共查询到19条相似文献,搜索用时 171 毫秒
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尺寸分布均一的碳量子点由于其良好的光学特性,在光电设备、离子检测、纳米传感器、生物成像和催化剂等领域具有广阔的应用前景。采用陶瓷膜"超滤-纳滤"双膜法,对微波合成的碳量子点进行分离和纯化。研究了pH对碳量子点料液荧光强度和粒径分布的影响。在pH=3时,碳量子点分散较好,荧光强度较高。陶瓷超滤膜可以有效截留碳量子点料液中的大颗粒杂质,渗透侧的碳量子点平均粒径约为2 nm,分散良好,无团聚现象。陶瓷纳滤膜对碳量子点具有良好的截留性能,在浓缩和水洗过程中可以进一步去除料液中的小分子杂质。经双膜法处理后,发射光谱由多峰分布变为单峰分布,且峰宽变窄,碳量子点的发光纯度得到了明显提高。 相似文献
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概述了原料易获取、合成简单且应用广泛的碳基材料碳点的合成方法——“自上而下”法与“自下而上”法,主要介绍了碳点的发光机制即表面态效应、尺寸效应、交联引起的荧光增强效应、溶剂效应等,并对碳点的荧光性能应用进行了总结与展望。 相似文献
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尺寸分布均一的碳量子点由于其良好的光学特性,在光电设备、离子检测、纳米传感器、生物成像和催化剂等领域具有广阔的应用前景。采用陶瓷膜“超滤-纳滤”双膜法,对微波合成的碳量子点进行分离和纯化。研究了pH对碳量子点料液荧光强度和粒径分布的影响。在pH=3时,碳量子点分散较好,荧光强度较高。陶瓷超滤膜可以有效截留碳量子点料液中的大颗粒杂质,渗透侧的碳量子点平均粒径约为2 nm,分散良好,无团聚现象。陶瓷纳滤膜对碳量子点具有良好的截留性能,在浓缩和水洗过程中可以进一步去除料液中的小分子杂质。经双膜法处理后,发射光谱由多峰分布变为单峰分布,且峰宽变窄,碳量子点的发光纯度得到了明显提高。 相似文献
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综述了近几年国内外碳量子点的研究现状,对电弧法、激光剥蚀法、电化学法、燃烧-水热法、模板法等合成碳量子点的方法进行了介绍,论述了碳量子点的发光性质及毒性。碳量子点有望取代传统半导体量子点,在生物成像、发光探针分析等领域进行广泛的应用。 相似文献
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量子点在生物学及生物医学中的应用是当今纳米技术领域中快速发展的研究方向。与传统的有机荧光染料相比,量子点发光的长程稳定性和同时探测多色信号的能力使其在生物成像和生物传感方面具有广泛的应用。概述了量子点的结构及合成方法,并介绍了量子点表面修饰的研究进展。 相似文献
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上转换发光纳米材料在生物分析和医学成像中具有优异的应用前景。对上转换过程的研究正迅速发展为光化学、生物物理学、固体物理学和材料学的交叉领域。与有机荧光染料和量子点相比,镧系掺杂纳米晶体在生物荧光标记方面具有更少的限制条件。概述了镧系掺杂纳米晶体的结构和上转换发光机理,综述了镧系掺杂上转换发光纳米材料的合成、发光颜色调控方法及其生物分析应用方面的研究进展。 相似文献
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Ⅱ-Ⅵ族半导体量子点在可见光区具有特殊而优良的荧光性质,这一性质使其在太阳能电池、发光器件等领域得到了广泛应用,随着研究的深入,其在生物及化学分析领域的应用也逐渐成为研究热点。综述了Ⅱ-Ⅵ型量子点的荧光特性及其在分析科学中的应用。 相似文献
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A nanoassembly of single-walled carbon nanotubes coated by a thin layer of silica followed by quantum dots was prepared. That the quantum dots retained their photoluminescent properties after deposition onto the silylated carbon nanotubes suggests that the thin layer of silica prevented the quenching of the fluorescence by the nanotubes. This fluorescent nanoassembly represents an excellent building block for photoelectric and optical devices and biological nanoprobes. 相似文献
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从量子点的光学特征、制备、核/壳结构的意义、量子点荧光标记物的优越性、量子点标记生物分子后在单个细胞及临床组织样品检测中的应用等方面综述了量子点在生命科学领域的研究进展。 相似文献
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ABSTRACT: Noble-metal nanostructure allows us to tune optical and electrical properties, which has high utility for real-world application. We studied surface plasmon induced emission of semiconductor quantum dots (QDs) on engineered metallic nanostructures. Highly passive organic ZnS capped CdSe QDs were spin coated on poly-(methyl methacrylate) (PMMA) covered Ag films which brought QDs near to metallic surface. We obtained the enhanced electromagnetic field and reduced fluorescence lifetimes from CdSe/ZnS quantum dots (QDs) due to the strong coupling of emitters wave function with the Ag plasmon resonance. Observed changes include a six-fold increase in the fluorescence intensity and striking reduction in fluorescence lifetimes of CdSe/ZnS QDs on rough Ag nanoneedle compared to the case of smooth surfaces. The advantages of using those nanocomposites are expected for high efficiency light-emitting diodes, platform fabrication of biological and environmental monitoring, and high contrast imaging. 相似文献
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《Carbon》2013
Graphene has been the subject of intense research in recent years due to its unique electrical, optical and mechanical properties. Furthermore, it is expected that quantum dots of graphene would make their way into devices due to their structure and composition which unify graphene and quantum dots properties. Graphene quantum dots (GQDs) are planar nano flakes with a few atomic layers thick and with a higher surface-to-volume ratio than spherical carbon dots (CDs) of the same size. We have developed a pulsed laser synthesis (PLS) method for the synthesis of GQDs that are soluble in water, measure 2–6 nm across, and are about 1–3 layers thick. They show strong intrinsic fluorescence in the visible region. The source of fluorescence can be attributed to various factors, such as: quantum confinement, zigzag edge structure, and surface defects. Confocal microscopy images of bacteria exposed to GQDs show their suitability as biomarkers and nano-probes in high contrast bioimaging. 相似文献
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《Carbon》2015
Microwave heating of an aqueous solution of citric acid, boric acid and urea affords boron-doped carbon dots (C-dots) with ultrafine size (2–6 nm) and quasi-spherical shape. The new dots are freely dispersible in water providing stable, optically transparent dispersions with olive-green color. The optical properties of the dots were studied in respect to their photoluminescence and nonlinear optical response. Boron-doped C-dots exhibit absorption–emission features that strongly resemble the optical properties of conventional quantum dots with a strong blue fluorescence under UV excitation. Importantly, we demonstrate for the first time that boron doping in C-dots causes a significant enhancement of the nonlinear optical response compared to un-doped carbon dots. This result is in line with previous studies reporting a similar effect on the non-linear optical properties of boron-doped silicon nanocrystals. 相似文献
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碳点因其结构独特、荧光发光性能优越而得到诸多关注,在光电器件与生物成像领域也具有非常重要的应用价值.为了调控碳点的结构和性能,研究者们尝试在碳点的制备过程中引入各种聚合物.综述了聚合物作为前驱体应用于碳点的制备,以及作为修饰剂应用于调控碳点光致发光性能的相关研究成果,并侧重于介绍聚合物在调控碳点的荧光发射波长、荧光量子... 相似文献