桑色素修饰金纳米粒子自组装膜的制备及其性能研究

采用水相硅烷化方法,将γ-氨基丙基三乙氧基硅烷[H₂N(CH₂)₃Si(OC₂H₅)₃](APES)组装在石英表面,在基底表面修饰上氨基为末端的单层膜,并进一步在这种功能化的单层膜基底上组装金纳米粒子得到金纳米粒子/APES/石英的纳米复合结构。以制备的金纳米粒子自组装膜修饰石英为基底及DL-半胱胺酸为中介,利用桑色素(Morin)和DL-半胱胺酸的化学吸附作用,将桑色素间接组装在金纳米粒子自组装膜修饰石英基底表面,所构建的桑色素修饰金纳米粒子自组装膜对三苯基锡有灵敏的荧光识别作用。文章着重研究了桑色素修饰金纳米粒子自组装膜的制备以及组装条件对其荧光行为的影响,探讨了膜的响应特性及响应机理。     

Pt纳米微粒自组装体系的电化学和原位FTIR反射光谱研究

用化学还原法制备了铂金属纳米微粒 ,透射电子显微镜 (TEM)表征纳米Pt微粒的平均直径为 2 5nm。通过二硫醇将Pt纳米微粒组装到多晶金电极表面。以Fe(CN) 4- 3-6 的氧化还原作为探针反应的电化学研究表明 ,Au表面组装二硫醇后抑制了电极 /溶液界面的电子传递过程 ,而在二硫醇上再组装铂纳米微粒后 ,电子传递又可进行。运用电化学FTIR反射光谱研究了Pt纳米微粒组装电极在酸性介质中CO的吸附 ,检测到CO的线型、桥式吸附态 ,分别在 2 0 30和 184 5cm- 1 附近给出红外吸收谱峰 ,并且有增强红外效应。此外 ,还观察到Pt纳米微粒上的CO孪生吸附态。红外吸收峰位于 2 10 0cm- 1 附近。     

纳米α-Al2O3磨料抛光单晶硅片光滑表面的形成机理

"将纳米α-Al2O3粉体配制成抛光液并冷冻成冰结抛光垫对单晶硅片进行了抛光,用原子力显微镜观察了抛光表面的微观形貌并测量了其表面粗糙度,采用透射电镜观察了单晶硅片抛光后的断面形貌．为进一步分析抛光过程中的化学作用机理,采用X射线光电子能谱分析了单晶硅片抛光后表面的化学成分．利用纳米压痕仪的划痕附件对单晶硅片进行了划痕测试,研究了抛光过程中的机械作用机理．结果表明纳米α-Al2O3磨料冰冻抛光单晶硅片时,在1 mm￡1 mm的范围内得到了微观表面粗糙度为0.367 nm的超光滑表面,亚表面没有任何损伤,材     

两种纳米粒子的自组装及表面增强拉曼光谱研究

在氨基硅烷化的单晶硅片表面通过静电自组装技术组装上金和金核铂壳两种纳米粒子,通过改变基底浸泡在溶胶中的时间控制基底上纳米粒子的密度。用扫描电子显微镜(SEM)对基底表面上的形貌进行表征,结果表明纳米粒子呈亚单层二维阵列分布。以吡啶(Py)为探针分子,用波长为632.8 nm的激发光作为激发光源,研究纯金和金铂复合基底上的表面增强拉曼光谱(SERS)行为。数据显示在金纳米粒子之间引入金核铂壳纳米粒子后,Py的两个特征峰的频率没有明显变化,但谱峰的强度却变弱了,其SERS信号衰减最大可至原来的24%。这是由于引入的铂的d态电子使金的等离子体激发猝灭,从而破坏了电磁场增强,使金的SERS信号衰减。     

功能性硅烷在纳米氧化硅表面的自组装

在分散体系中 ,两种功能性硅烷 ,甲基丙烯酰氧丙基三甲基硅烷 (MPTES)和氨丙基三甲基硅烷 (APTES)在纳米氧化硅表面形成自组装单分子层 ,用XPS和FTIR对所得自组装单分子层进行了表征 .元素分析结果表明 ,所得功能性纳米氧化硅中的功能基含量分别为 1.0 3mmol/g甲基丙烯酰氧基 /丙烯酰氧丙基纳米氧化硅 (MPSN)和 3.34mmol/g氨基 /氨丙基纳米氧化硅 (APSN) .LSS分析结果表明 ,未修饰纳米氧化硅、MPSN和APSN在甲苯分散体系中的平均流体力学直径大约分别为 2 4 0、4 5和 5 6 0nm .     

Ag-Cu_2O/RGO纳米复合物的的制备及其SERS活性的研究

通过简单的化学还原法在室温条件下成功的合成了三元的Ag-Cu2O/RGO纳米复合物,这种复合物结合了Ag,Cu2O以及石墨烯三者的特性,表现出了很高的SERS活性。Cu2O/RGO具有一定表面增强能力,复合了Ag纳米粒子后,Ag-Cu2O/RGO纳米复合物对探针分子PATP的检测可以达到10-9 mol·L-1,一方面由于石墨烯比表面积大并具有大π键结构对分子起到了很好的富集作用,另一方面是由于Cu2O和Ag共同的SERS增强作用提高了SERS信号。因此该基底在SERS检测上有潜在的应用。     

稀土纳米发光材料的燃烧法制备及光谱性质

用燃烧法制备了不同粒径的La2O3:Eu3 纳米微粒,研究了影响La2O3:Eu3 纳米微粒大小的实验条件,发现粒径大小随甘氨酸(Gly)与稀土离子比例的增大而减小.制备的纳米微粒由谢乐公式计算的粒径尺寸为12～28 nm.测量了样品的高分辨光谱.运用激光选择激发,研究了光谱在不同发光中心上的变化,表面态对于这些变化起着主要作用.     

纳米Cu/Al_2O_3组装体模板合成与光吸收

以有序的多孔氧化铝为模板,利用交流电在孔洞中沉积金属铜得到纳米Cu粒子/Al2O3组装体系.透射电镜观察显示随着交流电沉积时间的延长,孔洞中纳米Cu粒子数量增加.测量了纳米Cu粒子/Al2O3组装体系的紫外可见光吸收光谱,发现随着孔洞中纳米Cu粒子数量增加,纳米Cu粒子/Al2O3组装体系的吸收带边大幅度红移;根据雷利散射引起的消光增强解释了组装体吸收带边红移的原因.同时发现Cu粒子的表面等离子共振吸收峰消失及组装体在吸收带边区光吸收值满足间接带隙半导体光吸收边的表达式.     

Ag-MgF2复合纳米金属陶瓷薄膜的微结构及吸收光谱特性研究

对用真空蒸发技术制备的Ag-MgF2复合纳米金属陶瓷薄膜（Ag的质量分数为0.15、0.20、0.30）的微结构及吸收光谱特性进行了研究。微结构分析表明薄膜由平均粒径约18nm的fcc-Ag纳米晶粒嵌埋于主要呈非晶态的MgF2基体中所组成。对吸收光谱的研究表明，Ag纳米微粒的表面离子共振吸收峰出现在λ＝412nm-417nm波段范围内。随着Ag组分增加，吸收峰强度下降，呈现轻微红移并且逐渐宽化。     

(Au)_核(Ag)_壳纳米微粒-火焰原子吸收光谱法测定过氧化氢

在90 ℃水浴条件下,以粒径为10 nm的纳米金做晶种,用柠檬酸三钠还原硝酸银,制备了平均粒径为30 nm的（Au）核（Ag）壳纳米微粒,用高速离心纯化除去过量的柠檬酸三钠获得了较纯的（Au）核（Ag）壳纳米微粒。在pH 3.8的HAc-NaAc缓冲溶液中,Fe2＋催化H2O2反应产生的羟基自由基可氧化（Au）核（Ag）壳纳米微粒生成银离子。离心后,离心液中的银离子可用火焰原子吸收光谱法在328.1 nm波长处测量。随着H2O2浓度增大,离心液中银离子浓度增加,其吸光度值增加。H2O2浓度在2.64～42.24 μmol·L-1范围内与上清液中银离子的原子吸收值ΔA呈良好的线性关系,回归方程为ΔA=0.014c-0.013 1, 相关系数为0.998 4,检出限为0.81 μmol·L-1 H2O2。当用于水样中H2O2的测定,获得了满意的结果。     

光谱学研究硅烷钒锆复合钝化膜的结构和成膜机理

在热镀锌钢板表面制备了硅烷钒锆复合钝化膜。用X射线光电子能谱(XPS)、射频辉光放电发射光谱(rf-GD-OES)和傅里叶变换衰减全反射红外光谱(ATR-FTIR)表征了钝化膜的组成结构,分析了硅烷钒锆复合钝化膜的成膜机理。结果表明：硅烷之间互联构成了硅烷钒锆复合钝化膜的主成膜成分,无机缓蚀剂均匀分布在膜层中。钝化膜表面Si2p的XPS窄幅扫描谱100.7 eV处的拟合峰和红外光谱在波数1 100 cm-1 Si—O吸收峰变宽加强,表明硅烷以Si—O—Zn键的形式化学吸附在锌的表面,硅烷分子之间通过Si—O—Si键相互交联;红外光谱中1 650和1 560 cm-1的两个酰胺特征峰,结合910 cm-1的环氧特征峰的消失,表明γ-GPT的环氧基团在氨基活性氢的诱导下开环和γ-APT的氨基之间发生聚合反应形成交联的空间网状结构;rf-GD-OES分析发现钝化膜0.3 μm处存在一层富氧层,钝化反应生成的ZrF₄,ZrO₂和钒盐等无机物均匀分布在钝化膜中。分析膜层组成结构和成膜前后的ATR-FTIR光谱,研究了成膜过程中发生的物理过程和化学变化,提出了硅烷钒锆复合钝化膜的成膜机理。     

Initial growth process and surface structure of Ag on Si(111) studied by low-energy Ion-Scattering Spectroscopy (ISS) and LEED-AES

The growth process of silver on a Si(111) substrate has been studied in detail by low-energy ion-scattering spectroscopy (ISS) combined with LEED-AES. Neon ions of 500 eV were used as probe ions of ISS. The ISS experiments have revealed that the growth at room temperature and at high temperature are quite different from each other even in the submonolayer coverage range. The following growth models have been proposed for the respective temperatures. At room temperature, the deposited Ag forms a two-dimensional (2D) island at around 2/3 monolayer (ML) coverage, where the Ag atoms are packed commensurately with the Si(111)1 substrate. One third of the substrate Si surface remains uncovered there. Then it starts to develop into Ag crystal, and at a few ML coverage a 3D island of bulk Ag crystal grows directly on the substrate. An intermediate layer, which covers uniformly the whole surface before the growth of Ag crystal, does not exist. At high temperatures (>~200°C), the well-known Si(111)√3-Ag layer is formed as an intermediate layer, which consists of 2/3 ML of Ag atoms and covers the whole surface uniformly. These Ag atoms are embedded in the first double layer of the Si substrate. It is concluded that the formation of the √3 structure needs relatively high activation energy which may originate from the large displacement of Si atoms owing to the embedment of the Ag atoms, and does not proceed below about 200°C. The most stable state of the Ag atoms on the outermost Si layer is in the shape of an island, both for the Si(111) surface and for the Si(111)√3-Ag surface.     

Preparation and photoelectrochemical performance of Ag/graphene/TiO2 composite film

By dipping-lifting in sol-gel solution and reducing process, the graphene/TiO₂ composite film on the glass plate was first prepared. Then, the Ag/graphene/TiO₂ composite film was fabricated by interface reaction with AgNO₃ and N₂H₄·H₂O on the surface of graphene/TiO₂ composite film. The characterization results show that the uniform porous TiO₂ film is made up of the anatase crystal, and the Ag/graphene/TiO₂ composite film is constructed by doping or depositing graphene sheets and Ag nanoparticles on the surface of TiO₂ film. The photoelectrochemical measurement results indicate that the Ag/graphene/TiO₂ composite film has an excellent photoelectrochemical conversion property.     

Role of ion energy flux on the structural and morphological properties of silicon oxy-nitride composite films deposited by plasma focus device

ABSTRACT

Crystalline silicon oxy-nitride (SiON) composite films are deposited on Si substrate for multiple (5, 15, 25 and 50) focus shots (FS) by plasma focus device. The X-rays diffraction patterns reveal the development of various diffraction peaks related to Si, Si₃N₄, and SiO₂ phases which confirms the formation of SiON composite film. The intensity of Si₃N₄ (1 0 2) plane is linearly increased with the increase of FS. The Si₃N₄ (1 0 2) phase does not nucleate for 5 FS. Raman analysis confirms the formation of β–Si–N phase. Raman and Fourier transform infrared spectroscopy analysis reveals that the strength of chemical bonds like Si–N, Si–O formed during the deposition process of SiON composite films is associated with the bonds intensity which in turn depends on the number of FS. The field emission scanning electron microscopic analysis reveals that the surface morphology like size, shape and distribution of micro/nano-dimensional particles, film compactness and the formation of micro-rods, micro-teethes and micro-tubes of SiON composite films is entirely associated with the rise in substrate surface transient temperature which in turn depends on the increasing number of FS. The EDX spectrum confirms the presence of Si (22.5?±?4.7 at. %), N (13.4?±?4.5 at. %) and O (54.7?±?11.3 at. %) in the SiON composite film. The thickness of SiON composite film deposited for 50 FS is found to ～15.47?µm.     

一种新型硅基3C-SiC的生长方法及光谱学表征

采用LPCVD技术, 以CH4和H2混合气体为反应源气, 在n-Si（111）衬底上生长3C-SiC晶体薄膜。H2在反应过程中作为稀释气体和运输气体, CH4作为碳源, 硅源有衬底硅来提供。利用X射线衍射分析仪、场发射扫描电子显微镜、激光拉曼光谱和傅里叶变换红外光谱分别研究3C-SiC薄膜的晶相结构、表面形貌及其光谱性质。结果表明此生长方法可以成功的成长出3C-SiC薄膜。     

在Si(111)上用有机溶胶凝胶甩膜热解法制备(0001)定向的6H-SiC薄膜

在Si(111)衬底上用聚苯乙烯溶胶凝胶甩膜并经950℃真空(10^-3Pa)热解处理法,制备出晶态SiC薄膜.用FTIR,XRD,TEM,RamanXPS等方法研究了SiC薄膜的晶体结构、微结构、组成以及各元素的化学态等性质.结果表明制得的是沿(0001)高度择优取向的晶态6H-SiC薄膜.膜中SiC晶粒沿c轴柱状生长,其最大尺寸约150nm,膜厚约为0.3μm,SiC中的Si/C比约为1.表层有少许污染C(CH和CO)和少量O(Si₂O₃,CO态氧和吸附氧).从对比实验可知,在热解时将甩膜的Si片与另一空白Si片面面相贴可明显增加SiC的生成量. 关键词： 碳化硅 薄膜 溶胶凝胶     

Kinetics of surface droplet epitaxy and its application to fabrication of mushroom-shaped metal/Si heterostructure on nanometer scale

The variation in interfacial reaction between Au islands and Si substrates and the fabrication of a Au/Si heterojunction on a nanometer scale are described. Morphologies and elemental distribution were drastically changed around the interface between Au islands and the Si substrate on changing the surface conditions of the substrate. In particular, the Au/Si bilayer structure was formed on the clean Si surface by thermal annealing instead of the well-known interdiffusion of the two elements. This structure was fabricated through liquid phase epitaxy (LPE), in which migrating Si atoms on the surface play an important role. These results suggest that the kinetics of the interfacial reaction are variable and controllable even within the same material system. On the basis of this phenomenon, mushroom-shaped bilayer dots of Au/Si and Ag/Si were fabricated on a nanometer scale by employing metal particles as the transport medium for Si growth.     

Investigation on cell biocompatible behaviors of polyaniline film fabricated via electroless surface polymerization

Considering for the potential application in tissue engineering, polyaniline (PANi) film was fabricated via a two-step route: a self-assembled monolayer of C₆H₅NHC₃H₆Si(OMe)₃ was firstly formed on the single-crystal Si substrate; the conducting PANi film was then prepared through electroless surface polymerization of the aniline molecules on the aniline monolayer-bearing silane surface in an acidic aqueous solution. The formation of PANi film on Si surface was confirmed by characterizations of X-ray photoelectron spectroscope (XPS) and specular reflectance Fourier transform infrared (SR-FTIR) spectrum, etc. At last, the proliferation behaviors of PC-12 cells on the PANi film surface were studied by the [3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide] (MTT) colorimetric assays, acridine orange fluorometric staining, and scanning electron microscope (SEM) observation, etc. The results demonstrate that the as-prepared PANi film provides high ability for cell proliferation, exhibiting promising potentials as surface coating to cultivate neuronal cells for applications in the tissue engineering.     

Synthesis of ZnAl2O4/α-Al2O3 complex substrates and growth of GaN films

With the solid phase reaction between pulsed-laser-deposited (PLD) ZnOfilm and α-Al2O3 substrate, ZnAl2O4/α-Al2O3 complex substrates were synthesized. X-ray diffraction (XRD) spectra show that as the reaction proceeds, ZnAl2O4 changes from the initial (111)-oriented single crystal to poly-crystal, and then to inadequate (111) orientation. Corresponding scanning electron microscope (SEM)images indicate that the surface morphology of ZnAl2O4 transforms from uniform islands to stick structures, and then to bulgy-line structures. In addition, XRDspectra present that ZnAl2O4 prepared at low temperature is unstable at the environment of higher temperature. On the as-obtained ZnAl2O4/α-Al2O3 substrates, GaN films were grown without any nitride buffer using light-radiation heating low-pressure MOCVD (LRH-LP-MOCVD). XRD spectra indicate that GaN film on this kind of complex substrate changes from c-axis single crystal to poly-crystal as ZnAl2O4 layer is thickened. For the single crystal GaN, its full width at half maximum (FWHM) of X-ray rocking curve is 0.4°. Results indicate that islands on thin ZnAl2O4 layer can promote nucleation at initial stage of GaN growth, which leadsto the (0001)-oriented GaN film.     

反应气压对直流磁控反应溅射制备的氧化银薄膜的结构和光学性质的影响

利用直流磁控反应溅射技术,通过调节反应气压(RP),在250 ℃衬底温度下制备了一系列氧化银 (Ag_xO) 薄膜,并利用X射线衍射谱、能量色散谱和分光光度计重点研究了RP对Ag_xO薄膜的结构和光学性质的影响. 研究结果表明,随着RP从0.5 Pa升高到3.5 Pa,薄膜明显呈现了从两相(AgO+Ag₂O)到单相(Ag₂O)结构再到两相(Ag₂O+AgO)结构的演变. 特 关键词： 氧化银薄膜 直流磁控反应溅射 X射线衍射谱 光学性质