甲氰菊酯在纳米银膜上的SERS光谱检测

本文将聚乙烯醇(PVA)包覆的纳米银粒子组装在铝片表面形成的纳米银薄膜作为表面增强拉曼散射基底,使用扫描电镜对纳米银膜的表面形貌进行了表征。同时采用近红外激光(785nm)作为激发光对甲氰菊酯的丙酮溶液(10-4~10-7 mol/L)进行了近红外表面增强拉曼散射(NIR-SERS)光谱检测。结果表明该方法对甲氰菊酯的检测极限为10-6 mol/L。最后对甲氰菊酯的NIR-SERS光谱重现性进行了检测,即分别检测了浓度为10-4 mol/L和10-5 mol/L的甲氰菊酯丙酮溶液各6个样品,实验结果表明该纳米银膜在检测甲氰菊酯时体现出了较好的重复性。     

Al/Al_2O_3复合薄膜的制备及表面等离子体共振性能研究

为了探究氧化层对金属薄膜表面等离子体共振(SPR)特性的调制作用,实验采用直流磁控溅射技术,通过控制沉积功率和沉积时间制备不同厚度的金属铝基薄膜,而后调控退火时间和温度得到相应的铝/氧化铝(Al/Al203)复合薄膜。采用X射线衍射仪(XRD)、原子力显微镜(AFM)、紫外-可见-近红外分光光度计及拉曼光谱仪分别表征样品的结构、表面形貌及SPR特性。XRD测试结果表明,随着金属铝基薄膜厚度的增加,Al/Al203复合薄膜由非晶态转变为较低表面能方向择优生长,薄膜结晶质量提高。其吸收光谱在220 nm附近处出现由双层复合薄膜SPR吸收峰,830 nm附近的峰对应金属铝膜的本征吸收峰。以罗丹明B为例的拉曼光谱测试结果表明,拉曼散射强度随着铝薄膜厚度增加表现为先增强后减弱的趋势,当铝膜厚度为14.5 nm时,表面增强拉曼散射(SERS)效果最显著。实验结果表明,氧化铝膜层对不同厚度的金属铝基薄膜的SPR特性有很好的调制作用,氧化铝化学性质稳定,对样品起到很好的保护作用。     

4-(2-吡啶偶氮)-间苯二酚的共振散射光谱研究

研究了4-(2-吡啶偶氮)-间苯二酚(PAR)水溶液的共振散射光谱的形成机理与影响因素。在弱酸性溶液中,PAR可产生很强的共振光散射, 散射光谱形状与吸收光谱有关。溶液酸度影响PAR的电离平衡和存在状态,因而影响散射光谱。在pH 3.1～6.2之间,PAR为不带电荷的中性分子,可在疏水力的作用下结合形成分子聚合体,从而导致共振光散射增强。光偏振实验表明PAR的散射光为完全偏振光。在一定实验条件下,光散射强度与PAR浓度之间存在线性关系。     

Au/TiO_2薄膜的光催化与表面增强拉曼散射性能研究

采用浸渍提拉法将预先合成的TiO2溶胶均匀涂覆在玻璃表面制膜,并在膜表面负载上具有高表面增强拉曼散射(SERS)活性的Au纳米粒子,获得Au/TiO2多功能薄膜。通过X射线衍射(XRD)、扫描电镜(SEM)、紫外可见吸收光谱(UV-vis)、拉曼(Raman)等表征手段,考察了Au/TiO2薄膜的结构、形貌与性能。所得Au/TiO2薄膜在UV灯辐照下可有效地降解罗丹明B等染料分子,其中Au粒子有效抑制了薄膜表面光生电子-空穴的复合,增强了光生载流子的分离效率,提高了薄膜的光催化性能。同时拉曼实验表明,Au/TiO2薄膜也是一种优秀的SERS检测基底。更为重要的是,Au/TiO2薄膜可通过UV灯照射"清洗"掉薄膜表面吸附的上组SERS实验中的检测分子,实现基底的循环利用,有望解决传统SERS基底一次性使用的缺陷。     

Au/TiN复合薄膜制备及其表面增强拉曼光谱研究

表面增强拉曼散射光谱(SERS)已用于环境监测、生物医药、食品卫生等领域,而高活性SERS基底是表面增强拉曼散射光谱技术应用的关键。TiN作为新型等离子材料具有较强的SERS性能,同时化学稳定性及生物相容性较好,但其SERS性能不如贵金属金强。该研究采用氨气还原氮化法和电化学沉积法,在TiN薄膜表面沉积贵金属Au纳米颗粒制备出Au/TiN复合薄膜。在Au/TiN复合薄膜中单质Au和TiN两种物相共存;随着电化学沉积时间延长,TiN薄膜表面单质金纳米颗粒数量逐渐增多,金纳米颗粒尺寸增大,颗粒间距减小。由于金与TiN两者的本征表面等离子共振耦合作用,Au/TiN复合薄膜的共振吸收峰发生了偏移。利用罗丹明6G为拉曼探针分子,对Au/TiN复合薄膜进行SERS性能分析,发现Au/TiN复合薄膜上的R6G探针分子的拉曼峰信号强度随沉积时间延长呈现先增大后减小的规律;当电化学沉积时间为5 min时,R6G拉曼信号峰较高,复合薄膜样品的SERS活性最大。将Au/TiN复合薄膜和Au薄膜分别浸泡在10-3,10-5,10-7,10-8及10-9 mol·L-1 R6G溶液5 min,进行检测限分析,发现Au/TiN复合薄膜检测极限达10-8 mol·L-1,增强因子达到8.82×105,与Au薄膜和TiN薄膜相比,Au/TiN复合薄膜上对R6G探针分子SERS活性最高。这得益于Au/TiN复合膜中表面等离子体产生的耦合效应,使得局域电磁场强度增强,从而引起R6G探针分子拉曼信号增强。通过2D-FDTD模拟电场分布发现Au/TiN,Au及TiN薄膜具有电场增强作用,其中Au/TiN复合薄膜的增强作用尤为显著,这也证实了氮化钛与金纳米颗粒之间存在耦合效应。另外发现TiN与Au之间可能存在电荷转移,促进了4-氨基苯硫酚氧化反应,进而证实了TiN与Au薄膜的协同作用。此外,Au/TiN复合薄膜均匀性较好,相对平均偏差仅为7.58%。由此可见,采用电化学沉积制备的Au/TiN复合薄膜具有作为SERS基底材料的应用潜力。     

2-噻吩甲酸在Fe3O4@Ag基底上的吸附及表面增强拉曼光谱

采用共沉淀法合成Fe₃O₄纳米颗粒,再以柠檬酸三钠还原AgNO₃获得了具有SERS活性的Fe₃O₄@Ag磁性纳米复合材料。基于密度泛函理论(DFT)的量子化学计算方法和表面增强拉曼光谱(SERS)技术,从理论计算和实验测定表征探讨了2-噻吩甲酸(2-TCA)在Fe₃O₄@Ag表面的吸附行为和增强效应。结果表明:理论计算得到的拉曼光谱与实际测得的常规拉曼光谱基本一致,而在DFT理论计算中所键连的Ag原子数越多,与实测值就越接近。溶液的浓度和pH对拉曼增强效果有很大的影响,当溶液的pH=3且浓度为1×10^-4 mol·L^-1时有最大拉曼增强效应。峰强随2-TCA浓度的增加呈现先增大后减小的趋势,浓度过大会导致大量2-TCA分子吸附聚集在Ag表面形成局部"拥堵",阻碍了激发光尤其是光谱信号的散射通过,从而减弱了拉曼增强效应。pH的变化使溶液中2-TCA分子形态发生改变,结构形态不同,其在Ag表面的吸附方式也不同。中性C₄H₃SCOOH分子以环上S:形式垂直吸附键合在Ag表面,形成S—Ag配位键而产生SERS光谱。-1价C₄H₃SCOO^-离子以S—Ag配位和O—Ag共价"双键合"侧卧方式共同吸附在Ag表面而产生SERS光谱。在Ag表面,以单独S—Ag配位键吸附或键合的能力比S—Ag配位和O—Ag共价共同吸附方式要弱,但其产生的SERS信号更强,故2-TCA中性分子比2-TCA^-离子更有利于SERS的产生。随着pH值的增加,溶液中的2-TCA由中性分子逐渐转化为-1价的C₄H₃SCOO^-离子,因而在pH>3以后,拉曼增强效应逐步减弱。     

金纳米粒子掺杂DNA-CTMA-DPFP薄膜的表面增强拉曼散射特性

采用柠檬酸三钠还原氯金酸和离子交换法制备金纳米粒子掺杂DNA-CTMA材料,利用钯催化反应合成9,9-二乙基-2,7-二-(4-吡啶)芴荧光染料(DPFP),将DPFP与DNA-CTMA混合后,旋凃制备金纳米粒子掺杂的DNA-CTMA-DPFP薄膜样品。通过吸收光谱、荧光光谱和拉曼光谱的测量,研究了薄膜样品的光学特性和表面增强拉曼散射(SERS)特性。实验结果表明,薄膜样品在300～360 nm的吸收主要来自DPFP,在500～700 nm的吸收来自样品中金纳米粒子的局域表面等离子共振;样品在370,386,408 nm处的荧光峰分别对应DPFP的S₁₀-S₀₀、S₁₀-S₀₁和S₁₀-S₀₂能级的电子振动跃迁;在785 nm激光激发下,薄膜样品的拉曼散射主要来自DPFP分子,随着金纳米粒子掺杂比的增大,DPFP分子的拉曼散射峰强度逐渐增强。因此,金纳米粒子掺杂DNA-CTMA薄膜适合作为多种染料分子的SERS基底。     

基于SiC@Ag基底和银-生物素-链霉亲和素纳米聚集体双重SERS放大的miRNA-106a检测

基于SiC@Ag基底与Ag纳米颗粒的表面增强拉曼散射效应,提出了利用银-生物素-链霉亲和素纳米聚集体二次表面增强拉曼散射放大的超灵敏miRNA-106a检测方案.首先,将地高辛修饰的捕获DNA与固定在SiC@Ag基底上的抗地高辛链接,制备SiC@Ag@anti-digoxin/digoxin-DNA基底;将4-巯基苯甲酸(4MBA)标记的银纳米颗粒与修饰有氨基和生物素的探针DNA链接,制备Ag@4MBA@DNA-biotin探针.然后将制备的基底、探针与待测miRNA-106a组成"三明治"结构,获得表面增强拉曼散射信号放大.最后,依次加入链霉亲和素和制备的探针,形成银-生物素-链霉亲和素纳米聚集体,实现检测信号的二次放大.实验结果表明,利用SiC@Ag基底和银-生物素-链霉亲和素纳米聚集体双重表面增强拉曼散射放大,可以实现miRNA-106a的超灵敏检测,检测极限达到0.579fmol/L,对于肿瘤的早期诊断具有应用潜力.     

Mo_2N/TiN复合薄膜制备及其表面增强拉曼光谱

以四氯化钛和五氯化钼为原料,采用氨气还原氮化法制备出Mo_2N/TiN复合薄膜。利用XRD、XPS、SEM、UV-Vis和Raman测试手段研究了薄膜组成、形貌、表面增强拉曼光谱性能。结果表明,复合薄膜中TiN和Mo_2N两种物相共存,随着五氯化钼掺量增加,复合薄膜中晶粒逐渐细化,其吸收光谱位于400～600 nm的共振吸收峰峰强增加且逐渐宽化。利用罗丹明6G(R6G)作为探针分子探究Mo_2N/TiN复合薄膜的表面增强拉曼性能,研究发现,当五氯化钼添加量为6%时,复合薄膜的表面增强拉曼效应最佳,检测极限为10~(-5) mol/L,增强因子为0.31×10~3,且放置6个月后其拉曼增强性能仅降低20.76%。同时复合薄膜具有一定的耐高温特性,其经过500℃退火后仍具有表面增强拉曼特性,具有重复利用的潜力。     

分子束外延PbTe单晶薄膜的反常拉曼光谱研究

采用分子束外延(MBE)方法在BaF₂(111)衬底上生长了高质量的PbTe单晶薄膜， 拉曼光谱测量观察到了表面氧化物的振动模、布里渊区中心(q≈0)纵光学(LO)声子振动模以 及声子-等离子激元耦合模振动.随着显微拉曼光谱仪激光光斑聚焦深度的改变，各拉曼散射 峰的峰位、积分强度、半高宽等都表现出不同的变化趋势. 随着激光光斑聚焦位置从样品表 面上方3μm处变化到表面下方3μm处，PbTe外延薄膜的LO声子频率从119cm^-1移 动到124cm^{-1关键词： PbTe外延薄膜 拉曼散射 纵光学声子}     

Optical and non-linear optical properties of vanadium oxide phthalocyanine films

The optical and non-linear optical properties of peripheral-substituted vanadium oxide phthalocyanine (VOPc) film and substituted VOPc/polymer composite film were investigated using stationary and transient spectroscopy techniques. The absorption Q band of the VOPc/polymer composite film shows a red shift relative to that of the peripheral-substituted VOPc film, revealing the monomeric characteristics of VOPc molecules. Effective quenching of PL emission was observed for the VOPc/polymer composite film and could be assigned to the efficient VOPc–polymer interaction. From pump-probe and optical Kerr effect (OKE) measurements, two decay components were obtained by fitting the transients for both VOPc films. The fast component, in a femtosecond time domain, originates from the electron–phonon interaction, and the difference in their slow decay is an indication of an efficient ISC process in the VOPc/polymer composite film. The third-order non-linear optical susceptibilities of these films were determined to be in the order of 10^-11 esu. Received: 25 October 2001 / Revised version: 8 January 2002 / Published online: 7 February 2002     

溶剂处理对Pr4VOPc染料掺杂聚合物薄膜光谱的影响

制备了Ｐｒ４ＶＯＰｃ染料掺掺杂的聚合物ＰＭＭＡ（ＤＩＰ）薄膜。Ｐｒ４ＶＯＰｃ在染料掺杂聚合物薄膜形成阶段形成玻璃态Ⅰ，经有机溶剂蒸汽处理后，Ｐｒ４ＶＯＰｃ形成了热力学更稳定的相Ⅱ。     

Thin-film growth behavior of non-planar vanadium oxide phthalocyanine

The thin film properties of organic semiconductors are very important to the device performance. Herein, non-planar vanadyl phthalocyanine(VOPc) thin films grown on rigid substrates of indium tin oxide, silicon dioxide, and flexible substrate of kapton by organic molecular beam deposition under vacuum conditions are systematically studied via atomic force microscopy and x-ray diffraction. The results clearly reveal that the morphology and grain size are strongly dependent on the substrate temperature during the process of film deposition. Meanwhile, the VOPc films with the structure of phase I or phase II can be modulated via in situ annealing and post-annealing temperature. Furthermore, the crystalline structure and molecular orientation of vapor-deposited VOPc can be controlled using molecular template layer 3, 4, 9, 10-perylenetetracarboxylic dianhydride(PTCDA), the VOPc film of which exhibits the phase I structure. The deep understanding of growth mechanism of non-planar VOPc film provides valuable information for controlling structure-property relationship and accelerates the application in electronic and optoelectronic devices.     

Au nanoplate/polypyrrole nanofiber composite film: preparation,characterization and application as SERS substrate

Without any other additives or additional energy, Au nanoplates have been successfully prepared and integrated simultaneously with the dedoped polypyrrole nanofiber film via the in situ reduction of AuCl₄^– on the film surface. The morphology and structure of the as‐prepared composite film are characterized, and its application for surface‐enhanced Raman scattering is also investigated. It has been found that the morphology of as‐prepared Au nanoplates is dependent on the reaction duration, while the density is dependent on the concentration of AuCl₄^– ions in the reaction process. It is suggested that polypyrrole plays dual reducing and structure‐directing roles during the formation of Au nanoplates. Surface‐enhanced Raman scattering study shows that the Au nanoplates give an intensive and enhanced Raman scattering when 4‐aminothiophenol is used as a probing molecule. The employed approach may shed some light on simultaneously fabricating and immobilizing other noble metal micro/nanostructures with unique morphology. Copyright © 2011 John Wiley & Sons, Ltd.     

可溶性钒氧酞菁在不同介质中的吸收光谱研究

研究了四丙基取代钒氧酞菁（Ｐｒ４ＶＯＰｃ）在不同介质中的吸收光谱。Ｐｒ４ＶＯＰｃ分子在不同介质中的吸收光谱差别很大：在稀溶液中以分子的单体吸收为主（λｍａｘ＝７０７ｎｍ），在浓溶液和ＰＭＭＡ薄膜中由于形成平行排列结构的二聚体而使分子单体的吸收峰发生蓝移（λｍａｘ＝６６０ｎｍ），在蒸发膜中则由于形成斜交结构的二聚体使得分子单体的吸收峰发生分裂形成红移和蓝移峰（λｍａｘ＝７２０ｎｍ，６６０ｎｍ），在溶液沉积的固态薄膜中由于形成结晶相Ｉ而表现出强烈的近红外吸收（λｍａｘ＝８２６．９ｎｍ）。造成这种差别的原因是四个丙基的引入加大了ＶＯＰｃ分子的空间位阻效应。通过热处理或溶剂蒸汽处理，可以使Ｐｒ４ＶＯＰｃ蒸发膜转变成具有强近红外吸收的结晶相Ｉ；而只有通过溶剂蒸汽处理才能使ＰＭＭＡ介质中的Ｐｒ４ＶＯＰｃ转变成结晶相ＩＩ。     

Raman spectroscopy of the interface between a thin nanostructured ZnO film and fullerene C60

The resonance and nonresonance Raman scattering in the interface between a thin ZnO film with a well-developed nanostructured surface morphology and a layer of fullerene C60 molecules deposited on this film has been investigated. It is shown that the intensity of the interaction between the C60 molecules and ZnO film surface can be estimated based on the spectral scattering characteristics.     

水热制备Sr（MoO4）x（WO4）1-x固溶体微晶及其发光性能

采用水热法制备了Sr（MoO₄）_x（WO₄）_1-x固溶体微晶。通过X射线粉末衍射（XRD）、傅里叶变换红外光谱（FT-IR）、扫描电镜（SEM）和荧光分析（FA）表征了微晶的结构、表面形貌和发光性能。XRD和FT-IR结果表明制备的Sr（MoO₄）_x（WO₄）_1-x微晶皆呈现典型的四方晶相白钨矿结构。SEM结果表明制备的微晶为表面光滑且粒径均匀的球形颗粒。荧光发射光谱显示,在275 nm紫外光激发下,随着x值的增加,Sr（MoO₄）_x-（WO₄）_1-x固溶体微晶在350 nm处的发射逐渐减弱,470 nm处的发射逐渐增强。     

界面自组装的金/氧化石墨烯复合材料的表面增强拉曼散射行为研究

采用Frens法制备金纳米粒子溶胶,通过界面自组装技术在掺磷的非晶碳衬底表面构筑三维的金/氧化石墨烯/金复合结构.以罗丹明B为探针分子,考察金/氧化石墨烯/金复合材料的表面增强拉曼散射活性.结果表明,由于氧化石墨烯的化学增强和金纳米粒子的电磁场增强的协同作用,在该三维复合材料上获得了很强的罗丹明B拉曼信号.所设计的三维金/氧化石墨烯/金复合材料在生物分析、环境监测、疾病防控、食品安全等领域具有潜在的应用价值.     

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.