共查询到18条相似文献,搜索用时 125 毫秒
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以氧化镉、硒粉和二乙基二硫代氨基甲酸锌为原料,采用微流体法合成了稳定的CdSe@ZnS核-壳结构胶体量子点,利用X射线衍射仪(XRD)、透射电子显微电镜(TEM)、荧光光谱仪(PL)和紫外-可见吸收光谱(UV-vis)对量子点的结晶性能、微观形貌和发光性能进行了表征。将CdSe@ZnS核-壳结构量子点作为量子点发光二极管(QLED)的发光层材料,成功组装出ITO/PEDOT:PSS/Poly-TPD/Cd Se@ZnS/PCBM/Li F:Al三明治结构的量子点发光二极管,在2 V电压下成功点亮,器件发出黄色光,亮度达到4500 Cd/cm~2。 相似文献
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为了检测浓度超标的重金属离子,探讨了一种新的荧光探针传感器检测法。利用柠檬酸钠作为还原剂合成铜纳米晶,然后加入半胱氨酸作为刻蚀剂和保护剂,与铜纳米晶配体交换反应合成荧光铜纳米簇,以铜纳米簇作为荧光探针建立了一种检测水样中重金属钴离子的方法。该方法是基于钴离子存在时,破坏铜纳米簇,导致荧光迅速降低。在较宽的钴离子浓度范围(1~100μmol/L)内,铜纳米簇荧光淬灭程度与浓度呈线性关系(R=0.970 0),其检出限较低(0.567 1μmol/L)。铜纳米簇传感器特异性选择钴离子,不受其他金属离子干扰,检测的选择性较好。基于此,完成对钴离子的超灵敏免标记检测,且EDTA可作为钴离子的螯合剂,实现了铜纳米簇传感器的循环反复使用。 相似文献
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以谷胱甘肽(GSH)为稳定剂,在水相中制备了CdTe量子点,基于As3+离子对量子点荧光的淬灭作用,建立了定量测定As3+离子的方法。CdTe量子点对As3+离子呈现出高选择性,其它常见金属离子的存在对铜的测定几乎不产生干扰。考察了不同反应时间和不同价态砷等因素对CdTe量子点的影响,量子点的相对荧光强度与As3+离子的浓度呈很好的线性关系,该方法的线性范围为0.2~2·2μM,检出限为20 nM。本方法简单、快速,与文献报道的其它基于量子点荧光探针As3+离子分析方法相比,此法对As3+离子呈现出更高的选择性。将此法用于实际废水中As3+离子含量的测定,结果令人满意。 相似文献
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巯基乙酸稳定的CdSe/ZnS核壳结构量子点的制备与表征 总被引:1,自引:0,他引:1
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. 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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木质素磺酸盐是造纸工业主要副产物之一,本文利用木质素磺酸钙和柠檬酸为原料通过绿色简便的原位反应制备木质素磺酸钙/石墨烯复合量子点,利用荧光光谱、紫外可见光谱和透射电镜等研究了复合量子点的光学性能、结构模型和对金属离子的选择性吸附性能,结果表明该复合量子点的荧光强度是石墨烯量子点的4倍多,并且复合量子点可以选择性识别Fe3+,在10~500μmol/L范围内,Fe3+的浓度与复合量子点溶液的荧光强度有良好的线性关系,可应用于Fe3+的检测。此荧光探针制备简便,成本低廉,检测铁离子速度快,准确性高,选择性好,在离子检测方面有潜在的应用价值。 相似文献
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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。 相似文献
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Trisita Ghosh Rajkumar Sahoo Suman Kumar Ghosh Pallab Banerji Narayan Ch. Das 《Frontiers of Chemical Science and Engineering》2023,17(5):536
The past decade has witnessed a variety of members of the carbon family along with exposure of carbon dots due to their magnificent properties in sensing, bioimaging, catalytic applications, biomedical fields, and so on. Herein, we report the simple hydrothermal method to fabricate photoluminescent doped carbon quantum dots for the detection of noxious lead(II) ions. Lead(II) ion is very venomous for both the environment and human health for which its detection is demanded area in the research field. The as-prepared carbon dots show excellent photostability, low toxicity and significant photoluminescence properties along with good water solubility. Along with these properties, carbon dots have a quantum yield of approximately 15%. In the practical field of application, these carbon dots have been used as sensing probes for the detection of lead(II) ions with a detection limit of 60 nmol·L–1. The fluorescence intensity of carbon dots was remarkably quenched in the presence of the lead(II) ion selectively among all the tested metal ions. Furthermore, we have studied the Stern–Volmer relationship for lead(II) quenching along with the explanation of the probable quenching mechanism. Ability of the doped carbon dots in heavy metal ions sensing in an environmental sample was demonstrated. 相似文献
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A facile method of synthesizing 60 nm magnetic-fluorescent core-shell bifunctional nanocomposites with the ability to label cells is presented. Hydrophobic trioctylphosphine oxide (TOPO)-capped CdSe@ZnS quantum dots (QDs) were assembled on polyethyleneimine (PEI)-coated Fe(3)O(4) nanoparticles (MNP). Polyethyleneimine was utilized for the realization of multifunction, including attaching 4 nm TOPO capped CdSe@ZnS quantum dots onto magnetite particles, altering the surface properties of quantum dots from hydrophobic to hydrophilic as well as preventing the formation of large aggregates. Results show that these water-soluble hybrid nanocomposites exhibit good colloidal stability and retain good magnetic and fluorescent properties. Because TOPO-capped QDs are assembled instead of their water-soluble equivalents, the nanocomposites are still highly luminescent with no shift in the PL peak position and present long-term fluorescence stability. Moreover, TAT peptide (GRKKRRQRRRPQ) functionalized hybrid nanoparticles were also studied due to their combined magnetic enrichment and optical detection for cell separation and rapid cell labelling. A cell viability assay revealed good biocompatibility of these hybrid nanoparticles. The potential application of the new magnetic-fluorescent nanocomposites in biological and medicine is demonstrated. 相似文献
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Kai Li Chao Liu Zhiyong Zhao Zhao Deng Mengling Xia Ying Ye 《Journal of the American Ceramic Society》2018,101(11):5080-5088
In order to alleviate the effect of the surface defects on the emission properties of quantum dots, copper ions‐doped ZnSe quantum dots (QDs) in the glasses are prepared using melt‐quenching and subsequent thermal annealing methods. For glasses without copper doping, tunable band‐edge emission from ZnSe QDs is achieved. For glasses with copper doping, efficient energy transfer from ZnSe QDs to copper ions is observed, and efficient broad band emission from copper ions is realized at the expense of the band‐edge emission of ZnSe QDs. Absorption spectra, size‐dependent broad‐band emission spectra and electron spin resonance spectra show the cupric ions are doped into the ZnSe QDs. Results reported here shows that doping of transition‐metal ions into semiconductor QDs in glasses is promising for development of high efficient luminescent glasses. 相似文献
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Sensitive and selective detection strategies for toxic heavy metal ions, which are rapid, cheap and applicable to environmental and biological fields, are of significant importance. As a result of specific interaction between thiol(s) used as ligands and heavy metal ions, the photoluminescence intensity of quantum dots (QDs) in PBS buffer solution was quenched and the aggregation of QDs was formed at the same time. Herein, we present water-soluble, low toxic QDs, ZnSe/ZnS, which were applied for ultrasensitive Hg(2+) ion detection with a low detection limit (2.5 nM). In addition, a model has been proposed to explain the aggregation of QDs in the presence of heavy metal ions such as Hg(2+) ions. 相似文献
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This paper studies the detection of copper ions by using an iminodiacetatic acid (IDA) modified conducting copolymer electrode. The copolymer film comprising 3-methyl thiophene (3MT) and 3-thiophene acetic acid (3TA) was chosen as the selective metal cation sensing electrode. The carboxylic group of the copolymer was modified to produce IDA group for metal ion capture. The modified electrode was used for the electrochemical analysis of trace copper ions by square wave voltammetry (SWV) technique. The electrode was found to be highly selective to Cu2+ in the range of 0.1-10 μM. The modified electrode offered an excellent way, with a high stability and reusability, for selective determination of Cu2+ in a solution of mixed metal ions. 相似文献
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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. 相似文献
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钙钛矿量子点具有发光谱带较窄、发光可调、量子效率高等优异的光学性能,在发光二极管、激光发射器等领域广受关注。但是钙钛矿量子点由于强离子性、高表面能及表面配体易迁移等特性而对环境高度敏感,使其在实际应用中受到限制。本文简要介绍了钙钛矿量子点结构和不稳定的原因,综述了近年来提高钙钛矿量子点稳定性的主要方法,重点从离子掺杂、表面钝化、表面包覆及多重保护4个方面展开论述。最后从绿色环保的角度出发,对高稳定生物质基钙钛矿量子点材料的制备进行了展望,提出使用具有特定结构的生物质材料及其衍生材料取代传统石油基试剂作为配体、溶剂或吸附重金属离子的外壳材料,可加速钙钛矿量子点朝着绿色低毒的方向发展。 相似文献