Hydrothermal synthesis for high-quality CdTe quantum dots capped by cysteamine

We present a facile hydrothermal approach to synthesize high-quality cysteamine (CA)-capped CdTe quantum dots (QDs). Oil bath heating and vigorous stirring were used to obtain better heat transfer and more homogenous solutions during the synthesis process. By this approach, the quantum yield (QY) of the resultant QDs can reach as high as 19.7%, which is the best reported data for CA-stabilized CdTe QDs. The synthesis process is under a high concentration of the precursor (> 10 mM), suggesting the potential of this route to be used in mass production of CA-capped CdTe QDs. Moreover, the pH-dependent optical properties of CA-capped CdTe QDs were also investigated.     

Fabrication of lipid tubules with embedded quantum dots by membrane tubulation protein

The first one-dimensional (1D) assembly of low-toxicity CuInS(2) /ZnS quantum dots (QDs) embedded in lipid nanotubules, formed from liposomes using the Amphiphysin-BAR (Bin-Amphiphysin-Rvs domain of human amphiphysin) protein to elongate the structure, is reported. The QD-containing lipid nanotubules display a high aspect ratio of ≈500:1 (≈40 nm diameter and 20 μm length) and are stable for more than 20 h. Furthermore, this methodology is extended to the assembly of various nanoparticle species within 1D lipid nanotubules, and includes materials such as CdSe and Au. Encapsulation within the hydrophobic core of the bilayer makes these materials highly biocompatible. The developed methodology and materials with these unique characteristics could be useful for various applications in nanobiotechnology and nanomedicine.     

CdTe quantum dots accelerate the speed of Pfu-based polymerase chain reaction

It has not been previously reported that the speed of polymerase chain reaction (PCR) can be accelerated by quantum dots (QDs). In the present work, the addition of cadmium telluride (CdTe) QDs resulted in significant time-saving compared with the conventional PCR. The reaction time could be significantly shortened from 143 to 46 min without compromising the general efficiency in a PCR. CdTe QD-facilitated fast PCR also displayed excellent hot-start effects.     

UV-enhanced toxicity of water-stable quantum dots in human pancreatic carcinoma cells

Zn-based (capped with thioglycolic acid (TGA) or 3-mercaptopropionic acid (MPA)) and Cd-based quantum dots (QDs) (capped with TGA or L-glutathione), were synthesised and used to investigate their cytotoxicity to human pancreatic carcinoma cells (PANC-1) in absence and presence of UV irradiation. Zn-based QDs exhibited less intrinsic cytotoxicity than the Cd-based QDs, however, the excitation of 50?µg/mL-QDs using UV lamp significantly enhanced the cytotoxicity of both QDs. After 15?min of UV irradiation, the viability for cells exposed to Cd-based QDs capped with TGA or glutathione was 49%?±?6% or 56%?±?3%, respectively. The corresponding cell viability in the control test was 83%?±?8% after 15?min of UV irradiation. In turn, the viability for cells exposed to Zn-based QDs capped with 3-MPA or TGA was 64%?±?3% and 52%?±?3%, respectively, after 30?min of UV irradiation; the cell viability in the control test was 80%?±?7% for the same UV irradiation time. Laser scanning confocal analyses evidenced that QDs can be easily ingested by PANC-1. Based on their good compositional stability, Zn-based QDs capped with 3-MPA can be considered a promising material for nanomedicine applications until concentrations of 200?µg/mL.     

碳量子点的合成、性质及其应用

碳量子点(CQDs,C-dots or CDs)是一种新型的碳纳米材料,尺寸在10nm以下,具有良好的水溶性、化学惰性、低毒性、易于功能化和抗光漂白性、光稳定性等优异性能,是碳纳米家族中的一颗闪亮的明星。自从2006年[1]报道了碳量子点(CQDs)明亮多彩的发光现象后,世界各地的研究小组开始对CQDs进行了深入的研究。最近几年的研究报道了各种方法制备的CQDs在生物医学、光催化、光电子、传感等领域中都有重要的应用价值。这篇综述主要总结了关于CQDs的最近的发展,介绍了CQDs的合成方法、表面修饰、掺杂、发光机理、光电性质以及在生物医学、光催化、光电子、传感等领域的应用。     

稳定剂对水相制备CdTe量子点的荧光性能和细胞毒性影响研究

用巯基乙酸(TGA)、半胱氨酸(L-Cys)和谷胱甘肽(GSH)这三种巯基稳定剂在水相中制备了CdTe量子点(QDs).红外光谱(FTIR)分析结果表明,三种稳定剂都成功地利用Cd2+与巯基之间的配位与QDs相结合并起到保护及稳定的作用.利用荧光光谱对不同QDs的荧光性能进行了研究,结果表明当采用GSH作为稳定剂时,QDs的生长速率较快,且最大发射波长能够达到约680nm;L-Cys-CdTe的生长速率次之,也能生成具有较大发射波长的QDs;TGA-CdTe的生长速率最慢,且最大发射波长只能达到约620nm,但是其荧光强度较高,适于制备对荧光强度要求较高的QDs.通过MTT(噻唑蓝)比色法对细胞存活率进行测定,同时利用显微镜对细胞形貌进行观察,结果表明各量子点都具有一定的细胞毒性,但TGA-QDs对细胞的伤害作用更大,以20μg/mL的浓度对细胞培养24h后,细胞存活率只有52.6%.     

Dimension-controlled synthesis of CdS nanocrystals: from 0D quantum dots to 2D nanoplates

The dimension-controlled synthesis of CdS nanocrystals in the strong quantum confinement regime is reported. Zero-, one-, and two-dimensional CdS nanocrystals are selectively synthesized via low-temperature reactions using alkylamines as surface-capping ligands. The shape of the nanocrystals is controlled systematically by using different amines and reaction conditions. The 2D nanoplates have a uniform thickness as low as 1.2 nm. Furthermore, their optical absorption and emission spectra show very narrow peaks indicating extremely uniform thickness. It is demonstrated that 2D nanoplates are generated by 2D assembly of CdS magic-sized clusters formed at the nucleation stage, and subsequent attachment of the clusters. The stability of magic-sized clusters in amine solvent strongly influences the final shapes of the nanocrystals. The thickness of the nanoplates increases in a stepwise manner while retaining their uniformity, similar to the growth behavior of inorganic clusters. The 2D CdS nanoplates are a new type of quantum well with novel nanoscale properties in the strong quantum confinement regime.     

Synthesis and characterization of CdTe quantum dots embedded gelatin nanoparticles via a two-step desolvation method

Novel CdTe quantum dots (QDs) embedded gelatin nanoparticles (CdTe/gelatin nanoparticles) were synthesized via a two-step desolvation method. The morphology and size distribution of the nanoparticles were characterized by transmission electron microscope (TEM) and laser particle size analyzer. They are presented spherically and relatively uniform with a diameter of 150 nm. The luminescent properties of the nanoparticles were investigated by using fluorescence spectrophotometry and fluorescence microscopy. The fluorescence stability of nanoparticles was tested in vitro. It was found that the nanoparticles were stable in water and phosphate-buffered saline (PBS) solution (pH 7.4) for at least 15 days. A possible formation mechanism of the CdTe/gelatin nanoparticles was also proposed. The inherent stability and biocompatibility indicate that the nanoparticles are expected to be promising candidates for in vivo biological imaging studies.     

Polymer grafting from CdS quantum dots via AGET ATRP in miniemulsion

We report the synthesis of CdS quantum dot (QD)-poly(acrylate) nanocomposites using a recently developed catalytic system where activators are generated by electron transfer for atom-transfer radical polymerization (ATRP) in a miniemulsion. The QD surface was functionalized with a tris(alkyl)phosphine, previously modified with an ATRP chlorine initiator, and subsequent controlled polymerization was carried out from the functionalized surface of nanoparticles. The final material showed a high homogeneity and the QDs were evenly dispersed. The optical-absorption edge in the visible spectra of the nanocomposites attests the presence of the CdS QDs. Quantum confinement effects were assigned, though a blue shift in relation to the optical spectrum of the initial QDs has been observed.     

不同温度下硒化镉(CdSe)量子点的生长及荧光性研究

研究了以氧化镉（CdO）和硒（Se）粉为前驱体,在三辛基膦（TOP）和油酸中合成无机半导体量子点（quantum dots, QDs）CdSe.研究了在不同的反应温度下粒子的生长,通过紫外吸收光谱（UV-Vis）、荧光发射光谱（PL）、透射电子显微镜（TEM）等手段跟踪反应过程并对样品性能进行了表征.实验结果表明,反应温度和反应时间对量子点的生长和荧光性能有很大的影响.     

One-pot synthesis of highly luminescent CdTe quantum dots by microwave irradiation reduction and their Hg2+-sensitive properties

A facile one-pot microwave irradiation reduction route has been developed for the synthesis of highly luminescent CdTe quantum dots using Na₂TeO₃ as the Te source in an aqueous environment. The synthesis parameters of this simple and rapid approach, including the reaction temperature and time, the pH of the reaction solution and the molar ratio of the 3-mercaptopropionic acid (MPA) stabilizer to Cd²⁺, have considerable influence on the particle size and photoluminescence quantum yield of the CdTe quantum dots. The photoluminescence quantum yield of CdTe quantum dots prepared using relatively short reaction times (10–40 min) reached 40%–60% (emission peaks at 550–640 nm). Furthermore, the resulting products could be used as fluorescent probes to detect Hg²⁺ ions in aqueous media. The response was linearly proportional to the concentration of Hg²⁺ ion in the range 8.0×10⁻⁹ mol/L to 2.0×10⁻⁶ mol/L with a detection limit of 2.7×10⁻⁹ mol/L. Electronic Supplementary Material  Supplementary material is available for this article at and is accessible for authorized users.     

One-step synthesis of water-soluble ZnSe quantum dots via microwave irradiation

A facile strategy has been developed for the synthesis of glutathione-capped ZnSe quantum dots (QDs) in aqueous media. The reaction was carried out in air atmosphere with a single step by using Na₂SeO₃, a stable and commercial Se source, to replace the commonly adopted NaHSe or H₂Se. Moreover, microwave irradiation improved the photoluminescence quantum yield (PLQY) as well as lowered the trap emission of as-prepared ZnSe QDs. The obtained QDs performed strong band-edge luminescence (PLQY reached 18%), narrow size distribution (full width at half maximum was 26-30 nm) and weak trap emission without post-treatments. The results of transmission electron microscopy and X-ray diffraction demonstrated the small particle size (2-3 nm), good monodispersity and ZnSe(S) alloyed structure of as-prepared QDs. The experimental variables including precursors and stabilizer amounts as well as pH value had significant influence on the PL properties of the ZnSe QDs.     

Novel multifunctional nanocomposites from titanate nanosheets and semiconductor quantum dots

A novel synthesis for a titanate nanosheets loaded nanocomposite has been developed. On this basis, a multifunctional material for optical applications has been fabricated with tunable refractive index, improved processing behavior and luminescent properties imparted by the incorporation of semiconductor quantum dots.Titanate synthesis, host material choice and quantum dots functionalization have been here addressed to obtain films with good optical quality and stable photoluminescence.In order to assess the potential application of the obtained nanocomposites, imprinting lithography and aerosol-based deposition techniques have been applied with promising results.The obtained nanocomposites have been characterized by UV–Vis, photoluminescence and FT-IR spectroscopy, X-ray diffraction and Transmission Electron Microscopy. The optical properties of the nanocomposite film have been tested by spectroscopic ellipsometry and M-line technique.