准一维深色纳米ZnO的水热方法生长及其结构和光学性能的调变（英文）

本文以高纯度金属锌箔为Zn和衬底,利用传统的水热合成方法制备了深色的纳米结构ZnO.研究发现,改变制备温度可以调变ZnO样品的颜色和光学性能,尤其是提高温度可以显著地降低可见光波段太阳能的活性.推测这种现象与ZnO纳米棒顶端的尖锥形貌密切相关,这种结构加剧了光在ZnO纳米棒之间的折射和反应.改善ZnO的光吸收能力对于提升ZnO基太阳电池的效率有重要意义.     

醋酸锌热解温度对ZnO纳米棒的结构及光学性质的影响

采用水热法在普通载玻片上热解醋酸锌生成的ZnO种子层上制备ZnO纳米棒, 采用 X射线衍射仪、扫描电镜、分光光度计等测试手段详细研究了醋酸锌热解温度对 ZnO纳米棒的结构和光学性质的影响. 结果表明: 纳米棒的结晶质量、端面尺寸、宏观应力和透射率与醋酸锌热解温度有密切关系. 随着热解温度的增加, ZnO纳米棒具有的c轴择优取向性先增强后减弱, 拉应力先减小后增大, 可见光区的平均透射率先增大后减小. 热解温度为350 ℃时, ZnO纳米棒c轴择优取向性最强, 拉应力最小, 平均透射率最大. 端面尺寸诱导的表面散射 是影响ZnO纳米棒可见光区平均透射率的主要机制. 关键词： 醋酸锌 水热法 ZnO纳米棒     

ZnO纳米棒的低温溶液法制备、光电特性研究及其在有机/无机复合电致发光中的应用

利用水热法制备了垂直于衬底的定向生长的ZnO纳米棒,利用扫描电子显微镜及光致发光的方法对其形貌及光学特性进行了表征,利用场发射性能测试装置对ZnO纳米棒的场发射性能进行了测试.结果表明:利用水热法在较低的温度(95 ℃) 下生长了具有较好形貌和结构的ZnO纳米棒,并表现出了较好的场发射特性,当电流密度为1 μA/cm²时,开启电场是2.8 V/μm,当电场为6.4 V/μm时,电流密度可以达到0.67 mA/cm²,场增强因子为3360.稳定性测试表明,在5 h内,4.5 V/μm的电场下,其波动不超过25%.将制备的ZnO纳米棒应用到有机/无机电致发光中,其中ZnO纳米棒为电子传输层,m-MTDATA(4,4',4″-tris{N,(3-methylphenyl)-N-phenylamino}-triphenylamine) 为空穴传输层,得到了ZnO的342 nm的紫外电致发光,此发光较ZnO纳米棒光致发光的紫外发射有约40 nm的蓝移. 关键词： ZnO纳米棒 场发射 水热法 有机/无机复合电致发光     

两步法制备超疏水性ZnO纳米棒薄膜

采用两步法制备了超疏水性ZnO纳米棒薄膜,在用磁控溅射在普通玻璃衬底上生长一层ZnO籽晶层基础上,利用液相法制备了空间取向高度一致的ZnO纳米棒阵列,经修饰后由亲水性转变为超疏水性.用扫描电子显微镜观察了纳米棒的表面结构,用接触角测量仪测出水滴在ZnO纳米棒薄膜表面的接触角为151°±05°,滚动角为7°.用Cassie模型对ZnO纳米棒薄膜的超疏水性进行了验证. 关键词： ZnO纳米棒 超疏水 两步法     

ZnO纳米棒的制备及紫外探测性能

通过水热法在ITO衬底上成功合成了ZnO纳米棒,并以ITO为电极制备了ZnO纳米棒紫外探测器件。在室温下测试了所制备器件对紫外光的响应性能。测试结果表明,ZnO纳米棒对紫外光有很好的光响应,在0V附近,ZnO纳米棒紫外探测器的灵敏度能达到1500。此外,通过循环测试可以观测到ZnO纳米棒紫外探测器具有良好的重复性和稳定性。     

基于水热法制备的ZnO纳米棒的CO传感器

纳米结构的氧化锌(ZnO)可以吸附大量的气体,并且在吸附了气体之后形成特定的表面态,从而对其导电性产生显著的影响。用水热法在ITO电极之间制备了ZnO纳米棒阵列,通过扫描电镜(SEM)、X射线衍射(XRD)和高分辨透射电镜(HRTEM)等表征后发现,制得的ZnO纳米棒具有较好的结晶性。在200℃下,当1.25mg/L的CO气体通过ZnO纳米棒时,ITO电极两端的电流发生了较明显的改变,显示该装置对CO气体具有较明显的响应(灵敏度为18)。可以预见通过改变电极之间生长的ZnO纳米结构形貌,提高纳米结构的表面利用率,以及适当提高测试温度,可以进一步提高传感器的灵敏度。制作的气体传感器具有简单、廉价、环保的特点,对于气体传感器的设计提供了新的思路。     

ZnO纳米棒/CdS量子点的制备及紫外-可见探测性能研究

本文采用水热法在ITO衬底上制备了ZnO纳米棒阵列,然后用化学水浴沉积法在纳米棒上制备CdS量子点。分别利用SEM和XRD对样品形貌和晶体结构进行表征。结果表明,球状的CdS量子点均匀地包覆在ZnO纳米棒表面,且结晶质量较好。基于ZnO纳米棒和ZnO纳米棒/CdS量子点制备的探测器对紫外光都具有很好的响应,然而与ZnO纳米棒探测器相比,ZnO纳米棒/CdS量子点探测器在相同条件下的光电流提高了7倍,为0. 52 mA。此外,ZnO纳米棒/CdS量子点探测器对绿光和蓝光也表现出了很好的响应。     

水热反应中籽晶层对ZnO纳米棒的影响

以Zn(NO3)2·6H2O/HMT为反应物,通过低温水热反应过程,在籽晶衬底上制备了ZnO纳米棒,分别用场发射扫描电子显微镜和X射线衍射仪对ZnO纳米棒形貌与晶体结构进行了表征,并研究了不同方法制备的ZnO籽晶层以及籽晶层厚度对ZnO纳米棒形貌及结晶质量的影响.结果表明磁控溅射籽晶衬底上生长的ZnO纳米棒结晶质量最好,而籽晶层的厚度对ZnO纳米棒的垂直取向性有一定的影响.     

水热法制备Co掺杂ZnO纳米棒及其光学性能

采用水热法在石英衬底上以Zn(CH3COO)2.2H2O和Co(NO3)2.6H2O水溶液为源溶液,以C6H12N4(HMT)溶液作为催化剂,在较低温度下制备了Co掺杂的ZnO纳米棒。采用X射线衍射(XRD)和扫描电子显微镜(SEM)对所生长ZnO纳米棒的晶体结构和表面形貌进行了表征,考察了Co掺杂对ZnO纳米棒微观结构和对发光性能影响的机制。结果表明:Co掺杂的ZnO纳米棒呈六方纤锌矿结构,具有沿(002)面择优生长特性,Co掺杂使ZnO纳米棒的直径变细;同时室温光致发光(PL)谱检测显示Co掺杂ZnO纳米棒具有很强的近带边紫外发光峰,而与深能级相关的缺陷发光峰则很弱。本研究采用水热法在石英衬底上于较低温度下生长出了具有较高光学质量的Co掺杂ZnO纳米棒。     

湿化学法合成Co掺杂ZnO薄膜的微结构及发光特性

采用湿化学法在ITO玻璃衬底上制备了纳米棒结构的Co掺杂ZnO薄膜.XRD结果表明Co掺杂的ZnO没有出现杂相.SEM结果表明掺杂样品是由ZnO纳米棒团簇结构组成,且团簇的密度随着Co掺杂浓度的增大而增大.光致发光光谱表明Co掺杂导致薄膜的带隙发生红移.     

Improving light trapping and conversion efficiency of amorphous silicon solar cell by modified and randomly distributed ZnO nanorods

Three-dimensional （3D） nanostructures in thin film solar cells have attracted significant attention due to their appli- cations in enhancing light trapping. Enhanced light trapping can result in more effective absorption in solar cells, thus leading to higher short-circuit current density and conversion efficiency. We develop randomly distributed and modified ZnO nanorods, which are designed and fabricated by the following processes： the deposition of a ZnO seed layer on sub- strate with sputtering, the wet chemical etching of the seed layer to form isolated islands for nanorod growth, the chemical bath deposition of the ZnO nanorods, and the sputtering deposition of a thin Al-doped ZnO （ZnO：Al） layer to improve the ZnO/Si interface. Solar cells employing the modified ZnO nanorod substrate show a considerable increase in solar energy conversion efficiency.     

Growth, properties and dye-sensitized solar cells–applications of ZnO nanorods grown by low-temperature solution process

Hexagonal-shaped small ZnO nanorods were grown in a large-quantity via simple aqueous solution process by using zinc nitrate as a source of zinc ions at low temperature under stirring. The as-grown hexagonal-shaped ZnO nanorods were characterized in detail in terms of their structural, optical and photovoltaic properties. The detailed structural investigations by HRTEM, SAED and FFT revealed that the as-synthesized ZnO nanorods are well-crystalline, possessing a perfect hexagonal ideal growth habits of wurtzite zinc oxide and grown along the [0001] direction in preference. The optical properties, composition and quality of the as-synthesized nanorods were examined by using UV-visible and FTIR spectroscopy. Moreover, films of as-grown nanorods were used as photoanode materials to fabricate the dye sensitized solar cells (DSSCs). An overall light to electricity conversion efficiency of 0.70% with a fill factor of 47.2%, short-circuit current of 1.8 mA/cm² and open-circuit voltage of 0.76 V were achieved for the solar cell based on hexagonal-shaped small ZnO nanorods.     

CdS quantum dot-sensitized ZnO nanorod-based photoelectrochemical solar cells

ZnO nanorods have been grown using ZnO seed layer onto ITO-coated glass substrates. CdS quantum dots have been deposited onto ZnO nanorods using simple precursors by chemical method and the assembly of CdS quantum dots with ZnO nanorod has been used as photo-electrode in quantum dot-sensitized solar cells. X-ray diffraction results show that ZnO seed layer, ZnO nanorods, and CdS quantum dot-sensitized ZnO nanorods exhibit hexagonal structure. The particle size of CdS nanoparticle is 5 nm. The surface morphology studied using scanning electron microscope shows that the top surface of the vertically aligned ZnO nanorods is fully covered by CdS quantum dots. The ZnO nanorods have diameter ranging from 100 to 200 nm. The absorption spectra reveal that the absorption edge of CdS quantum dot-sensitized ZnO nanorods shift toward longer wavelength side when compared to the absorption edge of ZnO. The efficiency of the fabricated CdS quantum dot-sensitized ZnO nanorod-based solar cell is 0.69% and is the best efficiency reported so far for this type of solar cells.     

多环类苝四甲酸二酐插入层对ZnO纳米棒和聚合物复合太阳电池性能的影响

以ZnO纳米棒和聚[2-甲氧基-5-(2-乙基-己氧基)-1,4-苯撑乙烯撑](MEH-PPV)的复合体系作为光敏层制备了太阳电池.为了增大电池的光吸收,在ZnO纳米棒与MEH-PPV之间插入了有机n型小分子多环类苝四甲酸二酐(PTCDA),制备了不同厚度的PTCDA、结构为ITO/ZnO纳米棒/PTCDA/MEH-PPV/Au的太阳电池.实验发现,插入PTCDA后,电池在可见光区的吸收增强,光生激子数量增大,光电流密度增大.当蒸镀的PTCDA厚度为40 nm时,薄膜的粗糙度适中,表面形貌较为平滑,器件性 关键词： 有机太阳电池 ZnO纳米棒 聚合物     

Enormous enhancement of ZnO nanorod photoluminescence

ZnO nanorod arrays were grown on quartz slices in the aqueous solution of zinc acetate and hexamethylenetetramine at 90 °C. Then ZnO:Mg shells were epitaxially grown on the nanorods to form core/shell structures in the aqueous solution of zinc acetate, magnesium acetate and hexamethylenetetramine at the same temperature. Effects of the shells and UV laser beam irradiation on the crystal structure and photoluminescence properties of ZnO nanorods were studied. ZnO:Mg shells suppress the green emission and enhance the UV emission intensity of the nanorods by 38 times. Enhancement of the UV emission depends on the Mg content in the shells. Short time UV laser beam irradiation could improve ZnO nanorod emission efficiently. The UV emission intensity of ZnO nanorods is enhanced by 71 times by capping and subsequent UV laser beam irradiation.     

Polymer-assisted complexing controlled orientation growth of ZnO nanorods

The growth of the oriented zinc oxide (ZnO) nanorods on silicon substrates based on a simple novel chemical transformation and thermal hydrolysis by using polyvinyl alcohol (PVA) as self-assembling complex polymer was introduced in this paper. All the polymers were removed after chemical oxidation and only the carbonized grid backbones remained that confines the ZnO nanorod’s diameter and enhance the absorption and diffusion of ZnO at the tips of the nanorods during growth. The ZnO nanorods are investigated by FTIR, XRD and FE-SEM. The results indicated that these nanorods have fine hexagonal wurtzite crystal structure and their diameter varies from 20 to 90 nm and the length up to about 1 μm. A polymer-localized ZnO growth model is proposed, which well explains the growth behavior of ZnO nanorods.     

Polymer-assisted complexing controlled orientation growth of ZnO nanorods

The growth of the oriented zinc oxide (ZnO) nanorods on silicon substrates based on a simple novel chemical transformation and thermal hydrolysis by using polyvinyl alcohol (PVA) as self-assembling complex polymer was introduced in this paper. All the polymers were removed after chemical oxidation and only the carbonized grid backbones remained that confines the ZnO nanorod’s diameter and enhance the absorption and diffusion of ZnO at the tips of the nanorods during growth. The ZnO nanorods are investigated by FTIR, XRD and FE-SEM. The results indicated that these nanorods have fine hexagonal wurtzite crystal structure and their diameter varies from 20 to 90 nm and the length up to about 1 μm. A polymer-localized ZnO growth model is proposed, which well explains the growth behavior of ZnO nanorods.This revised version was published online in August 2005 with a corrected issue number.     

Enhanced power efficiency of ZnO based organic/inorganic solar cells by surface modification

We present series of strategies to enhance efficiency of ZnO nanorods based organic/inorganic solar cells with spin-coated P3HT:PCBM blend as active layer. The performance of the as-fabricated devices is improved by controlling the size of ZnO nanorods, annealing temperature and time of active layer, surface modification of ZnO with PSBTBT. Optimized device of ITO/ZnO nanorod/P3HT:PCBM/Ag device with PSBTBT surface modification and air exposure reaches an efficiency of 2.02% with a short-circuit current density, open-circuit voltage and fill factor of 13.23 mA cm⁻², 0.547 V and 28%, respectively, under AM 1.5 irradiation of 100 mW m⁻², the increase in efficiency is 7-fold of the PSBTBT surface modified ITO/ZnO nanorods/P3HT:PCBM/Ag device compared with the unmodified one, which is own to the increased interface contact, expanded light absorption, tailored band alignment attributed to PSBTBT. We found exposure to air and surface modification is crucial to improve the device performance, and we discussed the mechanisms that affect the performance of the devices in detail.     

Effect of Ultraviolet Light on Hybrid Zinc Oxide Polymer Bulk Heterojunction Solar Cells

Compared to conjugated polymer poly[2-methoxy-5-（3＇ ,7＇-dimethyloctyloxy）-l,4-phenylenevinylene] （MDMO-PPV） solar cells, bulk heterojunction solar cells composed of zinc oxide （ZnO） nanocrystals and MDMO-PPV have a better energy conversion efficiency. However, ultraviolet （UV） light deteriorates the performance of solar cells composed of ZnO and MDMO-PPV. We propose a model to explain the effect of UV illumination on these ZnO：MDMO-PPV solar cells. According to this model, the degradation from UV illumination is due to a decrease of exciton dissociation efficiency. Our model is based on the experimentM results such as the measurements of current density versus voltage, photoluminescence, and photocurrent.     

CdS/ZnO纳米复合结构的制备、表征及其光催化活性的改善

利用简单的水热法在ZnO纳米棒表面合成CdS纳米粒子.用扫描电镜(SEM)和X射线衍射(XRD)对CdS/ZnO异质结构进行表征.实验结果表明,在生长CdS的过程中ZnO被逐渐地腐蚀.选择CdS/ZnO纳米复合材料作为光催化剂在紫外光和绿光照射的条件下降解甲基橙(MO).CdS/ZnO纳米复合材料纳米棒作为光催化剂降解...