Surface Texturing of TiO_2 Film by Mist Deposition of TiO_2 Nanoparticles

Unique and various microstructures of titanium oxide(TiO_2 ) film including macroporous structure, chromatic veins and rings, have been easily fabricated by mist deposition method on silicon substrate with mild preparation conditions. Rutile phase TiO_2 nanoparticles were directly used as starting material to prepare film and led to a simple preparation process. It was found that several different microstructures existed in the sample and changed with the varied positions from the center to the edge of the film when the concentration of the TiO_2 suspension is 0.06 mol/l, the deposition time is 30 min, the flow rate is 1 l/min and the temperature is150. The surface texturing shows apparent distinction as the concentration of the TiO_2 suspension decreased to 0.03 mol/l and 0.01 mol/l.

Transient competition between photocatalysis and carrier recombination in TiO_2 nanotube film loaded with Au nanoparticles

Highly ordered TiO2 nanotube array （TNA） films are fabricated by using an anodic oxidation method. Au nanoparticles （NPs） films are decorated onto the top of TNA films with the aid of ion-sputtering and thermal annealing. An enhanced photocatalytic activity under ultraviolet C （UVC, 266 nm） light irradiation is obtained compared with that of the pristine TNA, which is shown by the steady-state photoluminescence （PL） spectra. Furthermore, a distinct blue shift in the nanosecond time-resolved transient photoluminescence （NTRT-PL） spectra is observed. Such a phenomenon could be well explained by considering the competition between the surface photocatalytic process and the recombination of the photo-generated carriers. The enhanced UV photocatalytic activities of the Au-TNA composite are evaluated through photo-degradation of methyl orange （MO） in an aqueous solution with ultraviolet-visible absorption spectrometry. Our current work may provide a simple strategy to synthesize defect-related composite photocatalytic devices.

Optical and electrical characterizations of nanoparticle Cu_2S thin films

Copper sulfide thin films are deposited onto different substrates at room temperature using the thermal evaporation technique. X-ray diffraction spectra show that the film has an orthorhombicchalcocite （7-Cu2S） phase. The atomic force microscopy images indicate that the film exhibits nanoparticles with an average size of nearly 44 nm. Specrtophotometric measurements for the transmittance and reflectance are carried out at normal incidence in a spectral wavelength range of 450 nm-2500 nm. The refractive index, n, as well as the absorption index, k is calculated. Some dispersion parameters are determined. The analyses of el and e2 reveal several absorption peaks. The analysis of the spectral behavior of the absorption coefficient, c~, in the absorption region reveals direct and indirect allowed transitions. The dark electrical resistivity is studied as a function of film thickness and temperature. Tellier＇s model is adopted for determining the mean free path and bulk resistance.

The Film-forming Behavior on the Interface between Air and Hydrosol of Fe_2O_3 Nanoparticles

The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy and transmission electron microscopy. It is found that the freshly prepared hydrosol of Fe2O3 nanoparticles is not stable. The surface pressure increases with the aging time and finally approaches a constant, and the smaller the concentration is, the smaller the surface pressure is stabilized at and the shorter the time the hydrosol reaching stable needs. The surface pressure also increases with compression until collapsed, and the longer the hydrosol is aged, the higher the collapsing pressure is. A uniform and compact film composed of nanoparticles with an average diameter of about 2-3 nm on the air-hydrosol interface is observed by Brewster angle microscope and transmission electron microscope.

Synthesis of Cu_2ZnSnS_4 thin film from mixed solution of Cu_2SnS_3 nanoparticles and Zn ions

The Cu2ZnSnS4 thin film was prepared by a facile solution method without vacuum environment and toxic substance. The formation mechanism of the film was studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Raman scattering measurements. Through cyclic voltammetry and photo-electricity tests, the electrocatalytic activity of the prepared film as the counter electrode of dye-sensitizedsolar cell was also studied. The results show that the mixed precursor solution mainly consists of Cu2SnS3 nanoparticles and Zn ions.After 550 °C annealing process on the precursor film prepared from the mixed solution, Cu2ZnSnS4 thin film is obtained. Besides, itis found that the prepared Cu2ZnSnS4 thin film has the electrocatalytic activity toward the redox reaction of I3?/I? and the dye-sensitized solar cell with the prepared Cu2ZnSnS4 thin film as the counter electrode achieves the efficiency of 1.09%.

Self-assembly of Ag-TiO_2 Nanoparticles: Synthesis, Characterization and Catalytic Application

The formation of Ag clusters on titanium oxide （TiO2） nanoparticles was achieved by self-assembly process and calcination. The obtained nanoparticles were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and ultraviolet visible spectroscopy （UV-Vis）, and conventional techniques （XRD, TEM and UV-Vis） were used to identify Ag particles on the TiO2 surfaces. The results show that Ag-TiO2 particles can be applied to improve catalytic activity of the epoxidation of styrene oxides. Styrene oxide is the main product of catalytic reaction with H2O2 as the oxidant by using Ag-TiO2 nanoparticles as catalysts. High catalytic activitity of styrene oxide can be obtainable at 80 ℃. The reaction temperature, reaction time, the molar ratio of H2O2/styrene and solvent affect greatly the catalytic epoxidation of styrene.

两亲SiO_(2)纳米颗粒的制备和界面扩张流变行为研究

制备了一种两亲SiO_(2)纳米颗粒,借助红外光谱及接触角测量证实了相关基团在SiO_(2)纳米颗粒表面的成功接枝,探究了其界面活性和界面扩张流变行为。通过动态界面张力测量及小幅正弦振荡实验发现,两亲SiO_(2)纳米颗粒相比亲水和疏水SiO_(2)纳米颗粒能够更稳定地吸附在界面形成一层吸附膜,降低界面张力,同时由于其扩散交换速度较慢,界面扩张模量大于亲水和疏水SiO_(2)纳米颗粒。进一步的大幅线性压缩实验发现两亲SiO_(2)纳米颗粒在表面比为0.35时其界面吸附量会发生激增,扩张模量迅速增大,其形成的界面膜具有抵抗较大程度形变的能力。

纳米TiO_(2)对NH_(3)-H_(2)O-LiBr工质降膜吸收性能的影响

为了探讨纳米TiO_(2)对三元NH_(3)-H_(2)O-LiBr工质降膜吸收的影响,本文利用数值分析建立了三元工作流体薄膜吸收的连续方程、能量方程和组分质量平衡方程,采用Matlab软件进行编程和计算纳米流体的降膜吸收性能,将其与实验数据进行对比验证,并进一步分析了纳米TiO_(2)质量分数、初始氨浓度、初始温度、冷却水进口温度、吸收压力和下降薄膜管长度对薄膜吸收性能的影响。研究表明:添加纳米TiO_(2)可以增强降膜吸收的传质速率,主要原因为液膜中氨的扩散系数增加。当纳米TiO_(2)质量分数从0%增加到0.1%、0.3%和0.5%时,扩散系数分别增加了3.44倍、6.42倍和11.76倍。此外,增加初始氨浓度、降低初始温度、提高冷却水进口温度或降低吸收压力都可以提高最终溶液的饱和度。

Synthesis of High Quality CulnSe2 Films with Oxygen Precursor by Non-vacuum Process

The CulnSe2 absorber was synthesized by non-vacuum process with a simple and low-cost method, which fabricated absorber layer of thin-film solar cell. The extra amount of Se was added into the ink to help reduction of the oxide and solid Se fountain was used to provide Se atmosphere during the selenization progress. The influence of same factors was investigated, such as the time of reduction in H2, the time of selenization and the Se vapor pressure. The selenizaion, processed at 550 ℃ for 60 min with the Se vapor pressure at 1.90 kPa, resulted in high quality CulnSe2 layer with very good chemical composition.

Preparation of CulnS2 Thin Film Using Sulfides Nanoparticle Precursor Ink

A low cost spin coating route of fabricating CuInS2 polycrystalline thin films by reactive sintering method was put forward. The ink for spin coating was optimized by pre-reducing the precursor powders in hydrogen, which turned the nanoparticle precursor powders from mixed sulfides into a mixture of CuInS2 and Cu-In metal alloys. The results of scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and Raman spectra showed that this optimization could highly improve the performance of CuInS2 polycrystalline thin films, including higher packing density, less impurity phases, and better quality. The energy gap of optimized CuInS2 thin film was determined to be about 1.45 eV by absorption spectroscopy measurement.

Low-temperature Preparation of Photocatalytic TiO_2 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.

Cu_(2)O-Au复合结构的制备及其在SERS中的应用

表面等离激元催化反应为表面过程的拓展提供了一条新的途径,但在单一贵金属表面的反应效率往往较低,因此发展符合纳米结构已经成为该领域的研究热点。通过合成八面体的氧化亚铜(Cu_(2)O),并引入高均匀性和高SERS活性的金纳米粒子单层膜(Au MLF),将两者完全结合,构建了Cu_(2)O-Au复合异质结SERS基底。以对硝基苯硫酚(PNTP)为探针,通过表面增强拉曼光谱(SERS)研究了Cu_(2)O-Au表面等离激元驱动的偶联反应。结果表明,Cu_(2)O与Au MLF的复合,其SERS性能及催化活性都得到了较大的提升,为发展高性能的新型复合纳米结构提供了实验基础。

Preparation of Ag-doped TiO_2 Thin Film by Sol-gel Method

The Ag-TiO2 thin film has been prepared on glass substrate by sol-gel process . The structure and properties of the materials were studied by DTA , XRD, and EPR. The photocatalytic activity was examined by the photocatalytic degradation of dichlorophos. The analysis results indicate that the photocatalytic activity of the Ag-TiO2 thin film is higher than that of pure TiO2 thin film. It is also influenced by the content of anatase and heating temperature . The ESR result shows that the Ag-TiO2 thin film has more hydroxide radicals than pure TiO2 thin film after illuminated by UV light.

全光谱SiO_(2)结构色薄膜的加色法制备及其光学性能

为解决在制备不同粒径的小球来实现全光谱结构色过程中工作量大的问题,采用溶剂调控法合成粒径均匀的304、260、200 nm的SiO_(2)纳米颗粒,利用三原色加色法原理将3种不同粒径的纳米SiO_(2)悬浮液按照不同质量比两两混合,然后放在烘箱中进行重力沉降自组装,制备出全光谱非晶光子晶体结构色薄膜,探究混合比例对SiO_(2)光子晶体结构色的影响。同时为提高结构色的饱和度,将墨水添加到不同混合比例的SiO_(2)悬浮液中,研究墨水质量分数对光子晶体结构色的影响。结果表明:随着小粒径SiO_(2)比例的增加,结构色会出现蓝移现象;墨水质量分数越高,结构色亮度越低,色度呈先增加后减小趋势,当墨水质量分数为0.4%时,结构色饱和度最好。

不同金属基体上MoS_2纳米微粒LB膜摩擦学行为研究

研究了Ｃｕ、Ａｇ及Ａｕ等金属基体上二烷基二硫代磷酸修饰ＭｏＳ２纳米微粒ＬＢ膜的摩擦学性能，用红外显微镜分析ＬＢ膜在摩擦过程中的结构变化，用电子探针分析考察不同金属基体上ＬＢ膜的磨痕形貌．结果表明：ＤＤＰ修饰ＭｏＳ２纳米微粒ＬＢ膜可有效降低Ａｇ和Ｃｕ与ＧＣｒ１５钢对摩时的摩擦系数；该ＬＢ膜极易向对偶转移并在摩擦过程中发生摩擦化学变化，主要包括无序化转变及修饰剂的部分分解；无机纳米核起主要承载和抗磨作用．Ｃｕ基体上的ＬＢ膜耐磨寿命较Ａｇ基体上ＬＢ膜的耐磨寿命高１００倍，这主要因ＬＢ膜与Ａｇ基体的结合较弱．

TiO_2纳米粒子膜的表面态性质对光催化活性的影响

TiO 2 nanoparticle film catalysts with different thicknesses were prepared by plasma enhanced chemical vapor deposition(PECVD) method and the surfaces were subsequently treated by TiCl 4 or O 2 plasma. Two kinds of TiO 2 films with different surface properties were obtained. Their surface microstructures and energy levels of surface states were tested by AFM, XRD, SPS. The photocatalytic activities of the catalysts were determined via photodegradation experiments of phenol. The results demonstrated that photocatalytic activities of samples whose surface was treated by O 2 plasma were greater than those treated by TiCl 4 plasma. Moreover, photodegradation ratio of phenol during the first hour catalyzed by 0.17 μm thickness TiO 2 nanoparticle film was greater than other samples. Especially, the difference of photocatalytic activities of TiO 2 nanoparticle films treated by TiCl 4 or O 2 plasma was respectively explained by energy band theory.

TiO_2纳米粒子膜的制备、表面态性质和光催化活性

在酸 性和碱性 条件下， 用 Ｔｉ Ｃｌ４ 水解 法制备 了 Ｔｉ Ｏ２ 纳米 粒子 膜催 化剂． 采 用原 子力 显微镜（ Ａ Ｆ Ｍ） ， Ｘ 射 线衍射（ Ｘ Ｒ Ｄ） ， 表面 光电压谱（ Ｓ Ｐ Ｓ） 和 场诱导 表面 光电 压谱（ Ｅ Ｆ Ｉ Ｓ Ｐ Ｓ） 测 定了 催化剂表面的 微结构 及能级结 构． 对 催化剂 进行了 光 催化 降 解苯 酚实 验， 测定 了其 光 催化 活 性． 结果表明，酸 性条件下 制备的 Ｔｉ Ｏ２ 膜催 化剂的 光催 化 活性 较高 ，其 结果 接 近于 Ｐ２５ ． 用能 带理 论 解释了 Ｔｉ Ｏ２ 纳米粒 子膜催化 剂光催化 活性的 差异，分析 了膜厚 对光催化 活性的

Preparation and characterization of sphere-like Cu_2SnS_3 nanoparticles and their dropcasted thin films

Ternary sphere-like Cu2 SnS3（CTS）semiconductor and 2D hexagonal sheets were synthesized via a simple solvothermal method using PVP as the surface ligand at two temperatures of 180 and 220 X.The structural,morphological,and chemical compositions as well as optical properties of as-synthesized CTS particles were characterized using X-ray diffraction（XRD）,Raman spectroscopy,energy dispersive X-ray spectrometry（EDS）,field emission scanning electron microscopy（FESEM）,and UV-Vis spectroscopy.The size of sphere-like particles and the side length of hexagonal sheets were within the range of 120-140 nm and 500 nm-2 μm,respectively.FESEM,XRD,and EDS were analyzed to investigate the mechanism of the morphological evolution of CTS particles.CTS particles showed proliferation of Sn atomic ratio,which is strongly sensitive to reaction temperature and,highly affects the increase of band gap energy from 1.36 to 1.53 eV due to generation metal defects and formation SnS2-The optical analysis via the transmittance and reflectance reveals that the band-gap energy of dropcasted CTS thin films decreases after annealing due to grain growth and change of chemical compositions.Photo-responses of CTS nanocrystal thin films indicated a considerable increase in the conductivity of the films under light illumination.All these results showed the potential of these films for solar cell applications.

Au-MgF_2复合纳米颗粒薄膜的制备和微结构

用射频磁控共溅射法制备了Au体积分数分别为 6 %、1 5 %、2 5 %、4 0 %、5 0 %和 6 0 %的Au MgF2 复合纳米颗粒薄膜。用X射线衍射、透射电镜、X射线光电子能谱对薄膜的微结构和组分进行了测试分析 ,分析结果表明 :制备的Au MgF2 复合纳米颗粒薄膜由fcc Au晶态纳米微粒镶嵌于主要为非晶态的MgF2 陶瓷基体中构成 ,当Au体积百分含量由 1 5 %增至 6 0 %时 ,其平均晶粒尺寸由 5 1nm增大到 2 1 2nm ,晶格常数由 0 39984nm增大到 0 4 0 74 3nm ;随Au体积百分含量由 6 %增至5 0 % ,其颗粒平均粒径则由 9 8nm增至 2 1 4nm。名义组分为vol.6 0 %Au MgF2 样品中Au的体积百分含量约为 6 2 6 % ,与设计值基本一致。

Thin films of α-Fe_(2)O_(3) nanoparticles using as nonmetallic SERS-active nanosensors for submicromolar detection

A new kind of nonmetallic nanosensors based on surface-enhanced Raman spectroscopy(SERS)have been successfully prepared by the assembly of α-Fe_(2)O_(3) nanoparticles(NPs)onto clean quartz surface via the cross-linker of hexamethylene diisocyanate(HDI).The resultant substrates have been characterized by electron micrographs,which show that the α-Fe_(2)O_(3) NPs distribute on the modified surface uniformly with a monolayer or sub-monolayer structure.4-mercaptopyridine(4-Mpy)and 2-mercaptobenzothiazole(2-MBT)molecules have been used as SERS probes to estimate the detection efficiency of the α-Fe_(2)O_(3) thin films.The SERS experiments show that it is possible to record high quality SERS spectra from probe molecules on the α-Fe_(2)O_(3) thin films at sub-micromolar(<10^(–6) mol/L)concentration.These results indicate that the highly ordered,uniformly roughed,highly sensitive and low-cost α-Fe_(2)O_(3) thin films are excellent candidates for nonmetallic SERS-active nanosensors.