Biosynthesis of silver sulfide quantum dots in wheat endosperm cells
25/06/2017 · Synthesis and Spectroscopy of Silver-Doped PbSe Quantum ..
Synthesis of near-infrared quantum dots in cultured …
Uniform silver quantum dots decorated TiO2 nanotubes(Ag-TiO2 NTs) were synthesized via a simple reductionreaction in ethanol solvent.
The scarcity and high cost of platinum-based electrocatalysts for the oxygen reduction reaction (ORR) has limited the commercial and scalable use of fuel cells. Heteroatom-doped nanocarbon materials have been demonstrated to be efficient alternative catalysts for ORR. Here, graphene quantum dots, synthesized from inexpensive and earth-abundant anthracite coal, were self-assembled on graphene by hydrothermal treatment to form hybrid nanoplatelets that were then codoped with nitrogen and boron by high-temperature annealing. This hybrid material combined the advantages of both components, such as abundant edges and doping sites, high electrical conductivity, and high surface area, which makes the resulting materials excellent oxygen reduction electrocatalysts with activity even higher than that of commercial Pt/C in alkaline media.
Synthesis of Zn3As2 and (CdyZn1–y)3As2 Colloidal Quantum Dots
Electronic impurity doping of bulk semiconductors is an essential component of semiconductor science and technology. Yet there are only a handful of studies demonstrating control of electronic impurities in semiconductor nanocrystals. Here, we studied electronic impurity doping of colloidal PbSe quantum dots (QDs) using a postsynthetic cation exchange reaction in which Pb is exchanged for Ag. We found that varying the concentration of dopants exposed to the as-synthesized PbSe QDs controls the extent of exchange. The electronic impurity doped QDs exhibit the fundamental spectroscopic signatures associated with injecting a free charge carrier into a QD under equilibrium conditions, including a bleach of the first exciton transition and the appearance of a quantum-confined, low-energy intraband absorption feature. Photoelectron spectroscopy confirms that Ag acts as a p-type dopant for PbSe QDs and infrared spectroscopy is consistent with · calculations of the size-dependent intraband transition energy. We find that to bleach the first exciton transition by an average of 1 carrier per QD requires that approximately 10% of the Pb be replaced by Ag. We hypothesize that the majority of incorporated Ag remains at the QD surface and does not interact with the core electronic states of the QD. Instead, the excess Ag at the surface promotes the incorporation of
Nanoparticles are used in a wide range of disciplines due to their properties. The most common preparation is by physical and chemical synthesis, which uses a toxic chemicals that are not environmentallyfriendly and also limits the potential of the nanoparticles in their clinical applications. It is because of the negative properties of nanoparticles prepared by classical synthesis that a new type of synthesis comesto the fore. This is made possible by the ability of organisms to biosynthesize the nanoparticles either in the body or in the environment. Ability of the biosynthesis was demonstrated in a variety of microorganisms,but also in arthropods or even in mammals. Biosynthesis ability of organisms can be used both for the preparation of nanoparticles and for the reduction of contamination, since the raw materials forthe synthesis are obtained from the environment. Biosynthesis by microorganisms could be a suitable alternative to conventional synthesis of quantum dots, mainly due to their low demands on the feedstockand the resulting biocompatibility of nanoparticles.
Synthesis and Spectroscopy of Silver-Doped PbSe Quantum Dots
We report a facile green approach for in situ growth of silver nanoparticles (AgNPs) on the surface of graphene quantum dots (GQDs). GQDs serve as both reducing agent and stabilizer, and no additional reducing agent and stabilizer is necessary. The GQDs/AgNPs hybrid exhibits a superior absorbance fading response toward the reduction of H2O2. A simple colorimetric procedure is thus proposed for ultrasensitive detection of H2O2 without additional chromogenic agent. It provides a record detection limit of 33 nM for the detection of H2O2 by the AgNPs-based sensing system. This colorimetric sensing system is further extended to the detection of glucose in combination with the specific catalytic effect of glucose oxidase for the oxidation of glucose and formation of H2O2, giving rise to a detection limit of 170 nM. The favorable performances of the GQDs/AgNPs hybrid are due to the peroxidase-like activity of GQDs.
We have many research interests in the Rosenthal lab – ranging from synthesis of new quantum dot structures, to fundamental spectroscopy and microscopyÂ of nanocrystals, to incorporating quantum dots into various applications:
Synthesis of metal nanoparticles and quantum dots …
Synthesis of Luminescent Graphene Quantum Dots …
07/11/2003 · Peptide-coated CdS quantum dots for the optical detection of copper(II) and silver(I)
Gram-scale synthesis of graphene quantum dots …
Thiolate-Mediated Photoinduced Synthesis of Ultrafine Ag2S Quantum Dots from Silver Nanoparticles
Synthesis of Colloidal Mn2+:ZnO Quantum Dots and …
Journal of Metallomics and Nanotechnologies -Biosynthesis of quantum dots
Synthesis of cadmium selenide quantum dots modified …
Here, we present a hot injection synthesis of colloidal Ag chalcogenide nanocrystals (Ag(2)Se, Ag(2)Te, and Ag(2)S) that resulted in exceptionally small nanocrystal sizes in the range between 2 and 4 nm. Ag chalcogenide nanocrystals exhibit band gap energies within the near-infrared spectral region, making these materials promising as environmentally benign alternatives to established infrared active nanocrystals containing toxic metals such as Hg, Cd, and Pb. We present Ag(2)Se nanocrystals In detail, giving size-tunable luminescence with quantum yields above 1.7%. The luminescence, with a decay time on the order of 130 ns, was shown to improve due to the growth of a monolayer thick ZnSe shell. Photoconductivity with a quantum efficiency of 27% was achieved by blending the Ag(2)Se nanocrystals with a soluble fullerene derivative. The co-injection of lithium silylamide was found to be crucial to the synthesis of Ag chalcogenide nanocrystals, which drastically increased their nucleation rate even at relatively low growth temperatures. Because the same observation was made for the nucleation of Cd chalcogenide nanocrystals, we conclude that the addition of lithium silylamide might generally promote wet-chemical synthesis of metal chalcogenide nanocrystals, including In as-yet unexplored materials.
Green synthesis of carbon quantum dots | Open Science
However, this cross-linking showed no effect to the miniemulsion stability and fluidity, and therefore, the synthesized materials can be easily processed for further uses/applications.
The miniemulsion procedure has also been extended to functionalizing CdS quantum dots with poly(n-butyl acrylate) using activators generated by electron transfer (AGET) ATRP. The quantum dots were first modified by complexation with a phosphorous-containing ligand, which was then further modified to contain an ATRP initiating group.
Synthesis of silver quantum dots
The polymerization of n-butyl acrylate further protected the QDs from degradation via chemical reaction, and the resulting materials were both well-distributed on the nanoscale and possessed the optical properties expected from quantum dots of their size.
A one-pot synthesis of thermally stable core/shell gold nanoparticles (Au-NPs) was developed via surface-initiated atom transfer radical polymn.
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