低含量铁掺杂纳米TiO2薄膜的制备及其抗菌机理研究

采用溶胶凝胶-浸渍提拉法,制备了玻璃基底上生长的Fe/TiO₂薄膜.利用XRD、XPS、AFM等对样品进行表征,研究了铁掺杂对TiO₂薄膜晶体结构和表面形貌的影响,并研究了不同掺铁量TiO₂薄膜对大肠杆菌的抗菌性能.结果表明,铁掺杂TiO₂薄膜的抗菌性能均优于纯TiO₂薄膜,其中掺铁量为0.1%时薄膜的抗菌性能最佳,高达98%.     

Sb2S3纳米粒子修饰ZnO纳米片微纳分级结构的光电化学性能

采用恒电位方法,选择氯化钾和乙二胺(EDA)为添加剂,在氧化铟锡(ITO)导电玻璃上制备了高度有序的ZnO纳米片阵列,通过二次电沉积得到了ZnO纳米片上生长纳米棒的微纳分级结构.利用化学浴沉积法在ZnO基底上沉积Sb₂S₃纳米粒子制备出了Sb₂S₃/ZnO纳米片壳核结构和Sb₂S₃/ZnO微纳分级壳核结构.利用扫描电子显微镜(SEM)、X射线衍射(XRD)、紫外-可见(UV-Vis)吸收光谱、瞬态光电流等对其形貌、结构组成和光电化学性能进行了表征和分析.结果表明, Sb₂S₃/ZnO纳米片上生长纳米棒分级壳核结构的光电流明显高于Sb₂S₃/ZnO纳米片壳核结构.在Sb₂S₃/ZnO纳米片壳核结构和Sb₂S₃/ZnO微纳分级壳核结构的基础上旋涂一层P3HT薄膜形成P3HT/Sb₂S₃/ZnO复合结构,以上述复合结构薄膜为光活性层组装成杂化太阳电池,其中, P3HT/Sb₂S₃/ZnO分级壳核结构杂化太阳电池的能量转换效率最高,达到了0.81%.     

苯基硅氧烷改性TiO2在聚苯硫醚抗紫外中的性能研究

首先以苯基三乙氧基硅烷（PTES）为改性剂,采用凝胶-溶胶法对金红石型TiO₂进行表面化学修饰,制备了抗紫外TiO₂/PTES纳米粒子.然后通过对TiO₂/PTES纳米粒子的系统表征,发现PTES的载入显著地抑制了TiO₂的光催化性能.最后将抗紫外性能优异的TiO₂/PTES-2纳米粒子以不同比例加入PPS中,制备了PPS复合薄膜,探讨了纳米粒子的添加对PPS抗紫外老化性能的影响.结果表明,当TiO₂/PTES-2纳米粒子的添加量为2.0 wt%时,PPS抗紫外性能达到最佳,即TiO₂/PTES-2/PPS复合薄膜紫外辐射192 h后的断裂强度保留率和断裂伸长保留率分别为93.75%和94.00%.     

基于多层二硒化钨的高性能场效应晶体管的实验优化和理论模拟

采用微机械剥离法制备了基于不同厚度的高质量WSe₂纳米片的场效应晶体管(WSe₂-FETs), 研究了其性能的影响因素. 通过调控WSe₂纳米片及介电层的厚度、 测试温度及退火处理等, 结合理论模拟分析, 获得了WSe₂-FETs的最佳电学性能. 最终, 基于7层WSe₂纳米片的场效应晶体管表现出最优异的电学性能, 室温下载流子迁移率可达93.17 cm²·V^?1·s^?1; 在78 K低温下, 载流子迁移率高达482.78 cm²·V^?1·s^?1.     

基于季铵盐改性SiO2空心球的抗菌/减反增透双功能薄膜的制备和研究

兼具减反增透和抗菌性能的双功能薄膜在医疗健康领域具有很重要的应用前景.然而，关于此类薄膜的研究尚且屈指可数.本工作选取最长烷基链为C₁₈的季铵盐为抗菌剂，通过化学键合方式改性酸催化SiO₂溶胶液并与空心球纳米粒子溶胶液复合.然后，采用浸涂法制备出具备抗菌和减反增透双功能的薄膜.通过调节上述两种溶胶液的混合比例，对薄膜的光学性能进行了优化.其中，涂覆最优薄膜的玻璃基底在可见光区域内（400~800 nm）展现出优异的透光性能（T_max=99.2%，T_ave=98.6%）.该方法操作简单，无需经过高温热处理，易于大面积制备，具有潜在的应用前景.     

水热法制备Bi2O3纳米片及其电化学性能的研究

以Bi(NO₃)₃和氨水为原料、水溶性淀粉为分散剂, 采用水热法制备了Bi₂O₃纳米片, 用X射线衍射(XRD)、扫描电子显微技术(SEM)和氮气吸附-脱附等对材料进行了表征. 结果表明Bi₂O₃纳米片厚度分布比较窄, 比表面积达到9.26 m²/g. 同时, 采用循环伏安法和充放电仪测试了Bi₂O₃纳米片的电化学性能, 结果显示其具有一定的电化学活性.     

TiO2/石墨烯复合材料的光生电荷分离调控与光催化产氢性能研究

半导体光生电荷分离是光催化过程中的关键步骤之一,其效率极大地影响了最终光催化性能.将TiO₂纳米片与石墨烯复合,能够促进TiO₂中光生电子和空穴的分离,从而提高其光催化活性.为了研究光生电荷的分离对TiO₂/石墨烯复合材料光催化性能的影响,通过调控TiO₂纳米片的尺寸来调节TiO₂/石墨烯复合材料中光生电荷分离的能力,然后研究其对TiO₂/石墨烯复合材料光催化性能的影响.合成了一系列不同厚度的TiO₂纳米片,将其与石墨烯复合,并通过光沉积负载Pt纳米颗粒作为助催化剂,用于光催化产氢.实验结果显示,随着TiO₂纳米片厚度减小,其与石墨烯形成的复合结构的光催化性能显著提高.这主要是由于TiO₂纳米片厚度减小时,光生电子沿厚度方向穿过TiO₂纳米片迁移到石墨烯的距离缩短,从而减少了光生电子在迁移过程中与空穴的复合;同时TiO₂纳米片厚度减小使其比表面积增大,使得TiO₂/石墨烯界面面积增大,从而使石墨烯更好地分离出TiO₂中的光生电子,有更多的光生电子到达石墨烯参与催化反应,提高TiO₂/石墨烯复合材料的光催化性能.此研究表明通过控制TiO₂纳米片的尺寸来调控TiO₂/石墨烯复合材料中光生电子和空穴的分离,是显著提高其光催化性能的有效途径.     

纳米Au-TiO2复合薄膜的溶胶-凝胶法制备、表征和性能

用溶胶-凝胶法制备了纳米Au-TiO₂复合薄膜.X射线衍射、X射线光电子能谱、原子力显微镜、紫外-可见光谱及摩擦磨损实验研究表明,复合薄膜均匀致密,Au以纳米晶粒形式均匀、不连续分散镶嵌于TiO₂基体中,纳米Au粒径为14～25nm;复合薄膜在可见光区有较强的吸收,吸收峰位置和强度与烧结温度和金的添加量有关;复合薄膜具有良好的抗磨减摩性能,在1N负荷下,摩尔分数为5%的Au-TiO₂薄膜的摩擦系数仅为0.09～0.10,耐磨寿命多于2000滑动周次.     

Y2O3/TiO2 "核-壳"结构在染料敏化太阳电池中的应用

在纳米TiO₂多孔薄膜表面包覆超薄绝缘体,形成"核-壳"结构的势垒层,是目前染料敏化太阳电池（DSC）光阳极改性的研究热点之一.本文选取氧化钇（Y₂O₃）作为包覆层材料,采用浸渍法对纳米TiO₂多孔薄膜进行修饰,研究Y₂O₃包覆处理对TiO₂薄膜微观结构及能带结构的影响;将浸渍法制备得到的Y₂O₃/TiO₂"核-壳"结构光阳极应用于DSC中,研究了饣覆层对电子传输复合以及DSC光电转换性能的影响.结果表明,Y₂O₃包覆处理后,薄膜的平带电势负移,且电子复合得到有效抑制,电子寿命增大,电池的开路电压明显提高.研究表明,适量引入Y₂O₃可以达改善电池性能的目的.     

TiO2-PTPAT纳米核/壳结构复合膜的制备及电致变色性能

通过水热法在氟掺杂氧化锡(FTO)导电玻璃基底上制备了垂直生长的二氧化钛(TiO₂)纳米棒阵列, 以TiO₂纳米棒阵列为模板采用电化学聚合法, 原位制备了TiO₂-聚三[2-(4-噻吩)苯]胺(PTPAT)纳米核/壳结构的复合薄膜, 相比于纯PTPAT薄膜, TiO₂-PTPAT复合薄膜显示出更好的电致变色(EC)性能. PTPAT薄膜在600 nm波长下的对比度为28%, 在1100 nm波长下的对比度为60%, 其褪色时间为3.86 s, 着色时间为5.52 s; TiO₂- PTPAT复合薄膜在600 nm波长下的对比度为43%, 在1100 nm波长下的对比度为79%, 其褪色时间为3.35 s, 着色时间为4.43 s, 表明核/壳复合结构薄膜的光学对比度和响应时间性能更加优异. 将PTPAT薄膜和TiO₂-PTPAT复合薄膜作为电致变色层组装成固态EC器件, 基于复合薄膜的器件具有更好的循环稳定性和更高的耐受电压. 复合薄膜在保持PTPAT薄膜原有的EC性能的基础上, 由于有序生长的纳米阵列结构的引入增加了薄膜的比表面积, 为电致变色过程中离子的掺杂和脱掺杂提供了更多有序通道, 从而加快了离子扩散速度. TiO₂阵列的引入也改善了聚合物薄膜与透明导电电极之间的界面结合情况, 从而提升了器件的稳定性.     

Synthesis of a perpendicular TiO2 nanosheet film with the superhydrophilic property without UV irradiation

A method was developed for preparing perpendicular TiO2 nanosheet films from titanate nanosheet films produced on a titanium metal sheet by hydrothermal treatment with aqueous urea. The method is based on the consideration of some important points relating to the thermodynamics of nucleation and crystal growth. The resulting anatase TiO2 nanosheet films showed a specific superhydrophilicity without the need for any prior UV irradiation.     

Photocatalytic properties of titania nanostructured films fabricated from Titania nanosheets

We examined the photochemical properties of well-ordered multilayer films of titania nanosheets prepared on quartz-glass substrate using the layer-by-layer deposition method. The photocatalytic decomposition of gaseous 2-propanol and bleaching of Methylene Blue dye under UV light illumination were measured to evaluate the photocatalytic oxidation ability. Photoinduced hydrophilicity was also studied by measuring the contact angle of water droplets on the film. The results indicated that titania nanosheets had good photoinduced hydrophilicity. The monolayer film of titania nanosheets showed almost identical activity compared with well investigated sol-gel derived anatase TiO(2) film, while its photocatalytic oxidation activity was low by more than an order of magnitude. This fact suggests that photoinduced hydrophilicity could not be explained simply in terms of the photocatalytic removal of hydrophobic organic species adsorbed on the surface. The photocatalytic oxidation activity and the photoinduced hydrophilic conversion rate decreased with increasing number of nanosheet layers, suggesting that photogenerated carriers produced in the internal part of the multilayer films can hardly diffuse to the surface layer. Photochemical properties of ultrathin anatase films obtained simply by heating the titania nanosheet films were evaluated as well, and also revealed high photoinduced hydrophilicity.     

Unusual crystallization behaviors of anatase nanocrystallites from a molecularly thin titania nanosheet and its stacked forms: increase in nucleation temperature and oriented growth

Crystallization behaviors of anatase nanocrystallites from an ultrathin two-dimensional reactant composed of exfoliated titania nanosheets have been studied by monitoring the heating process of their well-organized films, with which the film thickness can be controlled from a molecularly thin monolayer to a stacked multilayer structure with a stepwise increment of approximately 1 nm. The heated products were identified by means of total reflection fluorescence X-ray absorption near-edge structure analysis and in-plane X-ray diffraction measurements using a synchrotron radiation source. The films composed of five or more layers of stacked nanosheets were transformed into anatase at 400-500 degrees C, which is a normal crystallization temperature of anatase from bulk reactants. As the film became thinner by decreasing the number of nanosheet layers to five or less, the crystallization temperature was found to increase and finally reached 800 degrees C for the monolayer film. Interestingly, preferential growth of anatase along the c-axis was strongly promoted for these ultrathin films. These unusual behaviors may be understood in terms of crystallization from the two-dimensional system of scarcely distributed reactants. The titania nanosheet crystallite is much thinner than the unit cell dimensions of anatase, and therefore, extensive atomic diffusion is required for the transformation particularly for the ultrathin films with a critical number (2-3) of stacked nanosheet layers. There is some structural similarity between anatase and titania nanosheet, which may account for the oriented growth of anatase nanocrystallites.     

Chemical Vapor Deposition of FeOCl Nanosheet Arrays and Their Conversion to Porous α‐Fe2O3 Photoanodes for Photoelectrochemical Water Splitting

FeOCl nanosheet arrays were deposited on fluorine‐doped tin oxide glass substrates through a chemical vapor deposition method and further converted to hematite porous nanosheet arrays. A much enhanced photocurrent was obtained for such hematite films, which was three times higher than that of a planar hematite film at 1.23 V versus a reversible hydrogen reference electrode.     

Double-layered TiO2-SiO2 nanostructured films with self-cleaning and antireflective properties

Dual function of self-cleaning and antireflection can be created in double-layered TiO2-SiO2 nanostructured films. The film were prepared by (1) layer-by-layer deposition of multilayered SiO2 nanoparticles with polydiallyldimethylammonium (PDDA) cations, (2) layer-by-layer deposition of multilayered titanate nanosheets with polications on PDDA/SiO2 multilayer films, and (3) burning out the polymer and converting titanate nanosheets into TiO2 by hearing at 500 degrees C. The as-prepared films, consisting of a porous SiO2 bottom layer and a dense TiO2 top layer, improved the transmittance of glass or quartz substrates, as demonstrated by transmission spectra collected at normal incidence. The photocatalytic properties of the films were studied by the change of the water contact angle together with the decay of the IR absorption of the hydrocarbon chain of octadecylphosphonic-acid-modified films under 2.6 mW cm-2 UV illumination. Both the antireflective and the photocatalytic properties of the films were dependent on the number of PDDA/nanosheet bilayers deposited. however, excellent surface wettability of the films for water was obtained, independent of the preparation conditions. The experimental findings are discussed in terms of the special structure of the double-layered nanostructured film.     

Photoelectrochemical properties of alternating multilayer films composed of titania nanosheets and Zn porphyrin

Alternating multilayer films composed of titania nanosheets and Zn porphyrins were prepared by use of a previously reported Langmuir-Blodgett film-transfer method in order to fabricate photoelectrochemical devices. Closely packed titania nanosheet monolayers on indium tin oxide (ITO), mica, and quartz surfaces strongly adsorbed cationic [5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrinatozinc]4+ (ZnTMPyP4+) by electrostatic interactions. The alternating deposition process afforded nanometer-scale multilayer films with the following structure: solid surface/(titania nanosheet/ZnTMPyP4+)n (n is the number of layers). The multilayer films were characterized by various physical measurements, including AFM, XRD, and UV-visible spectra. The visible-light irradiation of this multilayer film on an ITO electrode in the presence of triethanolamine as an electron donor yielded an anodic photocurrent. The action spectrum was consistent with the absorption spectrum of ZnTMPyP4+, which indicates that the photoexcitation of ZnTMPyP4+ is responsible for the photocurrent generation. However, the photocurrent density decreased with an increasing number of layers, which indicates that the harvesting of photoexcited electrons vertically through the titania nanosheets in the ITO/(titania nanosheet/ZnTMPyP4+)n structure was not efficient. To overcome this problem, the use of a lateral interlayer connection to all of the titania nanosheets with Ag paste was examined. As a result, a dramatic improvement in the photocurrent density was obtained. Thus, for efficient photocurrent generation with the titania nanosheet-ZnTMPyP4+ composite material, the lateral connection to all of the titania nanosheet layers is effective.     

Fabrication of densely packed titania nanosheet films on solid surface by use of Langmuir-Blodgett deposition method without amphiphilic additives

Densely packed exfoliated nanosheet films such as Ti0.91O2, Ti0.8M0.2O2 (M = Co, Ni), Ti0.6Fe0.4O2, and Ca2Nb3O10 on solid substrates were prepared by the LB transfer method without any amphiphilic additives at the air-water interface. Nanosheet crystallites covered nearly 95% on the solid surface with minimum overlapping of nanosheets. The LB transfer method of the Ti0.91O2 nanosheet monolayer film is applicable for not only hydrophilic substrates such as quartz, silicon, indium-tin oxide (ITO), and glass but also the hydrophobic Au surface. On the basis of these points, the LB transfer method has advantages compared to the alternating layer-by-layer method, which makes use of oppositely charged polyelectrolytes such as poly(ethylenimine) (PEI). Adsorption of hydrophobic Ti0.91O2 nanosheets at the air-water interface is responsible for this LB transfer deposition method. The addition of tetrabutylammonium bromide into the subphase assisted the adsorption, causing an increase in the adsorbed amount of Ti0.91O2 nanosheets at the air-water interface.     

Photoinduced one-electron reduction of MV2+ in titania nanosheets using porphyrin in mesoporous silica thin films

Composite films of a meso-(tetramethylpyridinium)porphyrin (TMPyP) hybrid incorporated in mesoporous silica (MPS) and cast on a methyl viologen (MV2+)/titania nanosheet hybrid were synthesized and a light-induced charge separation between the two could be observed. These composite thin films were able to initiate a one-electron reduction of the MV2+ ions accompanied by the simultaneous decomposition of the TMPyP organic dye within the mesoporous silica channels.     

TiO2纳米片/巢状分级结构纳米阵列薄膜的制备及其在染料敏化太阳能电池中的应用

采用水热合成法在氟掺杂二氧化锡(FTO)导电玻璃基底上得到TiO2纳米阵列薄膜,并进一步通过NaOH溶液水热处理制备了由巢状纳米阵列及纳米片覆盖层构成的TiO2纳米阵列分级结构一体化薄膜.采用场发射扫描电镜(FE-SEM),X射线衍射(XRD),紫外-可见(UV-Vis)漫反射光谱和吸收光谱技术对TiO2薄膜的结构和性质进行表征.FE-SEM结果表明:分级结构TiO2薄膜膜厚为1.5μm,薄膜由一层纳米片覆盖层(约0.2μm高)和一层巢状纳米阵列层(约1.3μm高)组成.XRD谱图表明TiO2薄膜为锐钛矿相.UV-Vis光谱显示分级结构TiO2薄膜具有较强的光捕获能力和染料吸附能力.TiO2纳米片/巢状分级结构纳米阵列薄膜作为光阳极,可有效地提高染料敏化太阳能电池的光电转换效率,其短路电流(Jsc)为7.79mA·cm-2,开路电压(Voc)为0.80V,填充因子(FF)为0.40,光电转换效率(η)为2.48%,其光电转换效率较TiO2纳米阵列薄膜提高了近10倍.