油溶性CuInS2/ZnS量子点的制备及其温敏性聚丙烯酰胺胶束介导的水相转移

采用非热注法成功制备了高质量的油溶性CuInS₂/ZnS核壳量子点, 量子点的荧光发射峰在可见光到近红外范围内可调(550~800 nm), 且荧光量子产率最高达80%。本文进一步利用具有温敏特性的聚丙烯酰胺胶束作相转移剂, 成功地将油溶性的CuInS₂/ZnS核壳量子点转移入水相。水相中自组装形成的CuInS₂/ZnS量子点-胶束复合物不仅具有良好的荧光性质, 而且胶束原有的灵敏的热响应性被保留。这些研究初步表明, 无镉的低毒的CuInS₂/ZnS量子点可作为纳米胶束的荧光示踪探针。     

核/壳型CdTe@SiO2荧光纳米复合粒子的制备与表征

利用反相微乳法, 以巯基乙酸修饰的水溶性CdTe量子点为核, 包覆SiO₂, 制备得到核壳型CdTe@SiO₂荧光纳米复合粒子. 用紫外-可见(UV-vis)分光光度计, 荧光(PL)分光光度计, 红外(FT-IR)光谱仪, 透射电子显微镜(TEM)等分析测试手段, 对得到的荧光纳米复合粒子的性能进行表征, 结果表明: 得到的CdTe@SiO₂纳米复合粒子是核壳型结构, 由SiO₂壳层包覆多个量子点, 其大小均匀, 水溶性好, 有效地提高了量子点的稳定性, 大大增强了其抗光漂白性能, 为该材料的进一步生物应用打下了良好的基础.     

水热法合成AgInS2/ZnS核/壳结构量子点及其荧光性能

以硫脲为硫源,采用谷胱甘肽(GSH)和柠檬酸钠(SC)为配体,通过水热法制备了水溶性AgInS2/ZnS(AIS/ZnS)核/壳结构量子点。系统研究了反应温度和配体用量对量子点的合成及其荧光性能的影响。采用X射线衍射(XRD)、透射电子显微镜(TEM)、紫外可见吸收光谱(UV-Vis)和光致发光光谱(PL)分别对量子点的物相、形貌和光学性能进行了表征,并考察了量子点的稳定性。实验结果表明,随着反应温度从70℃升高至90℃,促进了ZnS壳层的形成,有效地钝化了量子点的表面缺陷,获得的AIS/ZnS核/壳量子点的发光强度显著提高,发光峰位从600 nm蓝移至580 nm。配体的添加可以有效地平衡Zn^2+的化学反应活性,减缓ZnS壳层的生长,抑制核壳界面缺陷的形成,还能消除量子点的表面态,当nGSH/nZn^2+=2.0,nSC/nZn^2+=2.5时,AIS/ZnS量子点的荧光性能最佳。此外,AIS/ZnS核/壳结构量子点还具有优异的光学稳定性。     

萘基桥联有机-无机杂化介孔材料的合成及其光学性质

以短链阳离子三聚表面活性剂C₁₀H₂₁N⁺(CH₃)₂(CH₂)₂N⁺(CH₃)(C₁₀H₂₁)(CH₂)₂N⁺(CH₃)₂C₁₀H₂₁]·3Br^?为结构导向剂, 通过2,7-二(3-三乙氧硅基氨丙酯基)萘(NIS)和四乙氧基硅烷(TEOS)共缩聚, 制备了有序的萘基桥联的杂化周期性介孔有机硅(PMOs). 样品通过X射线衍射(XRD)、高分辨透射电镜(HRTEM)、氮气吸附-脱附、差示扫描量热/热重分析(DSC/TGA)表征. 结果表明, 当NIS占NIS和TEOS总量40% (摩尔分数)时, 可以形成具有结晶态孔壁的有序介孔杂化材料. 当NIS含量低于或高于40%时, 分别形成无定形孔壁的有序介孔杂化材料和无孔杂化材料. 随着孔壁中萘基基团的增加, 由于有机基团之间π-π堆积作用增强, 杂化介孔材料显示良好的热稳定性. 由于在二氧化硅骨架中嵌入荧光萘基基团, 杂化有机-无机有序介孔材料显示了激基缔合物的光学行为. 随萘基基团含量的增加, 杂化材料的紫外吸收峰发生蓝移, 形成H聚集体; 由于聚集引起的荧光淬灭, 杂化材料的荧光量子产率明显降低.     

CdSe/ZnS量子点敏化太阳能电池电子注入与光伏性能表征

合成了CdSe/ZnS核壳结构量子点(QDs), 将其作为光敏剂吸附在TiO2纳米晶薄膜上, 组装成量子点敏化太阳能电池(QDSSCs), 从电子注入速率和电池性能两方面对QDSSCs进行了表征. 为了定量研究ZnS层包覆对电子注入的影响, 运用飞秒瞬态光谱技术, 测试了包覆ZnS前后, CdSe-TiO₂体系的电子注入速率. 实验测得ZnS包覆前后电子注入速率分别为7.14×10¹¹s^-1和2.38×10^-11s^-1, 可以看出包覆后电子注入速率明显降低, 仅为包覆前的1/3. 电池器件J-V性能测试表明, ZnS作为绝缘层包覆在CdSe的表面有效提高了QDSSCs的填充因子和稳定性, 但同时也导致了效率的降低. 上述结果说明了电子注入速率的降低是导致电池电流和效率下降的重要原因, 为今后优化核壳结构QDSSCs的电流和效率提供了依据.     

硫化亚铜对电极在量子点敏化太阳电池中的应用

报道了一种基于硫族金属复合物N₄H₉Cu₇S₄前驱体溶液制备硫化亚铜对电极的新方法. 分别制备了TiO₂纳米颗粒多孔薄膜和TiO₂纳米棒阵列结构的光阳极, 并在此基础上研究了基于硫化亚铜对电极的CdS/CdSe量子点敏化太阳电池的光电性能, 同时结合电化学阻抗技术考察了硫化亚铜对电极的催化性能. 结果表明: 与铂电极相比, 本方法制备的硫化亚铜电极对多硫电解质具有更高的催化活性, 所组装的CdS/CdSe量子点敏化太阳电池具有更优的光伏性能.     

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。     

非水稀溶液中SiO2包覆ZnO量子点的制备及其发光特性研究

本文利用溶胶-凝胶法在非水稀溶液中制备出SiO₂包覆的ZnO量子点。通过紫外-可见吸收光谱(UV-Vis)和荧光光谱对合成量子点的发光特性进行了研究。结果表明，在n_SiO2:n_ZnO=1∶4的条件下，ZnO量子点的发光性能最佳。经过Brus公式计算，该量子点的平均半径在2.8 nm左右，稳定性显著提高。其荧光光谱在363 nm处有一强而窄的激子发射峰，在519 nm处有一个宽而弱的绿色发射峰。说明SiO₂对ZnO形成了有效包覆，明显减少了ZnO的表面缺陷。     

多树枝结构和立方结构PbS的水热合成及形成机理

在无模板条件下,用Pb(NO₃)₂做铅源,(CH₄N₂S)做硫源,用水热法在160 ℃反应24 h制备了结晶度好的多树枝结构PbS。利用XRD、SEM、EDX、TEM对产物进行了表征,结果表明所得产物为面心立方多树枝状结构,单个树枝的长度为1.0～3.0 μm。此外,在碱性条件下丙三醇/水体系中制备了具有不同凹面的立方结构PbS,边长为2.0～5.0 μm。对2种不同形态PbS的影响因素进行了讨论,并提出了形成机理。同时对其荧光及紫外性质进行了研究,结果表明立方结构的PbS在309和373.5 nm处出现了2个荧光峰,在211和232 nm处出现了2个紫外吸收峰。     

二(桥-氯)-二[氯-(N，N，N′-三苄基乙二胺)铜(Ⅱ)]的晶体结构(英)

The crystal structure of the title complex, [Cu(C₂₃H₂₆N₂)Cl₂]₂·2CH₂Cl₂, has been determined by single-crystal, X-ray diffraction techniques. The compound crystallizes as dark-green prisms in space group P2₁/c of the monoclinic system, with Z=4 and unit cell dimensions a=1.710 9(7) nm, b=2.395 2(11) nm, c=1.348 9(6) nm and β=110.651(8)°. The complex consists of two similar but crystallographically independent dimers, of which Cu(Ⅱ) centers display five-coordinated trigonal-bipyramidal geometry with Cu-Cu separations in two centrosymmetric dimers are 0.345 1 and 0.347 8 nm, respectively, and in each dimer the two copper centers share a common edge formed by two bridging chloride ions, each being equatorial. Solvent molecules of CH₂Cl₂ are packed together in the crystal lattice. CCDC: 253299.     

Preparation and characterization of thiacalix[4]arene coated water-soluble CdSe/ZnS quantum dots as a fluorescent probe for Cu2+ ions

Highly fluorescent water-soluble CdSe/ZnS (core/shell) quantum dots (QDs) as a fluorescent Cu2+ ion probe were synthesized using thiacalix[4]arene carboxylic acid (TCC) as a surface coating agent. Hydrophobic trioctylphosphine oxide (TOPO) capped CdSe/ZnS QDs were overcoated with TCC in tetrahydrofuran at room temperature, and deprotonation of the carboxyl groups of TCC resulted in the formation of water-soluble QDs. The surface structure of the QDs was characterized by using transmission electron microscopy (TEM) and fluorescence correlation spectroscopy (FCS). TEM images showed that TCC-coated QDs were monodispersed with the particle size (core-shell moiety) of approximately 5 nm. Hydrodynamic diameter of the TCC-coated QDs was determined to be 8.9 nm by FCS, showing that the thickness of the surface organic layer of the QDs was approximately 2 nm. These results indicate that the surface layer of TCC-coated QDs forms a bilayer structure consisting of TOPO and TCC molecules. TCC-coated CdSe/ZnS QDs were highly fluorescent (quantum yield, 0.21) compared to the QDs surface-modified with mercaptoacetic acid and mercaptoundecanoic acid. Fluorescence of the TCC-coated QDs was effectively quenched by Cu2+ ions even in the presence of other transition metal ions such as Cd2+, Zn2+, Co2+, Fe2+, and Fe3+ ions in the same solution. The Stern-Volmer plot for the fluorescence quenching by Cu2+ ions showed a linear relationship up to 30 microM of Cu2+ ions. The ion selectivity of TCC-coated QDs was determined by measurements of fluorescence responses towards biologically important transition metal ions (50 microM) including Fe2+, Fe3+, Co2+>Zn2+, Cd2+. The fluorescence of TCC-coated QDs was almost insensitive to other biologically important ions such as Na+, K+, Mg2+, and Ca2+, suggesting that TCC-coated QDs can be used as a fluorescent Cu2+ ion probe for biological samples. A possible quenching mechanism by Cu2+ ions was also discussed on the basis of a Langmuir-type adsorption isotherm.     

pH-sensitive Photoluminescence of CdSe/ZnSe/ZnS Quantum Dots in Human Ovarian Cancer Cells

The photoluminescence of mercaptoacetic acid (MAA)-capped CdSe/ZnSe/ZnS semiconductor nanocrystal quantum dots (QDs) in SKOV-3 human ovarian cancer cells is pH-dependent, suggesting applications in which QDs serve as intracellular pH sensors. In both fixed and living cells the fluorescence intensity of intracellular MAA-capped QDs (MAA QDs) increases monotonically with increasing pH. The electrophoretic mobility of MAA QDs also increases with pH, indicating an association between surface charging and fluorescence emission. MAA dissociates from the ZnS outer shell at low pH, resulting in aggregation and loss of solubility, and this may also contribute to the MAA QD fluorescence changes observed in the intracellular environment.     

Synthesis and Characterization of ZnS：Ag Nanocrystals Surface-capped with Thiourea

Ag^＋ -doped ZnS nanocrystals surface-capped with thiourea （expressed as ZnS： Ag/thiourea） were synthesized through sol-gel method with thiourea as a surface modifier and characterized by X-ray diffraction（XRD）, transmission electron microscope（TEM）, X-ray fluorescence spectrum（XRF）, infrared spectrum （IR）, UV-Vis absorption spectrum（ UV-Vis）, and photoluminescence spectrum（PL）. The results show that Ag^＋ ions are doped in ZnS nanocrystals, and the sulfur atoms in thiourea molecules coordinate with metal ions on the surface of the nanocrystals. The spherical ZnS： Ag/thiourea nanocrystals with an average diameter of 5 nm have good fluorescent characteristics, and therefore have great potential for use in molecular assembly and novel luminescence materials.     

Characterization of primary amine capped CdSe, ZnSe, and ZnS quantum dots by FT-IR: determination of surface bonding interaction and identification of selective desorption

Surface ligands of semiconductor quantum dots (QDs) critically influence their properties and functionalities. It is of strong interest to understand the structural characteristics of surface ligands and how they interact with the QDs. Three quantum dot (QD) systems (CdSe, ZnSe, and ZnS) with primary aliphatic amine capping ligands were characterized primarily by FT-IR spectroscopy as well as NMR, UV-vis, and fluorescence spectroscopy, and by transmission electron microscopy (TEM). Representative primary amines ranging from 8 to 16 carbons were examined in the vapor phase, KBr pellet, and neat and were compared to the QD samples. The strongest hydrogen-bonding effects of the adsorbed ligands were observed in CdSe QDs with the weakest observed in ZnS QDs. There was an observed splitting of the N-H scissoring mode from 1610 cm(-1) in the neat sample to 1544 and 1635 cm(-1) when bound to CdSe QDs, which had the largest splitting of this type. The splitting is attributed to amine ligands bound to either Cd or Se surface sites, respectively. The effect of exposure of the QDs dispersed in nonpolar medium to methanol as a crashing agent was also examined. In the CdSe system, the Cd-bound scissoring mode disappeared, possibly due to methanol replacing surface cadmium sites. The opposite was observed for ZnSe QDs, in which the Se-bound scissoring mode disappeared. It was concluded that surface coverage and ligand bonding partners could be characterized by FT-IR and that selective removal of surface ligands could be achieved through introduction of competitive binding interactions at the surface.     

Reverse micelle-derived Cu-doped Zn1−xCdxS quantum dots and their core/shell structure

Reverse micelle chemistry-derived Cu-doped Zn_1?xCd_xS quantum dots (QDs) with the composition (x) of 0, 0.5, 1 are reported. The Cu emission was found to be dependent on the host composition of QDs. While a dim green/orange emission was observed from ZnS:Cu QDs, a relatively strong red emission could be obtained from CdS:Cu and Zn_0.5Cd_0.5S:Cu QDs. Luminescent properties of undoped QDs versus Cu-doped ones and quantum yields of alloyed ZnCdS versus CdS QDs are compared and discussed. To enhance Cu-related red emission of CdS:Cu and Zn_0.5Cd_0.5S:Cu core QDs, core/shell structured QDs with a wider band gap of ZnS shell are also demonstrated.     

水溶性InP/ZnS量子点的合成及其在指纹显现中的应用

以磷化锌、氯化铟为原料,以十二烷胺为溶剂,在150～200℃下合成了InP量子点,通过相转移和紫外光照得到了巯基乙酸修饰的水溶性InP/ZnS量子点.利用X射线衍射仪、透射电镜、高分辨透射电镜、荧光光谱仪等分析了不同温度下合成的量子点的粒径、形貌、荧光性能及指纹显现效果.结果表明,合成的InP和InP/ZnS量子点为球...     

Measurement of interfacial toughness of metal film wire and polymer membrane through electricity induced buckling method

Non-toxic, environment-benign colloidal CuInS(2) (CIS) quantum dots (QDs) were synthesized through a facile noninjection, one-pot approach by reacting Cu and In precursors with dodecanethiol dissolved in 1-octadecence at 220 °C. The Cu:In precursor molar ratio was varied from 1:1 to 1:4 to intentionally generate Cu-deficient CIS QDs. Depending on the stoichiometry of the QDs, their emission peak wavelengths were tuned in red-deep red region. More Cu-deficient CIS QDs (Cu:In=1:4) were found to be more efficient than ones with Cu:In=1:1. After successive ZnS shell was overgrown on the surface of core QDs with Cu:In=1:4, the resulting core/shell QDs exhibited a highly efficient yellow emission with a quantum yield of ~50%. A substantially blue-shifted emission from the core/shell QDs versus core ones was described by suggesting an alternative recombination pathway that may be induced by the ZnS shell coating.     

Highly-controllable imprinted polymer nanoshell at the surface of silica nanoparticles based room-temperature phosphorescence probe for detection of 2,4-dichlorophenol

This paper reports a facile and general method for preparing an imprinted polymer thin shell with Mn-doped ZnS quantum dots (QDs) at the surface of silica nanoparticles by stepwise precipitation polymerization to form the highly-controllable core–shell nanoparticles (MIPs@SiO₂–ZnS:Mn QDs) and sensitively recognize the target 2,4-dichlorophenol (2,4-DCP). Acrylamide (AM) and ethyl glycol dimethacrylate (EGDMA) were used as the functional monomer and the cross-linker, respectively. The MIPs@SiO₂–ZnS:Mn QDs had a controllable shell thickness and a high density of effective recognition sites, and the thickness of uniform core–shell 2,4-DCP-imprinted nanoparticles was controlled by the total amounts of monomers. The MIPs@SiO₂–ZnS:Mn QDs with a shell thickness of 45 nm exhibited the largest quenching efficiency to 2,4-DCP by using the spectrofluorometer. After the experimental conditions were optimized, a linear relationship was obtained covering the linear range of 1.0–84 μmol L⁻¹ with a correlation coefficient of 0.9981 and the detection limit (3σ/k) was 0.15 μmol L⁻¹. The feasibility of the developed method was successfully evaluated through the determination of 2,4-DCP in real samples. This study provides a general strategy to fabricate highly-controllable core–shell imprinted polymer-contained QDs with highly selective recognition ability.     

3-巯基丙酸修饰的CdSe/ZnS量子点的合成及测定牛血清白蛋白的研究

以3-巯基丙酸作为修饰剂,在水溶液中合成了稳定的CdSe/ZnS量子点(QDs),透射电镜观察所合成量子点的形貌近似球形,粒径约为25 nm.吸收光谱与荧光光谱的研究表明,CdSe QDs在410 nm处有最大吸收峰,而CdSe/ZnS QDs的最大吸收峰在470 nm处,CdSe/ZnS QDs的荧光强度是CdSe QDs的11倍.考察了缓冲溶液的体积、pH值、反应温度、反应时间对体系荧光的影响.在最佳实验条件下,体系的荧光强度与BSA的浓度呈线性关系,线性响应范围为0.746×10-7～4.48×10-7 mol/L,检出限为3.846×10-10 mol/L.并且CdSe/ZnS QDs荧光强度基本保持稳定,可达两个多月.该方法应用于合成样品的测定,结果满意.