Influence of the plasma expansion dynamics on the structural properties of pulsed laser ablation deposited tin oxide thin films

Tin oxide thin films were deposited by pulsed laser ablation at different oxygen partial pressures and substrate temperatures. Information on the structural and morphological properties of the deposited thin films has been obtained by means of X-ray photoelectron, Fourier transform infrared absorption spectroscopies and scanning electron microscopy. The expansion of the laser generated plasma has been studied by means of time resolved fast photography. Different expansion regimes were observed: in vacuum the plasma follows a free expansion one while the raise of the background oxygen pressure leads to the development of a shock wave. It was found that only at 13.3 Pa of oxygen gas, in the presence of a shock wave, the deposition of stoichiometric films, at relatively low substrates temperature, is attainable. The correlation between the observed dynamics of the plasma expansion and the structural properties of the deposited films is presented and discussed.     

聚合物/粘土纳米复合材料研究进展

聚合物/粘土纳米复合材料(PCN)是近几年纳米材料领域中的研究热点.综述了聚合物/粘土纳米复合材料的几种制备方法及研究进展,并将纳米复合材料与普通材料的物理性能相比较,得知纳米复合材料有优良的物理性能.总结了这一领域尚待解决的问题.     

聚合物/MMT纳米复合材料的结晶性能

综述了尼龙/MMT、PP/MMT、PET/MMT等代表性的结晶性聚合物/MMT纳米复合材料结晶行为,分析了MMT的加入对聚合物结晶的影响,提出建立聚合物/MMT纳米复合材料宏观性能和微观结构之间的关系,并展望了未来的发展方向.     

碳纳米管增强聚合物复合材料的研究进展

论述了碳纳米管/聚合物纳米复合材料的各种制备方法和最新进展。详细讨论了碳纳米管/聚合物纳米复合材料的结构和性能,并对今后的研究方向进行了展望。     

聚合物/蒙脱土纳米复合材料的制备与结晶性能

本文综述了制备聚合物 /蒙脱土纳米复合材料的插层方法 ,并对有代表性的结晶性聚合物 /蒙脱土纳米复合材料的结晶性能进行了讨论。蒙脱土的加入对聚合物的结晶有两种作用 ,一方面是对聚合物有异相成核的作用 ,可以提高聚合物的结晶温度和结晶速率 ,降低结晶活化能 ;另一方面是对聚合物结晶生长有阻碍作用 ,导致结晶速率下降 ,结晶活化能提高     

聚合物/有机改性蒙脱土纳米复合材料的制备方法研究进展

聚合物/蒙脱土纳米复合材料因具有独特的结构,以及较常规聚合物基复合材料更优异的性能,而展现出诱人的开发和应用前景。聚合物/蒙脱土纳米复合材料的制备也因此成为探索高性能复合材料的途径之一,受到新材料科学研究领域的普遍关注。本文综述了近年来在蒙脱土的有机改性、聚合物/蒙脱土纳米复合材料的制备方法方面的研究进展。     

Conductivity and adhesion enhancement in low-temperature processed indium tin oxide/polymer nanocomposites

We report on the conductivity and adhesion enhancement of indium tin oxide (In₂O₃:Sn; ITO) nanoparticle films by the application of polymers as matrix material. We fabricated ITO layers at a maximum process temperature of 130 °C by modifying and spin-coating nanoparticulate ITO dispersions. Dispersions containing the organic film-forming agent polyvinylpyrrolidone (PVP) and the organofunctional coupling agent 3-methacryloxypropyltrimethoxysilane (MPTS) have been developed to obtain transparent and conducting coatings on substrates which do not withstand high process temperatures like polymers or already processed glasses. The layers were cured by UV-irradiation as well as by low-temperature heat treatment (T = 130 °C) in air and under forming gas atmosphere (N₂/H₂). The influence of the additives on the electrical, optical, morphological and mechanical layer properties is reported. Compared to best pure ITO layers (3.1 Ω^− 1 cm^− 1), the ITO-MPTS-PVP nanocomposite coatings exhibit a conductance of 9.8 Ω^− 1 cm^− 1. Stable sheet resistances of 750 Ω/□ at a coexistent transmittance of 86% at 550 nm for a layer thickness of about 1.3 µm were achieved. The conductance enhancement is a consequence of the consolidation of the ITO nanoparticle network due to the acting shrinkage forces caused either by drying in the case of PVP or UV-irradiation induced condensation and polymerization reactions in the case of MPTS.     

高频辅助溅射沉积及氩气压对Co/Cu磁性多层膜结构和性能的影响

磁控溅射制备薄膜时，工作气体氩气的压强是一个非常重要的参量，氩气压的高低直接影响薄膜的结构形态，这在制备超薄多层膜过程中显得更为重要。利用高频辅助溅射沉积，可使工作气体的压强降低1个数量级，从实验和理论上给予了阐述。最后从巨磁电阻振荡效应方面，对所制备的磁性多层膜的界面状况进行了分析。     

Ellipsometry analysis of conformational change of immobilized protein monolayer on plasma polymer surfaces

The conformational stability of surface immobilized protein monolayers is a key issue in applications requiring preservation of the protein bioactivity such as in biosensors and in vivo implants. Ellipsometry was used to detect conformational changes in a single monolayer of immobilized proteins on plasma polymer surfaces. The areal mass density of immobilized proteins was used to validate the data analysis in the protein denaturation analysis. We observed that the rate of conformation change was strongly dependent on the properties of the immobilized protein. Immobilized catalase showed a significantly slower denaturation rate than the immobilized horseradish peroxidase, indicating that the tetramer catalase is more stable than the immobilized monomer horseradish peroxidase at the surface/air interfaces. The ellipsometry results were in a good agreement with the enzyme activity analysis.     

Sputter deposition and surface treatment of TiO2 films for dye-sensitized solar cells using reactive RF plasma

Sputter deposition followed by surface treatment was studied using reactive RF plasma as a method for preparing titanium oxide (TiO₂) films on indium tin oxide (ITO) coated glass substrate for dye-sensitized solar cells (DSCs). Anatase structure TiO₂ films deposited by reactive RF magnetron sputtering under the conditions of Ar/O₂(5%) mixtures, RF power of 600 W and substrate temperature of 400 °C were surface-treated by inductive coupled plasma (ICP) with Ar/O₂ mixtures at substrate temperature of 400 °C, and thus the films were applied to the DSCs. The TiO₂ films made on these experimental bases exhibited the BET specific surface area of 95 m²/g, the pore volume of 0.3 cm²/g and the TEM particle size of ∼ 25 nm. The DSCs made of this TiO₂ material exhibited an energy conversion efficiency of about 2.25% at 100 mW/cm² light intensity.     

The electrical and optical properties of indium zinc tin oxide thin films with different Sn/Zn ratio

Indium zinc tin oxide (IZTO) thin films with two different chemical compositions, i.e. IZTO15 and IZTO25, where In content was fixed at 60 at.% and Sn content was 15 and 25 at.%, respectively, were deposited onto alkaline-free glass substrate at temperature from 37 °C to 600 °C. The deposition process was carried out in argon using an RF magnetron sputter. After deposition, the films were annealed in argon atmosphere at 450 °C for 30 min. The effect of substrate temperature and annealing treatment was investigated, and the minimum resistivity value of 3.44 × 10^− 4Ω.cm was obtained from the film deposited at 400 °C using IZTO25 target followed by rapid thermal annealing at 450 °C for 30 min. The average optical transmittance was kept fairly high over 80%. It was proven that both substrate temperature and thermal annealing were important parameters in lowering the electrical resistivity without deteriorating optical properties.     

不同衬底上ZnO薄膜的射频磁控溅射制备及结构

利用射频磁控溅射镀膜的方法,在c面蓝宝石、石英玻璃和载破片衬底上成功制备了ZnO薄膜。用x射线衍射和扫描电子显微镜进行了结构分析并观察了样品的表面形貌。结果表明：制备的ZnO薄膜具有良好的C轴择优取向结晶度,并在石英玻璃和载玻片衬底上的ZnO薄膜表面发现了[101]取向的“米粒状”晶粒。     

Recent approaches to reduce aging phenomena in oxygen- and nitrogen-containing plasma polymer films: An overview

Plasma polymer films (PPFs) are well-known for their enhanced stability compared to conventional polymer coatings. However, PPFs tend to undergo aging in air or in aqueous environments due to oxidation, hydrophobic recovery, hydrolysis and dissolution of oligomeric fragments. Such aging mechanisms cause modifications of the PPFs that entail a change in surface properties. For example, PPF surfaces which are probed for protein adsorption or cell adhesion might therefore be substantially different from the initial PPF. It becomes thus necessary to understand the chemical reactions involved in the chemical modification (and/or degradation) of PPFs. Here, a summary of the most important aging mechanisms occurring in PPFs is given. More precisely, chemical reactions that can potentially occur in oxygen- and nitrogen-containing plasma polymer films when stored in air and in water were highlighted. On the basis of this understanding, recent strategies to reduce or delay aging mechanisms and/or to provide time-controlled degradable PPFs are discussed: the enhancement of the degree of cross-linking, the formation of a gradient structure in the PPF during plasma deposition, and the chemical post-plasma treatment to reduce the number of reactive sites. Finally, potential applications of such coatings will be considered.     

聚合物/层状硅酸盐纳米复合材料的阻燃性能研究进展

从热稳定性能、燃烧和发烟行为、成炭行为、氧指数和UL94阻燃级别等方面,对聚合物/层状硅酸盐纳米复合材料(PLSN)阻燃性能的研究进展进行了综述,分析和探讨了PLSN的阻燃机理,展望了其发展趋势和应用前景。     

Bi／Bi2O3晶格复合热电薄膜的制备及其性能研究

利用射频磁控溅射法在玻璃基片上制备Bi／Bi2O3晶格复合热电薄膜,考察了溅射功率对单层Bi薄膜表面粗糙度和热电性能的影响,结果表明,当溅射功率为22W时,薄膜具有最小的表面粗糙度16.3nm,电导率和功率因子分别为2．9×10^4S／m和5．74μV／k^2m,单层Bi薄膜最佳的工作温度为85～105℃。Bi／Bi2O3晶格复合热电薄膜最佳的溅射层数为5层,其电导率和功率因子分别为9．0×10^4S／m和21．0μN／k^2m,分别比单层Bi薄膜提高了2．1倍和2．65倍。     

调制周期对ReB2/TaN纳米多层膜的结构和力学性能影响

利用射频磁控溅射方法(衬底温度20℃)制备TaN,ReB2单层膜及ReB2/TaN纳米多层膜,并通过XRD,SEM,XP-2表面轮廓仪及纳米力学测试系统对薄膜的微结构和力学性能进行表征,分析调制周期对其影响.结果表明:TaN和ReB2均具有典型的六方结构,在其构成的多层膜中,当调制周期达到8～12nm附近时,纳米多层膜...     

HRTEM observations on composites of tin and tin dioxide nanoparticles dispersed on carbon nanotubes by single-atoms-to-clusters method

Nano-composites of tin and tin dioxide particles were synthesized on carbon nanotubes by the single-atoms-to-clusters (SAC) method, and their structures were investigated by high-resolution transmission electron microscopy. By changing the heat-treatment temperature during the SAC process, two different types of samples were obtained. The samples prepared around 450 K were aggregates of 2-4 nm-sized tin dioxide nanoparticles, and their size distributions on carbon nanotubes are in the range 20-40 nm. The other samples formed above 600 K had a core-shell structure of diameter 20-40 nm. The core and shell were made of tin single crystal and disordered oxidized tin, respectively. The thickness of the oxidized layers was ca. 4 nm.     

平面射频磁控溅射法制备YSZ薄膜及性能

研究了应用射频磁控溅射法在不同基板上制备ＹＳＺ薄膜和工艺条件对其微观结构的影响。结果表明,在清洁的基板上制备的ＹＳＺ 薄膜经６００ ℃以上热处理后,薄膜表面致密均匀,无裂纹,薄膜与基板的结合紧密。薄膜具有较高的电导率,完全可以作为固体电解质使用。     

HRTEM observations on composites of tin and tin dioxide nanoparticles dispersed on carbon nanotubes by single-atoms-to-clusters method

Nano-composites of tin and tin dioxide particles were synthesized on carbon nanotubes by the single-atoms-to-clusters (SAC) method, and their structures were investigated by high-resolution transmission electron microscopy. By changing the heat-treatment temperature during the SAC process, two different types of samples were obtained. The samples prepared around 450 K were aggregates of 2–4 nm-sized tin dioxide nanoparticles, and their size distributions on carbon nanotubes are in the range 20–40 nm. The other samples formed above 600 K had a core–shell structure of diameter 20–40 nm. The core and shell were made of tin single crystal and disordered oxidized tin, respectively. The thickness of the oxidized layers was ca. 4 nm.     

磁控溅射中工艺参数对ZnO:Al薄膜性能的影响

利用射频磁控溅射法,采用氧化锌铝(98%ZnO+2%Al2O3)为靶材,在普通载玻片上制备了ZAO(ZnO∶Al)薄膜,研究了溅射功率及溅射气压对薄膜晶体结构、电学和光学性能的影响.采用X射线衍射仪、场扫描电镜对薄膜的结构及表面形貌进行了分析,采用分光光度计和电阻率测试仪对薄膜的光电学性能进行了测试.结果表明,当溅射功率为120W、衬底温度为300℃、工作气压为0.5Pa时制得的薄膜具有良好的光电学性能,可见光平均透过率为88.21%,电阻率为8.28×10-4Ω·cm.