共查询到20条相似文献,搜索用时 31 毫秒
1.
Chuanmiao Yan Fangqiong Tang Linlin Li Hongbo Li Xinglu Huang Dong Chen Xianwei Meng Jun Ren 《Nanoscale research letters》2010,5(1):189-194
This work described a continuous method to synthesize CdTe/CdS/ZnS core/shell/shell quantum dots. In an integrated system
by flawlessly combining the chemical aerosol flow system working at high temperature (200–300°C) to generate CdTe/CdS intermediate
products and an additional heat-up setup at relatively low temperature to overcoat the ZnS shells, the CdTe/CdS/ZnS multishell
structures were realized. The as-synthesized CdTe/CdS/ZnS core/shell/shell quantum dots are characterized by photoluminescence
spectra, X-ray diffraction (XRD), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), and high-resolution
transmission electron microscopy (HRTEM). Fluorescence and XRD results confirm that the obtained quantum dots have a core/shell/shell
structure. It shows the highest quantum yield above 45% when compared to the rhodamine 6G. The core/shell/shell QDs were more
stable via the oxidation experiment by H2O2. 相似文献
2.
以TeO2为碲源,巯基丙酸(MPA)为稳定剂和还原剂,采用微波辅助加热法一步合成水溶性CdTe/ZnTe核壳结构的半导体量子点.考察了Cd/Zn反应物配比及MPA用量对CdTe/ZnTe量子点性能的影响,并用紫外、荧光光谱、高分辨透射电子显微镜(HRTEM)、X射线粉末衍射(XRD)光谱和EDX电子能谱对CdTe/ZnTe进行了表征.结果表明,在不需要另加NaBH4的条件下,同样能合成水溶性的CdTe/ZnTe量子点,且该核壳结构的CdTe/ZnTe量子点比单一的CdTe量子点具有更高的荧光量子产率. 相似文献
3.
Highly luminescent near-infrared (NIR) emitting CdTe/CdSe quantum dots (QDs) were prepared through a fast and convenient method, and a new type of multivalent polymer ligands was used as the surface substituents to prepare highly stable hydrophilic QDs with small sizes. The well-defined CdTe/CdSe QDs were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy and photoluminescence (PL) spectroscopy, respectively. The as-prepared CdTe/CdSe QDs were photostable with high PL quantum yields (QYs) (up to 66% at room temperature), low toxicity to cells at experimental dosages, and the QDs' fluorescence emissions were tunable between 700 and 820 nm. Furthermore, fluorescence imaging using CdTe/CdSe QDs conjugated with the AS1411 aptamer (targeting nucleolin) probe in cancer cells was reported, and the CdTe/CdSe QDs were also successfully applied for the fluorescence imaging of living animals. Our preliminary results illustrated that the CdTe/CdSe NIR-QDs with small sizes would be an alternative probe for ultrasensitive, multicolor, and multiplex applications, especially for in vivo imaging applications. 相似文献
4.
Ning Gan Jing Zhou Ping Xiong Tianhua Li Shan Jiang Yuting Cao Qianli Jiang 《International journal of molecular sciences》2013,14(5):10397-10411
The CdTe quantum dots (QDs), graphene nanocomposite (CdTe-G) and dextran–Fe3O4 magnetic nanoparticles have been synthesized for developing an ultrasensitive electrochemiluminescence (ECL) immunoassay for Carcinoembryonic antigen 19-9 (CA 19-9) in serums. Firstly, the capture probes (CA 19-9 Ab1/Fe3O4) for enriching CA 19-9 were synthesized by immobilizing the CA 19-9’s first antibody (CA 19-9 Ab1) on magnetic nanoparticles (dextran-Fe3O4). Secondly, the signal probes (CA 19-9 Ab2/CdTe-G), which can emit an ECL signal, were formed by attaching the secondary CA 19-9 antibody (CA 19-9 Ab2) to the surface of the CdTe-G. Thirdly, the above two probes were used for conjugating with a serial of CA 19-9 concentrations. Graphene can immobilize dozens of CdTe QDs on their surface, which can emit stronger ECL intensity than CdTe QDs. Based on the amplified signal, ultrasensitive antigen detection can be realized. Under the optimal conditions, the ECL signal depended linearly on the logarithm of CA 19-9 concentration from 0.005 to 100 pg/mL, and the detection limit was 0.002 pg/mL. Finally, five samples of human serum were tested, and the results were compared with a time-resolved fluorescence assay (TRFA). The novel immunoassay provides a stable, specific and highly sensitive immunoassay protocol for tumor marker detection at very low levels, which can be applied in early diagnosis of tumor. 相似文献
5.
Yunfeng Shi Lin Liu Huan Pang Hongli Zhou Guanqing Zhang Yangyan Ou Xiaoyin Zhang Jimin Du Wangchuan Xiao 《Nanoscale research letters》2014,9(1):115
A new strategy for facile preparation of highly luminescent CdTe quantum dots (QDs) within amine-terminated hyperbranched poly(amidoamine)s (HPAMAM) was proposed in this paper. CdTe precursors were first prepared by adding NaHTe to aqueous Cd2+ chelated by 3-mercaptopropionic sodium (MPA-Na), and then HPAMAM was introduced to stabilize the CdTe precursors. After microwave irradiation, highly fluorescent and stable CdTe QDs stabilized by MPA-Na and HPAMAM were obtained. The CdTe QDs showed a high quantum yield (QY) up to 58%. By preparing CdTe QDs within HPAMAM, the biocompatibility properties of HPAMAM and the optical, electrical properties of CdTe QDs can be combined, endowing the CdTe QDs with biocompatibility. The resulting CdTe QDs can be directly used in biomedical fields, and their potential application in bio-imaging was investigated. 相似文献
6.
Jana Drbohlavova Marina Vorozhtsova Radim Hrdy Rene Kizek Ota Salyk Jaromir Hubalek 《Nanoscale research letters》2012,7(1):123
The template-based methods belong to low-cost and rapid preparation techniques for various nanostructures like nanowires, nanotubes, and nanodots or even quantum dots [QDs]. The nanostructured surfaces with QDs are very promising in the application as a sensor array, also called ''fluorescence array detector.'' In particular, this new sensing approach is suitable for the detection of various biomolecules (DNA, proteins) in vitro (in clinical diagnostics) as well as for in vivo imaging.The paper deals with the fabrication of TiO2 planar nanostructures (QDs) by the process of titanium anodic oxidation through an alumina nanoporous template on a silicon substrate. Scanning electron microscopy observation showed that the average diameter of TiO2 QDs is less than 10 nm. Raman spectroscopic characterization of self-organized titania QDs confirmed the presence of an anatase phase after annealing at 400°C in vacuum. Such heat-treated TiO2 QDs revealed a broad emission peak in the visible range (characterized by fluorescence spectroscopy). 相似文献
7.
Transparent poly(styrene‐butadiene‐styrene) (SBS)‐quantum dots (QDs) composites (SBS/CdTe QDs) that simultaneously possess strong photoluminescence (PL) and enhanced mechanical properties are presented for the first time based on the facile blending of SiO2‐hybridized CdTe QDs with SBS. UV–vis spectrum and fluorescence measurement show that SBS/CdTe QDs composites exhibit good optical properties. The results of transmission electron microscopy show good dispersion of CdTe QDs in the SBS matrix. The results of dynamic mechanical thermal analysis indicate that the micro‐phase separated structure of the SBS is exist in the composites, and the presence of CdTe QDs can lead to an decrease of glass transition temperatures of polybutadiene (PB) and polystyrene(PS) domains. In addition, mechanical tests reveal that the addition of CdTe QDs is a useful approach to improve the mechanical properties of SBS. Meanwhile, the fluorescent photographs taken under ultraviolet light prove that SBS/CdTe QDs composites possess strong PL. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011. 相似文献
8.
Zhenjie Chen Yuming Zhou Tao Zhang Xiaohai Bu Xiaoli Sheng 《Journal of Inorganic and Organometallic Polymers and Materials》2014,24(3):591-599
Optically active polyacetylene@CdTe Quantum Dots (HPA@CdTe and RPA@CdTe) composites have been prepared based on the surface modification of CdTe quantum dots (QDs). The as-prepared HPA@CdTe and RPA@CdTe were characterized by Fourier-transform infrared spectroscopy, UV–Vis absorption spectra, X-ray diffraction, thermogravimetric analysis, transmission electron microscopy and scanning electron microscopy. The infrared emissivity of HPA@CdTe and RPA@CdTe was also investigated. The results indicate that the polyacetylenes were successfully grafted onto the surfaces of the CdTe QDs without destroying the original crystalline structure of the CdTe QDs. Moreover, the infrared emissivity values of the HPA@CdTe and RPA@CdTe composites were reduced to 0.392 and 0.454, which possess much lower infrared emissivity values than those of the pure polymers and nanoparticles. The results are attributed to interfacial interactions between the organic and inorganic components. Furthermore, the helical conformation may also reduce the infrared emissivity due to the more ordered stereo structure and regular secondary structure. 相似文献
9.
Zhenshun Li Shaolong Wan Wei Xu Yuntao Wang Bakht Ramin Shah Weiping Jin Yijie Chen Bin Li 《应用聚合物科学杂志》2015,132(17)
Robust and facile strategies are required to fabricate film with high luminescence for application in the fields of biomaterials. In this study, the luminescent electrospinning cellulose fibrous mats were decorated with CdTe quantum dots (QDs) and poly(diallyl dimethyl ammonium chloride) (PDDA) using layer by layer (LBL). The characterizations of the LBL films coated mats were executed by X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, fluorescent spectroscopy, X‐ray diffraction, thermal gravimetric analysis, and differential scanning calorimetry. The luminescent intensities were linearly increased with adding the amount of deposited bilayers. The green fabricated (QDs/PDDA)n coated mat through physical interactions is a promising luminescent material. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41893. 相似文献
10.
Ze-Quan Lin 《Electrochimica acta》2010,55(28):8717-8723
Shell-core nanostructured ZnS/CdS quantum dots (QDs) were assembled uniformly on the surface of TiO2 nanotube arrays by sequence chemical bath deposition (CBD) of CdS and ZnS in alcohol solution system. The morphology and chemical composition of the obtained composite thin films were characterized by scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The effect of solvent and immersion cycles for the photoanode preparation on the photoelectrochemical activity and photogenerated cathodic protection property was investigated. It is found that the nanostructured CdS QDs (20 cycles) coated on TiO2 nanotube arrays show a remarkably enhanced photoelectrochemical activity. The coating of ZnS QD shells (5 cycles) is able to improve the stability of the CdS@TiO2 photoanode under white-light irradiation. After the irradiation light is turned off, the photogenerated cathodic protection of 403 stainless steel (403SS) can be remained for several hours. 相似文献
11.
Yunfeng Shi Zhimin Ma Ningning Cui Yanli Liu Xiaoyu Hou Weimin Du Lin Liu Tong Gangsheng 《Nanoscale research letters》2014,9(1):121
A new strategy for in situ preparation of highly fluorescent CdTe quantum dots (QDs) with 3-mercaptopropionic acid (MPA) and hyperbranched poly(amidoamine)s (HPAMAM) as co-stabilizers was proposed in this paper. MPA and HPAMAM were added in turn to coordinate Cd2+. After adding NaHTe and further microwave irradiation, fluorescent CdTe QDs stabilized by MPA and HPAMAM were obtained. Such a strategy avoids the aftertreatment of thiol-stabilized QDs in their bioapplication and provides an opportunity for direct biomedical use of QDs due to the existence of biocompatible HPAMAM. The resulting CdTe QDs combine the mechanical, biocompatibility properties of HPAMAM and the optical, electrical properties of CdTe QDs together. 相似文献
12.
In this paper, we reported a new method to fabricate CdTe quantum dots (CdTe QDs), which were synthesized in aqueous solution using thioglycolic acid and L ‐phenylalanine (L ‐Phe) as costabilizing agent. Then, they were transferred into organic phase with the assistance of cetyltrimethylammonium bromide (CTAB) for further utilization. Finally, we use toluene diisocyanate as a bridge between CdTe QDs and polyacrylate (CPA), whose side chain has hydroxyl group, to synthesize a fluorescent composite polymer CdTe‐CPA. In addition, we synthesized an organic substance 4‐[2,4‐di(tert‐butyl)]phenoxy‐N‐(2‐hydroxyethyl)‐1,8‐naphthalimide (N), and obtained 1,8‐naphthahmide fluorescent polymer N‐CPA in the same way as it did on CdTe‐CPA. The resulting materials were characterized by Fourier transform infrared spectroscopy (FT‐IR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), transmission electron microscope (TEM), and photoluminescence (PL). Then, we studied the fluorescence resonance energy transfer (FRET) between CdTe‐CPA and N‐CPA. The data obtained from absorption and fluorescence emission spectral indicated that the FRET from N‐CPA to CdTe‐CPA could be efficiently triggered in the solution of chloroform. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
13.
Mehdi Asgari Maryam Shanehsaz Mojtaba Shamsipur Mahsa Behzad Mohammad Ghannadi Maragheh 《Journal of Applied Electrochemistry》2013,43(1):15-19
A novel modified electrode was constructed by immobilizing thioglycolic acid-capped CdTe quantum dots (QDs) on a glassy carbon electrode (GCE) using Nafion ionomers. The results obtained by electrochemical impedance spectroscopy, cyclic voltammetry, and rotating disk electrode using the modified QDs?CNafion/GCE in a 0.20?M phosphate buffer of pH 7.0 revealed that the QDs act as effective mediators for the electrocatalytic reduction of dioxygen. 相似文献
14.
15.
Miao Zhang Yanyan Xu Jianguo Lv Lei Yang Xishun Jiang Gang He Xueping Song Zhaoqi Sun 《Nanoscale research letters》2014,9(1):636
Highly ordered TiO2 nanotube arrays (TiO2-NTAs), with a uniform tube size on titanium substrate, were obtained by means of reoxidation and annealing. A composite structure, CdSe quantum dots@TiO2 nanotube arrays (CdSe QDs@TiO2-NTAs), was fabricated by assembling CdSe quantum dots into TiO2-NTAs via cyclic voltammetry electrochemical deposition. The X-ray diffractometer (XRD), field-emission scanning electron microscope (SEM), and transmission electron microscope (TEM) were carried out for the determination of the composition and structure of the tubular layers. Optical properties were investigated by ultraviolet-visible spectrophotometer (UV-Vis). Photocurrent response under visible light illumination and photocatalytic activity of samples by degradation of methyl orange were measured. The results demonstrated that the photo absorption of the composite film shifted to the visible region, and the photocurrent intensity was greatly enhanced due to the assembly of CdSe QDs. Especially, photocurrent achieved a maximum of 1.853 μA/cm2 after five voltammetry cycles of all samples. After irradiation under ultra violet-visible light for 2 h, the degradation rate of composition to methyl orange (MO) reached 88.20%, demonstrating that the CdSe QDs@TiO2-NTAs exhibited higher photocatalytic activity. 相似文献
16.
Pavlina Sobrova Marketa Ryvolova Jaromir Hubalek Vojtech Adam Rene Kizek 《International journal of molecular sciences》2013,14(7):13497-13510
Electrochemical detection of quantum dots (QDs) has already been used in numerous applications. However, QDs have not been well characterized using voltammetry, with respect to their characterization and quantification. Therefore, the main aim was to characterize CdTe QDs using cyclic and differential pulse voltammetry. The obtained peaks were identified and the detection limit (3 S/N) was estimated down to 100 fg/mL. Based on the convincing results, a new method for how to study stability and quantify the dots was suggested. Thus, the approach was further utilized for the testing of QDs stability. 相似文献
17.
18.
Zhan-Chao Wu Zhen Yang Xing-Xing Zhang Ming-Xia Jiao Jie Liu Li Ma Xiao-Jun Wang 《Journal of the American Ceramic Society》2020,103(5):3147-3156
In order to improve the quantum yield of red-emitting CdTe quantum dots (QDs), CdTe:Gd3+ QDs were synthesized by a facile one-step aqueous method. The composition, morphology, and photoluminescence property of CdTe:Gd3+ QDs were characterized. The results show that the doping of Gd3+ not only leads to a red-shift in the emission wavelength but also improves the photoluminescence quantum yield (PL QY) of CdTe QDs up to 85.74%. Doping of Gd element causes the Te dangling bond on the surface of CdTe QDs to be destroyed, thus reducing the nonradiative surface recombination, which is considered to be the reason of the increase in PL QY of CdTe QDs. Finally, high color rendition white light was generated from the CdTe:Gd3+ QDs-assisted phosphor-converted white light-emitting diode (WLED). Under operation of 50 mA forward bias current, the fabricated WLED emitted bright warm white light with a high color rendering index of 86, a low correlated color temperature (CCT) of 4020 K, a suitable Commission Internationale de l’Eclairage color coordinates of (0.3651, 0.3223), and an enhanced luminous efficiency of 68.52 lm/W. 相似文献
19.
The electrogenerated chemiluminescence (ECL) of semiconductor quantum dots (QDs) is generally believed to be independent of particle sizes or the capping agents used. Herein, we demonstrate that CdTe QDs with different sizes and stabilizers evidently exhibit different ECL behavior in aqueous solution. The ECL of CdTe QDs stabilized by 3-mercaptopropionic acid (MPA) displays two waves at potentials of about +1.17 V and +1.74 V vs. Ag/AgCl, respectively. ECL spectra confirm that the ECL of QDs is attributed to their band gap luminescence, in which the peak positions are changed with QD sizes. The ECL mechanism of CdTe QDs involves superoxide radical generation by reduction of dissolved oxygen at lower potential or water splitting at higher potential. Direct evidence for superoxide radicals in this medium was obtained via electron spin resonance (ESR) experiments. In comparison, the 2-mercaptoethylamine (MEA)-capped CdTe QDs did not exhibit any ECL in air-saturated pH 7.4 PBS. Both ESR and X-ray photon spectroscopy (XPS) experiments revealed that amine groups in MEA-capped QDs were responsible for the absence of ECL. The reaction of an amine group with a superoxide radical leads to the quenching of ECL. The ECL quenching of MPA-capped CdTe QDs was further used to detect melamine. Under the optimum conditions, the inhibited ECL was linear with the logarithm of concentration of melamine within the concentration range of 10(-9) to 10(-5) M and the detection limit was found to be 6.74 × 10(-10) M, which was 100-100?000 times lower than that of the most previous methods. 相似文献
20.
报道了一种室温下制备CdTe量子点-聚合物纳米荧光聚合物的方法。首先,使用巯基乙酸(TGA)作为稳定剂在水相中合成CdTe量子点,通过十六三甲基溴化铵(CTAB)将其转移进有机相中。使用N,N-二环己基碳二亚胺(DCC)作为脱水剂将量子点挂接到侧链含有羟基的聚丙烯酸酯(CPA)上。该荧光聚合物CdTe-CPA在室温下合成,能够促进碲化镉量子点-聚合物复合物的荧光性能和稳定性。我们还通过相同的方法,将1-芘丁酸(PBA)连接到聚丙烯酸酯侧链上合成了另一种荧光聚合物P-CPA。对产物通过傅里叶变换红外光谱(FI-IR)、凝胶渗透色谱(GPC)、差示扫描量热(DSC)、透射电镜(TEM)及荧光光谱进行表征。此外还研究了P-CPA和CdTe-CPA间的荧光共振能量转移(FRET)。从吸收和荧光发射光谱得到的数据表明,在二氯甲烷溶液中,从P-CPA到CdTe-CPA间发生了荧光共振能量转移。 相似文献