ZnO及其含锌混合氧化物薄膜的充放电性能研究

从充放电性能、晶体结构等方面考察了包括粉末状的ZnO、脉冲激光沉积方法制备的ZnO薄膜和含锌混合氧化物薄膜的电化学性质.结果表明,ZnO粉末制备的电极的嵌入容量随退火温度的升高而增大,掺入其他氧化物可以明显改善ZnO薄膜的电化学性能,在Ar气氛中,基片温度为400℃时,沉积的靶子成分为Zn:B:P:Al=1:1:0.5:0.5(摩尔比)的含锌混合氧化物薄膜具有较高的可逆容量,且循环性能良好.     

Polymer Nanocomposites for Emulsion‐Based Coatings and Adhesives

Emulsion‐based coatings and adhesives are in growing demand due to an increased awareness of health and safety issues arising from solvent‐based polymer manufacturing processes. However, emulsion‐based techniques often require additional development to achieve equal or better application performance compared to solvent‐based processes. The inclusion of nanoparticles in emulsion‐based coatings and adhesives can be considered as a promising means to enhance performance. This paper reviews the current progress on the synthesis of emulsion‐based nanocomposites for coating and adhesive applications and addresses the principles and techniques for nanoparticle dispersions and their inclusion into polymer latexes. The effects of nanoparticle shape and size on the enhancement of nanocomposite properties are also highlighted. Among the reinforcing nanoparticles such as nanoclays, carbon nanotubes, and cellulose nanocrystals (CNCs), CNCs are promising due to their abundance, nontoxicity, and accessible surface hydroxyl groups, which facilitate their compatibility with polymer latexes via physical and chemical treatments.     

微波合成氧化锌纳米棒聚集体

以草酸锌和碳酸钠的水溶液为前驱体溶液,微波低火辐射10 min,成功制备出结晶性好的氧化锌纳米棒聚集体(1),其结构和形貌经X-射线衍射、选区成份分析和场发射扫描电子显微镜表征.结果表明,1结晶性好,平均直径60 nm,长度在300 nm～400 nm,沿着c轴择优取向生长.对生长过程进行了分析.     

基于纳米ZnO的白光LED

白光发光二极管被誉为第4代照明光源。ZnO纳米结构因含有大量本征和/或非本征缺陷使其除出现在紫外区域的带边发射外还能产生覆盖400-700 nm可见光范围的深能级发光,从而可用于白光LED。本文系统地介绍了将ZnO纳米结构应用于白光LED的几种器件构造,并评述了各自的性能特点和研究进展。因为直接基于ZnO纳米结构电致发光的白光LED需要施加较高的偏压,所以将ZnO纳米结构与p型半导体复合制成异质结成为了研究的热点。ZnO纳米结构的制备方法和形貌特性会影响白光LED性能,对ZnO纳米结构进行掺杂是提升性能的重要手段。此外,将ZnO纳米材料和聚合物的优点集于一体的ZnO/聚合物异质结构也在白光LED中具有广阔的发展空间。最后,指出了纳米ZnO在白光LED应用中存在的问题和今后的发展方向。     

纳米氧化锌的标准摩尔生成焓

采用微乳液-水热辅助法合成了尺寸、形貌均匀的ZnO纳米棒,其长度约400 nm,直径约50 nm。基于将纳米ZnO与块体ZnO的标准摩尔生成焓相关联,依据热力学势函数法设计热化学循环,获得了纳米ZnO与块体ZnO标准摩尔生成焓的关系。结合微量热技术求算出了下所制备的ZnO纳米棒在298.15 K下的标准摩尔生成焓为(-331.70±0.42)kJ.mol-1。     

海水电解Ru-Ti-Ir-Sn氧化物阳极涂层研究

应用热分解法制备不同组分的Ru-Ti-Ir-Sn氧化物阳极涂层,并由SEM、EDX、强化电解寿命、电流效率、抗Mn2+污染、极化曲线和循环伏安等实验方法研究该Ru-Ti-Ir-Sn氧化物阳极涂层的物理性能和电化学性能.结果表明,优化配方的Ru-Ti-Ir-Sn氧化物阳极涂层对电解海水具有较好的综合性能.     

Sol-Gel Derived Calcium Phosphate Coatings for Biomedical Applications

Hydroxyapatite (HA) coatings have received considerable attention because they exhibit bone bonding capabilities. Unfortunately the common forms of coating production result in cracking and degradation of HA due to the thickness of the coatings and the elevated temperatures employed. This study demonstrates the production of sub-micron, crack-free calcium phosphate coatings on quartz glass substrates using a sol-gel dip-coating technique and firing temperatures below 1000°C.Coatings fired at 1000°C comprised a mixture of hydroxyapatite (HA) and tricalcium phosphate (TCP). XPS analysis of the coating surface showed that the Ca/P ratio lay in the range 1.5–1.67, and that there was a contribution from carbon in the form of carbonate.It is proposed that the sol-gel coatings comprising a resorbable (TCP) and an insoluble (HA) phase have potential benefits in certain implant applications.     

掺铟氧化锌纳米盘的制备、结构及性质研究

热蒸发Zn、In₂O₃和C粉混合物, 在没有催化剂的条件下制备出掺铟氧化锌纳米盘. 纳米盘呈六边形或十二边形, 均是结晶完好的纤锌矿结构的单晶, 对角线长度约1~3 μm , 厚度40~100 nm. 纳米盘的生长是由自催化固-液-气(V-L-S)机理控制, 在实验条件下Zn和In的液滴抑制纳米盘 [0001]方向的生长. EDS分析表明, 六边形纳米盘和十二边形纳米盘中In的含量相近, 约为2.2%. 室温光致发光谱显示掺杂后的紫外发射峰位稍有蓝移, 同时半高宽(HWHM)变大, 没有观察到绿光发射峰位.     

气相色谱法测定溶剂型木器涂料中异佛尔酮含量

建立一种快速测定溶剂型木器涂料中异佛尔酮含量的气相色谱法。样品经乙酸乙酯提取,采用Rtx–1701毛细管色谱柱分离后,以十四烷作内标物,内标法定量。该方法中异佛尔酮质量浓度在10~200 mg/L范围内呈良好的线性关系,相关系数r=0.999 98,方法检出限为10 mg/kg。样品平均加标回收率为92.2%~97.1%,测定结果的相对标准偏差为0.13%~1.25%(n=6)。该方法能有效地对溶剂型木器涂料中异佛尔酮进行定性、定量分析,而且具有简单、快速、准确、检出限低等特点,能满足实验要求。     

First-principles Study on Neutral Nitrogen Impurities in Zinc Oxide

The atomic geometries, electronic structures, and formation energies of neutral nitrogen im-purities in ZnO have been investigated by first-principles calculations. The nitrogen impuri-ties are always deep acceptors, thus having no contributions to p-type conductivity. Among all the neutral nitrogen impurities, nitrogen substituting on an oxygen site has the lowest formation energy and the shallowest acceptor level, while nitrogen substituting on a zinc site has the second-lowest formation energy in oxygen-rich conditions. Nitrogen interstitials are unstable at the tetrahedral site and spontaneously relax into a kick-out configuration. Though nitrogen may occupy the octahedral site, the concentrations will be low for the high formation energy. The charge density distributions in various doping cases are discussed, and self-consistent results are obtained.     

甲醇在氧化锌表面吸附的研究

摘要用原位红外和脉冲实验研究了甲醇在氧化锌表面的吸附行为. FTIR结果表明, 甲醇吸附于氧化锌上易生成甲氧基, 且其生成量随着吸附温度的提高而增加. 进一步的研究结果表明, 甲氧基是由甲醇同氧化锌表面的羟基反应生成的, 将其暴露于水蒸汽中后很快消失. 脉冲实验发现, 氧化锌上脉冲甲醇时产生水, 再脉冲水则产生甲醇. 因此甲醇在氧化锌表面吸附生成甲氧基和水的反应是可逆的.     

Characterization of Tin Oxide Based Sol-Gel Coatings on Borosilicate Glasses by X-Ray Reflectivity

The X-ray reflectivity technique was applied in the study of tin oxide films deposited by sol-gel dip-coating on borosilicate glasses. The influence of the withdrawal speed and temperature of thermal treatment on the film structure was analyzed. We have compared the thermal evolution of the density and the shrinkage of the films with these properties measured for the monolithic xerogel by helium picnometry and thermomechanical analysis. In agreement with the Landau-Levich model, the layer thickness increases by increasing the withdrawal speed. Nevertheless, it decreases with the increase of the thermal treatment temperature, due to the densification process. The values of apparent density are smaller than the skeletal density, which shows that the films are porous. The comparison between the film and the monolith indicates that shrinkage during firing is anisotropic, occurring essentially perpendicular to the coating surface.     

氧化锌薄膜的电化学沉积和表征

以透明导电玻璃(TCO)为衬底，用硝酸锌水溶液作为电解液，研究了阴极还原沉积ZnO薄膜的反应机理和电化学行为. 通过改变工艺条件来控制ZnO的生长速率， 得到了粒径为10～15 nm的纳米ZnO薄膜. XRD分析显示纳米ZnO薄膜纯度高， 呈纤锌矿结构. 光学测试结果表明，在可见光区其透光度高达90%，禁带宽度为3.37 eV.     

Transparent Aluminium Oxide Coatings of Polymer Brushes

A novel method for the preparation of transparent Al₂O₃ coatings of polymers is presented. An environmental‐friendly sol–gel method is employed, which implies mild conditions and low costs. A thermoresponsive brush is chosen as a model surface. X‐ray photoelectron spectroscopy is used to characterize the samples during the conversion of the precursor Al(OH)₃ into oxide and to prove the mildness of the protocol. The study evidences a relation between lateral homogeneity of alumina and the wettability of the polymer surface by the precursor solution, while morphology and elasticity are dominated by the polymer properties. The study of the swelling behavior of the underneath brush reveals the absence of water uptake, proving the impermeability of the alumina layer. The broad chemical and structural variety of polymers, combined with the robustness of transparent alumina films, makes these composites promising as biomedical implants, protective sheets and components for electric and optical devices.     

Comparative Studies on Degradation of Methyl Orange by Nanostructured Zinc and Zinc Oxide Films

Nanostructured zinc and zinc oxide films were prepared by magnetron sputtering processes and succeeded air annealing treatments. Comparison of reductive degradation rate of methyl orange (MO) by zinc films and photocatalytic degradation rate of MO by zinc oxide films was carried out. Both reductive degradation and photocatalytic degradation process of MO by zinc and zinc oxide films can be described by first order kinetic model. It was found that although MO liquid was most quickly decolorized by metallic zinc films, the mineraliza-tion of MO was not thorough. Observation of extra ultraviolet absorption peaks indicated the formation of aromatic intermediates. On the other hand, although the photocatalytic degradation rate of MO liquid by ZnO films was only as about 1/4 large as the reductive degradation rate by zinc films, no signs of aromatic intermediates were found. Moreover, it was found that partially oxidized zinc oxide film showed higher photocatalytic efficiency than the totally oxidized ZnO films. Synergy effect between zinc and zinc oxide phase in the partially oxidized films was considered to be responsible for the higher photocatalytic efficiency.     

溶液法制备的氧化锌多层膜及其场效应性质(英文)

通过旋涂法,采用不同浓度的前躯体制备了氧化锌多层膜,并制备了基于此多层膜的薄膜晶体管器件.实验证明,基于按照氧化锌前躯体浓度顺序为0.25、0.10和0.05 mol.L-1依次旋涂前躯体溶液制备的氧化锌薄膜的晶体管器件的载流子迁移率为0.02 cm.2V-.1s-1,高于按照浓度顺序为0.05、0.10和0.25 mol.L-1依次旋涂前躯体溶液制备的氧化锌薄膜的载流子迁移率(0.013 cm2.V-.1s-1).原子力显微镜(AFM)结果表明,前一种薄膜粗糙度的均方根值(rms)为3.95 nm,而后一种薄膜粗糙度的rms远远高于前者,为4.52 nm,这就说明了氧化锌薄膜的粗糙度对薄膜的半导体性质有很大的影响,这是由于平整的薄膜有利于形成理想的源/漏电极与半导体层的接触.在晶体管中,起传输作用的半导体层是靠近ZnO/SiO2界面处的几纳米的半导体层中的氧化锌晶粒,因此起始形成的氧化锌薄膜的结晶度影响着晶体管的性能.采用X射线衍射(XRD)测试了多层膜中起始形成的薄膜的结晶性能.对于前一种薄膜,起始形成的薄膜为多晶薄膜,而对于后一种薄膜,起始形成的薄膜是无定形薄膜.因此,粗糙度以及起始形成的薄膜的结晶度影响着多层半导体薄膜的性质.     

Pr6O11对ZnO压敏材料显微结构的影响

研究了在ZnO压敏材料组分中以溶液方式加入稀土氧化物Pr6O11后其微观结构的变化。结果表明，Pr6O11的加入改变了ZnO尖晶石相的生成途径，使该材料在低于700℃时生成大量焦绿石相（Bi3Zn2Sb3O14）。当烧成温度高于900℃时，焦绿石相分解生成细小的二次尖晶石相（Zn7Sb2O12）。这种二次生成的细小尖晶石使材料晶粒尺寸减小，分布均匀；此外，Pr6O11的引入能生成含Pr物相，以及Pr氧化物相也有利于材料的晶粒细化。晶粒细化结果改善了ZnO压敏材料的压敏电压和非线性特性，与掺杂前相比，压敏电压提高了约60％。     

Influence of the Layer Morphology on the Electrical Properties of Sol Gel Transparent Conducting Oxide Coatings

Tranparent conducting coatings have been prepared by sol gel methods either by a conventional sol-gel process (Antimony doped Tin Oxide—ATO, Aluminium doped Zinc Oxide—AZO) or a new wet chemical process using fully dispersed crystalline nanoparticles (ATO, Indium Tin Oxide—ITO). The dip coating technique has been used as deposition technique with single coating thickness varying from a few nanometer to ca. 400 nm. The layers have been fired in a furnace. Structural properties have been determined by x-ray diffraction and TEM analysis and the electrical properties by the van der Pauw/Hall measurement. Three different coating procedures have been used to investigate the effect on the structure, morphology and the electrical properties of the coatings. It is shown that the individual layer thickness in multilayer coatings influences dramatically the mentioned properties. Very thin individual layers favour a heterogeneous nucleation with dense columnar growth of the crystallites leading to low electrical resistivity ( 10^–3 cm), while thick individual layers result in a porous morphology made of small crystallites leading to resistivities in the 10^–2 cm range.     

涂液浓度对Ru-Ti-Ir氧化物阳极涂层性能的影响

应用热分解法制备了由不同浓度涂液形成的Ru-Ti-Ir氧化物阳极涂层,SEM,EDX,XRD、强化电解寿命、极化曲线、循环伏安和电化学阻抗等测试表明,涂液浓度对阳极涂层的表面形貌有着很大的影响,但不甚影响其析氯极化过程.随着涂液浓度的增加,阳极涂层的伏安电量和双电层电容都出现先降低后增加的变化趋势.