CdS/ZnO纳米复合结构制备及荧光特性研究

为增强CdS纳米粒子的荧光强度,以及稳定性,研究了Cd,S不同质量比,有无稳定剂等条件下CdS纳米粒子的制备及荧光特性。在碱性条件下,利用水热法合成了CdS/ZnO的纳米复合结构,并对所有样品进行了XRD、荧光光谱和SEM表征。测试结果表明所制备的CdS纳米粒子和CdS/ZnO的纳米复合结构粒子成分单一且纯净;ZnO复合在CdS表面;在紫外光(328.5 nm)激发下,CdS/ZnO纳米复合结构的发射峰位于463 nm处,峰形窄而对称,CdS/ZnO纳米复合结构的荧光强度比CdS纳米粒子的荧光强度有显著增强,且CdS和ZnO物质量之比为1∶1条件下,荧光强度最高,其荧光效率比单一CdS纳米粒子高出11%。通过第一性原理计算结果表明,CdS能带结构中,Cd-4d,S-3p和Cd-5s能带分别由5条、3条和1条能级构成,对比不同轨道的分态密度强度,看出CdS的导带边主要由Cd-5s轨道贡献,而价带边主要由S-3p轨道贡献,能量在-7 eV附近的电子态主要由Cd-4d轨道贡献。而ZnO上价带主要由O-2p电子构成,靠近费米能级的价带区域则主要由Zn-3d电子贡献,在导带部分,主要来源于Zn-4s和O-2p电子。由于在两种材料的复合结构中Zn-3d电子的能级和S-3p电子的能级接近,存在着二型带阶结构使能带变窄,容易形成跃迁,减小电子-空穴的复合,从而促进复合结构荧光效率的提高。     

不同表面结构的金纳米粒子荧光性质.

"研究了具有不同表面结构的金纳米粒子：裸金纳米粒子、三苯基膦修饰的金纳米粒子、巯基丙酸表面取代的金纳米粒子的荧光性质,及其对CdSe纳米粒子的荧光猝灭作用．发现不同的金纳米粒子荧光信号受粒子表面一价金离子与配体分子之间相互作用的影响,其荧光强度对其表面分子具有强烈的敏感性;具有不同表面结构的金纳米粒子对CdSe纳米粒子的荧光猝灭作用不同,与其吸收光谱和CdSe纳米粒子发射光谱的重叠程度相关."     

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。     

反胶束软模板法合成PANI/TiO2纳米棒复合材料及其性能研究

以阳离子表面活性剂十六烷基三甲基溴化胺(CTAB)形成的反胶束为模板,制备了一系列不同纳米TiO2含量的PANI/TiI2纳米复合材料.利用FTIR,UV-Vis,TG,TEM和荧光光谱等方法对产物进行了结构表征和性能研究.探讨了反胶束体系中PANI/TiO2复合纳米棒形成的自组装机理.结果表明:复合材料主要为直径30～40 nm,长约400 nm的PANI/TiO2复合纳米棒,二氧化钛纳米粒子与聚苯胺大分子之间存在强的相互作用,并对复合材料的热稳定性起到提高作用,PANI/TiO2纳米复合材料在紫外和可见光区域均有吸收,并在416 nm处激发产生荧光,荧光强度随着掺杂TiO2含量的提高得到了较大的增强.通过PANI/TiO2纳米棒复合材料中的激子离化和电荷传输过程探讨了PANI/TiO2的荧光量子效率和荧光强度增加的机理.     

粒子等离子共振对有机半导体共混体系中激发复合体荧光发射的作用

研究了具有局域等离子共振特性的金纳米岛状结构阵列对高分子材料共混体系中激发复合体荧光发射特性的影响.实验结果表明,当粒子等离子共振发生在激发复合体荧光光谱区时,其荧光发射的强度得到了显著增强,且荧光寿命也得以延长.可以认为,粒子等离子共振诱发的局域场增加了激子的扩散距离,利于在相分离界面处激发复合体的形成. 关键词： 金纳米岛状结构 粒子等离子共振局域场增强效应 聚合物共混体系 激发复合体     

Ag-BaO纳米薄膜红、蓝紫光波段光致荧光现象研究(Ⅰ)

金属纳米粒子/介质复合薄膜因其优良的光电特性和超快响应而成为应用背景很强的光电功能薄膜-采用真空沉积的方法制得了Ag-BaO纳米薄膜,测试到其在室温条件下的红光和蓝紫光波段的光致荧光光谱,认为Ag-BaO纳米薄膜的荧光发射主要来自于Ag纳米粒子的贡献-与该种材料的紫外-可见光吸收谱相比较,分析了Ag-BaO纳米薄膜材料不同可见光波段的荧光产生机理- 关键词：     

SiO_2/Ag核壳结构纳米粒子的制备及其表面荧光增强

以罗丹明B掺杂的SiO2球为核,通过化学还原的方法制备了二氧化硅/银核壳结构复合纳米粒子。采用透射电镜(TEM)、紫外-可见-近红外(UV-Vis-NIR)分光光度计和荧光分光光度计对二氧化硅/银核壳结构纳米粒子的表面形貌、表面等离子共振和表面荧光增强特性进行了研究和表征。结果表明,二氧化硅/银核壳结构纳米粒子的表面等离子共振峰具有明显的可调谐性,且其表面荧光增强强烈依赖于银壳层的表面等离子共振,随银壳层厚度的增大而增强。     

功能性硫化镉纳米粒子荧光增敏法测定诺氟沙星

室温条件下在水溶液中以硫代乙酰胺和硝酸镉为原料,采用微波法合成了粒度分布均匀、分散性好的CdS纳米粒子,在pH 7.4时,CdS纳米粒子的荧光强度能够被诺氟沙星增敏,且CdS纳米粒子的荧光光谱显示其带边发射位于495 nm,缺陷发射位于565 nm而且不明显,所以表明合成的CdS纳米粒子的光学性质较好,同时紫外吸收光谱和透射电子显微镜也证明了此推论。同时考察了缓冲液、pH值、离子强度、反应时间和温度等条件因素对CdS纳米粒子-诺氟沙星复合体系荧光光谱特性的影响。探讨了在最佳实验条件下,CdS纳米粒子与诺氟沙星之间的可能作用机理,荧光光谱法显示CdS纳米粒子的增加强度与诺氟沙星浓度成正比, 其浓度范围为1.25～11.25 μg·mL-1或11.25～100.0 μg·mL-1,检测限为1.5×10-3 μg·mL-1。该方法为研究诺氟沙星含量测定提供了一种新的思路, 同时为研究其在体内代谢提供了一定的指导意义。     

银纳米颗粒对掺铒铋酸盐玻璃光谱性质的影响

采用传统熔融淬火技术制备了一系列Er3+离子掺杂复合银纳米颗粒的铋酸盐玻璃样品.研究了纳米银含量的改变对Er3+离子荧光发射特性的影响.研究发现,铒在1.53 μm处的荧光强度在银纳米颗粒质量分数为0.2%处取得最大值,为未掺杂银纳米颗粒时的4.6倍.其荧光增强的原因归结于银纳米颗粒表面等离子体共振导致局域场增强和Ag...     

新型C60衍生物／Ag复合纳米材料的制备及光谱性质

利用1,3-偶极环加成反应合成了联吡啶基C60单加成衍生物N-甲基-2-[4′-(4″-甲基-2′,2″-联吡啶基)]-3,4-C60吡咯烷(C60BPY),并用NaBH4还原法和银溶胶直接组装法制备了C60BPY/Ag复合纳米结构。透射电子显微镜(TEM)表明,两种复合纳米结构的粒子粒径分别在30~45nm和40~55nm之间,粒子形状较规则,且分散性较好。在复合纳米结构形成过程中,C60BPY分子有效地控制了银粒子的生长和团聚,起到了很好的稳定和分散作用。紫外-可见吸收光谱中,两种复合纳米结构分别在430和490nm处出现了银纳米粒子的表面等离子体共振吸收峰,说明随着粒径的增大,吸收峰发生了红移。荧光发射光谱显示,C60BPY/Ag复合纳米体系猝灭了C60BPY在720和805nm处的发射峰,并对其机理进行了探讨。这种复合纳米体系有望在光电器件、传感器及催化领域有潜在的应用前景。     

Glucose-Sensitive Nanoassemblies Comprising Affinity-Binding Complexes Trapped in Fuzzy Microshells

A new design for glucose monitoring with "smart" materials based on self assembly, competitive binding, and resonance energy transfer (RET) is presented. The basic transduction principle is changing RET efficiency from fluorescein isothiocyanate (FITC) to tetramethylrhodamine isothiocyanate (TRITC), as FITC-dextran is displaced from TRITC-Concanavalin A (Con A) with the addition of glucose. Nanoscale fabrication by self-assembly of Con A/dextran into multilayer films, followed by polymer multilayers. The advantages of this approach include physical localization and separation of sensing molecules from the environment via entrapment of the biosensorelements in a semi-permeable polymeric shell, and only functional molecules are included in the sensors. To realize these nanostructures, dissolvable resin microparticles were coated with FITC-dextran+TRITC-Con A multilayers, followed by polyelectrolyte multilayers, and the core particles were then dissolved to yield hollow capsules. The nanoassembly process was studied using microbalance mass measurements, fluorescence spectroscopy, confocal fluorescence microscopy, and zeta-potential measurements. The key findings are that the specific binding between Con A and dextran can be used to deposit ultrathin multilayer films, and these exhibit changing RET in response to glucose. Fluorescence spectra of a microcapsules exhibited a linear, glucose-specific, 27% increase in the relative fluorescence of FITC over the 0-1800 mg/dL range. These findings demonstrate the feasibility of using self-assembled microcapsules as optical glucose sensors, and serve as a basis for work toward better understanding the properties of these novel materials.     

铕铽共掺稀土聚合物的光谱分析及发光性能研究

合成了一种新型的稀土配合物Eu_0.5Tb_0.5(TTA)₃Phen,并采用原位乳液聚合法进一步制备了Eu_0.5Tb_0.5(TTA)₃Phen/PMMA稀土聚合物。利用红外光谱仪(IR)、电子探针X射线能谱仪等对其结构进行了表征,利用扫描隧道电子显微镜(SEM)、荧光光谱仪(FS)等研究了其微观形貌,并探讨了其发光性能。结果表明,聚合物中PMMA与稀土部分Eu_0.5Tb_0.5(TTA)₃Phen通过键合的方式结合, 仍保持Eu0.5Tb_0.5(TTA)₃Phen原有的发光特性;在365 nm紫外光的激发下,产生发光峰在611.8 nm附近、谱线带宽为10.4 nm的红光发射,发光亮度高,色纯度高;Eu_0.5Tb_0.5(TTA)₃Phen/PMMA具有良好的发光性能,其发光强度与MMA加入的含量有关。     

Optical properties of (nanometer MCM-41)-(malachite green) composite materials

Nanosized materials loaded with organic dyes are of interest with respect to novel optical applications. The optical properties of malachite green (MG) in MCM-41 are considerably influenced by the limited nanoporous channels of nanometer MCM-41. Nanometer MCM-41 was synthesized by tetraethyl orthosilicate (TEOS) as the source of silica and cetyltrimethylammonium bromide (CTMAB) as the template. The liquid-phase grafting method has been employed for incorporation of the malachite green molecules into the channels of nanometer MCM-41. A comparative study has been carried out on the adsorption of the malachite green into modified MCM-41 and unmodified MCM-41. The modified MCM-41 was synthesized using a silylation reagent, trimethychlorosilane (TMSCl), which functionalized the surface of nanometer MCM-41 for proper host-guest interaction. The prepared (nanometer MCM-41)-MG samples have been studied by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, low-temperature nitrogen adsorption-desorption technique at 77 K, Raman spectra and luminescence studies. In the prepared (nanometer MCM-41)-MG composite materials, the frameworks of the host molecular sieve were kept intact and the MG located inside the pores of MCM-41. Compared with the MG, it is found that the prepared composite materials perform a considerable luminescence. The excitation and emission spectra of MG in both modified MCM-41 and unmodified MCM-41 were examined to explore the structural effects on the optical properties of MG. The results of luminescence spectra indicated that the MG molecules existed in monomer form within MCM-41. However, the luminescent intensity of MG incorporated in the modified MCM-41 are higher than that of MG encapsulated in unmodified MCM-41, which may be due to the anchored methyl groups on the channels of the nanometer MCM-41 and the strong host-guest interactions. The steric effect from the pore size of the host materials is significant. Raman spectra firmly demonstrated the stable form obtained after the MG incorporation into the nanometer MCM-41. Therefore, nanometer MCM-41 appears to have a good potential for its use as a support for dyes and the (nanometer MCM-41)-MG composite materials may give a wide optical application.     

芪盐LB多层膜的三维荧光谱分析

采用稳态、时间分辨荧光和三维荧光光谱技术研究了芪盐有机分子在溶液和芪盐/花生酸交替LB多层膜中的激发态的动力学特性.研究表明,芪盐分子在LB膜中形成H-聚集体,使得其荧光光谱发生蓝移.由于偶极间的相互作用使得聚集体的能级发生分裂,荧光衰减曲线可用双指数函数进行拟合.三维荧光谱发现随着衰减时间的推移,荧光峰逐渐向长波方向移动,不同波段具有不同的衰减驰豫时间.     

Single particle spectroscopy on composite MEH-PPV/PCBM nanoparticles

The preparation and characterization of composite MEH-PPV/PCBM nanoparticles with doping levels up to 75 wt% PCBM is reported. These nanoparticles represent structures in between single molecules and bulk that allow for a detailed investigation of the role of nanostructure on the properties of the corresponding functional materials. Combining this material system with single particle spectroscopy studies reveals molecular scale information on the extent to which variations in polymer chain folding and interactions between polymer chains and fullerenes affect material morphology and photophysical properties. Key observations are that the single particle ensemble spectra shift with respect to each other depending on PCBM doping levels, and that the vibronic structure of the single particle ensemble spectra changes with PCBM doping levels. These observations are indicative of a reduction in conducting polymer conjugation length and interchain interactions due to steric effects caused by the presence of PCBM that result in reduced exciton transport.     

GOSs-稀土配合物紫外增强材料的光谱分析与稳定性研究

氧化石墨烯薄片(GOSs)作为一种新型的二维片状材料,具有较高的比表面积、丰富的表面含氧官能团以及良好的光热稳定性。而稀土配合物通过无机稀土元素与有机配体的结合表现出优异的荧光特性。为了将两类材料具有的物化特性结合起来应用于紫外光谱探测领域。选取了合适的有机配体啉菲罗啉(1,10-邻二氮杂菲,phen)、2’2-联嘧啶(bpm)作为桥联分子,把氧化石墨烯(GOSs)与稀土配合物通过氢键自组装作用进行复合,制备了高效稳定可调的GOSs-稀土配合物复合荧光材料GOSs-Eu(BA)3phen和GOSs-Eu(TTA)3bpm,并且制备了相应的聚乙烯醇(PVA)共混紫外增强薄膜,对其光谱特性与稳定性进行了深入的研究。采用红外光谱、扫描电镜和金相显微镜等方法,对紫外增强材料进行了性能表征。采用吸收光谱,荧光光谱等方法,对紫外增强薄膜进行了性能表征。此外,通过热重测试(TGA)表征了GOSs氢键复合前后紫外增强材料的热稳定性,通过荧光强度-紫外光照次数表征了GOSs氢键复合前后紫外增强薄膜的光稳定性。红外光谱分析发现,进行配位前后有机配体的特征峰产生了频移,表明稀土配合物中Eu 3+与配体之间存在着明显的配位作用。在进行复合之后,桥联配体的特征峰也产生了偏移,表明GOSs与稀土配合物通过桥联分子的氢键作用进行了进行复合。吸收光谱与荧光光谱测定结果表明增强薄膜吸收峰在200~400 nm,荧光主峰在612 nm左右,为Eu 3+特征红色荧光峰,且不同配体可以实现不同范围的吸收产生差异化的荧光表现。扫描电镜和金相显微镜清晰地展示了稀土配合物复合前后的微观形貌,即颗粒状稀土配合物附着在石墨烯薄片上。光稳定性测试表明经过GOSs氢键复合之后,Eu(BA)3phen和Eu(TTA)3bpm稀土配合物荧光材料在进行25次荧光强度测试后光漂白程度分别下降了4.26%和6.41%,提高了其光稳定性。热重测试也表明在经过GOSs氢键复合之后,稀土配合物的热稳定性有了很大提高。总之,得益于GOSs和稀土配合物的特性结合,所制备的紫外增强材料表现出优异的荧光特性与稳定性,必将在紫外探测方面有着广阔的应用前景。     

基于ESIPT机理检测Al3+荧光探针分子结构和电子光谱的理论研究

本文应用密度泛函理论（DFT）和含时密度泛函理论（TD-DFT）方法,研究了具有激发态分子内质子转移（ESIPT）特性的3-羟基黄酮（3HF）及其两种氰基和氨基取代衍生物（3HF-CY和3HF-AM）作为水溶液中Al3+离子检测的荧光探针分子结构和电子光谱性质. 计算得到了与ESIPT过程相关的键长、键角以及势能曲线,模拟计算了单独分子和分子@Al3+复合物的吸收和荧光光谱. 结果表明,氰基或氨基的引入均会抑制3HF的质子在基态（S0）或激发态（S1）的转移. 而从得到的吸收光谱可以看出,在3HF中引入吸电子基团氰基可以引起其吸收光谱的红移,而给电子基团氨基的引入则出现相反现象. 此外,与3HF-AM的荧光光谱相比,3HF-AM@Al3+复合物发生了75.88 nm的蓝移,由此推测3HF-AM与水中的Al3+反应后,在光激发下溶液荧光会由绿色转变为紫色,表明3HF-AM分子可以作为有效检测水中Al3+的荧光探针.     

蒽、苝和1-氨基蒽醌水溶胶的制备及其荧光性能的研究

用再沉淀法分别制备了蒽、苝和1-氨基蒽醌水溶胶,研究了三者在水溶液中的荧光光谱,通过与其对应的分子荧光光谱比较,发现蒽和苝的水溶胶荧光光谱发生了红移,而1-氨基蒽醌分子从无荧光到它的水溶胶有荧光的转变,根据荧光和分子结构关系,得出3种溶胶是通过分子之间相互重叠聚集而成。同时因为他们为平面型分子,因此π电子共轭度大,使得荧光容易激发和发射,荧光光谱向长波方向移动。     

Fluorescence properties of biochemicals in dry NaCl composite aerosol particles and in solutions

Several fluorophores, such as tryptophan, NADH, NADPH, and riboflavin are found in airborne micro-organisms. In this work, the fluorescence properties of these biochemicals were studied both in dry NaCl composite aerosol particles and in saline solutions by means of laser-induced fluorescence. Fluorescence spectra were measured from individual, airborne aerosol particles and from solutions in cuvette. The excitation wavelength was varied in steps from 210 nm to 419 nm and the fluorescence was detected within a wavelength band of 310–670 nm. For each sample, the measured fluorescence emission spectra were combined into fluorescence maps. The fluorescence maximum of riboflavin in a dry NaCl composite particle is 20 nm red-shifted compared with the solution, whereas the maxima are blue-shifted by about 25 nm for tryptophan and 15 nm for NADH and NADPH. The molecular fluorescence cross sections have significant differences between the aerosol particles and the solutions, except for tryptophan. For NADH and NADPH the cross sections are over 20 times larger in the aerosol particles than in the solutions probably as a result of partial quenching of fluorescence in solution caused by the collision or stacking with the adenine moiety. The fluorescence cross section of riboflavin is almost 60 times larger in the solution than in the dry NaCl composite aerosol. This is probably caused by the different microenvironment around the fluorophore molecule and by the concentration quenching in the particles where the fluorescing molecules are relatively close to each other.     

1,5-萘二胺衍生物的光谱分析及发光性能研究

合成了一种纯度较高的1,5-萘二胺衍生物(NPN),制备了NPN薄膜.利用紫外-可见吸收光谱和荧光发射光谱研究了NPN的发光行为,并结合电化学循环伏安法研究了其电子能级结构.结果表明,NPN的荧光光谱表现出明显的溶剂效应,认为其发生了从电子给体N原子到电子受体芳环之间的分子内电子转移,形成分子内电子转移络合物;从NPN薄膜与其溶液的吸收光谱峰值比较中看出吸收峰红移,认为薄膜中分子形成"J-聚集体";NPN的HOMO能级为-5.74 eV,光学禁带为2.79 eV;在365 nm紫外光的激发下,产生发光峰在448.6 nm附近、谱线带宽为72.6 nm的蓝光发射,发光亮度高,色纯度高.