开更多
A novel method was presented for synthesis of ZnO and ZnO-CuO composites in the form of nanowires, nanorods and nanoflakes on oxidized silicon substrates. Further, the use of the synthesized nanostructures for gas sen...A novel method was presented for synthesis of ZnO and ZnO-CuO composites in the form of nanowires, nanorods and nanoflakes on oxidized silicon substrates. Further, the use of the synthesized nanostructures for gas sensing was demonstrated. Pure brass （Cu0.65-Zn0.35） films were deposited on oxidized Si substrate by radio frequency （RF） diode sputtering. Subsequently, these films having thickness in the range of 100-200 nm were oxidized in different oxidizing ambient in the temperature range of 300-550 ℃. The effect of temperature, time and oxidizing ambient on the growth of nanostructures was investigated by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD） and photoluminescence （PL） techniques. The nanostructures surface was analyzed by X-ray photoelectron spectroscopy （XPS）. The synthesized nanowires had diameter in the range of 60-100 nm and length up to 50 μm. Based on these observations, the growth mechanism has been suggested. For the nanorods, the diameter was observed to be -150 nm. Samples having dense nanowires, nanorods and nanoflakes were used as a gas sensing material. The performance Of the sensor was investigated for different nanostructured materials for various volatile organic compounds （VOCs）, It was observed that ZnO- CuO nanoflakes were more sensitive to VOC sensing compared to ZnO nanowires and nanorods.展开更多
Nanosized ZnO powders were prepared with a two-step precipitation method. The average size of ZnO particles was about 80 nm and their size distribution was narrow. Combining with ultrafine additive powders, ZnO base v...Nanosized ZnO powders were prepared with a two-step precipitation method. The average size of ZnO particles was about 80 nm and their size distribution was narrow. Combining with ultrafine additive powders, ZnO base varistor was produced via an oxide mixing route. ZnO varistor derived from normal reagent grade starting materials was investigated for comparison purpose. Outstanding microstructure of the ZnO varistor derived from nanosize ZnO powders and ultrafine dopants was obtained: uniform distribution of fine ZnO grains (less than 3 microns), grain boundary and the dopant position. Higher varistor voltage (U=492 V/mm) and nonlinear coefficient (α=56.2) as well as lower leakage current (TL=1.5 μuA) were achieved. The better electrical properties were attributed to the uniform microstructure, which in turn led to stable and uniform potential barriers. Also this improved technique is more feasible for producing ZnO nanopowders and resulting varistor in large scales.展开更多
Nano zinc oxide(ZnO)has excellent performance and low cost,but ZnO has a wide band gap and its electron-hole is difficult to achieve effective separation,which greatly limits its photocatalytic activity.This paper int...Nano zinc oxide(ZnO)has excellent performance and low cost,but ZnO has a wide band gap and its electron-hole is difficult to achieve effective separation,which greatly limits its photocatalytic activity.This paper introduces the structural properties of ZnO and the mechanism of photocatalytic degradation of organic pollutants,and summarizes the preparation of ZnO nanomaterials and the application studies in improving its photocatalytic properties,in order to promote the research and development of ZnO nanomaterials.展开更多
Fabrication and characterization of metal-semiconductor-metal ultraviolet （MSM UV） photodetector based on ZnO ultra thin （nano scale） films with Pd Schottky contact are reported. The ZnO thin film was grown on gla...Fabrication and characterization of metal-semiconductor-metal ultraviolet （MSM UV） photodetector based on ZnO ultra thin （nano scale） films with Pd Schottky contact are reported. The ZnO thin film was grown on glass substrate by thermal oxidation of preeposited zinc films using vacuum deposition technique. With applied voltage in the range from -3V to 3V, the contrast ratio, responsivity, and detectivity for an incident radiation of 0.1 mW at 365 nm wavelength were estimated. The proposed device exhibited a high gain which was attributed to the hole trapping at semiconductor-metal interface. I-V characteristics were studied and the parameters, such as ideality factor, leakage current, resistance-areaproduct, and barrier height, were extracted from the measured data.展开更多
P-type nitrogen-doped ZnO films are prepared successfully by in-situ thermal oxidation of Zn3N2 films. The prepared films are characterized by x-ray diffraction, non-Rutherford back.scattering （non-RBS） spectroscopy...P-type nitrogen-doped ZnO films are prepared successfully by in-situ thermal oxidation of Zn3N2 films. The prepared films are characterized by x-ray diffraction, non-Rutherford back.scattering （non-RBS） spectroscopy, x- ray photoelectron spectroscopy, and photoluminescence spectrum. The results show that the Zn3N1 films start to transform to ZnO at 400℃ and the total nitrogen content decreases with the increasing annealing temperature. The p-type fihns are achieved at 500℃ with a low resistivity of 6.33Ω.cm and a high hole concentration of ＋8.82 × 10^17 cm-3, as well as a low level of carbon contamination, indicating that the substitutional nitrogen （No） is an effective acceptor in the ZnO：N film. The photoluminescence spectra show clear UV emissions and also indicate the presence of oxygen vacancy （Vo） defects in the ZnO：N films. The p-type doping mechanism is briefly discussed.展开更多
A new type of inorganic-polymer materials of epoxy Titanium Dioxide and Zinc Oxide was prepared. In this work, the mechanical properties of polymer composites reinforced with ceramic nanoparticles were investigated. T...A new type of inorganic-polymer materials of epoxy Titanium Dioxide and Zinc Oxide was prepared. In this work, the mechanical properties of polymer composites reinforced with ceramic nanoparticles were investigated. Three points bending tests demonstrated an enhancement in flexural strength and flexural modulus respectively, compared to the pure epoxy. The reinforcement of nanoparticulate materials was Titanium Dioxide and Zinc Oxide with various weight fraction. Experimental tests results indicated that the composite materials have significantly higher modulus of elasticity than the matrix material. It was found that the enhancement in modulus of elasticity was directly proportional to the weight fraction of reinforcement material, and that Zinc Oxide composites have higher modulus of elasticity than Titanium Dioxide composites with equivalent of weight fraction. The wear results showed that nanoparticles improved the wear resistance of epoxy nanocomposites, the Titanium Dioxide matrix particles could improve the wear resistance of the epoxy more efficiently than Zinc Oxide particles. The fatigue test showed that the fatigue resistance of epoxy Zinc Oxide matrix particles was higher than that of Titanium Dioxide matrix particles.展开更多
Two different morphologies of ZnO（lotus-shaped, rod-shaped） and ZnO/PVDF composite materials were prepared. The morphologies of ZnO and composite materials were characterized by scanning electron microscopy（SEM） a...Two different morphologies of ZnO（lotus-shaped, rod-shaped） and ZnO/PVDF composite materials were prepared. The morphologies of ZnO and composite materials were characterized by scanning electron microscopy（SEM） and transmission electron microscopy（TEM）. Fourier transform infrared spectroscopy（FT-IR）, thermal gravimetry（TG）, and X-ray diffraction（XRD） were also used to characterize the chemical structures and phase composites of ZnO and ZnO/PVDF composite materials. Breakdown voltage, dielectric constant and dielectric loss of ZnO/PVDF composite materials were also tested. Microstructure analysis showed that ZnO nanoparticles dispersed uniformly in the matrix. And the dielectric constant expresses a significantly improvement while the dielectric loss and breakdown voltage expresses no significant change. Moreover, dielectric constant keeps an improvement tendency with increasing content of ZnO.展开更多
Traditional wastewater mostly contains pharmaceutical ingredients. Therefore, the wastewater must be completely free from antibiotics before its release into the environment. In the present study, photocatalytic degra...Traditional wastewater mostly contains pharmaceutical ingredients. Therefore, the wastewater must be completely free from antibiotics before its release into the environment. In the present study, photocatalytic degradation was done to investigate the removal efficiency of Oxytetracycline Dihydrate (OTC) using ZnO, ZnO/3%BaTiO<sub>3</sub> (3 BZ), ZnO/18%BaTiO<sub>3</sub> (18 BZ), ZnO/ 33%BaTiO3 (33 BZ) and ZnO/48%BaTiO<sub>3</sub> (48 BZ) under UV light. After the exposure time of 420 min, about 99.57% and 97.87% of OTC was degraded using ZnO and 3 BZ respectively. Further, increasing the amount of BaTiO<sub>3</sub> in ZnO prolongs the degradation time. Therefore, faster efficiency was found using ZnO nanoparticles. The observed reaction rate constant using ZnO was 0.00933 min<sup>-1</sup> which decreased to 0.00532 min<sup>-1</sup> using 48 BZ, indicating the decrease of reaction rate for increasing the amount of BaTiO<sub>3</sub>. Hence, the use of ZnO photocatalyst is anticipated to be a promising technique for the photocatalytic degradation of contaminated wastewater with oxytetracycline antibiotics using UV light.展开更多
In this study,the functional gradient materials(FGMs)were the first attempt to homogenise the electric field distribution in the cable accessory,where zinc oxide particles(ZnO_(k))were filled into ethylene propylene d...In this study,the functional gradient materials(FGMs)were the first attempt to homogenise the electric field distribution in the cable accessory,where zinc oxide particles(ZnO_(k))were filled into ethylene propylene diene monomer with the composi-tionally gradient distribution using laminating and hot-pressing methods.The constructed FGMs with significantly improved non-linear conductivity can avoid the electric field distortion in cable accessories.The results show that the configuration of compositionally gradient structured fillers can significantly improve the electrical conductivity of FGMs compared to the homogeneous distribution.Additionally,compositionally gradient structures of ZnOk fillers can also improve the thermal conductivity of FGM composites,which facilitates the heat dissipation of dielectric and reduces the probability of electrothermal coupling breakdown.The mechanical properties of the composites are deeply affected by the filler's content and configuration,both improved tear elongation and tensile strength can be achieved at an optimal content and gradient structure of ZnOk fillers.Finally,the simulation analysis results show that FGM composites can homogenise the electric field more efficiently in comparison with homogeneous composites.This work demonstrates that compositionally gradient structures can improve the utilisation of functional fillers and develop the FGM composites for high-voltage direct current cable accessory applications.展开更多
A method for obtaining a new type of surface acoustic wave(SAW)transducer operating at double frequency with a single-phase closed-loop lattice and a piezoelectric zinc oxide film is developed and experimentally inves...A method for obtaining a new type of surface acoustic wave(SAW)transducer operating at double frequency with a single-phase closed-loop lattice and a piezoelectric zinc oxide film is developed and experimentally investigated.A method for calculating such a transducer has been developed,its equivalent circuit has been compiled,taking into account propagation losses,losses in the metal film and the inductance of the connecting wires.When the frequency is doubled,the SAW attenuation per unit length increases.展开更多
In recent years, energy-retrofitting is becoming an imperative aim for existing buildings worldwide and increased interest has focused on the development of nanoparticle blended concretes with adequate mechanical...In recent years, energy-retrofitting is becoming an imperative aim for existing buildings worldwide and increased interest has focused on the development of nanoparticle blended concretes with adequate mechanical properties and durability performance, through the optimization of concrete permeability and the incorporation of the proper nanoparticle type in the concrete matrix. In order to investigate the potential use of nanocomposites as dense barriers against the permeation of liquids into the concrete, three types of nanoparticles including Zinc Oxide (ZnO), Magnesium Oxide (MgO), and composite nanoparticles were used in the present study as partial replacement of cement. Besides, the effect of adding these nanoparticles on both pore structure and mechanical strengths of the concrete at different ages was determined, and scanning electron microscopy (SEM) images were then used to illustrate the uniformity dispersion of nanoparticles in cement paste. It was demonstrated that the addition of a small number of nanoparticles effectively enhances the mechanical properties of concrete and consequently reduces the extent of the water permeation front. Finally, the behavioral models using Genetic Algorithm (GA) programming were developed to describe the time-dependent behavioral characteristics of nanoparticle blended concrete samples in various compressive and tensile stress states at different ages.展开更多
In the early-stage diagnosis of lung cancer,the low-concentration(<5 ppm)volatile organic compounds(VOCs)are extensively identified to be the biomarkers for breath analysis.Herein,the urchin-like sodium(Na)-doped z...In the early-stage diagnosis of lung cancer,the low-concentration(<5 ppm)volatile organic compounds(VOCs)are extensively identified to be the biomarkers for breath analysis.Herein,the urchin-like sodium(Na)-doped zinc oxide(ZnO)nanoneedles were synthesized through a hydrothermal strategy with the addition of different contents of citric acid.The Na-doped ZnO gas sensor with a 3:1 molar ratio of Na^(+)and citric acid showed outstanding sensing properties with an optimal selectivity to various VOCs(formaldehyde(HCOH),isopropanol,acetone,and ammonia)based on working temperature regulation.Specifically,significantly enhanced sensitivity(21.3@5 ppm)compared with pristine ZnO(~7-fold),low limit of detection(LOD)(298 ppb),robust humidity resistance,and long-term stability of formaldehyde sensing performances were obtained,which can be attributed to the formation of a higher concentration of oxygen vacancies(20.98%)and the active electron transitions.Furthermore,the improved sensing mechanism was demonstrated by the exquisite band structure and introduction of the additional acceptor level,which resulted in the narrowed bandgap of ZnO.展开更多
基金supported by NASA funding NNX08BA47ANCC-1-02038+1 种基金NIH-1P20MD001822-1NSF(RISE)HRD-0734846
文摘Nanoparticles are increasingly being recognized for their potential utility in biological applications including nanomedicine.Here,we have synthesized zinc oxide(ZnO)nanorods using zinc acetate and hexamethylenetetramine as precursors followed by characterizing using X-ray diffraction,fourier transform infrared spectroscopy,scanning electron microscopy and transmission electron microscopy.The growth of synthesized zinc oxide nanorods was found to be very close to its hexagonal nature,which is confirmed by X-ray diffraction.The nanorod was grown perpendicular to the long-axis and grew along the[001]direction,which is the nature of ZnO growth.The morphology of synthesized ZnO nanorods from the individual crystalline nucleus was confirmed by scanning and transmission electron microscopy.The length of the nanorod was estimated to be around 21 nm in diameter and 50 nm in length.Our toxicology studies showed that synthesized ZnO nanorods exposure on hela cells has no significant induction of oxidative stress or cell death even in higher concentration(10μg/ml).The results suggest that ZnO nanorods might be a safer nanomaterial for biological applications.
基金financially supported by the National Natural Science Foundation of China(No.21276086)
文摘The effect of mixed oxide support on the performance of Ni/ZnO in the reactive adsorption desulfurization(RADS) reaction was investigated in a fixed bed reactor by using thiophene as the sulfur-containing compound in the model gasoline. A series of oxide supports for Ni/ZnO were synthesized by the co-precipitation method and characterized by XRD, N_2-adsorption, TPR and NH_3-TPD techniques. It was found that the desulfurization capacity of Ni/ZnO was enhanced greatly when active components were supported on the proper mixed oxide. Ni/ZnO supported on oxides exhibited much higher desulfurization efficiency and sulfur adsorption capacity than the unsupported Ni/ZnO and the synthesized Ni/ZnO-SA adsorbent exhibited the highest efficiency for thiophene removal. The higher desulfurization activity and sulfur capacity of Ni/ZnO supported on SiO_2-Al_2O_3 with small particle size, high specific surface area and large pore volume could promote the high dispersion of active metal phase and the transfer of sulfur to ZnO with lower mass transfer resistance. γ-Al_2O_3 species could weaken the interaction of active phases and SiO_2 as well as could increase greatly the amount of weak acids. Therefore, these oxides could impose a great influence on the structure and chemical properties of the catalyst.
基金Supported by the Program of Jiangsu Development & Reform Commission(2005)the Industrial-ization Boosting Program of College Scientific Reserach Achievements of the Education Department of Jiangsu Province(JHB06-03)~~
文摘Nano-ZnO particle （nZnOp） reinforced polyethylene glycol （PEG）/polyethylene terephthalate （PET） （nZnOp/PEG/PET） copolymeric composites with different mass fractions and molecular weights of PEG are synthesized via in-situ polymerization. The dispersion of nZnOp in copolymer matrixes and the effects of PEG and nZnOp particles on the crystallization behavior of the composites are studied by TEM, differential scanning calorimetry（DSC）, XRD and Fourier thansform infrared spectroscopy （FTIR ）. The results reveal that nZnOp particles are dispersed in the matrixes with nano-scale, and the addition of PEG induces more homogeneous dispersion of nZnOp. Simultaneously, these nanoparticles become nucleating centers during the crystallization of the matrixes. PEG segments can improve the flexibility of the PET molecular chain, resulting in the drop of the cold crystallization temperature and the rise of the crystallization rate of the composites. Furthermore, PEG （4 000） with the mass fraction of 10% can promote the crystallization rate of the composites. The mechanical properties show that the nano-particles strengthen and toughen the PET matrix, whereas PEG weakens these improve- ments.
基金The work has been supported by the Science and Engineering Research Board(SERB),Department of Science and Technology(SR/FTP/PS-175/2012)。
文摘Reactive sputtered boron-doped zinc oxide(BZO) film was deposited from argon,hydrogen and boron gas mixture.The reactive sputtering technique provides us the flexibility of changing the boron concentration in the produced films by using the same intrinsic zinc oxide target.Textured surface was obtained in the as-deposited films.The surface morphology and the opto-electronic properties of the films can be controlled by simply varying the gas concentration ratio.By varying the gas concentration ratio,the best obtained resistivity ~6.51×10^-4Ω-cm,mobility ~19.05 cm^2 V^-1 s^-1 and sheet resistance ~7.23Ω/□ were obtained.At lower wavelength of light,the response of the deposited films improves with the increase of boron in the gas mixture and the overall transmission in the wavelength region 350-1100 nm of all the films are>85 %.We also fabricated amorphous silicon(a-Si) thin film solar cell on the best obtained BZO layers.The overall efficiency of the a-Si solar cell is 8.14 %,found on optimized BZO layer.
基金the National Natural Science Foundation of China(No.50702029)Shandong Provincial Education Department(No.J05D08)Natural Science Foundation of Qingdao(No.05-1-JC-89)
文摘Ordered zinc oxide （ZnO） rod arrays with very high orientation were fabricated on Si substrates by using a solution method. The substrate surfaces were functionalized by Self-Assembly Monolayers （SAMs）. In the very early growth stage, the oriented ZnO crystals had already grown, which appeared to be the main reason why ZnO nanorods showed very high orientation. The un-dense and un-uniform SAMs provided a surface that was heterogeneous to ZnO nucleation. Consequently, highly oriented ZnO rods were selectively grown on the ＂coin-like＂ SAM-uncovered regions. The route developed here can provide some helpful information to control the nucleation and orientation of ZnO in aqueous solution. Also, the site-selective growth mechanisms can indicate a clue to grow patterned highly oriented ZnO nanorod arrays by the organic template.
基金supported by the National Natural Science Foundation of China (No.31270620)the Dalian Scientific and Technological Innovation Foundation (No.2018J12SN072)。
文摘BiOI/ZnO/rGO(reduced graphene oxide) composite photocatalyst was fabricated using a simple one-step hydrothermal process and applied to the degradation of antibiotic chloramphenicol(CAP). By tuning the Bi/Zn ratios, the structure and photoelectric properties of the catalyst were investigated and characterized in terms of their morphological, structural, optical and photoelectrochemical properties. The as-synthesized composite photocatalysts are well-crystalline, uniform dispersion and exhibit good photocatalytic properties.The photocatalytic degradation rate of CAP by BiOI/ZnO/rGO composite is 8.1 times and 1.8times that of BiOI and ZnO, respectively. The photocatalytic mechanism studies revealed that the synergistic effect between rGO and BiOI/ZnO can effectively separate photogenerated electron–hole, enhance photocurrents and conductivity, and improve charge carrier densities. Moreover, BiOI/ZnO/rGO possesses good stability and reusability that the degradation efficiency remained above 80% even after 5 recycling. This study reveals that both the introduction of rGO and heterostructure construction between BiOI and ZnO play a crucial role in their photoelectrochemical and photocatalytic properties.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50931002, 51072094 and 51372135)the Ministry of Education of the People’s Republic of China(Grant No. 113007A)the Tsinghua University Initiative Scientific Research Program
文摘In the past several decades, dilute magnetic semiconductors, particularly the dilute magnetic oxides have evolved into an important branch of materials science due to their potential application in spintronic devices combining of properties of semiconductors and ferromagnets. In spite of a major effort devoted to the mechanism of ferromagnetism with a high Curie temperature in these materials, it still remains the most controversial research topic, especially given the unexpected do ferromagnetism in a series of undoped wide-band-gap oxides films or nanostructures. Recently, an abundance of research has shown the critical role of various defects in the origin and control of spontaneous magnetic ordering, but contradicting views from intertwined theoretical calculations and experiments require more in-depth systematic research. In our previous work, considerable efforts have been focused on two major oxides, i.e. ZnO and Zr02. This review will present a summary of current experimental status of this defect-driven ferromag- netism in dilute magnetic oxides （DMOs）.
基金National Agricultural Innovation Project(NAIP)Indian Council of Agricultural Research(ICAR)for their financial support under the project C10125(component-4)
文摘A novel method was presented for synthesis of ZnO and ZnO-CuO composites in the form of nanowires, nanorods and nanoflakes on oxidized silicon substrates. Further, the use of the synthesized nanostructures for gas sensing was demonstrated. Pure brass （Cu0.65-Zn0.35） films were deposited on oxidized Si substrate by radio frequency （RF） diode sputtering. Subsequently, these films having thickness in the range of 100-200 nm were oxidized in different oxidizing ambient in the temperature range of 300-550 ℃. The effect of temperature, time and oxidizing ambient on the growth of nanostructures was investigated by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD） and photoluminescence （PL） techniques. The nanostructures surface was analyzed by X-ray photoelectron spectroscopy （XPS）. The synthesized nanowires had diameter in the range of 60-100 nm and length up to 50 μm. Based on these observations, the growth mechanism has been suggested. For the nanorods, the diameter was observed to be -150 nm. Samples having dense nanowires, nanorods and nanoflakes were used as a gas sensing material. The performance Of the sensor was investigated for different nanostructured materials for various volatile organic compounds （VOCs）, It was observed that ZnO- CuO nanoflakes were more sensitive to VOC sensing compared to ZnO nanowires and nanorods.
文摘Nanosized ZnO powders were prepared with a two-step precipitation method. The average size of ZnO particles was about 80 nm and their size distribution was narrow. Combining with ultrafine additive powders, ZnO base varistor was produced via an oxide mixing route. ZnO varistor derived from normal reagent grade starting materials was investigated for comparison purpose. Outstanding microstructure of the ZnO varistor derived from nanosize ZnO powders and ultrafine dopants was obtained: uniform distribution of fine ZnO grains (less than 3 microns), grain boundary and the dopant position. Higher varistor voltage (U=492 V/mm) and nonlinear coefficient (α=56.2) as well as lower leakage current (TL=1.5 μuA) were achieved. The better electrical properties were attributed to the uniform microstructure, which in turn led to stable and uniform potential barriers. Also this improved technique is more feasible for producing ZnO nanopowders and resulting varistor in large scales.
基金National Natural Science Foundation of China(No.11672198)。
文摘Nano zinc oxide(ZnO)has excellent performance and low cost,but ZnO has a wide band gap and its electron-hole is difficult to achieve effective separation,which greatly limits its photocatalytic activity.This paper introduces the structural properties of ZnO and the mechanism of photocatalytic degradation of organic pollutants,and summarizes the preparation of ZnO nanomaterials and the application studies in improving its photocatalytic properties,in order to promote the research and development of ZnO nanomaterials.
基金support by Indo-Iraq Cultural Exchange Program of ICCR (Indian Council for Cultural Relations)
文摘Fabrication and characterization of metal-semiconductor-metal ultraviolet （MSM UV） photodetector based on ZnO ultra thin （nano scale） films with Pd Schottky contact are reported. The ZnO thin film was grown on glass substrate by thermal oxidation of preeposited zinc films using vacuum deposition technique. With applied voltage in the range from -3V to 3V, the contrast ratio, responsivity, and detectivity for an incident radiation of 0.1 mW at 365 nm wavelength were estimated. The proposed device exhibited a high gain which was attributed to the hole trapping at semiconductor-metal interface. I-V characteristics were studied and the parameters, such as ideality factor, leakage current, resistance-areaproduct, and barrier height, were extracted from the measured data.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10775033 and 11075038
文摘P-type nitrogen-doped ZnO films are prepared successfully by in-situ thermal oxidation of Zn3N2 films. The prepared films are characterized by x-ray diffraction, non-Rutherford back.scattering （non-RBS） spectroscopy, x- ray photoelectron spectroscopy, and photoluminescence spectrum. The results show that the Zn3N1 films start to transform to ZnO at 400℃ and the total nitrogen content decreases with the increasing annealing temperature. The p-type fihns are achieved at 500℃ with a low resistivity of 6.33Ω.cm and a high hole concentration of ＋8.82 × 10^17 cm-3, as well as a low level of carbon contamination, indicating that the substitutional nitrogen （No） is an effective acceptor in the ZnO：N film. The photoluminescence spectra show clear UV emissions and also indicate the presence of oxygen vacancy （Vo） defects in the ZnO：N films. The p-type doping mechanism is briefly discussed.
文摘A new type of inorganic-polymer materials of epoxy Titanium Dioxide and Zinc Oxide was prepared. In this work, the mechanical properties of polymer composites reinforced with ceramic nanoparticles were investigated. Three points bending tests demonstrated an enhancement in flexural strength and flexural modulus respectively, compared to the pure epoxy. The reinforcement of nanoparticulate materials was Titanium Dioxide and Zinc Oxide with various weight fraction. Experimental tests results indicated that the composite materials have significantly higher modulus of elasticity than the matrix material. It was found that the enhancement in modulus of elasticity was directly proportional to the weight fraction of reinforcement material, and that Zinc Oxide composites have higher modulus of elasticity than Titanium Dioxide composites with equivalent of weight fraction. The wear results showed that nanoparticles improved the wear resistance of epoxy nanocomposites, the Titanium Dioxide matrix particles could improve the wear resistance of the epoxy more efficiently than Zinc Oxide particles. The fatigue test showed that the fatigue resistance of epoxy Zinc Oxide matrix particles was higher than that of Titanium Dioxide matrix particles.
基金Funded by the National Natural Science Foundation of China(51677045)the Natural Science Foundation of Heilongjiang Province of China(E201224)
文摘Two different morphologies of ZnO（lotus-shaped, rod-shaped） and ZnO/PVDF composite materials were prepared. The morphologies of ZnO and composite materials were characterized by scanning electron microscopy（SEM） and transmission electron microscopy（TEM）. Fourier transform infrared spectroscopy（FT-IR）, thermal gravimetry（TG）, and X-ray diffraction（XRD） were also used to characterize the chemical structures and phase composites of ZnO and ZnO/PVDF composite materials. Breakdown voltage, dielectric constant and dielectric loss of ZnO/PVDF composite materials were also tested. Microstructure analysis showed that ZnO nanoparticles dispersed uniformly in the matrix. And the dielectric constant expresses a significantly improvement while the dielectric loss and breakdown voltage expresses no significant change. Moreover, dielectric constant keeps an improvement tendency with increasing content of ZnO.
文摘Traditional wastewater mostly contains pharmaceutical ingredients. Therefore, the wastewater must be completely free from antibiotics before its release into the environment. In the present study, photocatalytic degradation was done to investigate the removal efficiency of Oxytetracycline Dihydrate (OTC) using ZnO, ZnO/3%BaTiO<sub>3</sub> (3 BZ), ZnO/18%BaTiO<sub>3</sub> (18 BZ), ZnO/ 33%BaTiO3 (33 BZ) and ZnO/48%BaTiO<sub>3</sub> (48 BZ) under UV light. After the exposure time of 420 min, about 99.57% and 97.87% of OTC was degraded using ZnO and 3 BZ respectively. Further, increasing the amount of BaTiO<sub>3</sub> in ZnO prolongs the degradation time. Therefore, faster efficiency was found using ZnO nanoparticles. The observed reaction rate constant using ZnO was 0.00933 min<sup>-1</sup> which decreased to 0.00532 min<sup>-1</sup> using 48 BZ, indicating the decrease of reaction rate for increasing the amount of BaTiO<sub>3</sub>. Hence, the use of ZnO photocatalyst is anticipated to be a promising technique for the photocatalytic degradation of contaminated wastewater with oxytetracycline antibiotics using UV light.
基金National Engineering Research Center of UHV Technology and Novel Electrical Equipment Basis,Grant/Award Number:NERCUHV-2023-KF-02。
文摘In this study,the functional gradient materials(FGMs)were the first attempt to homogenise the electric field distribution in the cable accessory,where zinc oxide particles(ZnO_(k))were filled into ethylene propylene diene monomer with the composi-tionally gradient distribution using laminating and hot-pressing methods.The constructed FGMs with significantly improved non-linear conductivity can avoid the electric field distortion in cable accessories.The results show that the configuration of compositionally gradient structured fillers can significantly improve the electrical conductivity of FGMs compared to the homogeneous distribution.Additionally,compositionally gradient structures of ZnOk fillers can also improve the thermal conductivity of FGM composites,which facilitates the heat dissipation of dielectric and reduces the probability of electrothermal coupling breakdown.The mechanical properties of the composites are deeply affected by the filler's content and configuration,both improved tear elongation and tensile strength can be achieved at an optimal content and gradient structure of ZnOk fillers.Finally,the simulation analysis results show that FGM composites can homogenise the electric field more efficiently in comparison with homogeneous composites.This work demonstrates that compositionally gradient structures can improve the utilisation of functional fillers and develop the FGM composites for high-voltage direct current cable accessory applications.
基金supported by Southern Federal University Research Project No.07/2020-06-MMthe 10th Anniversary International Conference on“Physics and Mechanics of New Materials and Their Applications”(PHENMA 2021-2022).
文摘A method for obtaining a new type of surface acoustic wave(SAW)transducer operating at double frequency with a single-phase closed-loop lattice and a piezoelectric zinc oxide film is developed and experimentally investigated.A method for calculating such a transducer has been developed,its equivalent circuit has been compiled,taking into account propagation losses,losses in the metal film and the inductance of the connecting wires.When the frequency is doubled,the SAW attenuation per unit length increases.
文摘In recent years, energy-retrofitting is becoming an imperative aim for existing buildings worldwide and increased interest has focused on the development of nanoparticle blended concretes with adequate mechanical properties and durability performance, through the optimization of concrete permeability and the incorporation of the proper nanoparticle type in the concrete matrix. In order to investigate the potential use of nanocomposites as dense barriers against the permeation of liquids into the concrete, three types of nanoparticles including Zinc Oxide (ZnO), Magnesium Oxide (MgO), and composite nanoparticles were used in the present study as partial replacement of cement. Besides, the effect of adding these nanoparticles on both pore structure and mechanical strengths of the concrete at different ages was determined, and scanning electron microscopy (SEM) images were then used to illustrate the uniformity dispersion of nanoparticles in cement paste. It was demonstrated that the addition of a small number of nanoparticles effectively enhances the mechanical properties of concrete and consequently reduces the extent of the water permeation front. Finally, the behavioral models using Genetic Algorithm (GA) programming were developed to describe the time-dependent behavioral characteristics of nanoparticle blended concrete samples in various compressive and tensile stress states at different ages.
基金the Outstanding Youth Foundation of Jiangsu Province of China(No.BK20211548)the Yangzhou Science and Technology Plan Project(No.YZ2023246)the Qinglan Project of Yangzhou University,and the Research Innovation Plan of Graduate Education Innovation Project in Jiangsu Province(No.KYCX23_3530).
文摘In the early-stage diagnosis of lung cancer,the low-concentration(<5 ppm)volatile organic compounds(VOCs)are extensively identified to be the biomarkers for breath analysis.Herein,the urchin-like sodium(Na)-doped zinc oxide(ZnO)nanoneedles were synthesized through a hydrothermal strategy with the addition of different contents of citric acid.The Na-doped ZnO gas sensor with a 3:1 molar ratio of Na^(+)and citric acid showed outstanding sensing properties with an optimal selectivity to various VOCs(formaldehyde(HCOH),isopropanol,acetone,and ammonia)based on working temperature regulation.Specifically,significantly enhanced sensitivity(21.3@5 ppm)compared with pristine ZnO(~7-fold),low limit of detection(LOD)(298 ppb),robust humidity resistance,and long-term stability of formaldehyde sensing performances were obtained,which can be attributed to the formation of a higher concentration of oxygen vacancies(20.98%)and the active electron transitions.Furthermore,the improved sensing mechanism was demonstrated by the exquisite band structure and introduction of the additional acceptor level,which resulted in the narrowed bandgap of ZnO.
