TiO_2/CdSe纳晶复合薄膜电极的制备及表征

研究了CdSc敏化TiO_2纳晶多孔薄膜电极的制备及其表征,采用化学沉积法在TiO_2纳晶薄膜电极表面制备了窄带隙纳米微粒CdSe,对丝网印刷制备的TiO_2纳晶薄膜电极进行敏化处理,制备了TiO_2/CdSe纳晶复合薄膜电板;同时利用XRD、SEM、TEM、XPS对TiO_2/CASe复合薄膜电极的晶型、粒径、元素组成和表面结合态进行了表征分析.     

阳极氧化电压对钛合金TC4阳极氧化TiO_2膜层表面的影响

在草酸盐、硅酸盐和磷酸盐电解液体系中,在钛合金Ti-6Al-4V(TC4)表面制备阳极氧化TiO_2膜层,研究了TiO_2膜层的表面显微结构、化学组成和生物活性。在室温用恒压阳极氧化法制备TC4表面阳极氧化TiO_2膜,以TC4为阳极,不锈钢为阴极,电解液组成为:20 g/L的Na_2C_2O_4、10 g/L的Na_2SiO_3·9H_2O、9.25 g/L的NaH_2PO_4和2 g/L的NaOH,阳极氧化电压为10-120 V,氧化时间50 min,电源频率200 Hz。用XRD、AFM、SEM及XPS等手段分别测量了膜层的物相、三维形貌、氧化膜层表面的显微结构及化学组成。结果表明:氧化电压对TiO_2膜层的物相组成基本没有影响,氧化膜层呈非晶态TiO_2。当氧化电压为30 V时,TiO_2膜层表面由孔径1.3μm左右的孔和凸起颗粒组成的粗糙结构,随着氧化电压增加表面凸起颗粒逐渐减少,粗糙度降低,当氧化电压为100 V时场致溶解的作用使TiO_2膜层表面凸起颗粒不明显,TiO_2膜层表面的粗糙度低于TC4基体,表面孔径为240 nm。TC4阳极氧化TiO_2膜层表面的微纳米结构和大量的羟基—OH,有利于提高TiO_2膜层的生物活性和骨生长特性。     

TiO2薄膜的自组装及其光电性能研究

采用蒸发诱导自组装方法,在导电玻璃基体上制备了具有高热稳定性、高比表面积的TiO_2薄膜。运用扫描电子显微镜、X射线衍射分析仪对TiO_2薄膜的形貌和结构进行了分析,表明制备出的纳米晶TiO_2薄膜具有多孔的锐钛矿结构,晶粒平均尺寸d为29.2nm。以D102染料敏化的TiO_2薄膜为阳极,0.3mol/L KI溶液为电解液,铂电极为阴极,组成太阳能电池,通过电流-电压曲线研究了太阳能电池的性能。结果表明:太阳能电池的J短路为17.80mA·cm-2,U开路为0.60V,填充因子FF为0.54,光电转换效率为0.39%。     

Cu-Ti合金与H_2O_2直接氧化法制备Cu掺杂TiO_2薄膜EI北大核心CSCD

以Cu-Ti合金为基体,采用含H_2O_2溶液直接氧化法制备Cu掺杂TiO_2薄膜,利用扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)对薄膜形貌、化学成分和相组成进行分析。结果表明:所制薄膜通过溶解-沉积机理形成,合金表面先沉积Cu掺杂的非晶态TiO_2薄膜,经空气中450℃热处理1h获得Cu掺杂的锐钛矿型晶态TiO_2薄膜。含H_2O_2溶液中需加入一定量聚碳酸酯或聚乙烯乙酸酯,以促进非晶态TiO_2在合金表面的沉积。所制薄膜对罗丹明B具有优异的光催化降解作用,在12W紫外光下照射4h后,Cu_(30)Ti_(70)合金表面形成的薄膜对罗丹明B溶液(20mg/L)的降解率达到31.7%。     

用Ti板制备高比表面积TiO_2纳米管的响应面实验设计

本工作采用Ti板和Al箔为原料,通过阳极氧化法制备了高比表面积的TiO_2纳米管;介绍一种制备高比表面积纳米管的实验设计方法,通过控制氧化电压和离子液浓度的全因子实验设计拟合了模型参数,得出当氧化电压和乙二醇及氟化铵混合离子液浓度分别为70 V和9.25 g/L时,制得的TiO_2纳米管薄膜的比表面积最大,为51.165 m~2/g。然后根据拟合模型进行了响应曲面设计,将纳米管薄膜的比表面积增大了3.1倍,为211.125 m~2/g,并得出在纳米管壁上长出的微小颗粒的粒径为1～10 nm,这与大自然树干、树枝的垂直结构是一致的。     

微波烧结TiC/Ti6Al4V复合材料的高温氧化行为

采用微波烧结法制备TiC/Ti6Al4V复合材料,研究TiC/Ti6Al4V复合材料在550、650和750℃空气中的恒温氧化行为,并对氧化膜的表面、截面形貌及相组成进行了分析。结果表明:TiC/Ti6Al4V复合材料由TiC、ɑ-Ti+β-Ti三种物相组成。随着氧化温度的增加,TiC/Ti6Al4V复合材料的氧化规律由抛物线型转变为直线型,在650℃温度以下,复合材料的氧化产物主要由TiO_2组成,而750℃时氧化层主要有外层极薄的TiO_2、中间层Al_2O_3和TiO_2混合区及大部分内层TiO_2三部分组成。随着TiC含量增加,氧化激活能增大,氧化物粒径减小,TiC/Ti6Al4V复合材料的抗氧化性能也越好。     

电沉积-热解法制备Cr2O3薄膜及其抗高温氧化性能

Cr2O3薄膜具有保护性,采用电沉积-热解法制备还未见报道.采用电沉积-热解法在304不锈钢表面制备Cr2O3薄膜,并将其于900℃高温氧化100 h,研究了电沉积溶液[Cr(NO3)3酒精]浓度、沉积电压对Cr2O3薄膜抗高温氧化性能的影响,分析高温氧化样的组织结构.结果表明:电沉积-热解法制备的Cr2O3薄膜显著提高了304不锈钢的抗高温氧化性能;沉积电压为25 V,电沉积溶液浓度为0.10 mol/L条件下制备的Cr2O3薄膜抗高温氧化性能最佳.     

Al2O3/TiO2复合光催化薄膜的制备、表征及性能研究

近年来,二氧化钛光催化技术正成为光化学、能源、环境以及材料等领域的研究热点。作为一种新型的环境净化材料,TiO_2光催化剂可广泛应用于污水处理、空气净化、抗菌除臭、表面防污、自清洁等方面,目前,TiO_2光催化剂的固定化及其光催化活性的改善是 TiO_2光催化材料设计、开发和应用中急需解决的问题。本文利用阳极氧化和电沉积技术,在铝合金表面成功地制备出具有较好光催化活性的 Al_2O_3/TiO_2复合薄膜。系统研究了复合薄膜的制备工艺;表征了复合薄膜的形貌、结构、成分以及光谱特性;详细分析了复合薄膜的光催化性能,并对这种特殊的复合薄膜形成机理进行了探讨。研究结果表明:电沉积液温度在薄膜制备过程中是最重要的影响因素,合理地控制沉积过程中的工艺参数可得到具有最佳表面质量和光催化性能的 Al_2O_3/TiO_2复合薄膜,H_2SO_4-Al_2O_3/TiO_2复合薄膜经热处理,表面有锐钛矿结构 TiO_2生成,TiO_2的晶粒尺寸在纳米量级;TiO_2在加热过程中主要发生表面吸附水和吸附有机物的脱附、结晶水的失去及非晶相的晶化三种变化,且 TiO_2由无定形结构向锐钛矿晶体结构转变的温度为425℃左右;三种类型 Al_2O_3/TiO_2复合薄膜的表面形貌存在较大差异,这主要归因于三种铝阳极氧化膜的膜厚及表面微孔结构的不同;三种类型的复合薄膜均具有紫外光光催化活性;通过 Fe 离子掺杂改性以及萘酚蓝黑染料敏化处理后,复合薄膜的光催化性能可得到明显地改善;由薄膜形成机理的分析可知,TiO_2主要通过交流电沉积过程中的阴极反应沉积于铝阳极氧化膜微孔处和表面上。     

退火对TiO_2磁控溅射薄膜结构和光催化活性的影响

采用磁控反应溅射制备了纯TiO_2薄膜和Fe掺杂的TiO_2薄膜,研究了退火对2种TiO_2薄膜结构和光催化活性的影响.退火前TiO_2薄膜与基体结合良好,退火后薄膜发生了开裂,薄膜与基体的结合变差.TiO_2薄膜在700℃以下退火后仍保持着锐钛矿型晶体结构,但衍射峰的强度有明显的增强,说明组成薄膜的晶粒在退火过程中长大;当退火温度高于800℃时,发生了从锐钛矿向金红石型的转变.退火后TiO_2薄膜的紫外可见光透射率有较大辐度的下降;甲基橙溶液的光催化降解速率随着退火温度升高而下降.     

TiO_2纳米薄膜杀菌效果

以TiCl_4的乙醇溶液作为前驱体,采用溶胶-凝胶法制备TiO_2溶胶,用浸渍-提拉法在载玻片表面制成了具有抗菌作用的TiO_2薄膜以及铁掺杂TiO_2薄膜,考察了原菌液浓度、镀膜次数以及铁掺杂量对薄膜对大肠杆菌的抗菌性能的影响。     

Fast fabrication of long TiO2 nanotube array with high photoelectrochemical property on flexible stainless steel

Oriented highly ordered long TiO2 nanotube array films with nanopore structure and high photoelectrochemical property were fabricated on flexible stainless steel substrate (50 microm) by anodization treatment of titanium thin films in a short time. The samples were characterized by means of field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and photoelectrochemical methods, respectively. The results showed that Ti films deposited at the condition of 0.7 Pa Ar pressure and 96 W sputtering power at room temperature was uniform and dense with good homogeneity and high crystallinity. The voltage and the anodization time both played significant roles in the formation of TiO2 nanopore-nanotube array film. The optimal voltage was 60 V and the anodization time is less than 30 min by anodizing Ti films in ethylene glycerol containing 0.5% (w) NH4F and 3% (w) H2O. The growth rate of TiO2 nanotube array was as high as 340 nm/min. Moreover, the photocurrent-potential curves, photocurrent response curves and electrochemical impedance spectra results indicated that the TiO2 nanotube array film with the nanoporous structure exhibited a better photo-response ability and photoelectrochemical performance than the ordinary TiO2 nanotube array film. The reason is that the nanoporous structure on the surface of the nanotube array can separate the photo electron-hole pairs more efficiently and completely than the tubular structure.     

Improvement in performances of dye-sensitized solar cell with SiO2-coated TiO2 photoelectrode

The pure TiO2 and the nano-porous SiO2-coated TiO2 (STO) films were deposited on the FTO substrates by spray technique for the application of dye-sensitized solar cells (DSSCs). XRD pattern shows the pure TiO2 and STO films exhibits the same structure. We found that there is no much difference in dye absorption between the STO and the pure TiO2 films. The electrochemical impedance spectra reveal that insulating nature of the porous SiO2 increases surface resistance of the TiO2 film and supresses back transfer of the photogenerated electrons to the electrolyte. The field-emission scanning electron microscopy (FE-SEM) and energy dispersion X-ray spectroscopy (EDS) reveal that the surface morphology and the existence of SiO2 layer on the surface of the TiO2 films, respectively. The photoelectrochemical results show that the short-circuit photocurrent (J(SC)) increased from 16.73 mA cm(-2) to 18.31 mA cm(-2) and the open-circuit voltage (V(OC)) value changed from 0.71 V to 0.74 V for the STO films. The efficiency of cell has been greatly improved from 8.25 to 9.3%.     

染料敏化太阳能电池中CuO/TiO2薄膜制备及应用

采用普通直流电沉积和超声直流电沉积制备Cu∕TiO2纳米管阵列∕Ti基复合薄膜,而后在NaOH溶液中用电氧化的方法将Cu单质氧化成CuO,制备了CuO∕TiO2纳米管阵列∕Ti基复合薄膜。利用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对两种复合薄膜电极的形貌和结构进行了表征,详细考察了电镀工艺参数(电流密度)和超声波对复合薄膜形貌的影响。同时通过稳态光电响应技术对复合薄膜电极组成的染料敏华太阳能电池(DSSC)的光电性能进行了研究,结果表明:通过普通直流电沉积在工艺参数(3mA/cm2、5min)处制备的复合薄膜组装的DSSC具有该体系下的最佳光电性能(Jsc=9.00mA/cm2、Voc=0.664V、FF=0.512、η=3.06%);在同等条件下通过超声辅助直流电沉积制备的复合薄膜组装的DSSC的最佳光电性能(Jsc=15.50mA/cm2、Voc=0.688V、FF=0.505、η=5.39%)出现在工艺参数为(6mA/cm2、5min)处。对比可知超声条件下的光电性能较好,且最佳光电性能工艺参数发生了后移。     

Characterization of Sol-gel-derived TiO2 and TiO2-SiO2 Films for Biomedical Applications

In order to improve the corrosion resistance and biocompatibility of NiTi surgical alloy, TiO2 and TiO2-SiO2 thin films were prepared by sol-gel method. The surface characteristics of the film, which include surface composition, microstructure and surface morphology, were studied by X-ray diffraction (XRD), atomic force microscopy (AFM) and X-ray photoelectron spectra (XPS), respectively. A scratching test was used to assess the interface adhesive strength between the film and substrate. The corrosion resistance of NiTi alloy coated with oxide films were studied by anodic polarization curves measurement in biological solution. Additionally, a preliminary study of the in vitro bioactivity of the films was conducted. The results indicated that TiO2 and TiO2-SiO2 (Ti/Si=4:1) films have higher electrochemical corrosion resistance and can be used as protective layers on NiTi alloy. In addition, TiO2-SiO2 composite films have better bioactivity than TiO2 film.     

聚苯乙烯和聚乙二醇对TiO2薄膜微观结构及DSSC性能的影响

用水热法制备了多孔TiO2光电薄膜;分析了聚苯乙烯和聚乙二醇对纳米TiO2晶体薄膜微观结构的影响;用紫外-可见-近红外分光光度计和场发射扫描电镜对纳米TiO2薄膜进行了表征;并对组装的染料敏化太阳能电池进行了光电性能测试,发现用聚苯乙烯处理后的TiO2薄膜提高了染料敏化太阳能电池(DSSC)的开路电压、短路电流密度、填充因子和光电转换效率.     

Fabrication and characterization of epitaxial Ba<Subscript>0.6</Subscript>Sr<Subscript>0.4</Subscript>TiO<Subscript>3</Subscript>/LaNiO<Subscript>3 </Subscript>heterostructures

Epitaxial Ba0.6Sr0.4TiO3 (BST)/LaNiO3 (LNO) heterostructures were fabricated on LAO (100) substrates using pulsed laser deposition (PLD). Their structural properties were investigated by X-ray diffraction (XRD). The θ–2θ scans showed single crystalline BST and LNO layers with a (100) orientations perpendicular to the substrate plane. Phi scans (ϕ) on the (220) plane of BST layer indicated that the films have two in-plane orientations with respect to the substrate. The atomic force microscope (AFM) surface morphologies showed a smooth and crack-free surface with the average grain size of 55 nm and the root-mean-square (RMS) of 4.53 nm for BST films. Capacitance–voltage curves are measured. From the capacitance, a dielectric constant of 762, tunabilty of 82.81% and loss tangent of 0.032 are obtained. The current–voltage curve shows that the leakage current is 2.41 × 10⁻⁷ A/cm² under an applied voltage of 2 V.     

Investigation of exciton photodissociation, charge transport and photovoltaic response of poly(N-vinyl carbazole):TiO(2) nanocomposites for solar cell applications

The photogeneration of charge carriers in spin-coated thin films of nanocrystalline (nc-)TiO(2) particles dispersed in a semiconducting polymer, poly(N-vinylcarbazole) (PVK), has been studied by photoluminescence and charge transport measurements. The solvent and the TiO(2) particle concentration have been selected to optimize the composite morphology. A large number of small domains leading to a large interface and an improved exciton dissociation could be obtained with tetrahydrofuran (THF). The charge transport mechanism and trap distribution at low and high voltage in ITO/nc-TiO(2):PVK/Al diodes in the dark could be identified by current-voltage measurements and impedance spectroscopy. The transport mechanism is space charge limited with an exponential trap distribution in the high voltage regime (1-4?V), whereas a Schottky process with a barrier height of about 0.9?eV is observed at low bias voltages (<1?V). The current-voltage characteristics under white illumination have shown a dramatic increase of the short circuit current density J(sc) and open circuit voltage V(oc) for a 30% TiO(2) volume content corresponding to the morphology exhibiting the best dispersion of TiO(2) particles. A degradation of the photovoltaic properties is induced at higher compositions by the formation of larger TiO(2) aggregates. A procedure has been developed to extract the physical parameters from the J-V characteristics in the dark and under illumination on the basis of an equivalent circuit. The variation of the solar cell parameters with the TiO(2) composition confirms that the photovoltaic response is optimum for 30% TiO(2) volume content. It is concluded that the photovoltaic properties of nc-TiO(2):PVK nanocomposites are controlled by the interfacial area between the donor and the acceptor material and are limited by the dispersion of the TiO(2) nanoparticles in the polymer.     

Low-temperature Preparation of Photocatalytic TiO2 Thin Films on Polymer Substrates by Direct Deposition from Anatase Sol

Anatase TiO2 sol was synthesized under mild conditions （75℃ and ambient pressure） by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution and subsequent reflux to enhance crystallization. At room temperature and in ambient atmosphere, crystalline TiO2 thin films were deposited on polymethylmethacrylate （PMMA）, SiO2-coated PMMA and SiO2-coated silicone rubber substrates from the as-prepared TiO2 sol by a dip-coating process. SiO2 layers prior to TiO2 thin films on polymer substrates could not only protect the substrates from the photocatalytic decomposition of the TiO2 thin films but also enhance the adhesion of the TiO2 thin films to the substrates. Field-emission type scanning electron microscope （FE-SEM） investigations revealed that the average particle sizes of the nanoparticles composing the TiO2 thin films were about 35-47 nm. The TiO2 thin films exhibited high photocatalytic activities in the degradation of reactive brilliant red dye X-3B in aqueous solution under aerated conditions. The preparation process of photocatalytic TiO2 thin films on the polymer substrates was quite simple and a low temperature route.     

V_2O_5-TiO_2离子存储电极薄膜的溶胶-凝胶法制备与性能研究

利用无机溶胶-凝胶技术制备了V2O5-(TiO2)x离子存储电极薄膜。采用X射线衍射(XRD)、原子力显微镜(AFM)、Raman光谱、循环伏安法(CV)和紫外-可见光透射光谱分别研究了复合薄膜的微观结构、化学计量、锂离子注入性能以及光学性能。结果表明复合薄膜具有V2O5的层状结构,其c轴方向的结构取向性有所降低;颗粒尺寸和表面粗糙度显著减小;同时TiO2的复合导致薄膜中V2O5的化学计量发生偏移,氧空位数量增多。当x=0.2时,薄膜具有相对较高的离子存储容量及循环稳定性,并且在离子注入/脱出状态均获得相当高的可见光透过性。     

有序多孔结构二氧化钛薄膜的制备和应用

本文探讨了一种制备二氧化钛高度有序多孔结构的方法及其在染料敏化太阳电池中的应用。采用聚苯乙烯悬浮液,采取垂直沉积法得到了聚苯乙烯胶体晶体;以该模板制备了高度有序的纳米二氧化钛反蛋白石多孔薄膜。对胶体晶体模板和二氧化钛反蛋白石有序膜的微观结构进行表征和讨论。用所制得的二氧化钛反蛋白石有序膜组装成染料敏化太阳电池。通过电流...