采用复合晶种法在大孔载体上制备高性能ZSM-5沸石膜

采用复合晶种法在α-Al2O3载体上制备ZSM-5沸石膜.首先采用热浸渍-擦涂法在大孔α-Al2O3载体上预涂一层由纳米ZSM-5分子筛团聚而成的大晶种颗粒,对载体表面的大孔进行初步修饰;然后在此基础上利用提拉法涂覆小晶种,从而形成一层薄而连续的晶种层;最后在175℃下利用二次生长法制备ZSM-5沸石膜.采用SEM和XRD等方法,对制备的ZSM-5沸石膜进行表征,并对其进行渗透汽化性能测试.结果表明:制备的ZSM-5膜连续、致密且厚度为8μm;在温度353 K下,分离质量分数为90％的乙酸/水体系,其渗透通量可达0.89 kg/(m2·h),分离系数接近于无穷大.     

Photocatalytic properties of visible-light enabling layered titanium oxide/tin indium oxide films

Visible-light enabling titanium oxide/tin indium oxide (TiO₂/ITO) thin films deposited on unheated glass slides with prolonged deposition duration were investigated in this study. Structural properties characterized by X-ray diffraction (XRD), Raman spectra and scanning electron microscopy (SEM) showed typical polycrystalline structure with primary anatase phase along with elongated pyramid-like grains lying on the film surface and densely packed columnar structure from cross-sectional profile. The XRD preferential peak of (2 1 1) and the Raman peak intensity at 640 cm⁻¹ dramatically increased without noticeable broadening and shift as the deposition time was prolonged beyond 2 h. This implies that more perfectly crystalline structure, less internal stress, and comparatively larger grains were obtained by this technique. The Ti2p_3/2 and O1s XPS peaks shifted toward higher binding energy suggest that the local chemical state was influenced by the prolonged deposition duration in the film, which resulted in red shift of absorption threshold into visible-light region. Under ultra-violet (UV) and visible-light illumination, the visible-light enabling film exhibited the best photocatalytic activity on MB degradation with the rate-constant of about 0.231 h⁻¹. Hydrophilic conversion rate was estimated to be 8.14 × 10⁻³ deg⁻¹ min⁻¹ and long-term UV-induced hydrophilicity of 10° in the dark storage up to 72 h was observed. In addition to its inherent characteristics of the layered TiO₂/ITO structure on hole/electron separation, all these could be attributed to more perfectly formed crystalline structure, densely packed columnar crystals and the surface roughness along with its enlarged surface area.     

Transparent and conductive indium tin oxide/polyimide films prepared by high‐temperature radio‐frequency magnetron sputtering

A highly transparent and thermally stable polyimide (PI) substrate was prepared and used for the fabrication of indium tin oxide (ITO)/PI films via radio‐frequency magnetron sputtering at an elevated substrate temperature. The effect of the deposition conditions, that is, the oxygen flow rate, substrate temperature, sputtering power, and working pressure, on the optical and electrical properties of the ITO/PI films were investigated from the microstructural aspects. The results indicate that the optical and electrical properties of ITO were sensitive to the oxygen. Moreover, it was beneficial to the improvement of the ITO conductivity through the adoption of a high substrate temperature and sputtering power and a low working pressure in the deposition process. A two‐step deposition method was developed in which a thick bulk ITO layer was overlapped by deposition on a thin seed ITO layer with a dense surface to prepare the highly transparent and conductive ITO/PI films. The ITO/PI film after annealing at 240°C gave a transmittance of 83% and a sheet resistance of 19.7 Ω/square. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42753.     

氧化钒薄膜制备方法专利技术分析

氧化钒由于其独特的光电性能在红外探测器、光电调节器、智能窗、光存储及传感器等应用领域备受关注。对制备氧化钒薄膜采用的专利技术进行了梳理,对日后氧化钒薄膜的制备及性能优化具有很好的指导意义。     

Li-ion diffusion kinetics in LiFePO4 thin film prepared by radio frequency magnetron sputtering

LiFePO₄ thin films were prepared by radio frequency (RF) magnetron sputtering and were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscope (AFM). Li-ion chemical diffusion coefficients, , were measured by potentiostatic intermittent titration technique (PITT), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The effects of Ag content, film thickness, and film orientation on the electrochemical performance and Li-ion chemical diffusion coefficients of the LiFePO₄ thin films were investigated. values were measured using the liquid electrolyte and the solid electrolyte, and the obtained values were discussed. The values by PITT and EIS were in the range of 10⁻¹⁴ to 10⁻¹² and 10⁻¹⁵ to 10⁻¹² cm² s⁻¹, respectively and that by CV was in the order of 10⁻¹⁴ cm² s⁻¹.     

Effect of oxygen flow rate on the ultraviolet sensing properties of zinc oxide nanocolumn arrays grown by radio frequency magnetron sputtering

Highly transparent metal–semiconductor–metal ultraviolet (UV) photoconductive sensors were fabricated using thin (less than 100 nm in thickness), dense, small-diameter ZnO nanocolumn arrays prepared via low-power, catalyst-free radio frequency (RF) magnetron sputtering at different oxygen flow rates ranging from 0 to 25 sccm. The FESEM images revealed the average nanocolumn diameter decreased with increasing oxygen flow rate. The transmittance spectra show that with the introduction of oxygen, the transmittance of the nanocolumn arrays in the visible region improves relative to that of a film prepared in the absence of oxygen with values greater than 95%. The UV responsivity and sensitivity were significantly improved for sputtered ZnO nanocolumn arrays prepared at oxygen flow rates up to 10 sccm, with the highest values of 9.70 mA/W and 2.20×10⁴. Furthermore, the responsivity and sensitivity decreased at oxygen flow rates greater than 10 sccm, which can be attributed to the increased electrical resistance of the nanocolumn arrays. Our findings indicate that a high-performance UV photoconductive sensor can be realised using very thin sputtered ZnO nanocolumn arrays and that such a sensor would exhibit high sensitivity.     

Influence of radio frequency magnetron sputtering parameters on the structure and performance of SiC films

Amorphous SiC films fabricated by Radio frequency (RF) magnetron sputtering have been widely used due to their excellent properties including high strength, good hardness and outstanding abrasion resistance. However, most researches set a lower target-substrate distance, which limits its large-scale coating for practical industrial application. In this work, the distance between the target and substrate was enlarged to 120 mm, and the effective coating area was about four to ten times than other researches. Furthermore, the effects of sputtering power, deposition pressure, substrate temperature and bias voltage on the structure and performance of SiC films were also investigated. Finally, SiC films with high elasticity modulus (310.8 GPa) and hardness (35.6 GPa) are obtained by RF magnetron sputtering.     

氧气含量对射频磁控溅射Ba0.5Sr0.5TiO3薄膜介电性能的影响

采用射频磁控溅射法在镀氧化铟锡的Corning 1737玻璃基片上制备了用于无机电致发光显示器绝缘层的Ba0.5Sr0.5TiO3介电薄膜,该薄膜厚约400 nm.研究了O2和Ar O2的体积比V(O2)/V(Ar O2)对薄膜沉积速率、结晶性和介电性能的影响.当V(O2)/V(Ar O2)由0增加至0.5时,薄膜的结晶取向、介电常数、介电损耗、击穿场强和漏电流密度并没有明显的规律性可循.V(O2)/V(Ar O2)为0.1时,薄膜的品质因子最好,其值为5 μC/cm2.     

Comparative study on the microstructure and properties of 10 wt%- and 35 wt%- tin doped indium oxide materials

Due to the resource shortage of indium, the application of 10 wt%- tin doped indium oxide (10 wt%- ITO) with 74.4 wt% of indium is restricted in the field of flat panel display. A new ternary compound TCO material with 53.8 wt% of indium (35 wt%- ITO) was prepared by In₂O₃-35 wt% SnO₂ powders, whose microstructure and properties were studied in comparison to 10 wt%- ITO. The research findings show that: (1) The phase composition of 35 wt%- ITO target is mainly In₄Sn₃O₁₂ and In₂SnO₅, without In₂O₃: Sn phase for 10 wt%- ITO; (2) When films possess the strong crystalline structure, the photoelectric properties of 35 wt%- ITO films are superior to 10 wt%- ITO. In addition, the crystalline structure of 35 wt%- ITO films could be changed from In₄Sn₃O₁₂ + amorphous to In₄Sn₃O₁₂ + In₂O₃ by annealing, but for 10 wt%- ITO, only the crystallinity is changed.     

Gallium oxide films deposition by RF magnetron sputtering; a detailed analysis on the effects of deposition pressure and sputtering power and annealing

In this study, gallium oxide (Ga₂O₃) thin films were deposited on sapphire and n-Si substrates using Ga₂O₃ target by radio frequency magnetron sputtering (RFMS) at substrate temperature of 300 °C at variable RF power and deposition pressure. The effects of deposition pressure and growth power on crystalline structure, morphology, transmittance, refractive index and band gap energy were investigated in detail. X-ray diffraction results showed that amorphous phase was observed in all the as-deposited thin films except for the thin films grown at low growth pressure. All the films showed conversion to poly-crystal β-Ga₂O₃ phase after annealing process. When the deposition pressure increased from 7.5 mTorr to 12.20 mTorr, change in the 2D growth mode to 3D columnar growth mode was observed from the SEM images. Annealing clearly showed formation of larger grains for all the thin films. Lower transmission values were observed as the growth pressure increases. Annealing caused to obtain similar transmittance values for the thin films grown at different pressures. It was found that a red shift observed in the absorption edges and the energy band gap values decrease with increasing growth pressure. For as-deposited and annealing films, increasing sputtering power resulted in the increase refractive index.     

Reducing the environmental load of triacetyl cellulose film production using wood pulp

Triacetyl cellulose (TAC) films, which are currently produced mainly from cotton linter, are widely used for liquid crystalline display (LCD) applications. However, cotton linter is an expensive source of cellulose and the environmental load related with cotton cultivation is notoriously heavy. Herein, the replacement of cotton linter by wood pulp was systematically investigated to explore the possibility of TAC production using a less expensive source. The mechanical and thermal properties of TAC films made from wood (wTAC) were outstanding compared to those of TAC films made from cotton (cTAC). The optical transparency of wTAC was also excellent. While Tinuvin (a UV stabilizer) produced more isotropic structures in cTAC films, it produced more anisotropic structures in wTAC films. Overall, the optical films of wTAC showed good performance for LCD applications, comparable to that of cTAC. These results could be used to develop more environmentally friendly production methods for optical TAC films. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42146.