硅基ZnO纳米棒阵列异质结太阳能电池的水热合成及其光伏性能

通过低温水热法,在图案化的p型硅衬底上合成氧化锌（ZnO）纳米棒阵列薄膜,制备出具有p-Si/n-ZnO纳米棒（NR）阵列结构的异质结太阳能电池（HSCs）。通过直流磁控溅射技术,分别在前后面板溅射沉积ITO和Al膜接触电极层。研究ZnO籽晶层的退火温度、ZnO纳米棒阵列水热合成的时间等因素对ZnO纳米棒阵列的晶体结构、表面形貌和光学性能的影响。p-Si/n-ZnO纳米棒阵列HSCs的最佳短路电流密度和总能量转换效率分别为11.475 mA·cm^-2和2.0%。相比p-Si/n-ZnO薄膜HSCs,p-Si/n-ZnO纳米棒阵列HSCs的光伏性能得到了有效提高。     

Growth of ZnO nanorod arrays on soft substrates by hydrothermal process

ZnO nanorod arrays with quite homogeneous size and shape were fabricated by introducing ZnO seed-layer as nucleation centers on the soft ITO substrates prior to the hydrothermal reaction. The samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and photoluminescence method. After the ZnO seed-layer is introduced, the resulting deposits on the substrates develop into nanorods, and the diameter decreases obviously to about 100 nm. Influences of the coated nanocrystal seed nuclei on the morphology of ZnO nanorod arrays were discussed. The results show that each nanorod is monocrystalline with wurtzite-type structure and oriented in c-axis direction. The increase of the intensity ratio of ultraviolet to visible emissions in room-temperature photoluminescence spectra and the decrease of the ultraviolet PL linewidths show the improvement of the quality of ZnO nanorods. A simple and effective method to synthesize ZnO nanorod arrays with fairly uniform size and shape on soft substrates is dip-coating ZnO nanocrystals prior to hydrothermal reaction, and it may be also feasible for the fabrication of other small-size metal oxide nanostructures on soft substrates.     

Field emission enhancement of ZnO nanorod arrays with hafnium nitride coating

Vertically well-aligned single crystal ZnO nanorod arrays were synthesized and enhanced field electron emission was achieved with hafnium nitride (HfN_x) coating under proper sputtering condition. HfN_x films with various composition have been coated on ZnO nanorod arrays using a reactive direct current (DC) magnetron sputtering system. Morphology and crystal configuration of the ZnO nanorod arrays were investigated by scanning electron microscopy and X-ray diffraction. The field emission properties of the coated and uncoated ZnO nanorod arrays were characterized. The as-grown ZnO nanorod arrays showed a turn-on electric field of 6.60 V μm^− 1 at a current density of 10 μA cm^− 2 and an emission current density of 1 mA cm^− 2 under the field of 9.32 V μm^− 1. While the turn-on electric field of the coated ZnO nanorod arrays sharply decreased to 2.42 V μm^− 1, an emission current density of 1 mA cm^− 2 under the field of only 4.30 V μm^− 1 can be obtained. A method to accurately measure the work function of the coated films was demonstrated.     

Fabrication of highly oriented ZnO nanorod arrays by galvanostatic deposition

Highly oriented ZnO nanorod arrays were suecessfully 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 [001] direction with an orientation perpendicular to the substrate.When the wavelength of incident is over 380 nm,the ZnO nanorod arrays show a high optical transmission of above 95%.Furthermore,the possible growth mechanism of the nanorod arrays was discussed.     

钛基表面PDLLA/ZnO纳米阵列材料的制备及生物学性能

采用水热生长法,在钛基表面制备高度有序、尺寸可控的氧化锌纳米棒阵列,再通过静电吸附的方法在其表面自组装一层具有良好生物相容性的聚乳酸生物涂层。利用SEM,MTT,LDH方法对细胞形态和生物活性进行表征。结果表明,氧化锌阵列上细胞形态呈圆形,无铺展现象。而经聚乳酸修饰过的材料表面MC3T3细胞外基质铺展较好,细胞分泌的丝状伪足嵌入了阵列结构的空隙中,并且表面细胞数量最多,细胞活性明显高于氧化锌纳米棒及纯钛片。结果表明,聚乳酸涂层提高了氧化锌阵列的生物相容性,为细胞生长提供适宜的微环境,有效促进了细胞的黏附与增殖。     

Ag-TiO2纳米棒阵列的抗菌性和光催化性能研究

目的：制备一种高抗菌性和高光催化活性的Ag掺杂TiO2（Ag-TiO2）纳米棒阵列。方法通过磁控溅射与水热复合处理法,在钛箔片表面制备出Ag掺杂TiO2（Ag-TiO2）纳米棒阵列,酸化处理过的试样在500℃下煅烧2 h。采用X射线衍射（XRD）进行物相分析,利用场发射扫描电子显微镜（SEM）、场发射透射电子显微镜（TEM）、能量分散谱仪(EDS)观察试样的表面、截面形貌、微观结构和组成,并探究其对大肠杆菌和金黄色葡萄球菌的杀菌性能和对亚甲基蓝的光催化降解能力。结果该工艺下制备的 Ag-TiO2纳米棒大小均匀,取向明显,主要由锐钛矿型 TiO2相组成。Ag-TiO2纳米棒对大肠杆菌和金黄色葡萄球菌具有优异的杀菌效果,杀菌率几乎达到100%。Ag-TiO2纳米棒能有效地提高亚甲基蓝的降解率。结论磁控溅射与水热复合处理法在钛箔片表面成功制备出Ag-TiO2纳米棒阵列,此阵列具有优异的杀菌能力、高抗菌和光催化降解性能。     

Role of Substrate Roughness in ZnO Nanowire Arrays Growth by Hydrothermal Approach

The role of substrate roughness in ZnO nanowire(NW) arrays hydrothermal growth has been systematically studied.Six silicon substrates with different roughness by chemical etching have been selected to grow ZnO NW arrays hydrothermally after sputtering 5-nm-thick ZnO seed layer as catalyst.The as-grown samples reveal that average diameters and number densities of ZnO NW arrays are inversely proportional to the increasing substrate roughness observed by atomic-force microscopy and scanning electron microscopy.Furthermore,the theoretically derived equations based on nucleation with the Gibbs free energy to describe relations of substrate roughness versus average NW diameter and NW number density match well with experimental results.Research results in this paper can be used to control the number density and the average diameter of ZnO NW arrays by alternating substrate roughness.     

Growth and optical properties of ZnO nanorods prepared through hydrothermal growth followed by chemical vapor deposition

We report on the synthesis of high-quality ZnO nanorods by combining hydrothermal growth (HG) and chemical vapor deposition (CVD) processes. Vertically aligned and closely packed ZnO nanorods were grown by HG on a sputtered ZnO seed layer on a SiO₂/Si (0 0 1) substrate. The top surface of the HG-prepared ZnO nanorods showed very flat surfaces compared with that of the sputtered ZnO seed layer. Therefore, the HG-prepared ZnO nanorods were used as a new alternative seed material for the CVD growth of the ZnO nanorods. Vertical ZnO nanorods were grown by CVD on both the new HG-prepared nanorod seed material and the sputtered ZnO seed layer. The CVD-prepared ZnO nanorods on new HG-prepared nanorod seed material showed better crystalline quality and superior optical properties than the CVD-prepared ZnO nanorods on sputtered seed layer. The former showed negligible deep-level emissions at room temperature photoluminescence measurements. The intensity ratio of near-band-edge emissions to deep-level emissions from the former was about 910, but that from the latter was about 151. This implies that the HG-prepared ZnO nanorods can be used as a promising new seed material for nanostructure synthesis.     

Formation of ZnO nanorod arrays on polytetraflouroethylene (PTFE) via a seeded growth low temperature hydrothermal reaction

ZnO nanorod arrays were formed by a low temperature hydrothermal process on seeded polytetraflouroethylene (PTFE) sheets. The seed layer was formed using thermal oxidation of a thin evaporated Zn film on the PTFE sheet at 300 °C in air for 10 min. The formation of ZnO nanorod arrays in the hydrothermal reactive bath consisting of hexamethylamine (HMT) and Zn ions occurred via the reaction of hydroxyl ions released during the thermal degradation of HMT with the Zn ions. The seed layer provided a template for the nucleation of the ZnO and HMT which also acted as a chelating agent that promoted growth of the ZnO along the c-axis, leading to the formation of exclusively (0 0 2) ZnO nanorods. The effect of exposure time of the seeded PTFE to the reactive solution on the formation of the nanorods was investigated. Well aligned, relatively uniform tapered 300 nm long nanorods can be formed after 8 h of exposure. Longer exposure times to 24 h resulted in the formation of more uniform nanorods with base diameter averaged of ∼100 nm and the tip diameter of ∼50 nm. XRD analysis showed that the ZnO nanorod array had a hexagonal wurtzite structure. This result is in agreement with HR-TEM observations and Raman scattering analysis. Photoluminescence study showed that a strong UV emission peak was obtained at 380 nm and a small peak at 560 nm, which is associated with green emission. The optical band gap measured from these plots was at 3.2 eV on average.     

水热法制备高定向掺铝氧化锌纳米棒阵列

为了制备高定向光电性能优异的掺铝氧化锌(ZAO)纳米棒阵列,采用溶胶-凝胶法在玻璃基片上制备掺铝氧化锌薄膜,以ZAO薄膜为种子层,通过控制掺铝量、稳定荆等工艺参数,采用水热法制备出了高定向ZAO纳米棒阵列.实验表明,铝掺杂量为2%,直径在50nm左右的ZAO纳米棒阵列薄膜具有最好的光致发光性能,表面活性剂可以促进ZAO纳米结构的棒状生长,形成高定向ZAO纳米棒阵列.     

Oriented growth of ZnO nanostructures on different substrates via a hydrothermal method

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.     

垂直生长于锌基底的Co掺杂ZnO纳米棒阵列显著室温铁磁性能

通过简单的水热合成法在锌片基底上一步制备了Co掺杂的ZnO纳米棒阵列。纳米棒在基底上均匀分布,取向一致,垂直于基底大面积生长。样品结构均为六方纤锌矿结构,具有高结晶质量,不含其它杂相。随着Co掺杂浓度的增加,紫外发射峰强度逐渐下降,近带隙发射峰的半峰宽也较纯ZnO变宽。拉曼光谱显示Co的掺杂使纳米棒出现了氧空位和锌填隙本征缺陷。随着Co浓度的增加这些缺陷也随之增加。掺杂纳米棒阵列的磁滞回线表明样品具有明显的铁磁特征,并有较大的矫顽力Hc~660 Oe。这种ZnO基稀磁半导体纳米棒阵列是一种在自旋电子器件中具有应用潜力的纳米材料。     

Low-temperature synthesis and photoluminescence of ZnO nanostructures by a facile hydrothermal process

We reported a facile route to large-scale ZnO nanostructures by a poly (styrene-alt-maleic acid sodium) (PSMA)-assisted hydrothermal process. Various nanostructures including nanowires, nanobelts and nanorod arrays were fabricated depending on the experimental conditions. The structural studies reveal that all the nanostructures are single crystal with hexagonal phase and preferentially grow along [0 0 0 1]. The organic additive PSMA offers a spatial template for the one-dimensional (1D) growth of ZnO. The photoluminescence (PL) spectra of these nanostructures exhibit coexistence properties of ultraviolet (UV) and green emission. The nanorod arrays and nanobelts exhibit the strongest UV performance and green emission, respectively. We deduce that quantity of surface defects should be responsible for the difference in PL properties of these nanostructures.     

Oriented growth of ZnO nanostructures on Si and Al substrates

Aligned ZnO nanorod arrays and oriented ZnO nanoplates were synthesized on Si and Al substrates, respectively, using a hydrothermal method without any surfactant. The process involved the deposition of ZnO seeds on the substrate and the oriented growth of ZnO nanostructure in aqueous solution. The ZnO seeds were indispensable for the alignment of ZnO nanorods and TEM and XRD analysis confirmed that the ZnO rods are single crystalline grown along [001] direction. Al substrate caused formation of (001) surface dominated ZnO nanoplates, in which ZnO preferential growth direction was suppressed. The photoluminescence spectra of the as-grown ZnO products were measured to indicate their structural and optical quality. These oriented ZnO nanostructures are expected to be prospectively applied in nanodevices fabrication.     

Relative photoluminescence of ZnO nanorods size-controlled by changing the precursor ratio in metal organic chemical vapor deposition

The photoluminescent (PL) properties of vertically and laterally well-oriented ZnO nanorod arrays (NRAs) synthesized by metalorganic chemical vapor deposition on Al₂O₃ (0001) substrates were investigated. The size of the NRAs was controlled by systematic tuning of the precursor ratio. Regardless of the size of the NRAs, the PL properties were the same when measured at room temperature and at low temperatures. This observation suggests that changing the precursor ratio is a good way of controlling the size of ZnO NRAs while maintaining consistent PL properties.     

KOH处理对ZnO纳米棒阵列结构及光电性能的影响(英文)

采用简单的化学沉积结合KOH碱刻蚀的方法,在导电玻璃(FTO)上生长ZnO纳米棒阵列(ZnONRs)。用X射线衍射(XRD)、扫描电子显微镜(SEM)、电流—电压(I—V)曲线对所得样品的晶型、形貌及光电性能进行测试,结果表明:ZnONRs呈纤铅矿型;ZnONRs的形貌及光电性能与KOH的浓度及刻蚀时间密切相关,经0.1mol/LKOH刻蚀1h后可得到排列高度有序且分布均匀的ZnONRs;KOH刻蚀后的ZnONRs与未刻蚀前高密度的ZnONRs相比,其光学性能得到提高。0.1mol/LKOH刻蚀1h的ZnONRs作为太阳能电池的光阳极,其光电转换效率、短路电流、开路电压较未刻蚀的ZnONRs分别提高了0.71%、2.79mA和0.03V。     

Synthesis of GaN nanorods on Si substrates with assistance of the volatilization of ZnO middle layers

GaN nanorods have successfully been synthesized on Si(111) substrates via ammoniating ZnO/Ga2O3 films at 950℃. Ga2O3 thin films and ZnO middle layers were deposited in turn on Si(111) substrates by r.f. magnetron sputtering system. ZnO volatilized at 950℃ in the ammonia ambience and Ga2O3 reacted to NH3 to fabricate GaN nanorods in the later ammoniating process. The volatilization of ZnO layers played an important role in the fabrication. The structure and composition of the GaN nanorods were studied by X-ray diffraction (XRD) and Fourier transform infrared spectrophotometer (FTIR). The orphology ofGaN nanorods was investigated using scanning electron microscopy (SEM) and transmission electronic microscope (TEM). The analyses of measured results revealed that GaN nanorods with hexagonal wurtzite stxucture were prepared by this method.     

Site-specific synthesis of ZnO nanocrystalline networks via a hydrothermal method

ZnO nanocrystalline networks (NCNWs) consisting of percolating nanocrystals with irregular shape and size were synthesized using Al seed layers in a hydrothermal process. Various thicknesses of Al films were used to assess the effects of film thickness on the formation of ZnO NCNWs; the coverage and size of the ZnO nanocrystals increased with an increasing Al film thickness. In addition, by exploiting the seed layer-dependent crystal growth behaviors, two distinctly different ZnO nanostructures, nanorods on ZnO seed and NCNWs on Al seed, could be selectively achieved on the same substrate under the same growth conditions. Spectrally- and spatially-resolved investigations of these two ZnO nanostructures were performed using cathodoluminescence, which provided a significant opportunity to study the effect of the nanostructures on the luminescent characteristics. The ZnO NCNWs have an extremely high surface to volume ratio and sufficient inter-space, which enabled the conversion of the surface property from hydrophilic to superhydrophobic.     

密度可控钛纳米棒阵列的制备及其矿化性能研究

通过控制电解液中的草酸含量,在医用纯钛表面构建密度可控的钛纳米棒阵列。利用场发射扫描电镜(FE-SEM)和原子力显微镜(AFM)对钛表面纳米棒阵列形貌和密度进行了表征,并在模拟体液(2SBF)中对其矿化性能进行研究。结果表明:钛纳米棒阵列密度随着草酸含量的增加而增大,钛表面构建纳米棒阵列结构有利于类骨钙磷矿物的沉积,当纯钛表面纳米棒阵列密度为(1.79±0.04)×1010/cm2时,在模拟体液中矿化性能优异,可见这种结构有利于材料与骨组织形成骨性结合,提高临床疗效。     

Effect of polyethyleneimine on the growth of ZnO nanorod arrays and their application in dye-sensitized solar cells

A series of oriented hexagonal wurtzite ZnO nanorod-array films were grown on fluorine-doped tin oxide (FTO) coated glass substrates by chemical process. The effect of polyethyleneimine (PEI) on the structure and micro-morphology of ZnO nanorod array films, as well as the photoelectric conversion properties in dye-sensitized solar cells (DSSCs) was analyzed. It was found that with the addition of PEI in growth solution, the ZnO nanorods became smaller in diameter and longer in length and hence the dye absorption and the photovoltaic performance of DSSCs were improved. A power conversion efficiency of 2.30% had been achieved on a DSSC based on a 7.9 μm-long nanorod array film prepared by a growth solution containing the PEI.