基于CdSe/ZnS量子点荧光猝灭法测定硫胺素

以CdSe/ZnS量子点为荧光探针,基于硫胺素(VB1)与CdSe/ZnS量子点间通过静电作用而有效猝灭CdSe/ZnS量子点荧光强度的机制,建立了一种可快速测定VB1的荧光检测方法.在最优实验条件下(pH 7.4,反应时间25 min),硫胺素(VB1)浓度在0.01 ～1 μmol/L时,CdSe/ZnS量子点荧光猝灭变化强度与硫胺素(VB1)浓度呈良好的线性关系:F0/F=0.67cCB1+1.05(R=0.999 2),方法检出限为5.1×10-3 μmol/L,相对标准偏差为1.09％.该方法可用于人体尿样中VB1的快速测定.     

核壳式CdSe/ZnS量子点对邻苯二甲酸二丁酯的快速高灵敏荧光测定

用水热反应法制备了核壳式CdSe/ZnS量子点并用透射电镜进行形貌表征,将该量子点作为荧光探针,基于邻苯二甲酸二丁酯(DBP)的荧光增强效应,建立了一种快速测定DBP的方法。在最优条件(pH7.0,反应时间15 min,水作溶剂)下,DBP对CdSe/ZnS量子点的荧光增强作用最显著,在1.0～20.0μg/L范围内荧光信号强度与DBP浓度的对数呈线性关系,检出限为0.21μg/L,相关系数R²为0.99。该方法可用于白酒中DBP的含量测定,与现有标准方法GC-MS比较,具有高的检测灵敏度和准确性。     

巯基乙酸稳定的CdSe/ZnS核壳结构量子点的制备与表征

用非均相成核原理,在水溶液中制备CdSe/ZnS核壳结构量子点,并研究合成工艺,包括前驱物的滴加方式和用量、CdSe核的水浴反应时间、CdSe与ZnS的摩尔比等因素对CdSe/ZnS核壳结构量子点荧光性能的影响.用透射电子显微镜和x射线衍射仪测试核壳结构量子点的形貌和结构.用紫外吸收光谱与荧光光谱表征CdSe/ZnS核壳结构量子点的荧光性能.结果表明:ZnS壳层在CdSe核量子点表面外延生长,形成了核壳结构;CdSe/ZnS核壳结构量子点的荧光性能明显高于单一的CdSe量子点;合成的工艺条件会显著影响CdSe/ZnS核壳结构量子点的荧光性能.     

DPA螯合型CdSe:Tb~(3+)量子点的光学特性

通过水相合成法快速且低成本地合成了荧光量子产率高、粒径均匀、光稳定良好的吡啶二羧酸(DPA)螯合型CdSe:Tb~(3+)量子点。并且通过紫外分光光度计、荧光分光光度计和扫描电子显微镜(SEM)对产物进行了表征。本课题研究了[Tb~(3+)]/[DPA]比例、反应温度、反应转速对DPA与Tb~(3+)的螯合后光学性质的影响。结果表明:当[Tb~(3+)]/[DPA]=10∶1、t=60℃、反应转速为400 r/min时,得到了DPA激发Tb~(3+)的最佳条件,将此条件运用到制备DPA螯合型CdSe:Tb~(3+)量子点中,制成的DPA-CdSe:Tb~(3+)量子点的最大吸收峰在400 nm处,它的荧光发射峰在560 nm处,相比较于未经修饰的CdSe量子点,荧光发射峰向右偏移了10 nm,荧光强度得到了增强且量子点比较稳定,合成的吡啶二羧酸(DPA)螯合型CdSe:Tb~(3+)量子点荧光强度较强、稳定性好、量子产率高。     

硅壳包裹核/壳型CdSe/CdS纳米晶的制备与性能研究

采用低温水热技术,分别以柠檬酸、聚乙二醇(PEG400)和甲硫氨酸为稳定剂,在水相中合成了核壳型CdSe/CdS量子点,研究了稳定剂、CdSe与CdS物质的量比对量子点发光性能和结构的影响。XRD结果表明,当CdSe∶CdS在1∶3~4时,CdS主要在CdSe的外延生长,形成核壳型纳米粒子,当比例达到1∶5时,CdS单独成晶现象严重。CdSe∶CdS=1∶4时,核壳型量子点具有较高的荧光发射效率。TEM研究表明CdS在CdSe外表面生长形成较为完整的壳层,有效钝化CdSe表面,减少表面缺陷,从而显著提高CdSe量子点的发光效率。CdSe核尺寸为2~3nm的核壳型纳米粒子外包裹一层SiO2壳后,荧光发射效率没有显著提高,发射峰位置无明显红移。量子点包壳后能有效提高该量子点的光化学稳定性,提高量子点的生物相容性。     

11-巯基烷酸修饰的核/壳量子点CdSe/ZnS的合成及分析应用研究

以11-巯基烷酸作为修饰剂,在水相中合成了CdSe/ZnS量子点荧光探针(QDs),并将其用于测定牛血清白蛋白.从透射电子显微镜看到该量子点外观近似球形,粒径约为15 nm.该核/壳量子点紫外吸收峰为460 nm,荧光发射峰为548nm,其荧光强度比单核量子点增强2.1倍.而且在至少40 d里,荧光强度基本保持稳定.在最佳条件下,实验表明了CdSe/ZnS QDs-BSA体系的荧光强度与BSA浓度呈线性关系,线性响应范围为10.0～50.0 mg/L,线性方程为△F=141.29 1.259c(c:mg/L),r=0.999 1.该方法应用于合成样品的测定中得到满意的结果.     

CdSe量子点的合成及其对潜指纹的荧光显现研究

以水热法在水相中直接合成了巯基乙酸修饰的CdSe量子点,并将合成的CdSe量子点进行表征、纯化。在波长365nm紫外光的激发下,CdSe量子点发射出明亮的黄绿色荧光,荧光发射峰约位于528nm,将得到的CdSe量子点纳米发光材料应用于非渗透性客体上潜指纹的荧光标记成像研究,发现CdSe量子点溶液显现的手印纹线流畅,显现细节特征明显,呈现明亮的黄绿色荧光指纹,具有很高的实用价值和鉴定价值。     

CdSe量子点与对氨基苯磺酸偶联反应研究

以巯基丙酸为修饰剂合成水溶性硒化镉量子点(CdSe/MPA),利用碳化二亚胺(EDC)和琥珀酰亚胺(NHS)两种偶联剂,将对氨基苯磺酸与硒化镉量子点进行偶联以制备量子点-对氨基苯磺酸偶合物.通过透射电子显微镜、紫外-可见光谱、荧光光谱、荧光寿命、红外光谱、毛细管电泳对偶合物进行了表征.结果表明:量子点和对氨基苯磺酸偶联...     

CdSe/CdS-PVP纳米复合材料的制备及其光学性能研究

量子点由于高表面能而易于团聚,影响其使用价值。通常需要对量子点进行表面修饰,以提高材料的光电稳定性。首先通过化学键合法在水溶性CdSe/CdS量子点表面引入4,4-偶氮双(4-氰基戊酸)(ACVA),制备一种新型量子点引发剂CdSe/CdS-azo,然后引发单体N-乙烯基吡咯烷酮(NVP)聚合,成功制备出一种新型水溶性纳米复合材料CdSe/CdS-PVP。光学测试结果表明CdSe/CdS-PVP在多种溶剂中具有稳定而优异的发光性能。因此,该水溶性纳米复合材料CdSe/CdS-PVP有望作为生物荧光探针和示踪材料。     

水溶液中CdSe量子点的制备

以硫脲为稳定剂直接在水相中合成了CdSe量子点,通过对前躯体制备时的温度,反应时间的考察,以及量子点合成阶段的溶液pH,稳定剂种类选择,稳定剂用量等综合条件的实验,得到了最佳的制备方案.该方案制备的水溶性量子点荧光强度好,原材料利用率高,环境亲和性好,有利于生物检测等运用.     

Facile Phosphine-Free Synthesis of CdSe/ZnS Core/Shell Nanocrystals Without Precursor Injection

A new simple method for synthesis of core/shell CdSe/ZnS nanocrystals (NCs) is present. By adapting the use of cadmium stearate, oleylamine, and paraffin liquid to a non-injection synthesis and by applying a subsequent ZnS shelling procedure to CdSe NCs cores using Zinc acetate dihydrate and sulfur powder, luminescent CdSe/ZnS NCs with quantum yields of up to 36% (FWHM 42–43 nm) were obtained. A seeding-growth technique was first applied to the controlled synthesis of ZnS shell. This method has several attractive features, such as the usage of low-cost, green, and environmentally friendlier reagents and elimination of the need for air-sensitive, toxic, and expensive phosphines solvent. Furthermore, due to one-pot synthetic route for CdSe/ZnS NCs, the approach presented herein is accessible to a mass production of these NCs.     

电化学方法制备CdSe纳米材料的研究进展

纳米CdSe作为一种重要的半导体纳米材料,近年来引起了人们的广泛关注,各种制备方法也由此应运而生。因制备方法的不同,所得的纳米粒子的粒径、粒度均匀性及相结构也不同,进而影响它们的性质。主要综述了电化学方法在制备CdSe纳米材料领域中的应用及国内外研究现状,并对这一领域的发展方向作了展望。     

微乳液法制备CdSe纳米线的表征

利用CTAB／环己烷／异丁醇／水作为反应介质,在微乳液体系中制备了CdSe纳米线。利用X射线衍射（XRD）、透射电子显微镜（TEM）、扫描电子电镜（SEM）表征了CdSe纳米线的形貌和粒径尺寸,研究陈化时间、反应物浓度对CdSe纳米线的影响,结果表明当陈化时间为24h,反应物浓度为0．2mol·L^-1时可合成性能比较好的CdSe纳米线,此时CdSe纳米线产率高、稳定性好。     

CdSe敏化TiO2纳米晶多孔膜电极的制备及其光电性能研究

研究了CdSe敏化TiO2纳米晶多孔薄膜电极的制备及其表征,采用涂敷法将溶胶-凝胶法制备的TiO2胶体制备成纳米晶多孔薄膜,采用化学沉积法制备的CdSe对其进行了敏化处理.敏化后增加了对可见光的吸收作用和光生载流子的输运速度,减少了CdSe上光生载流子的复合,改善了电极内光生电荷的传递特性,获得了较大的稳态光电流.这种薄膜电极改进后可用于制作敏化太阳能电池的光阳极.     

水热法制备CdSe和PbSe共负载TiO2纳米带复合材料

采用两步水热合成过程制得了CdSe或/和PbSe负载的TiO2纳米带复合材料。用XRD、SEM、TEM、UV-Vis吸收和FTIR等测试技术对产物进行了一系列表征。结果表明,六方相CdSe粒子或/和立方相PbSe粒子直接负载在四方相锐钛矿型TiO2纳米带表面,其中呈近球形CdSe粒子的粒径主要在100~400 nm,而呈近立方体形PbSe粒子的边长主要在300~1 000 nm。CdSe和PbSe共负载TiO2纳米带复合材料在可见光区域有强的光吸收。由FTIR谱图推断,在复合材料载体TiO2纳米带结构中掺杂有少量Cd2+或/和Pb2+离子。     

CdSe nanocrystal sensitized ZnO core-shell nanorod array films: Preparation and photovoltaic properties

ZnO/CdSe core-shell nanorod array films were synthesized via a two-step method. ZnO nanorod array films were first grown on a TCO substrate, and then CdSe nanocrystals were deposited on the nanorods to form core-shell structured films. The resulting films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis absorption spectroscopy. Especially, dark-field images and transmission electron diffraction of the TEM were used to study the morphology and the chemical nanostructure of the ZnO/CdSe core-shell nanorods in detail. We investigated the photovoltaic performance of the resulting ZnO/CdSe core-shell nanorod array films as solar cell photoanodes. Parameters, such as the length of the ZnO nanorods, the shell phase structure and the deposition time of the CdSe nanocrystals were found to affect the photovoltaic performance of the solar cell. This study provides a facile method to prepare nanocomposite photoanodes of solar cells, and gives some insight about the fundamental mechanisms that improve the performance.     

Electrospinning of fluorescent fibers from CdSe/ZnS quantum dots in cellulose triacetate

Fluorescent cellulose triacetate (CTA) fibers were prepared by electrospinning solutions of CTA dissolved in an 8 : 2 v/v cosolvent system of methylene chloride (MC) and methanol (MeOH) which contained CdSe/ZnS quantum dots (QDs). The relatively low loading of colloidal nanoparticles was sufficient to impart fluorescence to the fibers but did not significantly alter fiber morphologies, which tended toward smooth surfaces with the occasional longitudinal feature. The fibers were birefringent due to the alignment of the polymer chains which occurred during electrospinning and had widths on the order of a hundred nanometers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Time-dependent pH sensing phenomena using CdSe/ZnS quantum dots in EIS structure

Time-dependent pH sensing phenomena of the core-shell CdSe/ZnS quantum dot (QD) sensors in EIS (electrolyte insulator semiconductor) structure have been investigated for the first time. The quantum dots are immobilized by chaperonin GroEL protein, which are observed by both atomic force microscope and scanning electron microscope. The diameter of one QD is approximately 6.5 nm. The QDs are not oxidized over a long time and core-shell CdSe/ZnS are confirmed by X-ray photon spectroscopy. The sensors are studied for sensing of hydrogen ions concentration in different buffer solutions at broad pH range of 2 to 12. The QD sensors show improved sensitivity (38 to 55 mV/pH) as compared to bare SiO₂ sensor (36 to 23 mV/pH) with time period of 0 to 24 months, owing to the reduction of defects in the QDs. Therefore, the differential sensitivity of the QD sensors with respect to the bare SiO₂ sensors is improved from 2 to 32 mV/pH for the time period of 0 to 24 months. After 24 months, the sensitivity of the QD sensors is close to ideal Nernstian response with good linearity of 99.96%. Stability and repeatability of the QD sensors show low drift (10 mV for 10 cycles) as well as small hysteresis characteristics (<10 mV). This QD sensor is very useful for future human disease diagnostics.