化学浴沉积法在氧化锌衬底上制备氧化锌微/纳米棒阵列

用磁控溅射在玻璃上制备一层氧化锌作为衬底,采用化学浴沉积法在衬底上制备出排列整齐的氧化锌微／纳米棒阵列,并用扫描电子显微镜对样品形貌进行了表征。分析了不同前驱液浓度、pH值对样品形貌的影响。分析发现：前驱物浓度越大,长出的氧化锌微／纳米棒直径越大;溶液初始pH值对样品的形貌有很大影响;在合适的pH值环境下,氧化锌微／纳米棒生长速度明显快于其他样品,且对生长条件要求不高,非常适合用于氧化锌微／纳米棒大面积制备,笔者采用此方法制备出形貌均匀的,面积达15cm×15cm的氧化锌微／纳米棒。     

棒状形貌纳米氧化锌的合成及其应用

以六水硝酸锌和氨水-氢氧化钠为原料,采用液相沉淀法制备出氧化锌纳米棒。研究了氨水的初始浓度、滴加速度以及加热方式对纳米氧化锌形貌和尺寸的影响。结果表明：在氨水初始浓度为5%（质量分数）、滴加速度为60 g/h,并采用两段加热（成核生长温度为60 ℃、陈化温度为80 ℃）的方式,合成的纳米氧化锌呈棒状形貌,分散均匀,长径比达到11。纳米氧化锌对大肠杆菌具有很好的抑菌效果。水性聚氨酯中加入1.5%（质量分数）的棒状形貌纳米氧化锌后,可吸收250～400 nm的紫外线,拉伸强度从2.7 MPa增加到4.5 MPa。     

不同碳酸盐沉淀剂热分解法制备纳米氧化锌

以硝酸锌为锌源,分别以碳酸钠和碳酸氢铵为沉淀剂,采用热分解碱式碳酸锌工艺制备纳米氧化锌。通过热重分析、晶型测试、平均粒径测试、微观形貌观察等系列对比,分析了以两种碳酸盐为沉淀剂制备氧化锌的过程,建立了生长动力学方程,对比了微观形貌和分散状态。实验结果表明,以碳酸氢铵为沉淀剂制备的前驱体在煅烧温度为200 ℃后直接生成纳米氧化锌,而以碳酸钠为沉淀剂制备的前驱体在煅烧温度为200~250 ℃时先生成碳酸锌然后在300 ℃时完全转变为氧化锌;两种沉淀剂制备纳米氧化锌的生长过程符合不同指数方程生长关系,以碳酸钠为沉淀剂制备纳米氧化锌的生长满足方程y=2.775 04e^{0.004 76x},而以碳酸氢铵为沉淀剂制备纳米氧化锌的生长满足方程y=5.152 96e^{0.002 85x},对比来看以碳酸氢铵为沉淀剂制备纳米氧化锌在相同温度下得到的晶粒尺寸要小;从粒度分布和透射电镜观察分析,在相同温度下也是以碳酸氢铵为沉淀剂制备的纳米氧化锌的粒径较小。     

超快速混合微反应器制备纳米氧化锌

以七水硫酸锌和碳酸氢钠为原料,在超快速混合微反应器中合成氧化锌前驱体碱式碳酸锌,再通过焙烧获得纳米氧化锌。考察了各操作条件对纳米氧化锌颗粒制备的影响,采用TEM、XRD、BET等手段对所得的样品做了表征。结果表明,采用快速沉淀法,通过超快速混合微反应器可实现纳米氧化锌的可控制备,所得纳米氧化锌平均粒径为14~55 nm,晶型为六方晶系结构,样品粒径分布窄,分散性良好。     

均相成核—水热法制备纳米氧化锌

制备纳米氧化锌的关键是成核与生长控制。采用尿素为均相沉淀剂 ,结合水热处理 ,温度 130℃ ,反应时间为 3～ 5h制备了粒径小 ,分布窄的纳米氧化锌。Zn2 +的均相成核与其浓度、OH- 的浓度有关 ,体系中Zn(OH) 2 的过饱和度越大 ,则成核数量越多 ,所制备的氧化锌颗粒越小 ;与以氢氧化锌胶体为前驱体的共沉淀技术相比 ,均相沉淀技术有利于氧化锌纳米晶粒均匀生长 ;此外 ,添加有机物作分散剂可以减弱微小晶粒间的叠合生长 ,有利于制备均一性较好的纳米氧化锌。     

乙醇辅助低温水热法生长TiO2纳米棒阵列

本文采用乙醇作为添加剂，通过低温水热法在透明导电玻璃衬底上制备晶化良好的金红石相TiO₂纳米棒阵列。对样品进行了X射线衍射(XRD)、扫描电子显微镜(SEM)等结构形貌表征和光电化学性能测试。实验发现乙醇加入有利于前驱物水解缩聚反应，同时提高水热反应压力，促进TiO₂晶粒低温成核和生长，从而实现70℃直接在基底表面生长出TiO₂纳米棒阵列。通过调控水热反应温度、时间以及乙醇添加量等参数可有效调控TiO₂纳米棒阵列的形貌，改善其光电化学性能。同时低温水热制备工艺也降低了对衬底材料的限制，拓展了TiO₂纳米棒阵列的应用领域，表现出良好的应用前景。     

氧化锌纳米棒的制备与表征

本论文探索一种良好制备ZnO纳米棒的方法。通过高分子络合软模板法在硅衬底和聚丙烯酰胺膜中间生长出顶面平滑具有六棱柱形结构的ZnO纳米棒。用扫描电子显微镜、X射线衍射仪对ZnO米棒微观形貌和结构进行分析:SEM观察到纳米氧化锌呈棒状,分布均匀且排列整齐;XRD图谱分析显示ZnO纳米棒为六方晶系的红锌矿型ZnO,且具有良好的晶体结构。     

水热法制备花簇形氧化锌纳米棒结构及其光催化性能

采用简单的水热法,以氯化锌(AR)和氢氧化钠(AR)为原料制备了花簇形氧化锌纳米棒.通过改变溶液的pH值、水热温度、水热时间等因素研究对样品结构和成貌的影响,并利用X射线衍射仪(XRD)、扫描电镜(SEM)、紫外-可见光谱仪(UV)对氧化锌纳米棒的结构、形貌及光催化性能进行研究,结果表明在温度为80℃,反应时间为18h、锌碱比为1∶7.5时,氧化锌成貌最佳,且光催化性能较好.     

水热法制备纳米氧化锌的影响因素研究

简单介绍了水热法的原理,主要讨论了在水热法制备纳米氧化锌的过程中,浓度、温度、反应时间、pH值、Zn2+/OH-物质的量比、添加剂和掺杂等因素对产物尺寸、形貌的影响,最后对水热法制备纳米氧化锌进行了展望。     

簇状氧化锌纳米棒的合成及其光催化性能研究

采用醋酸锌和氨水为原料、水作为溶剂,以水热法在80℃条件下反应20 h制备出了簇状氧化锌纳米棒,用XRD、SEM分别分析了制备产物的物相和形貌。以ZnO纳米棒为光催化剂对有机染料甲基橙进行了光催化降解实验,研究了甲基橙溶液初始浓度和催化剂添加量对光催化的影响。结果表明,合成的氧化锌纳米棒均为六方晶系铅锌矿结构;产物为从中心发散的簇状纳米棒结构,纳米棒直径分布均匀且分散性好,每个簇由几十个纳米棒组成,每个纳米棒平均直径约为150 nm,长度约为5μm。制备的ZnO有良好的光催化性能。     

Al doping influences on fabricating ZnO nanowire arrays: Enhanced field emission property

Increase of free electrons concentration and decrease of defects density are the most desirable solution for stimulating the field emission property in semiconductor nanostructures. To implement this, herein we study the field emission efficiency of Al-doped ZnO nanowire arrays with different Al doping concentration, which were prepared by a simple facile hydrothermal method. The Al doping concentration plays a very important role on the structure, morphology, photoluminescence and field emission properties of the as-assembled samples. The results indicate that Al-doped ZnO nanowire arrays with Al doping concentration of 7 at% exhibit the highest quality crystalline structure and lowest defect density relative to others samples thanks to the suitable modification of Al doping, and this led to the increase of free electrons concentration and decrease of defects density, which have an excellent field emission performance with the lower turn on field of 1.03 V/μm and higher field enhancement factor of 20658. This remarkable field emission performances of the Al-doped ZnO nanowire arrays may provide promising applications for different field emission devices.     

Al掺杂量对ZnO多晶性能影响的研究

采用固相反应法制备了六方纤锌矿结构Zn1-xAlxO(0≤x≤0.005)系列多晶,探究了Al掺杂对ZnO多晶的微观形貌和热电输运性质的影响.Al掺杂促使ZnO晶粒长大联结,晶界减少,x=0.005时出现在晶界分布的ZnAl2O4尖晶石相.各组分样品经二次烧结后,电阻率均比对应组分的一次烧结样品增大1~2个数量级.掺杂后样品由ZnO的半导体行为转变为电阻率显著下降的金属行为,一次烧结样品在x=0.004有最小的室温电阻率~10 mΩ·cm,主要由于掺杂使样品载流子浓度和迁移率显著提高;300~950 K下掺杂样品热电势的绝对值和功率因子均随温度升高而增大,x=0.004时有最大的室温功率因子~0.11 mW/m·K2.综合得到ZnO中Al掺杂的饱和固溶度在0.004~0.005之间.     

ZnO纳米棒水热法生长与表征

采用两步法在FTO导电玻璃衬底上制备ZnO纳米棒,首先利用浸渍-提拉法在FTO导电玻璃衬底上制备ZnO晶种层,然后把有ZnO晶种层的FTO衬底放入盛有生长溶液的反应釜中利用水热法制备ZnO纳米棒.研究了生长溶液的浓度、生长温度和生长时间对所制备的对ZnO纳米棒阵列的微结构和光致发光性能的影响,利用X射线衍射(XRD)、扫描电子显微镜(SEM)和光致发光谱(PL)研究了ZnO样品的结构、形貌和光学性质.实验结果表明:所制备的ZnO纳米棒呈现六方纤锌矿结构,沿(002)晶面择优取向生长,纳米棒的平均直径约为100 nm,长度约为2.5 μm.所制备的ZnO纳米棒在390 nm附近具有很强的紫外发光峰和在550 nm附近有较弱的宽绿光发光峰.     

A two-step route to synthesize highly oriented ZnO nanotube arrays

Large-scale and highly oriented ZnO nanotube arrays are synthesized on transparent conductive glass substrates by a two-step route. First, ZnO nanorod arrays were prepared by electrochemical deposition from an aqueous solution of zinc nitrate. Then, hollow ZnO nanotubes were obtained by the selective dissolution of the electrodeposited ZnO nanorods in potassium hydroxide solution. Field emission scanning electron microscopy (FESEM) and X-ray powder diffraction (XRD) have been used to characterize the morphology and structure of the derived products. The effect of the concentration of alkali, dissolution time, and temperature on the formation process and morphologies of ZnO nanotube arrays has been discussed.     

Controllable growth of ZnO nanorod arrays with different densities and their photo-electric properties

ABSTRACT: Since the photo-electric response and charge carriers transport can be influenced greatly by the density and spacing of the ZnO nanorod arrays, controlling of these geometric parameters precisely is highly desirable but rather challenging in practice. Here, we fabricated patterned ZnO nanorod arrays with different density and spacing distance on silicon (Si) substrate by electron beam lithography (EBL) method combined with the subsequent hydrothermal reaction process. By using the EBL method, patterned ZnO seed layers with different areas and spacing distances were obtained firstly. ZnO nanorod arrays with different density and various morphologies were obtained by the subsequent hydrothermal growth process. The combination of EBL and hydrothermal growth process was very attractive and made us could control the geometric parameters of ZnO nanorod arrays expediently. Finally, the vertical transport properties of the patterned ZnO nanorod arrays were investigated through the micro probe station equipment and the I-V measurement results indicated that back-to-back Schottky contacts with different barriers height were formed in dark conditions. Under UV light illumination, the patterned ZnO nanorod arrays showed a high UV light sensitivity, and the response ratio was about 104. The controllable fabrication of patterned ZnO nanorod arrays and understanding for their photo-electric transport properties were helpful to improve the performance of nanodevices based on them.     

氧化锌纳米棒光催化降解染料废水的研究

采用水热合成法制备了ZnO纳米棒阵列。利用SEM和XRD对ZnO纳米棒的形貌和物相结构进行了表征。研究了光照时间、pH、ZnO投加量等因素对染料废水吸光度去除率的影响。实验结果表明,在紫外光照2 h、pH为10、ZnO纳米棒投加量为0.02 g的优化反应条件下,亚甲基蓝废水、分散橙GFL废水和直接耐酸大红4BS废水的吸光度去除率分别为19.32%、9.28%和13.50%。     

Preparation and enhanced ferromagnetic, semi-conductive, and optical properties of Co-doped ZnO rod arrays

In this study, co-doped ZnO rod arrays with wurtzite crystal structure were successfully prepared on zinc substrate by the co-precipitation method. The results of crystal analysis indicated that the dopant Co²⁺ was incorporated into ZnO crystal. Photoluminescence (PL) spectra and magnetization curves proved that their PL intensity and ferromagnetism were increased with the increase of Co²⁺ concentrations in a ZnO host. Current?Cvoltage characteristic curves of Co-doped ZnO rod arrays indicated that as-prepared samples were n-type semiconductors. Co-doped ZnO rod arrays could be envisioned to detect diseases and bacteria based on these properties.     

Ba-doped ZnO nanostructure: X-ray line analysis and optical properties in visible and low frequency infrared

In this work, X-ray diffraction analysis and optical properties of pure and Ba-doped ZnO nanoparticles prepared by the precipitation method were investigated. X-ray analysis was employed to evaluate the micro structural parameters of ZnO nanoparticles in terms of crystallite sizes and lattice strain by the Williamson–Hall method. The average crystallite size of Ba-doped ZnO nanoparticles estimated by the Williamson–Hall method varied as the doping concentration increased. The effect of Ba doping on the photoluminescence (PL) emission spectrum of ZnO was also investigated. The temperature dependence of the PL emissions was also studied, and it was found that at low temperature, the samples show stronger emissions than those at room temperature in both UV and visible regions. As a final point, the FT–IR reflection spectrum along with Kramers–Kronig (K–K) method and classical dispersion theory was applied to obtain optical properties of the samples at low frequency infrared regime.     

不锈钢丝网上氧化锌纳米线阵列的 可控生长及光催化性能研究

利用水热法在不锈钢丝网上制备了氧化锌纳米线阵列,借助扫描电镜（SEM）对产物的形貌进行了表征,探讨了反应物浓度和反应时间对产物形貌的影响,并以橙黄Ⅱ为目标降解物,研究了不同生长条件下氧化锌纳米线阵列的光催化降解性能。研究结果表明：硝酸锌浓度和反应时间对氧化锌纳米线阵列的密度、长度、直径和晶形有重要影响,在硝酸锌浓度为0.1 mol/L、反应时间为6 h条件下,制得的氧化锌纳米线阵列具有较佳的光催化活性,多次循环实验结果表明其稳定性较高。另外,双层叠合的氧化锌纳米线的光催化降解性能优于单层氧化锌纳米线的实验结果,其不锈钢丝网的网状结构为制备多维纳米阵列和薄膜提供了一种新的研究思路。