ZnO nanorod arrays with tunable size and field emission properties on an ITO substrate achieved by an electrodeposition method

In the present work, vertically aligned ZnO nanorod arrays with tunable size are successfully synthesized on nonseeded ITO glass substrates by a simple electrodeposition method. The effect of growth conditions on the phase, morphology, and orientation of the products are studied in detail by X-ray diffraction （XRD）, scanning electron mi-croscopy （SEM）, and transmission electron microscopy （TEM）. It is observed that the as-prepared nanostructures exhibit a preferred orientation along c axis, and the size and density of the ZnO nanorod can be controlled by changing the concentration of ZnC12. Field emission properties of the as-synthesized samples with different diameters are also studied, and the results show that the nanorod arrays with a smaller diameter and appropriate rod density exhibit better emission properties. The ZnO nanorod arrays show a potential application in field emitters.

Effect of rubrene:P3HT bilayer on photovoltaic performance of perovskite solar cells with electrodeposited ZnO nanorods

Improved photovoltaic performance of perovskite solar cells is demonstrated through the synergistic effect of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as electron and hole-transporting layers,respectively. Highly crystalline ZnO nanorods were obtained by electrochemical deposition in a chloride medium. Additionally, rubrene interlayer was able to passivate or cover the grain boundaries of perovskite film effectively that led to reduced leakage current. A perovskite solar cell optimized with ZnO nanorods and rubrene：P3HT bilayer achieved a maximum efficiency of 4.9% showing reduced hysteresis behavior compared with the device having P3HT as the only hole-transporting layer. The application of longer nanorods led to better perovskite infiltration and shorter charge carrier path length. These results highlight the potential of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as charge selective layers for efficient perovskite solar cells.

Fabrication of highly oriented ZnO nanorod arrays by galvanostatic deposition

Highly oriented ZnO nanorod arrays were successfully prepared on the indium tin oxide （ITO） substrate using a galvanostatic electrodeposition method. The ITO substrate was pretreated with ZnO nanoparticles via simple low-temperature solution route. The crystallinity, microstructure of surface, and optical properties of the obtained ZnO were characterized by X-ray diffraction, scanning electron microscope, and transmittance spectrum. The results indicate that the average diameter of ZnO nanorod arrays is about 30 nm, and the narrow size distribution ranges from 20 to 50 nm. The nanorod arrays are growing along wavelength of incident is over 380 nm, the ZnO nanorod arrays growth mechanism of the nanorod arrays was discussed. [001] direction with an orientation perpendicular to the substrate. When the show a high optical transmission of above 95%. Furthermore, the possible

Controllable Synthesis of Well-aligned ZnO Nanorod Arrays on Varying Substrates via Rapid Electrodeposition

A facile and rapid electrodeposition route was developed to controllably synthesize well-aligned ZnO nanorod arrays on diverse substrates, such as seed-layer pre-formed, pristine indium tin oxide （ITO） and Si, using Zn（NO3）2·6H2O and hexamethylenetetramine （HMT） as the precursors. X-ray diffraction （XRD） and transmission electron microscopy （TEM） results indicated that seed-layer pre-modified of ZnO nanorod arrays （ZNRs） possessed single crystalline, a wurtzite crystal structure with preferential growth orientation along [0001] direction. The ZNRs on pre-modified ZnO seed-layer （ZSL） had diameters of 30-50 nm, and aligned vertically to the substrates. ZNRs on ZSL/ITO substrate exhibited a high transmittance （above 80%） in visible wavelength range and the red-shift of band gap energy. An electrochemical reaction model was proposed to explain the growth process of ZnO nanorods. Importantly, the rapid synthesis of ZNRs provided the feasibility of preparation of SERS （surface enhanced Raman scattering） nanocomposite within shorter time by a subsequent electrochemical etching.

Hydrogen peroxide biosensor based on electrodeposition of zinc oxide nanoflowers onto carbon nanotubes film electrode

A new amperometric biosensor for hydrogen peroxide was developed based on adsorption of horseradish peroxidase at the glassy carbon electrode modified with zinc oxide nanoflowers produced by electrodeposition onto multi-walled carbon nanotubes （MWNTs） film. The morphology of the MWNTs/nano-ZnO electrode has been investigated by scanning electron microscopy （SEM）, and the electrochemical performance of the electrode has also been studied by amperometric method. The resulting electrode offered an excellent detection for hydrogen peroxide at -0.11 V with a linear response range of 9.9×10^-7 to 2.9×10^-3 mol/L with a correlation coefficient of 0.991, and response time 〈5 s. The biosensor displays rapid response and expanded linear response range, and excellent stability.

Free-standing ZnO nanorod arrays modified with single-walled carbon nanotubes for betavoltaics and photovoltaics

A full-duplex radiant energy converter based on both betavoltaic and photovoltaic effects in an easyto-implement way is an attractive alternative for the autonomous wireless sensor microsystem.Here,we report a novel beta/photovoltaic cell based on free-standing Zn O nanorod arrays(ZNRAs)modified with metallic single-walled carbon nanotubes(m-SWCNTs),using radioisotope63 Ni as beta-emitting source.The ZNRAs were grown on Al-doped Zn O(AZO)conductive glass using hydrothermal method.The optimum length and diameter of Zn O nanorods were determined by Monte Carlo simulation for beta energy deposition in ZNRAs.The m-SWCNTs were anchored into the ZNRAs to form a three-dimensional(3-D)Schottky junction structure for effectively separating the beta/photo-excited electron-hole pairs.Experimentally,the betavoltaic and photovoltaic effects were confirmed through the I-V measurements of beta/photovoltaic cells under beta/UV/Vis irradiations,respectively.It is suggested that the m-SWCNTs play key role for the enhancement of beta/photovoltaic performance through the formation of extensive3-D Schottky junction,the conductive network for hole transport,and the surface plasmon resonance exciton absorption for visible light.

Growth of Variable Aspect Ratio ZnO Nanorods by Solochemical Processing

In this work,variable aspect ratio（length divided by diameter） zinc oxide nanorods were synthesized through a simple solochemical method by reacting a Zn2+precursor with sodium hydroxide at low reaction temperatures.The analysis of the X-ray diffraction data indicated that the samples had hexagonal wurtzite structure and nanometric size crystallites.The transmission electron microscopy（TEM） images of the products prepared at60 and 80 ℃ exhibited rod-like architecture,showing that the reaction temperature did not affect the ZnO morphology.The average aspect ratio of the ZnO nanorods decreased from 3.4 to 2.4 when the reaction temperature was raised from 60 to 80 ℃.The samples presented a blue shift in the excitonic absorption compared to ZnO bulk that increased alongside with reaction temperature.In addition,this research investigated the results obtained by varying the concentration of zinc chloride solution.At the same temperature,it could be verified that when the zinc concentration was increased,the diameter of the ZnO nanorods also slightly increased,and much shorter nanorods were achieved,especially in the reactions performed at 50 and 70 ℃.Finally,the growth mechanism of the ZnO nanostructures was proposed based on the results obtained by changing the zinc precursor concentration and reaction temperature.

Formation of a ZnO nanorods-patterned coating with strong bactericidal capability and quantitative evaluation of the contribution of nanorods-derived puncture and ROS-derived killing

To endow Ti-based orthopedic implants with strong bactericidal activity,a ZnO nanorods-patterned coating(namely ZNR)was fabricated on Ti utilizing a catalyst-and template-free method of micro-arc oxidation(MAO)and hydrothermal treatment(HT).The coating comprises an outer layer of ZnO nanorods and a partially crystallized inner layer with nanocrystalline TiO_(2) and Zn_(2)TiO_(4) embedded amorphous matrix containing Ti,O and Zn.During HT,Zn^(2+)ions contained in amorphous matrix of the as-MAOed layer migrate to surface and react with OHin hydrothermal solution to form ZnO nuclei growing in length at expense of the migrated Zn^(2+).ZNR exhibits intense bactericidal activity against the adhered and planktonic S.aureus in vitro and in vivo.The crucial contributors to kill the adhered bacteria are ZnO nanorods derived mechano-penetration and released reactive oxygen species(ROS).Within 30 min of S.aureus incubation,ROS is the predominant bactericidal contributor with quantitative contribution value of ~20%,which transforms into mechano-penetration with prolonging time to reach quantitative contribution value of ~96% at 24 h.In addition,the bactericidal contributor against the planktonic bacteria of ZNR is relied on the released Zn^(2+).This work discloses an in-depth bactericidal mechanism of ZnO nanorods.

Germinant ZnO nanorods as a charge-selective layer in organic solar cells

A facile method was introduced and demonstrated to synthesize zinc oxide(ZnO) nanorods(NRs) as an electron transporting layer(ETL) for organic solar cells(OSCs).Hydrothermal synthesis of the NRs showed a constant growth rate of 5.5 nm min-1 from germination to sub-micrometer length.The properties were characterized using scanning electron microscopy(SEM),transmission electron microscopy(TEM),absorption spectrophotometry and so on.Based on these measurements,the germinant growth mechanism and its corresponding orientation characteristics were investigated.As an ETL of the OSCs,ZnO NRs enhance the charge extraction from the active layer due to their increased interfacial surface area,but there is an optimal length because of the shunt path formation and UV absorption of long ZnO NRs.As a re sult,the OSC with the ZnO NRs as ETL shows power conversion efficiency(PCE) up to 6.2%.The J-V characteristics and incident photon-to-current conversion efficiency(IPCE) measurement also reveal that the efficiency enhancement is an assembly of individual results from optical,physical and electrical characteristic of the ZnO NRs.

Controlled Growth of ZnO Array on FTO Glass Substrate by Electrodeposition

In this study, ZnO nanotube and nanorod array films were respectively synthesized directly on F-doped Sn02 glass substrate （FTO） using a direct electrodeposition from a simple aqueous zinc salt solution. The effects of potential value, electro- deposition mode and solution stirring speed on the product morphology were investigated. Controlling the reaction under potentiostatic condition of-0.7 V at stirring speed of 300 r/min, large-scale nanotube arrays perpendicular to the substrate can be synthesized at a low temperature of 70℃. By varying the reaction parameters, we can also obtain ZnO nanorod arrays. The results of X-ray diffraction, scanning electron microscopy, transmission electron microscopy and high-resolution transmission electron microscopy have been provided to characterize the structure and morphology of the nanotube and nanorod arrays. Experiment results show that the as-obtained ZnO has a single crystalline structure and c-axis oriented direction. The room-temperature photoluminescence spectrum of the ZnO nanotube array film displayed its high crystal property available as a photonic material. Electrodeposition is an effective method to prepare ZnO nanotube array films in quantity.

Synthesis and luminescence characteristics of ZnO nanotubes

ZnO nanotubes have been fabricated through a carbon thermal reduction deposition process. Structure characterization results show that the ZnO nanotubes have a single crystalline wurtzite hexagonal structure pref- erentially oriented in the c-axis. The diameters of ZnO nanotubes are in the range of 90-280 nm and the wall thickness is about 50-100 nm. Room-temperature photoluminescence measurements of the ZnO nanotubes exhibit an intensive ultraviolet peak at 377 nm and a broad peak centered at about 517 nm. The UV emission is caused by the near band edge emission while the green emission may be attributed to both oxygen vacancy and the surface state. Raman and cathodoluminescence spectra are also discussed. Finally, a possible growth mechanism of the ZnO nanotubes is proposed.

电沉积制备ZnO纳米棒修饰电极上氧化还原蛋白的电化学行为

采用恒电位阴极还原法在金电极表面一步修饰ZnO纳米棒,制备成ZnO纳米棒修饰电极.扫描电子显微镜(SEM)和X射线衍射(XRD)结果显示制得的ZnO为直径约100nm的六棱柱状纤锌矿晶体纳米棒.使用ZnO纳米棒修饰的金电极研究细胞色素c的直接电化学行为,结果表明:ZnO纳米棒修饰的金电极能有效探测到细胞色素c的铁卟啉辅基在不同价态下的电化学行为;细胞色素c吸附后,ZnO纳米棒修饰的金电极对过氧化氢的电流响应呈现良好的线性关系.

电沉积法制备ZnO纳米棒/管阵列及其机理研究

采用恒电位电沉积法在未经修饰的ITO导电玻璃基底上用一步法制备了ZnO纳米棒阵列结构,并经碱蚀制备了ZnO纳米管阵列结构。通过阴极线性扫描分析了通氧及添加剂六次甲基四铵(HMT)对沉积ZnO薄膜的电化学行为的影响。结果表明,电沉积体系中通入氧气对阴极还原反应起到了加速作用,而电沉积体系中的HMT通过水解作用对电沉积反应起到了稳定剂作用。在氧气和HMT的协同作用下可使ZnO更加充分地成核生长,得到结构清晰分明的六方棱柱ZnO晶种,进而形成规则均一的ZnO薄膜。

温度对ZnO薄膜电沉积的影响

通过0.1mol·L-1Zn(NO3)2体系在不同温度下的电势-pH图、组分的分布系数和ZnO/Zn(OH)2沉淀的溶解度热力学计算得出最佳电沉积实验条件及最终沉积产物.随后用沉积过程的循环伏安曲线、电流密度-时间曲线、薄膜的X射线粉末衍射(XRD)、扫描电子显微镜(SEM)和热重-差热(TG-DSC)实验结果验证了热力学理论分析.光学研究发现,ZnO薄膜在可见光区具有高透光度(>80%)和较为陡峭的吸收边缘.提出硝酸锌水溶液中电沉积ZnO的反应机理.

N-TiO_2/ZnO复合纳米管阵列的掺杂机理及其光催化活性

以ZnO纳米柱阵列为模板,采用溶胶-凝胶法制备出TiO2/ZnO和N掺杂TiO2/ZnO的复合纳米管阵列.扫描电镜(SEM)、X射线光电子能谱(XPS)和紫外-可见漫反射吸收光谱(UV-Vis)的结果表明:两种阵列的纳米管均为六角形结构,直径约为100nm,壁厚约为20nm;在N-TiO2/ZnO复合纳米管阵列中,掺入的N离子主要是以N-Ox、N-C和N-N的形式化学吸附在纳米管表面,仅有少量的N离子以取代式掺杂的方式占据TiO2晶格O的位置;表面N物种形成的表面态能级和取代式掺杂导致带隙的窄化,增强了纳米管阵列的光吸收效率,促进了光生载流子的分离.光催化实验结果表明,N离子的掺杂有利于N-TiO2/ZnO复合纳米管阵列光催化活性的提高.

电沉积法制备ZnO纳米棒阵列及其发光特性

本文以掺F的SnO2导电玻璃为基板,以硝酸锌水溶液为电解液,采用三电极恒电位体系电沉积制备ZnO纳米棒阵列,系统考察了硝酸锌浓度和沉积电位等工艺参数对ZnO纳米棒阵列的微观形貌及其发光性能的影响规律。结果表明,硝酸锌浓度和沉积电位对纳米棒阵列的形貌有显著影响,控制适宜的工艺条件可以制备出直径分布均匀、结晶性好且纯度高的六方纤锌矿ZnO纳米棒阵列。荧光光谱分析表明,电沉积制备出的ZnO纳米棒阵列在385 nm附近有一个强荧光发射峰,且发光性能稳定、对纳米棒阵列微观形貌的细微变化不敏感,使其在发光二极管和激光器等领域具有广阔的应用前景。

电泳法制备ZnO掺杂纳米管阵列及其形貌表征

以阳极氧化铝膜为模板,采用电泳的方法,在溶液中先制备出了锌盐掺杂的前驱体,然后通过退火处理得到了ZnO:Tb3+的纳米管阵列.经扫描电镜观察该纳米管直径尺寸和管壁厚度分别为80 nm和15 nm.由XRD谱图和高分辨透射电镜分析,Tb3+离子已经进入到ZnO的晶格中并占据了Zn的格位或者位于ZnO的间隙位,最后提出了ZnO:Tb3+纳米管阵列的;形成机制.

ZnO纳米棒为模板的TiO_2纳米管制备及其场发射性能研究

以水热法生长ZnO纳米棒阵列为模板,利用液相沉积法成功制备了TiO2纳米管阵列,并系统研究了液相沉积液浓度和沉积时间对ZnO纳米棒的溶解情况,以及所制备TiO2纳米管阵列的场发射性能。实验结果表明:硼酸浓度越大、沉积时间越长,对ZnO纳米棒的溶解作用越明显,因而越不利于TiO2纳米管的制备。利用该种方法制备的TiO2纳米管长径比和致密性可通过ZnO纳米棒的水热生长条件来控制,本实验制备的TiO2纳米管具有优异的场发射性能,其开启场强为4.60 V/μm,场增强因子为10239。

低温水热制备ZnO纳米棒及其生长机理

以Zn(NO3)2.6H2O为前驱体,在碱性环境中,低温水热方法直接制备了ZnO纳米棒.应用场发射扫描电子显微镜(FESEM)、能谱仪(EDS)和X射线衍射仪(XRD)对样品进行了表征;通过光催化降解亚甲基蓝来评价ZnO的光催化活性;对60℃,1～24h范围内不同水热样品,进行了形貌观察,分析了ZnO的形核过程.结果表明:ZnO为六边棱柱状纳米棒,晶型为纤锌矿结构;ZnO纳米棒的表观生长速率约为0.7μm/h,表观形核时间约为3min;碱性条件是影响形核的重要因素;光催化活性随水热时间的增加而增强.

纳米ZnO生长及性质分析

利用低压金属有机化学气相沉积(LP-MOCVD)技术,在表面含有ZnO颗粒作为催化剂的Si(111)衬底上制备了ZnO纳米柱阵列。采用X射线衍射(XRD)、喇曼光谱(Raman)、扫描电子显微镜(SEM)、光致发光(PL)谱分析了样品的晶体结构质量、表面性质和光学性质。结果表明,生长出来的纳米ZnO具有较好的c轴择优取向性。发现氧分压对ZnO纳米柱的生长有重要影响:当氧分压较低时,生长基于VLS机制;当氧分压较高时,生长基于VS机制;通过对N2O流量的控制可实现对ZnO纳米材料的可控生长。