中空纳米二氧化硅复合微球的制备及其对蛋白的亲和分离

利用水热法合成了中空巯基纳米二氧化硅微球(SiO₂-SH), 然后在其表面修饰亚氨基二乙酸基团(-IDA), 形成了中空SiO₂-SH/IDA双功能化纳米微球。利用该纳米微球表面的-SH和-IDA双功能团, 可以更多的吸附溶液中的Ni²⁺, 形成SiO₂-SH/IDA-Ni²⁺复合微球从而可以更好的分离以六聚组氨酸为标签的(His-tagged)蛋白。结果显示制备的样品对分离His-tagged蛋白具有广谱性, 并且具有较好的再生能力。     

中空纳米二氧化硅复合微球的制备及其对蛋白的亲和分离

利用水热法合成了中空巯基纳米二氧化硅微球(SiO₂-SH), 然后在其表面修饰亚氨基二乙酸基团(-IDA), 形成了中空SiO₂-SH/IDA双功能化纳米微球。利用该纳米微球表面的-SH和-IDA双功能团, 可以更多的吸附溶液中的Ni²⁺, 形成SiO₂-SH/IDA-Ni²⁺复合微球从而可以更好的分离以六聚组氨酸为标签的(His-tagged)蛋白。结果显示制备的样品对分离His-tagged蛋白具有广谱性, 并且具有较好的再生能力。     

CrOx/SiO2催化剂上丙烷在CO2气氛中脱氢反应的研究

采用XRD、UV-vis DRS、ESR和微分吸附量热等技术,考察了铬担载量分别为2.5、5和10wt%的CrO_x/SiO₂催化剂的结构、表面性质和氧化还原性能。结果表明,催化剂表面上存在多种Cr的氧化态和聚集形式。随着Cr担载量从2.5wt%到10wt%的逐渐增大,催化剂表面占主导地位的Cr物种由CrO₃单体转为多聚CrO₃和Cr₂O₃晶相。在CO₂气氛中催化剂对丙烷转化率和丙烯选择性的大小顺序为2.5wt%CrO_x/SiO₂>5wt%CrO_x/SiO₂>10wt%CrO_x/SiO₂,反应过程中的原位ESR和UV-visDRS测定结果表明,催化剂表面的反应活性中心为Cr⁵⁺,Cr⁵⁺可由催化剂预处理过程中Cr³⁺的氧化及丙烷反应过程中CrO₃单体的还原产生,在反应中CO₂可使Cr³⁺重新氧化为Cr⁵⁺.     

用ATRP方法制备聚苯乙烯/纳米二氧化硅杂化粒子

采用过量的甲苯-2,4-二异氰酸酯(TDI)对SiO₂纳米粒子表面进行修饰, 将原子转移自由基聚合(ATRP)引发剂引入到SiO₂粒子表面合成大分子引发剂, 采用ATRP技术将聚苯乙烯(PS)大分子链接枝到SiO₂表面制备出以纳米二氧化硅为核, 聚苯乙烯为壳的PS/SiO₂杂化粒子. 利用红外光谱(FTIR)、核磁共振谱( NMR)、凝胶色谱(GPC)等实验手段对杂化粒子及表面接枝聚苯乙烯进行了表征分析.     

吲哚方酸菁半导体在场效应晶体管中的应用

研究了2,3,3-三甲基-1-H-吲哚方酸菁的场效应性质, 通过X射线衍射证实了方酸菁分子内电荷分离结构以及分子间面面堆积模式, 并在Si/SiO₂基片上通过真空蒸镀和旋涂的方法制备了p型晶体管器件. 通过对器件性能与沟道形态的研究, 我们发现退火处理能促进方酸菁薄膜由无定形态向多晶态转变, 从而使薄膜晶体管的迁移率从10^-5 cm²?V^-1?s^-1量级提高到10^-3 cm²?V^-1?s^-1量级. 顶接触结构单晶器件获得了7.8×10^-2 cm²?V^-1?s^-1的迁移率. 未封装的方酸菁晶体管在大气中也表现出较好的稳定性.     

三维有序大孔Fe2SiO4/SiO2@C锂离子电池负极纳米玻璃陶瓷-碳复合材料制备及电化学性能

以聚苯乙烯（PS）胶晶作为铸模,采用纳米铸造工艺及后续煅烧的方法合成了三维有序大孔Fe₂SiO₄/SiO₂@C纳米玻璃陶瓷锂离子电池负极材料。溶胶-凝胶工艺产生的凝胶在650℃氩气氛炉中煅烧后,Fe₂SiO₄纳米晶体从含铁元素的SiO₂基玻璃中结晶析出,形成由Fe₂SiO₄纳米晶体、铁离子（Fe³⁺）修饰的玻璃态SiO₂和非晶碳组成的三维有序大孔纳米玻璃陶瓷。在50 mA·g^-1电流密度下进行充放电时,其放电容量可达450 mAh·g^-1以上,电流密度增加到250 mA·g^-1时可逆放电容量仍旧稳定地保持在260 mAh·g^-1,而具有同样有序大孔结构和含碳量的非晶态SiO₂@C材料的放电比容量在50 mA·g^-1电流密度时仅为15 mAh·g^-1。这些结果表明,Fe₂SiO₄纳米晶体及Fe³⁺有助于SiO₂基玻璃陶瓷实现可逆储锂过程。     

表面修饰纳米二氧化硅及其与聚合物的作用

本文综述了近几年国内外对纳米二氧化硅的表面化学修饰及其在聚合物基纳米复合材料中与基体作用方式的研究工作。对纳米SiO₂进行表面修饰可以改善纳米颗粒与聚合物基体间的亲和性,同时可以使纳米SiO₂表面功能化,有利于SiO₂与聚合物基体间形成强的结合力。纳米SiO₂与聚合物基体间可以以吸附力、氢键、共价键等方式结合,不同的结合方式对材料性能也会产生不同程度的影响。     

新型铕配合物二氧化硅荧光纳米粒子DPPDA-Eu3+/SiO2的制备与表征

本文首先合成配位体4,7-二苯基-1,10-菲罗啉-2,9-二羧酸(DPPDA,C₂₆H₁₆N₂O₄)及铕配合物DPPDA-Eu³⁺((C₂₆H₁₆N₂O₄)₂Eu·15H₂O),然后采用反相微乳液法,通过正硅酸乙酯和3-氨丙基三甲氧基硅烷的共水解、聚合作用成功制备出表面带氨基的二氧化硅包裹铕配合物DPPDA-Eu³⁺的核壳型荧光纳米颗粒DPPDA-Eu³⁺/SiO₂。利用透射电子显微镜、荧光光谱、紫外-可见光谱等手段进行表征,并进行了光稳定性、荧光泄露与氨基测定等实验,结果表明所制备的纳米粒子呈规则球状,大小均匀,粒径为80±8 nm,具有良好的单分散性和光稳定性,不易发生荧光分子从二氧化硅壳层中泄露,纳米粒子表面带有氨基,可不需要进行表面修饰而直接与生物分子反应。该纳米粒子可望作为一种新型的稀土荧光探针应用于时间分辨荧光免疫分析、生物芯片及生物传感器等。     

新型纳米多孔SiO2气凝胶微球材料的制备

A new type of nanoporous SiO₂ aerogel microsphere materials were synthesized by using SiO₂ sols as raw materials in the W/O emulsion formed by the emulsification of Tween-85 and Span-80. The obtained wet gel microspheres were aged by a successive solvent exchanging of alcohol, tetraethylorthosilicate (TEOS)/ethanol solution and ethanol at 60 ℃, and then were dried at ambient pressure to produce SiO₂ aerogel microspheres. The resultant SiO₂ aerogel microspheres were characterized by SEM, TEM and nitrogen adsorption-desorption. The results show that the prepared SiO₂ aerogel microspheres are nanoporous materials with coherent network nanoporous structure consisting of SiO₂ nanoparticles with an average diameter of about 10 nm. The apparent density of a typical sample is 0.4 g·cm^-3, while the specific surface area is 386 m²·g^-1, and the average pore size is 18 nm with the porosity of 84%. Various SiO₂ aerogel microspheres with the apparent particle sizes of 10～200 μm can be synthesized by controlling the stirring speed at 600～2 000 r·min^-1, the volume ratio of water/oil from 0.10 to 0.30, and the weight ratio of Tween-85/Span-80 less than 0.40.     

锂离子电池Si@void@C复合材料的制备及其电化学性能

以纳米Si颗粒为核心,正硅酸四乙酯（TEOS）为SiO₂源,采用Stober法在Si表面包覆一层SiO₂,再以多巴胺为碳源,通过碳化处理将SiO₂表面的聚多巴胺层转化成碳层。最后,用HF刻蚀SiO₂并留下空隙,得到Si@void@C复合纳米颗粒。利用X射线衍射、扫描电镜、透射电镜和恒流充放电测试对材料的物相、微观形貌和电化学性能进行表征。结果表明,在0.1 A·g^-1电流密度下,Si@void@C负极材料充放电循环100次后充电比容量仍然有1 319.5 mAh·g^-1,容量保持率为78.4%,表现出优异的电化学性能。     

Molecular orientation and interface compatibility for high performance organic thin film transistor based on vanadyl phthalocyanine

Organic thin film field-effect transistors (OTFTs) with mobility up to 1.0 cm2 V(-1) s(-1) and on/off ratio of 10(6)-10(8) as well as good environmental stability were demonstrated by using vanadyl phthalocyanine (VOPc), a pyramid-like compound with an ultra closely pi-stacked structure. The high performance, remarkable stability, low price, easy availability and nontoxicity of VOPc enabled it to be a promising candidate for OTFTs. Furthermore, we found that the mobility of the devices on OTS-modified Si/SiO2 substrates was 2 orders of magnitude higher than that of devices on Si/SiO2 substrates. Significantly, the relationship between field effect property and insulator surface property was explained from two new aspects of distribution of molecular orientation and interface compatibility, which might provide not only a useful model to explain why the surface modification with OTS could largely improve the field-effect performance but also a guide for rational optimization of device structure for higher performance. In addition, the field effect property of VOPc devices under vacuum, i.e., the oxygen doping effect on the VOPc devices, was measured. We found that the hole mobility decreased by several orders of magnitude with decreasing pressure. At a pressure below 10(-2) Pa, the device on OTS-modified substrates exhibited ambipolar conduction. These results indicated that the oxygen doping exerted essential effect on the field-effect property of VOPc, which was clearly distinct from that observed for pentacene-based OFETs.     

SrS/α-SiO~2界面的XPS研究

TFEL器件中绝缘层与发光层之间的界面对电荷的输运特性、发光特性等有着十分重要的作用。本文通过XPS的测量,分析了新结构器件中SrS/α-SiO~2界面的各成分的芯电子能谱的变化和深度分布,发现Sr^2^+向SiO~2中扩散较深并以氧化物的形态存在,介质层以SiO~x(x=1.65～1.70)的形态存在。这些丰富的界面态有可能成为TFEL器件的初电子源而对SrS:Ce发光有贡献。     

Ultrathin polymer gate buffer layer for air‐stable,low‐voltage,n‐channel organic thin‐film transistors

An ultrathin poly(methyl methacrylate) (PMMA) buffer layer was developed to improve the performance of n‐channel organic thin‐film transistors (OTFTs). The 8 nm‐thick PMMA film, prepared by spin‐coating, provided a very smooth surface and a uniform coverage on SiO₂ surface reproducibly, which was confirmed by X‐ray reflectivity (XR) measurement. Then, we fabricated N,N′‐ditridecyl‐3,4,9,10‐perylenetetracarboxylic diimide (PTCDI‐C13) thin‐film transistors with and without this 8 nm‐thick PMMA insulating layer on SiO₂ gate insulators and achieved one‐order increase of field‐effect mobility (up to 0.11 cm²/(Vs) in a vacuum), one‐half decrease of threshold voltage, and reduction of current hysteresis with the PMMA layer. Only TFTs with the PMMA layer displayed n‐channel operation in air and showed field‐effect mobility of 0.10 cm²/(Vs). We consider that electrical characteristics of n‐channel OTFTs were considerably improved because the ultrathin PMMA film could effectively passivate the SiO₂ insulator surface and decrease interfacial electron traps. This result suggests the importance of the ultrathin PMMA layer for controlling the interfacial state at the semiconductor/insulator interface and the device characteristics of OTFTs. Copyright © 2009 John Wiley & Sons, Ltd.     

Lipid membrane formation by vesicle fusion on silicon dioxide surfaces modified with alkyl self-assembled monolayer islands

Using atomic force microscopy, we have investigated the formation of the dipalmitoylphosphatidylcholine (DPPC) membrane by the vesicle fusion method on SiO2 surfaces modified with self-assembled monolayer (SAM) islands of octadecyltrichlorosilane (OTS) with sizes comparable to those of the vesicles. OTS-SAM islands with various sizes and coverages can be constructed on the SiO2 surfaces prepared by thermal oxidation followed by partial hydroxylation in a H2O2/H2SO4 solution. When vesicles are sufficiently smaller than the SiO2 domains, DPPC bilayers and DPPC/OTS layers form on the SiO2 and OTS domains, respectively. However, the adhesion of larger vesicles onto SiO2 is prevented by the OTS islands; therefore only DPPC/OTS layers form without formation of DPPC bilayers on the SiO2 domains. On surfaces with domains on the scale of tens to hundreds of nanometers, the relative size between the hydrophilic domains and the vesicles becomes an important factor in the membrane formation by the fusion of vesicles.     

Thermally curable organic/inorganic hybrid polymers as gate dielectrics for organic thin‐film transistors

New low‐temperature curable organic/inorganic hybrid polymers were designed and synthesized as gate dielectrics for organic thin‐film transistors (OTFTs). Allyl alcohols were introduced to polyhedral oligomeric silsesquioxane (POSS) via hydrosilyation to produce an alcohol‐functionalized POSS derivative (POSS‐OH). POSS‐OH was then reacted with hexamethoxymethylmelamine at carrying molar ratios at 80 °C in the presence of a catalytic amount of p‐toluenesulfonic acid to give highly cross‐linked network polymers (POSS‐MM). The prepared thin films were smooth and hard after the thermal cross‐linking reaction and had very low leakage currents (<10^?8 A/cm²) with no significant absorption over the visible spectral range. Pentacene‐based OTFTs using the synthesized insulators as gate dielectric layers had higher hole mobilities (up to 0.36 cm²/Vs) than a device using thermally cross‐linked poly(vinyl phenol) and melamine as the gate dielectric layer (0.18 cm²/Vs). © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3260–3268     

Studies of tetracene- and pentacene-based organic thin-film transistors fabricated by the neutral cluster beam deposition method

The neutral cluster beam deposition (NCBD) method has been applied to produce and characterize organic thin-film transistors (OTFTs) based upon tetracene and pentacene molecules as active layers. Organic thin films were prepared by the NCBD method on hexamethyldisilazane (HMDS)-untreated and -pretreated silicon dioxide (SiO2) substrates at room temperature. The surface morphology and structures for the tetracene and pentacene thin films were examined by atomic force microscopy (AFM) and X-ray diffraction (XRD). The measurements demonstrate that the weakly bound and highly directional neutral cluster beams are efficient in producing high-quality single-crystalline thin films with uniform, smooth surfaces and that SiO2 surface treatment with HMDS enhances the crystallinity of the pentacene thin-film phase. Tetracene- and pentacene-based OTFTs with the top-contact structure showed typical source-drain current modulation behavior with different gate voltages. Device parameters such as hole carrier mobility, current on/off ratio, threshold voltage, and subthreshold slope have been derived from the current-voltage characteristics together with the effects of surface treatment with HMDS. In particular, the high field-effect room-temperature mobilities for the HMDS-untreated OTFTs are found to be comparable to the most widely reported values for the respective untreated tetracene and pentacene thin-film transistors. The device performance strongly correlates with the surface morphology, and the structural properties of the organic thin films are discussed.     

Preparation of surface plasmon resonance biosensor based on magnetic core/shell Fe3O4/SiO2 and Fe3O4/Ag/SiO2 nanoparticles

In this paper, surface plasmon resonance biosensors based on magnetic core/shell Fe(3)O(4)/SiO(2) and Fe(3)O(4)/Ag/SiO(2) nanoparticles were developed for immunoassay. With Fe(3)O(4) and Fe(3)O(4)/Ag nanoparticles being used as seeding materials, Fe(3)O(4)/SiO(2) and Fe(3)O(4)/Ag/SiO(2) nanoparticles were formed by hydrolysis of tetraethyl orthosilicate. The aldehyde group functionalized magnetic nanoparticles provide organic functionality for bioconjugation. The products were characterized by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), FTIR and UV-vis absorption spectrometry. The magnetic nanoparticles possess the unique superparamagnetism property, exceptional optical properties and good compatibilities, and could be used as immobilization matrix for goat anti-rabbit IgG. The magnetic nanoparticles can be easily immobilized on the surface of SPR biosensor chip by a magnetic pillar. The effects of Fe(3)O(4)/SiO(2) and Fe(3)O(4)/Ag/SiO(2) nanoparticles on the sensitivity of SPR biosensors were also investigated. As a result, the SPR biosensors based on Fe(3)O(4)/SiO(2) nanoparticles and Fe(3)O(4)/Ag/SiO(2) nanoparticles exhibit a response for rabbit IgG in the concentration range of 1.25-20.00 μg ml(-1) and 0.30-20.00 μg ml(-1), respectively.     

Coaxially gated in-wire thin-film transistors made by template assembly

Nanowire field effect transistors were prepared by a wet chemical template replication method using anodic aluminum oxide membranes. The membrane pores were first lined with a thin SiO2 layer by the surface sol-gel method. Au, CdS (or CdSe), and Au wire segments were then sequentially electrodeposited within the pores, and the resulting nanowires were released by dissolution of the membrane. Electrofluidic alignment of these nanowires between source and drain leads and evaporation of gold over the central CdS (CdSe) stripe affords a "wrap-around gate" structure. At VDS = -2 V, the Au/CdS/Au devices had an ON/OFF current ratio of 103, a threshold voltage of 2.4 V, and a subthreshold slope of 2.2 V/decade. A 3-fold decrease in the subthreshold slope relative to that of planar nanocrystalline CdSe devices can be attributed to coaxial gating. The control of dimensions afforded by template synthesis should make it possible to reduce the gate dielectric thickness, channel length, and diameter of the semiconductor segment to sublithographic dimensions while retaining the simplicity of the wet chemical synthetic method.     

Low-voltage organic field-effect transistors and inverters enabled by ultrathin cross-linked polymers as gate dielectrics

The quest for high-performance organic thin-film transistor (OTFT) gate dielectrics is of intense current interest. Beyond having excellent insulating properties, such materials must meet other stringent requirements for optimum OTFT function: efficient low-temperature solution fabrication, mechanical flexibility, and compatibility with diverse gate materials and organic semiconductors. The OTFTs should function at low biases to minimize power consumption, hence the dielectric must exhibit large gate capacitance. We report the realization of new spin-coatable, ultrathin (<20 nm) cross-linked polymer blends exhibiting excellent insulating properties (leakage current densities approximately 10(-)(8) Acm(-)(2)), large capacitances (up to approximately 300 nF cm(-)(2)), and enabling low-voltage OTFT functions. These dielectrics exhibit good uniformity over areas approximately 150 cm(2), are insoluble in common solvents, can be patterned using standard microelectronic etching methodologies, and adhere to/are compatible with n(+)-Si, ITO, and Al gates, and with a wide range of p- and n-type semiconductors. Using these dielectrics, complementary invertors have been fabricated which function at 2 V.     

含杂原子的并五苯类似物合成及场效应性能研究

以N,N'-二苯基-1,4-苯二胺为原料, 合成了含硫和氮杂原子的并五苯类似物, 用可见-紫外吸收光谱和电化学测试对这类化合物进行表征, 确定了其光学带隙及轨道能级, 与并五苯相比它们具有低的最高占用分子轨道能级. 得到了三苯并二噻嗪的单晶结构, 分子具有平面结构, 分子间具有强的π…π相互作用和N…S相互作用. 首次将该类并五苯类似物应用于有机薄膜场效应晶体管中, 器件显示好的场效应特性, 迁移率为0.01 cm²·V^-1·s^-1.