膨胀石墨层间生长高活性氧化锌及其光催化性能

以醋酸锌和膨胀石墨为原料, 采用真空辅助压力诱导手段使反应溶液注入膨胀石墨层间, 在180℃下溶剂热反应12 h, 一步得到氧化锌纳米棒/石墨烯复合光催化剂, 采用X射线衍射仪(XRD)和透射电子显微镜(TEM)等对复合光催化剂的结构和形貌进行了表征. 结果表明, 合成的氧化锌纳米棒具有六方晶系纤锌矿结构; 氧化锌纳米棒在石墨烯表面分散性较好, 其平均直径约50 nm, 长度约150~200 nm. 所得氧化锌纳米棒/石墨烯复合材料对亚甲基蓝的降解效率优于目前应用最广泛的光催化剂Degussa P25.     

Co掺杂ZnO纳米棒的水热法制备及其光致发光性能

以Zn(NO3)2·6H2O 和Co(NO3)2·6H2O为原料, 通过水热法在较低温度下制备了纯ZnO和Co掺杂的ZnO(ZnO:Co)纳米棒. 利用XRD、EDS、TEM和HRTEM对样品进行了表征, 结合光致发光(PL)谱研究了样品的PL性能. 结果表明, 水热法制备纯ZnO和ZnO:Co纳米棒均具有较好的结晶度. Co2+是以替代的形式进入ZnO晶格, 掺入量为2%(原子分数)左右. 纯的ZnO纳米棒平均直径约为20 nm, 平均长度约为180 nm; 掺杂样品的平均直径值约为15 nm, 平均长度约为200 nm左右; Co掺杂轻微地影响ZnO纳米棒的生长. 另外, Co掺杂能够调整ZnO纳米棒的能带结构、提高表面态含量, 进而使得ZnO:Co纳米棒的紫外发光峰位红移, 可见光发光能力增强.     

ZnO模板法合成的MnO2纳米棒及其电容特性研究

以自制的 ZnO 纳米棒为模板合成了 MnO2 纳米棒.x-射线衍射、红外光谱和透射电镜等对产物成分、晶型结构及其形貌的分析结果表明,所得样品均为平均直径20nm左右、平均长度约180nm的α-MnO2 纳米棒.循环伏安和恒流充放电测试分析所得样品超级电容特性的结果表明,在 1mol/L Na2SO4 水溶液中,2mA...     

铜掺氧化锌多孔纳米棒的水热合成及其光催化性能

通过两步法合成铜掺杂的氧化锌纳米棒,通过X射线衍射（XRD）、扫描电子显微镜（FESEM）、透射电子显微镜（TEM）、X射线光电子能谱（XPS）和紫外-可见（UV-Vis）分光光谱等技术对系列样品进行了表征,研究并探索了铜掺杂的氧化锌纳米棒光降解染料罗丹明B（RhB）和气体乙醛的催化活性。通过对多孔Cu掺杂ZnO纳米棒光催化分解乙醛进行了评价。多孔Cu掺杂ZnO纳米棒（CZ-5）光催化剂具有最高的催化分解乙醛的能力,比其它多孔Cu掺杂ZnO纳米棒具有很高的催化活性。多孔Cu掺杂ZnO纳米棒光催化剂在室温下在可见光（435 nm）下照射16 h,5.50×10^-4（φ,体积分数）的乙醛气体完全降解为二氧化碳（CO₂）。多孔铜掺杂的氧化锌纳米棒光催化剂的光催化性能的改善主要归因于铜和氧化锌纳米棒之间的协同作用。这种改进的光催化协同作用归因于Cu掺杂ZnO的可见光吸收的延伸和光生电子空穴对的抗重组。     

微波固相合成氧化锌纳米棒

通过前驱体的微波固相热分解法快速合成了氧化锌纳米棒, 其直径在60～385 nm之间, 长可达数微米. 前驱体则通过一步室温固相反应制备. 用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、能量色散X射线分析(EDX)和透射电子显微镜(TEM)对产物的结构和形貌进行了表征. 同时, 对氧化锌纳米棒的光致发光(PL)性能作了测试, 结果表明在355 nm处有一个明显的近带隙发射峰. 另外, 对比实验表明, 微波辐射在氧化锌纳米棒的形成过程中起了关键性作用, 并对其形成机理进行了初步探讨.     

β-Ga2O3:Dy3+ 纳米棒束的制备和光致发光性质

采用水热法及后续热处理制备了β-Ga2O3：Dy^3＋纳米棒束. 利用X射线粉末衍射（XRD）, 场发射电子扫描显微镜（FESEM）、发光光谱等测试手段对β-Ga2O3：Dy^3＋的物相、形貌、发光性质等进行了研究. FESEM等测试表明水热样品是由直径约100 nm, 长约2 μm的纳米棒组成的长径比约为3的羟基氧化镓（GaOOH）纳米棒束. 经过900 ℃高温热处理, 得到了形貌和尺寸基本保持不变的β-Ga2O3：Dy^3＋纳米棒束. 光致发光测试表明, Dy^3＋的发光由分别归属于4F9/2-6H15/2的蓝光（460～505 nm, 491 nm为最强峰）和4F9/2-6H13/2的黄光（570～600 nm, 580 nm为最强峰）组成. Β-Ga2O3基质可以有效地向Dy^3＋传递能量. 与固相法样品相比, 采用水热后续热处理方法制备的样品在分散性、形貌、能量传递和寿命方面明显优于固相法样品.     

Gd2O3∶Eu3+纳米棒的制备与发光性能

在表面活性剂辅助的水热条件下合成出尺寸均一的Gd2O3∶Eu3+纳米棒, 对其结构和荧光性质进行了表征, 并对其生长机理进行了初步讨论. XRD结果表明, 水热前驱体样品为六方晶相的Gd(OH)3, 经过灼烧之后样品为立方相的Gd2O3. TEM照片表明, 所得样品为直径60 nm、长度约600 nm的纳米棒. 荧光光谱表明, 在波长为254 nm 的紫外光激发下, Gd2O3∶Eu3+纳米棒产生了不同于前驱体的特征红光发射, 对应于Eu3+ 的5D0-7F2跃迁, 表明Gd2O3是红色发光材料的良好基质.     

Gd_2O_3:Eu~(3+)纳米棒的制备与发光性能

在表面活性剂辅助的水热条件下合成出尺寸均一的Gd2O3:Eu3+纳米棒,对其结构和荧光性质进行了表征,并对其生长机理进行了初步讨论.XRD结果表明,水热前驱体样品为六方晶相的Gd(OH)3,经过灼烧之后样品为立方相的Gd2O3.TEM照片表明,所得样品为直径60 nm,长度约600 nm的纳米棒.荧光光谱表明,在波长为254 nm 的紫外光激发下,Gd2O3:Eu3+纳米棒产生了不同于前驱体的特征红光发射,对应于Eu3+ 的5D0-7F2跃迁,表明Gd2O3是红色发光材料的良好基质.     

聚3-氯噻吩修饰CdSe纳米棒复合膜电极光电化学性能研究

采用水热法制备了具有闪锌矿和纤维锌矿结构的CdSe纳米棒. 纳米棒直径约为100 nm, 长度约为300 nm. 当外加电极电势为-0.6 V 时, 经聚3-氯噻吩[Poly(3-chlorothiophene), P3CT]修饰的CdSe纳米棒具有最大光电流, 并且CdSe/P3CT复合膜电极最高光电转换效率(IPCE)为13.5%, 低于CdSe纳米棒膜电极17.7%的最高IPCE. CdSe/P3CT复合膜电极中存在p-n异质结, p-n异质结的存在使得CdSe/P3CT复合膜电极在长波区(>410 nm)的IPCE整体高于CdSe纳米棒薄膜电极的IPCE.     

模板-电泳沉积法制备TiO2纳米棒

室温(约25℃)下,将钛酸四丁酯水解制得TiO2溶胶,利用电泳沉积法在氧化铝模板中填充胶体,经450℃煅烧处理,制备了TiO2纳米棒.用透射电子显微镜和X射线衍射仪对样品进行了表征.结果表明,所得到的TiO2纳米棒表面光滑、致密,直径约180 nm,具有锐钛矿型结构.     

Precursor-induced hydrothermal synthesis of flowerlike cupped-end microrod bundles of ZnO

Flowerlike cupped-end ZnO microrod bundles have been hydrothermally synthesized from precursor ZnCl2(N2H4)2 in sheet shape at 140 degrees C for 12 h; under the same conditions using the same precursor in rod shape, uniform ZnO nanorods were obtained. XRD pattern indicated the sample is ZnO with hexagonal cell contants a = 3.251 A and c = 5.206 A. FE-SEM and TEM show the formation process of the ZnO sample. HRTEM revealed that the flowerlike cupped-end ZnO microrod bundles grow along the [101] axis. The UV emission peak at approximately 396 nm and the blue band emission peak at approximately 469 nm were observed by PL spectra. A possible formation mechanism was proposed.     

Optical properties of ZnO and ZnO:In nanorods assembled by sol-gel method

Self-assembled zinc oxide (ZnO) and indium-doping zinc oxide (ZnO:In) nanorod thin films were synthesized on quartz substrates without catalyst in aqueous solution by sol-gel method. The samples were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), Raman-scattering spectroscopy, room-temperature photoluminescence (PL) spectra, and temperature-dependent PL spectra measurements. XRD and Raman spectra illustrated that there were no single In2O3 phase in ZnO lattice after indium doping. The PL spectra of ZnO showed a strong UV emission band located at 394 nm and a very weak visible emission associated with deep-level defects. Indium incorporation induced the shift of optical band gap, quenching of the near-band-edge photoluminescence and enhanced LO mode multiphonon resonant Raman scattering in ZnO crystals at different temperatures. Abnormal temperature dependence of UV emission integrated intensity of ZnO and ZnO:In samples is observed. The local state emission peak of ZnO:In samples at 3.37 eV is observed in low-temperature PL spectra. The near-band-edge emission peak at room temperature was a mixture of excitons and impurity-related transitions for both of two samples.     

Preparation and Photoluminescence of ZnO Comb-Like Structure and Nanorod Arrays

A large quantity of Zinc oxide (ZnO) comb-like structure and high-density well-aligned ZnO nanorod arrays were prepared on silicon substrate via thermal evaporation process without any catalyst. The morphology, growth mechanism, and optical properties of the both structures were investigated using XRD, SEM, TEM and PL. The resulting comb-teeth, with a diameter about 20 nm, growing along the 0001 direction have a well-defined epitaxial relationship with the comb ribbon. The ZnO nanorod arrays have a diameter about 200 nm and length up to several micrometers growing approximately vertical to the Si substrate. A ZnO film was obtained before the nanorods growth. A growth model is proposed for interpreting the growth mechanism of comb-like zigzag-notch nanostructure. Room temperature photoluminescence measurements under excitation wavelength of 325 nm showed that the ZnO comb-like nanostructure has a weak UV emission at around 384 nm and a strong green emission around 491 nm, which correspond to a near band-edge transition and the singly ionized oxygen vacancy, respectively. In contrast, a strong and sharp UV peak and a weak green peak was obtained from the ZnO nanorod arrays.     

退火温度对PLD法制备ZnO:Eu3+,Li+薄膜结构和发光性质的影响

采用脉冲激光沉积(PLD)法在Si(111)衬底上制备了Eu3+,Li+共掺杂的ZnO薄膜,分别在450,500,550和600℃条件下进行退火,退火气氛为真空。利用X射线衍射(XRD)仪和荧光分光光度计研究了退火温度对薄膜结构和光致发光(PL)的影响。研究结果表明,Eu3+,Li+共掺杂的ZnO薄膜具有c轴择优取向,Eu3+,Li+没有单独形成结晶的氧化物,均以离子形式掺入ZnO晶格中。PL谱中有较宽的ZnO基质缺陷发光,ZnO基质与稀土Eu3+之间存在能量传递,但没有有效的能量传递。随着退火温度的增加,薄膜发光先增强后减弱,退火温度为550℃时发光最强。当用395 nm的激发光激发样品时,仅观察到稀土Eu3+在594 nm附近的特征发光峰,但发光强度随退火温度变化不明显。     

Soft template synthesis of ZnO nanorods and their optical properties

A simple solution route was developed to fabricate monodisperse wurtzite ZnO nanorods. The as-prepared samples were 5 ??m in length and 70?C100 nm in diameter. The crystallinity, morphology, and structure of the rod-like ZnO microcrystals were examined. The crystal phases and the microstructure of the nanorods were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Room- and low-temperature photoluminescence (PL) and Raman spectra were employed to investigate the surface states of the samples. The deep-level emission band was barely observable at both room and cryogenic temperatures.     

化学溶液沉积法制备单分散氧化锌纳米棒阵列

在由溶胶凝胶法制备的纳米ZnO薄膜基底上, 采用化学溶液沉积法制备了单分散、高度取向的ZnO纳米棒阵列膜. 通过控制纳米ZnO薄膜的制备工艺, 可以调节氧化锌纳米棒的直径. 利用FESEM, TEM, HRTEM, SAED和XRD表征了氧化锌纳米棒阵列的形貌和晶体结构. ZnO纳米棒的室温PL谱具有很高的紫外带边发射峰, 在可见光波段无发射峰, 表明该方法制备的ZnO纳米棒晶体结构完整, 晶体中O空位的浓度很低.     

超声化学合成半导体氧化锌纳米杯

在室温下,以硝酸锌和六次甲基四胺的水溶液为前驱体溶液,通过超声辐照20 min制得了半导体ZnO纳米杯。粉体用XRD、EDS、FESEM、TEM、SAED和HRTEM进行了表征。结果表明：ZnO纳米杯为六方纤锌矿相的单晶结构,产量高,杯高在90 nm左右。讨论了超声时间和碱的浓度对晶体生长的影响,分析了可能的反应机理。室温下的PL光谱表明粉体有在389 nm处较强的激子发射和中心区在530 nm处较宽的黄绿光发射。     

Fabrication and photoluminescent properties of heteroepitaxial ZnO/Zn0.8Mg0.2O coaxial nanorod heterostructures

ZnO/Zn0.8Mg0.2O coaxial nanorod heterostructures were prepared by employing catalyst-free metal-organic vapor-phase epitaxy, and their structural and photoluminescent (PL) properties were investigated using transmission electron microscopy (TEM) and temperature-dependent PL spectroscopy. TEM images show that ZnO/Zn0.8Mg0.2O layers were epitaxially grown on the entire surfaces of the ZnO nanorods and the ZnO nanorod diameters as a core material were as small as 9 +/- 2 nm. A dominant PL peak was observed at 3.316 eV, from room-temperature PL spectra of ZnO/Zn0.8Mg0.2O coaxial nanorod heterostructures with ZnO core diameters of 9 nm, indicating a PL blue shift of 30 meV, which resulted from a quantum confinement effect along the radial direction in ZnO nanorods. Furthermore, temperature-dependent PL properties of the coaxial nanorod heterostructures were investigated, showing much higher PL intensity for the coaxial nanorod heterostructures than that of bare ZnO nanorods at room temperature. The origin of the enhanced PL intensity and reduced thermal quenching for the coaxial nanorod heterostructures is also discussed.