硒化镉量子点的合成及表征

在氩气条件下和非配位溶剂十八烯（ODE）中,利用单质Se和CdO在油酸（OA）配体中,高温成核,低温增长合成量子点CdSe。利用紫外吸收光谱和荧光对量子点进行表征和分析,初步产物的荧光谱图呈现两个荧光发射峰,分别为短波处较窄的带边发射和长波处较宽的缺陷发射。利用一种修饰剂对量子点表面进行修饰,有效的消除缺陷发射,修饰后的量子点在荧光谱图中表现为仅有一个发射峰位,峰位处于410nm左右。在紫外灯照射下显示紫色。     

石墨烯量子点的制备与表征

介绍了一种改进的溶剂热法制备石墨烯量子点(GQDs)。该方法以N,N-二甲基甲酰胺(DMF)和氧化石墨烯(GO)作为溶剂和原料,过程中会对GO进行微波膨胀预处理,然后进行反应。分别采用紫外可见吸收、光致发光、红外、透射电镜对石墨烯量子点进行结构、形貌以及荧光性能的表征。通过该方法制备的GQDs的荧光发射光谱表明其具有可激发性且具有良好的荧光性能。     

量子点荧光探针在生物医学领域的研究进展

量子点是一种新型的半导体荧光纳米材料,由于其特殊的纳米结构所导致的表面、介电、量子等效应而具有许多优异的光学性能,近年来在分析化学、生物医学等领域得以快速应用和发展.介绍了量子点的制备方法、表面修饰及量子点荧光探针在生物医学领域的应用进展,并对未来的发展方向作出了展望.     

Magnetic Fluorescent Quantum Dots Nanocomposites in Food Contaminants Analysis: Current Challenges and Opportunities

The presence of food contaminants can cause foodborne illnesses, posing a severe threat to human health. Therefore, a rapid, sensitive, and convenient method for monitoring food contaminants is eagerly needed. The complex matrix interferences of food samples and poor performance of existing sensing probes bring significant challenges to improving detection performances. Nanocomposites with multifunctional features provide a solution to these problems. The combination of the superior characteristics of magnetic nanoparticles (MNPs) and quantum dots (QDs) to fabricate magnetic fluorescent quantum dots (MNPs@QDs) nanocomposites are regarded as an ideal multifunctional probe for food contaminants analysis. The high-efficiency pretreatment and rapid fluorescence detection are concurrently integrated into one sensing platform using MNPs@QDs nanocomposites. In this review, the contemporary synthetic strategies to fabricate MNPs@QDs, including hetero-crystalline growth, template embedding, layer-by-layer assembly, microemulsion technique, and one-pot method, are described in detail, and their advantages and limitations are discussed. The recent advances of MNPs@QDs nanocomposites in detecting metal ions, foodborne pathogens, toxins, pesticides, antibiotics, and illegal additives are comprehensively introduced from the perspectives of modes and detection performances. The review ends with current challenges and opportunities in practical applications and prospects in food contaminants analysis, aiming to promote the enthusiasm for multifunctional sensing platform research.     

石墨烯量子点的制备及应用

石墨烯量子点(GQDs)作为石墨烯家族的最新一员,除了继承石墨烯的优异性能,还因量子限制效应和边界效应而显现出一系列新的特性,引起了化学、物理、材料和生物等各领域科研工作者的广泛关注。GQDs的制备方法通常分自上而下和自下而上的方法。对其各种制备方法和应用分别进行了介绍,并结合各种应用对GQDs的要求给出了制备方法的建议。指出了GQDs研究中存在的问题及发展方向。     

二氧化锡量子点的制备、表征及缺陷研究

以SnCl4·5H2O为原料、三重蒸馏水为溶剂,结合溶胶凝胶法与水热法合成了9种不同粒径的SnO2量子点胶体及其对应的粉末颗粒。分析了不同合成条件对量子点的影响,用XRD和TEM对其粉末结构和形貌进行了表征,对SnO2纳米粒子的Uv-Vis光谱以及光致发光光谱进行了分析,计算了量子点粒径大小以及禁带宽度,并对其荧光发光机理进行了探讨。结果表明,合成的Sn02量子点的粒径为3．2～4．6nm,粒径分布均匀,分散性较好。SnO2纳米粒子光致发光在430nm、530nm和600nm处有发光峰,分别是由锡间隙、单电子氧缺陷以及表面态引起的深能级跃迁所致。     

石墨烯量子点在生物传感和成像技术中的应用

石墨烯量子点具有许多吸引人的优点,如低细胞毒性、溶解能力强、稳定的光致发光、良好的生物相容性、高比表面积、电子高迁移率和可调节带隙等,因此,适用于构建传感系统和生物成像。根据近几年来,基于石墨烯量子点性质构建的光学生物传感器和电化学生物传感器以及石墨烯量子点在生物成像技术中的应用进行了综述。     

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。     

碳量子点的制备及其在发光二极管中的应用

碳量子点是纳米材料领域一个备受关注的荧光纳米材料,仅近几年里,基于碳量子点的研究,在制备和应用方面均取得了许多突破性的进展。本文简述了碳量子点的优异特性及其合成方法,重点概述了碳量子点的修饰、复合材料的制备以及在发光二极管(LED)应用方面的最新研究进展。以期为碳量子点的发展应用提供思路和参考。     

Direct Generation of Mn‐Doped ZnS Quantum Dots/Alginate Nanocomposite Beads Based on Gelation and In Situ Synthesis of Quantum Dots

Herein, a concise and novel method is developed to directly generate Mn‐doped ZnS QDs/alginate nanocomposite beads. In this method, the ionic gelation of alginate is employed to produce alginate gel beads in a solution of Zn²⁺ and Mn²⁺ ions. Subsequently, the gel beads serve as the reaction support for in situ synthesis of Mn‐doped ZnS QDs in the beads through the reaction of sodium sulfide with Zn²⁺ and Mn²⁺ ions. The method has many benefits such as the simple preparation, the environmentally friendly process, the mild conditions, and the easy post‐treatment for the beads. The resulting QDs/alginate beads are homogeneous and stable gel spheres which show clear fluorescence. TEM images demonstrate that Mn‐doped ZnS QDs are homogeneously distributed within the QDs/alginate nanocomposite, and their average size is 2.4 ± 0.3 nm. Potentially, the QDs/alginate beads can be utilized for fluorescence bioimaging, as well as fluorescence detection toward metal ions.     

CdS/Chitosan量子点的制备及其光学性能的研究

以壳聚糖(Chitosan)为稳定剂和包裹剂,在水相中合成了CdS/Chitosan量子点,研究了反应时间、壳聚糖用量、反应温度以及镉硫源摩尔比等对其发光性能的影响,并用紫外可见吸收光谱、红外光谱、X-射线粉末衍射等对量子点进行了表征。结果表明,随着反应时间的延长、反应温度的升高、壳聚糖用量的减少、镉硫源摩尔比的增大,量子点的紫外特征吸收峰会发生红移,从而推测量子点的粒径在不断变大。     

表面修饰CdTe量子点的合成及其光学特性

在水相中合成高发光性能的CdTe量子点,研究以巯基乙酸(TGA)为稳定剂对CdTe表面进行修饰,制备在水中分散性良好的纳米晶,通过对CdTe量子点合成反应条件的摸索,掌握了其合成的反应规律.同时用紫外分光光度计、荧光分光光度计和透射电子显微镜对其进行了表征.结果表明,回流时间、n(Cd2+):n(HTe-)、反应物浓度、TGA用量、反应体系pH值,对纳米晶的光学性质具有显著影响.回流2 h制得的CdTe纳米粒子直径约为5 nm,其发射峰窄且对称,表现出良好稳定的光学性质.     

碲化镉量子点与金纳米粒子用于DNA检测

A DNA fluorescence probe system based on fluorescence resonance energy transfer （FRET） from CdTe quantum dot （QD） donors to Au nanoparticle （AuNP） acceptors is presented. CdTe QDs, 2.5nm in diameter, as energy donors, were prepared in water. Au nanoparticles, 16nm in diameter, as energy acceptors, were prepared from gold chloride by reduction. CdTe QDs were linked to 5＇-NH2-DNA through 1-ethyl-3-（dimethylaminopropyl）car- bodiimide hydrochloride （EDC） as a linker, and the 3＇-SH-DNA was self-assembled onto the surface of AuNPs. The hybridization of complementary double stranded DNA （dsDNA） bound to the QDs and AuNPs （CdTe-dsDNA-Au） determined the FRET distance of CdTe QDs and Au nanoparticles. Compared to the fluorescence of CdTe-DNA, the fluorescence of CdTe-DNA-Au conjugates decreased extremely, which indicated that the FRET occurred between CdTe QDs and Au nanoparticles. The fluorescence change of this conjugate depended on the ratio of Au-DNA to CdTe-DNA. When the AuNPs-DNA to QD-DNA ratio was 10：1, the FRET efficiency reached a maximum. The probe system would have a certain degree of fluorescence recovery when a complementary single stranded DNA was introduced into this system, which showed that the distance between CdTe QDs and Au nanoparticles was increased.     

量子点荧光纳米材料的化学合成及其在潜手印显现中的应用

随着纳米科技的发展,将量子点荧光纳米材料作为一种新型显现试剂并应用于潜手印显现技术已引起了研究者的浓厚兴趣。合成出高质量、高荧光性能的量子点是拓展其在手印显现方面广泛应用的前提条件。本文针对量子点荧光纳米材料的化学法合成及其在潜手印显现领域中的应用进展进行了较为详尽的归纳和总结。     

两亲性苯乙烯嵌段共聚物的合成及结构表征

以α,α'-二甲基-α-乙酸-三硫代碳酸酯(BDATC)为链转移剂,采用可逆-加成-断裂链转移(RAFT)自由基聚合方法合成了末端带有—COOH官能团的两亲性嵌段共聚物聚苯乙烯-b-聚甲基丙烯酸聚乙二醇单甲醚-b-聚苯乙烯(PSt-b-POEOMA-b-PSt),这种含有亲水性端基的嵌段共聚物可以自组装成核-壳结构的纳米微粒,用于载药高分子的模板研究。利用FTIR、1HNMR、GPC对产物结构进行表征,用热失重(TG)和差示扫描量热(DSC)的方法研究了3种不同比例的嵌段共聚物的热性能。实验结果表明,通过RAFT聚合方法得到了所设计的嵌段共聚物,相对分子质量(简称分子量,下同)分布1.35左右;嵌段共聚物的热稳定性较好,通过玻璃化转变温度(Tg)的变化推测出嵌段共聚物中两种嵌段比例对两嵌段相容性的影响。     

Substrate Temperature Dependent Surface Morphology and Photoluminescence of Germanium Quantum Dots Grown by Radio Frequency Magnetron Sputtering

The visible luminescence from Ge nanoparticles and nanocrystallites has generated interest due to the feasibility of tuning band gap by controlling the sizes. Germanium (Ge) quantum dots (QDs) with average diameter ~16 to 8 nm are synthesized by radio frequency magnetron sputtering under different growth conditions. These QDs with narrow size distribution and high density, characterized using atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) are obtained under the optimal growth conditions of 400 °C substrate temperature, 100 W radio frequency powers and 10 Sccm Argon flow. The possibility of surface passivation and configuration of these dots are confirmed by elemental energy dispersive X-ray (EDX) analysis. The room temperature strong visible photoluminescence (PL) from such QDs suggests their potential application in optoelectronics. The sample grown at 400 °C in particular, shows three PL peaks at around ~2.95 eV, 3.34 eV and 4.36 eV attributed to the interaction between Ge, GeO_x manifesting the possibility of the formation of core-shell structures. A red shift of ~0.11 eV in the PL peak is observed with decreasing substrate temperature. We assert that our easy and economic method is suitable for the large-scale production of Ge QDs useful in optoelectronic devices.     

铝铋离子掺杂对ZnO量子点荧光性能的影响研究

以二水合醋酸锌作为前驱体,无水乙醇作为溶剂,聚乙二醇(PEG-400)作为分散稳定剂,利用一种简单温和的方法制备Al~(3+)、Bi~(3+)掺杂氧化锌量子点,分别研究Al~(3+)、Bi~(3+)单掺,共掺对量子点荧光光谱性能的影响。结果表明:在紫外灯照射下,量子点颜色为绿色。在360 nm的激发下,ZnO量子点在524 nm附近有较的发射峰。随着掺杂离子用量的增加,ZnO量子点可见光区发射峰形状不变,单掺和共掺Al~(3+)、Bi~(3+)都使ZnO量子的荧光峰值减弱,但单掺Al~(3+)使荧光峰发生了红移。     

Experimental Evaluation of Quantum Dots and Antibodies Conjugation by Surface Plasmon Resonance Spectroscopy

The application of antibody-functionalized quantum dots (QDs) in different areas has been widely described in the literature. However, a standard routine method for obtaining information on the conjugation efficiency of QDs with antibodies in terms of the interaction of the functionalized QDs with a specific antigen is still lacking. Herein, surface plasmon resonance (SPR) spectroscopy is proposed for this purpose. Gold-coated SPR sensor disks were modified with a self-assembled monolayer of 11-mercaptoundecanoic acid, and carbodiimide cross-linker chemistry was used to covalently immobilize the CD44 biomarker on the premodified surface (Au/CD44). Meanwhile, QDs functionalized with amine-derivatized polyethylene glycol (PEG) (QDs-NH₂) were chosen for conjugation with antibodies because of their low non-specific adsorption on the Au/CD44 surface. Prior to conjugation, the surface binding capacity (B_max) and equilibrium dissociation constant (K_D) of the specific antibodies against CD44 (anti-CD44) were found to be 263.32 ± 2.44 m° and 1.00 × 10⁻⁷ ± 2.29 × 10⁻⁹ M, respectively. QDs-NH₂ and anti-CD44 were conjugated at their initial molar ratios of 1:3, 1:5, 1:10 and 1:12. SPR measurements showed that the conjugates (QDs-anti-CD44) prepared using 1:10 and 1:12 molar ratios interacted comparably with immobilized CD44 biomarkers. The equilibrium angles in the case of 10- and 12-fold concentrations of anti-CD44 were calculated to be 60.43 ± 4.51 and 61.36 ± 4.40 m°, respectively. This could be explained by the QDs-NH₂ and anti-CD44 having a similar surface loading (about four molecules per QDs-NH₂) and similar hydrodynamic diameters, which were 46.63 ± 3.86 and 42.42 ± 0.80 nm for the 1:10 and 1:12 ratios, respectively. An initial QDs-NH₂: anti-CD44 molar ratio of 1:10 was chosen as being optimal. SPR spectroscopy proved to be the right choice for QDs-anti-CD44 conjugation optimization, and can be used for the evaluation of conjugation efficiency for other nanostructures with various bio-recognition molecules.     

N-乙酰半胱氨酸修饰CdTe量子点的合成及其用于二价铜离子检测的研究

利用"一锅法"合成N-乙酰半胱氨酸修饰的CdTe量子点,并利用紫外-可见分光光度法和荧光光谱法对其进行表征。根据CdTe量子点与Cu~(2+)反应发生荧光淬灭的原理来检测水体中Cu~(2+)的浓度。研究表明,CdTe量子点荧光淬灭程度与Cu~(2+)离子浓度有很好的线性关系,该方法检测Cu~(2+)离子的下限浓度为6.59×10~(-9)mol/L。本研究建立了一种灵敏快速测定Cu~(2+)的方法。