Additive-Free Electrophoretic Deposition of Graphene Quantum Dots Thin Films

The electrophoretic deposition (EPD) of graphene-based materials on transparent substrates is highly potential for many applications. Several factors can determine the yield of the EPD process, such as applied voltage, deposition time and particularly the presence of dispersion additives (stabilisers) in the suspension solution. This study presents an additive-free EPD of graphene quantum dot (GQD) thin films on an indium tin oxide (ITO) glass substrate and studies the deposition mechanism with the variation of the applied voltage (10–50 V) and deposition time (5–25 min). It is found that due to the small size (≈3.9 nm) and high content of deprotonated carboxylic groups, the GQDs form a stable dispersion (zeta-potential of about −35 mV) without using additives. The GQD thin films can be deposited onto ITO with optimal surface morphology at 30 V in 5 min (surface roughness of approximately (3.1±1.3) nm). In addition, as-fabricated GQD thin films also possess some interesting physico-optical properties, such as a double-peak photoluminescence at about λ=417 and 439 nm, with approximately 98 % visible transmittance. This low-cost and eco-friendly GQD thin film is a promising material for various applications, for example, transparent conductors, supercapacitors and heat conductive films in smart windows.     

Preparation of Thick Films by Electrophoretic Deposition Using Surface Modified Silica Particles Derived from Sol-Gel Method

Thick films were prepared by the electrophoretic sol-gel deposition of organically modified, sub-micron silica particles. The silica particles were modified with 3-aminopropyltriethoxysilane (APS) and vinyltriethoxysilane (VTES). Smooth and crack-free films ca. 15 m thick were obtained when APS modified silica particles were used for the cathodic electrophoretic deposition. Thick films with decreased open spaces among particles were obtained when silica particles modified with VTES were co-deposited with an organic polymer, polyethylene maleate.     

金属铝诱导法低温制备多晶硅薄膜

以氢气稀释的硅烷(SiH₄)和硼烷(B₂H₆)为气源,利用等离子体增强化学气相沉积法(PECVD)制备出p型a-Si薄膜.采用铝诱导晶化技术对不同厚度的铝膜对a-Si薄膜晶化的影响进行了研究.实验中发现,铝膜溅射为10 s的非晶硅薄膜样品在450℃下退火10 min后,p型a-Si结构仍为非晶态,铝膜溅射为20 s的非晶硅薄膜在450℃下退火20 min后,p型a-Si薄膜开始晶化为poly-Si薄膜,并且铝膜厚度越厚,则a-Si薄膜晶化程度越强.     

Preparation of Barium Titanate with Patterned Microstructure by a Novel Electrophoretic Deposition Method

In order to prepare barium titanate (BaTiO₃) with patterned microstructure, a novel electrophoretic method that uses a partially hydrolyzed highly concentrated solution of barium and titanium alkoxides was developed. By using electron beam lithography, a micro-patterned mold, that is a mold with an array of air holes of 250 nm arranged in a triangular lattice with a lattice constant of 500 nm was prepared on a Pt/Ti/SiO₂/Si substrate. Electrophoretic deposition of BaTiO₃ gel was carried out by negatively biasing the Pt/Ti/SiO₂/Si substrate as cathode which had the resist mold on the surface. Removal of the resist mold left a gel material with a patterned structure that was transferred from the pattern of the mold. The gel material was confirmed by ICP-AES to have nearly the stoichiometric composition of BaTiO₃, that is, a composition in which Ba:Ti = 1:1 in molar ratio.     

LC4铝合金表面电泳沉积硅锆有机-无机杂化涂层的制备及性能

采用阴极电泳沉积的方法在LC4铝合金表面制备硅锆有机-无机杂化涂层, 并探讨了电泳沉积条件对涂层形貌、结构以及耐蚀性的影响. 采用纳米粒度仪检测了不同硅锆杂化溶胶的zeta电位; 采用扫描电子显微镜(SEM)和原子力显微镜(AFM)观察了涂层的表面微观形貌和粗糙程度; 采用傅里叶红外光谱(FTIR)研究了涂层的化学结构; 采用电化学方法研究了沉积电压对涂层耐蚀性能的影响, 进而探讨了电泳沉积增强杂化涂层耐蚀性的机理. 结果显示沉积体系的pH为1.6、沉积电压为5 V时为最佳的沉积条件, 所获得的硅锆有机-无机杂化涂层表面均匀致密性最好, 粗糙程度和耐蚀性都得到了明显的改善, 在3.5% NaCl溶液中体现出较好的耐蚀作用.     

电泳沉积制备氧化石墨烯-银电极及其氧还原催化性能

通过在1-甲基-2-吡咯烷酮（NMP）中超声剥离氧化石墨制备出稳定的氧化石墨烯（GO）分散液,添加AgNO₃使氧化石墨烯吸附Ag+而带正电荷。采用电泳沉积法使GO沉积到阴极的玻璃碳电极上,Ag+被电化学还原为单质银,均匀的分散在GO片层当中。通过AFM、SEM、Raman、XRD及元素面扫分析对制备电极的形貌、结构进行表征。在碱性环境中进行氧还原测试,结果表明GO+Ag电极的氧还原起始电位较玻璃碳电极最大正移228mV,还原电流密度最大为7.564mA·cm^-2,是玻璃碳电极的3.4倍。通过不同转速下的线性扫描曲线绘制Koutechy-Levich图,计算氧还原反应的电子转移数为3.3。     

电泳沉积制备氧化石墨烯-银电极及其氧还原催化性能

通过在1-甲基-2-吡咯烷酮(NMP)中超声剥离氧化石墨制备出稳定的氧化石墨烯(GO)分散液,添加AgNO3使氧化石墨烯吸附Ag+而带正电荷。采用电泳沉积法使GO沉积到阴极的玻璃碳电极上,Ag+被电化学还原为单质银,均匀的分散在GO片层当中。通过AFM、SEM、Raman、XRD及元素面扫分析对制备电极的形貌、结构进行表征。在碱性环境中进行氧还原测试,结果表明GO+Ag电极的氧还原起始电位较玻璃碳电极最大正移228 mV,还原电流密度最大为7.564 mA·cm-2,是玻璃碳电极的3.4倍。通过不同转速下的线性扫描曲线绘制Koutechy-Levich图,计算氧还原反应的电子转移数为3.3。     

Electrophoretic Deposition Polymerization of Diacetylenes with Tunable Structure

Serial novel chiral polydiacetylenes (PDAs) are efficiently prepared at room temperature by the controllable electrophoretic deposition of diacetylenes with tunable structure as designed from easily available starting materials. The colorimetrically reversible properties of PDAs in the range between 25 and 85 °C are influenced by the different amino acid moiety in the PDAs as anticipated. The PDA containing aromatic ring is much better for the colorimetrically reversible properties, while irreversible thermochromism is displayed for the PDA with the structure of the longer methylene units in the main chain of amino acid moiety.

     

造孔剂对电泳沉积制备多孔HA涂层及其生物活性的影响

采用水热法制得的羟基磷灰石(HA)纳米粉体,分别与造孔剂葡萄糖(Glu)、壳聚糖(CS)、炭粉(C)3种微粒(＜38.5 μm)配置成质量比1∶1的悬浮液,电泳沉积 烧结制备钛基多孔HA涂层,并对制得的3种多孔HA涂层在模拟体液浸泡前后的表面形貌、化学组成及物相变化进行表征。 结果表明,经700 ℃烧结处理后制得的3种多孔HA涂层在1.5倍人体模拟体液中浸泡5 d后,多孔HA涂层表面均被层状生长的碳磷灰石颗粒完全覆盖,颗粒直径在5~25 μm,说明这些多孔HA涂层均具有良好的生物活性。 其中以CS为造孔剂制得的多孔HA涂层结合强度最高,达19.5 MPa,有望开发成为新型的人骨植入生物陶瓷材料。     

Preparation and Characterization of CuInS2 Thin Films for Solar Cells by Chemical Bath Deposition

Introduction Recent years, chalcopyrite semiconductors have been successfully applied as absorber layers for polycrystalline thin-film solar cells. Among the ternary compound semiconductors, CuInS2 thin films with a direct bandgap of about 1.50 eV and a large absorption coefficient in the range of 104-105cm-1[1] are one kind of the most promising optical absorbers for high efficiency thin film solar cells.To date, CuInS2-based solar cells have shown conversion efficiency of about 12. 5%[2]. They exhibit long-term stability without any signs of degradation.     

模板-电泳沉积法制备TiO2纳米棒

室温(约25℃)下,将钛酸四丁酯水解制得TiO2溶胶,利用电泳沉积法在氧化铝模板中填充胶体,经450℃煅烧处理,制备了TiO2纳米棒.用透射电子显微镜和X射线衍射仪对样品进行了表征.结果表明,所得到的TiO2纳米棒表面光滑、致密,直径约180 nm,具有锐钛矿型结构.     

Electrophoretic Deposition of Chain Macromolecules: Conformation and Density Profiles, Roughening, and Deroughening

Electrophoretic deposition of polymer chains is studied by computer simulations. Effects of molecular weight (L _c), field (E), and temperature (T) on the growth of the interface width, roughness, and density profiles are examined on a discrete lattice with kink-jump segmental dynamics of chains. Effect of faster segmental dynamics will be pointed out.     

水热沉积电压对ZrSiO4抗氧化涂层显微结构及抗氧化性能的影响

以硅酸锆粉体为原料,异丙醇为溶剂,碘为荷电介质,采用水热电泳沉积法在C/C-SiC复合材料基体表面制备了硅酸锆外涂层。通过X射线衍射(XRD)、扫描电子显微镜(SEM)对涂层的晶相结构和微观形貌进行表征。研究了水热电泳沉积电压对涂层的显微结构及高温抗氧化性能的影响,并分析了涂层试样在1 773 K下静态空气中的氧化行为。结果表明：电泳沉积电压在160~200 V范围内,复合涂层的致密程度、厚度及抗氧化性能随着沉积电压的升高而提高。但沉积电压过高(220 V),复合涂层中出现微裂纹等缺陷,此时涂层的抗氧化性能下降。沉积电压控制在200 V时所制备的复合涂层可在1 773 K静态空气中有效保护C/C复合材料332 h,氧化失重率仅为0.2%,相应的氧化失重速率稳定在48.3 μg·cm^-2·h^-1的极低水平。     

水热温度对SiC-C/C复合材料表面水热电泳沉积MoSi2抗氧化涂层的影响

采用水热电泳沉积法和固相渗透法在C/C复合材料表面制备了MoSi2/SiC复合抗氧化涂层。分别采用X射线衍射、扫描电子显微镜和等温静态氧化实验对复合涂层的晶相组成、显微结构和抗氧化性能进行了表征。主要研究了水热电泳沉积温度对MoSi2外涂层显微结构及高温抗氧化性能的影响,重点分析了涂层试样在1500℃和1630℃下的静态氧化行为及失效机理。结果表明:外涂层主要由MoSi2和少量MoO3晶相组成。外涂层的致密程度、厚度及抗氧化性能随着水热温度的升高而提高。MoSi2/SiC复合涂层具有较好的抗氧化和抗热震能力,在1 500℃下有效保护基体320 h同时经历17次1 500℃与室温之间的热循环后,氧化失重率仅为1.07%;在1630℃下氧化88 h后失重率为2.17%。复合涂层在1 630℃下的氧化失效主要是由于经过长时间氧化后SiO2玻璃膜层不能及时有效填补涂层中的缺陷,涂层试样在热循环过程中产生了贯穿性的孔洞导致的。     

A Study on the Influences of Processing Parameters on the Growth of Oxide Nanorod Arrays by Sol Electrophoretic Deposition

Template-based sol electrophoretic deposition has been demonstrated as an attractive method for the synthesis of oxide nanorod arrays, including simple and complex oxides in the forms of amorphous, polycrystalline, and single crystal. This paper systematically studied a number of processing parameters to control nanorod growth by sol electrophoretic deposition. The influences of particle and template zeta potentials, condensation rate, deposition rate (or externally applied electric field), the presence of organic additives, and sol concentration on the growth of nanorod arrays were studied. It was found that higher zeta potential or electric field resulted in higher growth rates but less dense packing. Templates with charge opposite to that of the sol particles prevented formation of dense nanorods, sometimes resulting in nanotubes, depending on the field strength during electrophoresis. In addition, the pH of the sol and chelating additives were also varied and likely affected the deposition process by affecting the condensation reactions.     

玻璃表面原位聚合沉积pani薄膜机理的探讨

分散聚合;原位沉积;聚苯胺薄膜;纳米sio2;生长机理     

Low-Pressure Chemical Vapor Deposition of Silicon Carbide Thin Films from Organopolysilanes

(Me₃Si)₂SiMe₂, (Me₃Si)₃SiMe and (Me₃Si)₄Si were used as precursors for the deposition of polycrystalline β-SiC thin films on silicon substrates at 1000–1200°C in a low-pressure hot-wall chemical vapor deposition reactor. The thin films were analyzed by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy.     

微波等离子体化学气相沉积法低温制备直纳米碳管膜

Among the three main methods for the synthesis of carbon nanotubes (CNTs)， chemical vapor deposition (CVD) has received a great deal of attention since CNTs can be synthesized at significantly low temperature. Plasma chemical vapor deposition methods can synthesize CNTs at lower temperature than thermal CVD. But in the usual catalytic growth of CNTs by CVD， CNTs are often tangled together and have some defects. These will limit the property research and potential applications. How to synthesize the straight CNTs at low temperature becomes a challenging issue. In this letter， straight carbon nanotube (CNT) films were achieved by microwave plasma chemical vapor deposition (MWPCVD) catalyzed by round Fe-Co-Ni alloy particles on Ni substrate at 610℃. It was found that， in our experimental condition， the uniform growth rate along the circumference of round alloy particles plays a very important role in the growth of straight CNT films. And because the substrate is conducting， the straight CNT films grown at low temperature may have the benefit for property research and offer the possibility to use them in the future applications.     

电泳沉积法制备V2O5薄膜的结构和性能

V2O5 thin films were successfully prepared on ITO substrate with electrophoresis deposition (EDP) through V2O5 sol. X-ray diffraction and scanning electron microscopy were used for studying the structure of the films. The optical and electrochemical properties were measured by the transmittance spectra and cyclic voltammetry measurements, respectively. It is found that V2O5 thin films deposited by EDP are a compact microstructure with finer adhesive force with ITO substrate and the thickness is uniform. During the cycle experiment, the films exhibited reversible two-color (yellow at oxidation and green at reduction) with a maximum transmittance change of around 30%. Moreover, the films had an excellent cycle for lithium intercalation/deintercalation and good cycle stability, the cycle efficiency for the 50th cycle was 88.02% and the films still had fine adhesive force with ITO substrate with no dissolving over more than 50 cycles. The Li+ diffusion coefficient in V2O5 thin film was 5.10×10-12 cm2/s by the electrochemical impedance spectra method. All results indicate that V2O5 thin films by the electrophoresis deposition may be suitable for the use in the electrochromic devices.