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We designed a temperature-controllable droplet microreactor with more precisely temperature control and shorter synthesis time for water-soluble AgInS2 QDs synthesis. When reaction temperature increased from 30 ℃ to 70 ℃, QDs fluorescence peak constantly red-shifted from 590 nm to 720 nm along with enhanced fluorescence QY and intensity, we can get products with the maximum fluorescence intensity and the QY of 8.8% at 70 ℃. 相似文献
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Ag2Se quantum dots (QDs) with near‐infrared (NIR) fluorescence have been widely utilized in NIR fluorescence imaging in vivo because of their narrow bulk band gap and excellent biocompatibility. However, most of synthesis methods for Ag2Se QDs are expensive and the reactants are toxic. Herein, a new protein‐templated biomimetic synthesis approach is proposed for the preparation of Ag2Se QDs by employing bovine serum albumin (BSA) as a template and dispersant. The BSA‐templated Ag2Se QDs (Ag2Se@BSA QDs) showed NIR fluorescence with high fluorescence quantum yield (≈21.2 %), excellent biocompatibility and good dispersibility in different media. Moreover, the obtained Ag2Se@BSA QDs exhibited remarkable photothermal conversion (≈27.8 %), which could be used in photothermal therapy. As a model application in biomedicine, the Ag2Se@BSA QDs were used as “gatekeepers” to cap mesoporous silica nanoparticles (MSNs) by means of electrostatic interaction. By taking the advantages of NIR fluorescence and photothermal property of Ag2Se@BSA QDs, the obtained MSN‐DOX‐Ag2Se nanoparticles (MDA NPs) were employed as a nanoplatform for combined chemo‐photothermal therapy. Compared with free DOX and MDA NPs without NIR laser, the laser‐treated MDA NPs exhibited lower cell viability in vitro, implying that Ag2Se@BSA QDs are highly promising photothermal agents and the MDA NPs are potential carriers for chemo–photothermal therapy. 相似文献
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CdSe quantum dots (QDs) have traditionally been synthesized in organic phase and then transferred to aqueous solution by functionalizing their surface with silica, polymers, short-chain thiol ligands, or phospholipid micelles. However, a drastic increase in the hydrodynamic size and biotoxicity of QDs may hinder their biomedical applications. In this paper, the TGA-capped CdSe QDs are directly synthesized in aqueous phase at freezing temperature, and they prove to possess high QY (up to 14%). 相似文献
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用L-半胱氨酸(L-cysteine)作为稳定剂,以制备的CdTe量子点为核模板,水相合成了具有近红外发光的Ⅱ型核壳CdTe/CdSe半导体量子点。实验考察了合成温度,核模板的尺寸和组分比等因素对合成高质量的CdTe/CdSe量子点的影响。用紫外-可见吸收和荧光光谱研究了合成的量子点的光学性质。在优化的合成条件下,荧光发射光谱在586~753nm范围连续可调,荧光量子产率高达68%;通过X-射线衍射(XRD),X射线光电子能谱(XPS)和透射电镜(TEM)对合成的Ⅱ型核壳CdTe/CdSe量子点进行了结构和形貌表征。 相似文献
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采用非热注法成功制备了高质量的油溶性CuInS2/ZnS核壳量子点, 量子点的荧光发射峰在可见光到近红外范围内可调(550~800 nm), 且荧光量子产率最高达80%。本文进一步利用具有温敏特性的聚丙烯酰胺胶束作相转移剂, 成功地将油溶性的CuInS2/ZnS核壳量子点转移入水相。水相中自组装形成的CuInS2/ZnS量子点-胶束复合物不仅具有良好的荧光性质, 而且胶束原有的灵敏的热响应性被保留。这些研究初步表明, 无镉的低毒的CuInS2/ZnS量子点可作为纳米胶束的荧光示踪探针。 相似文献
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采用非热注法成功制备了高质量的油溶性CuInS2/ZnS核壳量子点,量子点的荧光发射峰在可见光到近红外范围内可调(550~800 nm),且荧光量子产率最高达80%。本文进一步利用具有温敏特性的聚丙烯酰胺胶束作相转移剂,成功地将油溶性的CuInS2/ZnS核壳量子点转移入水相。水相中自组装形成的CuInS2/ZnS量子点-胶束复合物不仅具有良好的荧光性质,而且胶束原有的灵敏的热响应性被保留。这些研究初步表明,无镉的低毒的CuInS2/ZnS量子点可作为纳米胶束的荧光示踪探针。 相似文献
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采用热分解法制备了三维的亚稳态正交相AgInS_2和六方相CuInS_2花状微米球。通过X射线衍射(XRD),场发射扫描电子显微镜(FESEM)等对样品进行表征,对AgInS_2的光催化性能进行了评估,并借助于热重-差热分析(TG-DTA)等手段研究了亚稳态正交相AgInS_2和六方相CuInS_2花状微米球的生长机理。实验结果表明,反应温度和反应物中金属离子的投料比对生成纯相的MIn S2均有影响,而AgInS_2花状微米球能在可见光下较好地催化降解亚甲基蓝。 相似文献
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A simple and convenient method has been developed for synthesis of water‐soluble CdTe quantum dots (QDs) under ambient atmospheric conditions. In contrast to the traditional aqueous synthesis, green to red emitting CdTe QDs were prepared by using TeO2 to replace Te or Al2Te3 as tellurium source in this method. The influences of experimental variables, including pH value, 3‐mercaptopropionic acid (MPA)/Cd and Te/Cd molar ratios, on the emission peak and photoluminescence (PL) quantum yield (QY) of the obtained CdTe QDs have been systematically investigated. Experimental results indicate that green to red emitting CdTe QDs with a maximum photoluminescence quantum yield of 35.4% can be prepared at pH 11.3 and n(Cd):n(Te):n(MPA)=1:0.1:1.7. 相似文献
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A study on hydrothermal synthesis of CdTe quantum dots, highly luminescent nanocrystals at a relatively lower temperature, via changing the concentration of the CdTe precursors, is described. The full width at half maximum ranged from 40 to 80 nm and quantum yield (QY) was detected to be 27.4% at room temperature. The as-prepared CdTe QDs were labeled with BSA for fluorescence probes without pretreatment. Conjunction experimental results suggested that the as-prepared CdTe QDs are suitable for the application of biotechnology. 相似文献
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硫脲修饰法制备高发光性能CdTe量子点 总被引:1,自引:0,他引:1
通过巯基水解制备了具有优异荧光特性的碲化镉量子点. 详细研究前驱体镉离子与巯基丙酸(MPA)摩尔比、镉离子浓度等制备条件对大尺寸、高量子产率的亲水性碲化镉量子点光学性能的影响. 在不同的水热生长时间下, 可制备出荧光发射峰位于485-660 nm范围内的不同尺寸的碲化镉水溶性量子点, 荧光发射峰半高宽控制在40-75 nm之间, 量子点的最高量子产率(QY)达到了45%. 并利用硫脲缓慢水解和光解释放自由硫离子, 修饰碲化镉表面, 检测修饰后的量子点在12天内光学性能的变化情况. 通过考察硫脲用量对量子点修饰效果, 发现当n(CdTe)/n(thiourea)=1:4(量子点浓度以镉离子浓度计)时, 硫脲对发射峰为505 nm的碲化镉量子点修饰效果最为理想, 量子点荧光强度加强了5倍, 量子产率达到68.3%. 相似文献
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Georgi G. Yordanov Hideyuki Yoshimura Ceco D. Dushkin 《Colloid and polymer science》2008,286(8-9):1097-1102
Here, we report a novel strategy to prepare fluorescent semiconductor quantum dots (QDs) of core–shell type with CdSe–CdS QDs as a model system. Our synthesis was carried out in liquid paraffin, which is a natural, nontoxic, and cheap solvent. We applied a single injection of precursor for the shell growth at low temperature and gradual heating of the reaction mixture after that. By this manner, the Ostwald ripening of the cores was reduced, homogenous nucleation of the shell material was avoided, and highly monodisperse in size core–shell QDs were prepared. Our synthesis method allows working on open air; it is relatively fast and allows fine control over the shell growth process. It leads to the formation of core–shell CdSe–CdS QDs with fluorescence quantum yield as high as 65%. We described the optical properties of core–shell QDs by the model of attenuated quantum confinement. 相似文献
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High-quality cysteamine-coated CdTe quantum dots (CA-CdTe QDs) were successfully synthesized in aqueous phase by a facile one-pot method. Through hydroxylamine hydrochloride-promoted kinetic growth strategy, water-soluble CA-CdTe QDs could be obtained conveniently in a conical flask by a stepwise addition of raw materials. The photoluminescence quantum yield (PL QY) of the obtained QDs reached 9.2% at the emission peak of 520 nm. The optical property and the morphology of the QDs were characterized by UV–vis absorption spectra, photoluminescence spectra (PL) and transmission electron microscopy (TEM) respectively. Furthermore, the fluorescence of the resultant QDs was quenched by copper (II) (Cu2+) and mercury (II) (Hg2+) meanwhile. It is worthy of note that to separately detect Hg2+, cyanide ion could be used to eliminate the interference of Cu2+. Under the optimal conditions, the response was linearly proportional to the logarithm of Hg2+ concentration over the range of 0.08–3.33 μM with a limit of detection (LOD) of 0.07 μM. 相似文献
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The one‐pot synthesis of water‐soluble and biologically compatible yellow CdSe quantum dots (QDs) featuring the use of glutathione (GSH) as the capping and reducing agent was achieved under aqueous conditions at 150 °C. The synthesized yellow CdSe QDs with quantum yield (QY) up to 20% exhibit zinc blende cubic structure particles with an average diameter of 4‐5 nm. It was found that both molar ratio of Se/Cd and reaction time had a significant effect on size distribution of GSH‐CdSe QDs. Meanwhile, the interaction of QDs bioconjugated to bovine hemoglobin (BHb) was studied by absorption and fluorescence(FL) spectra. With addition of BHb, the FL intensity of CdSe QDs largely quenched due to the static mechanism. The linear range is 5.0 × 10?8 mol/L to 3.0 × 10?6 mol/L, and the correlation coefficient is 0.9991, suggesting that could be used as a probe to label biological molecules and bacterial cells. 相似文献
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Herein, we synthesized molybdenum oxide quantum dots using bovine serum albumin as a ligand (BSA-MoOx QDs) via a simple method. The synthesized fluorescent BSA-MoOx QDs were stable, and blue fluorescence was noticed upon exposure to UV lamp at 365 nm. When excited at 320 nm, BSA-MoOx QDs showed an emission peak at 406 nm. Atomic force microscopic images demonstrated that the thickness of BSA layer on the surface of MoOx QDs is 3.9 ± 1.6 nm. The as-synthesized BSA-MoOx QDs acted as a sensor for the detection of digoxin, La3+, and epinephrine via fluorescence OFF-ON-OFF mechanisms, exhibiting linear ranges of 1–25, 0.125–5, and 0.5–10 μM with lower detection limits of 9.74, 23.08, and 4.58 nM for digoxin, La3+, and epinephrine, respectively. This method was successfully demonstrated to be an effective analytical platform for measuring digoxin and epinephrine in pharmaceutical and biofluid samples. 相似文献
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Dr. Chin‐Ping Huang Cheng‐Fu Chao Mo‐Yuan Shen Prof. Dr. Teng‐Ming Chen Prof. Dr. Yaw‐Kuen Li 《化学:亚洲杂志》2012,7(12):2848-2853
An improved method for the synthesis of high‐performance and water‐soluble quantum dots (QDs) involving the encapsulation of mercaptosuccinic acid coated QDs (MSA‐QDs) with poly(diallyldimethylammonium chloride) (PDDA) followed by their direct photoactivation with fluorescent radiation near 295 K to yield PDDA‐coated QDs (PDDA‐QDs) has been demonstrated. The quantum yield (QY) of the PDDA‐QDs was significantly improved from 0.6 (QY of MSA‐QDs) to 48 %. By using this synthetic strategy, highly photoluminescent PDDA‐QDs of varied size were readily prepared. The surface properties of PDDA‐QDs and MSA‐QDs were extensively characterized. The highly luminescent and positively charged PDDA‐QDs serve as a useful and convenient tool for protein adsorption. With a Δ5‐3‐ketosteroid isomerase adsorbed PDDA‐QD complex, the biorecognition of steroids was demonstrated through the application of fluorescent resonance energy transfer. 相似文献
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A one‐step method was developed for preparing Ag2S quantum dots (QDs) using a common protein [bovine serum albumin (BSA)] to entrap QDs precursors (BSA–Ag+). Fluorescence (FL) and ultraviolet spectra showed that the molar ratio of Ag+/BSA, temperature, and pH are the crucial factors for the quality of QDs. The QDs absorption wavelength and emission wavelength were about 340 and 450 nm. The average QDs particle size was estimated to be less than 5 nm, determined by transmission electron microscopy. The X‐ray power diffraction and XPS results showed that the synthesized product was indeed monoclinic Ag2S. With Fourier transform infrared spectra and thermogravimetry analysis, there might be conjugated bonds between Ag2S QDs and –OH, –NH, and –SH groups in BSA. In addition, FL spectra suggest that the designed QDs can produce static quenching with BSA and the Stern–Volmer quenching constant (Ksv) was calculated as 2.145 × 104. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Feng Liu Junke Jiang Yaohong Zhang Chao Ding Taro Toyoda Shuzi Hayase Ruixiang Wang Shuxia Tao Qing Shen 《Angewandte Chemie (International ed. in English)》2020,59(22):8421-8424
Phase‐stable CsSnxPb1?xI3 perovskite quantum dots (QDs) hold great promise for optoelectronic applications owing to their strong response in the near‐infrared region. Unfortunately, optimal utilization of their potential is limited by the severe photoluminescence (PL) quenching, leading to extremely low quantum yields (QYs) of approximately 0.3 %. The ultra‐low sodium (Na) doping presented herein is found to be effective in improving PL QYs of these alloyed QDs without alerting their favourable electronic structure. X‐ray photoelectron spectroscopy (XPS) studies suggest the formation of a stronger chemical interaction between I? and Sn2+ ions upon Na doping, which potentially helps to stabilize Sn2+ and suppresses the formation of I vacancy defects. The optimized PL QY of the Na‐doped QDs reaches up to around 28 %, almost two orders of magnitude enhancement compared with the pristine one. 相似文献