We report on the "flash" synthesis of CdSe/CdS core–shell quantum dots (QDs). This new method, based a seeded growth approach and using an excess carboxylic acid, leads to isotropic epitaxial CdS shell wurtzite CdSe core. The method is particularly fast efficient, allowing controllable very thick shells (up 6.7 nm in present study) no more than 3 min, which considerably shorter previously reported methods. prepared materials state-of-the-art properties with narrow emission high...

Hybrid SiN-QD microlasers coupled to a passive SiN output waveguide with 7{\mu}m diameter and record low threshold density of 27 {\mu}J cm-2 are demonstrated. A new design unique processing scheme starting from SiN/QD/SiN stacks offer long term stability facilitate in depth laser characterization. This approach opens up paths for optical communication, lab-on-a-chip, gas sensing and, potentially, on-chip cavity quantum electrodynamics optics.

While initial theories on quantum confinement in colloidal dots (QDs) led to analytical band gap/size relations or sizing functions, numerical methods describe size quantization more accurately. However, because of the lack reliable researchers fit experimental data sets using models with redundant, physically meaningless parameters that break down upon extrapolation. Here, we propose a new function based proportional correction for nonparabolic bands. Using known bulk parameters, predict...

The use of quantum dots (QDots) as bright and photostable probes for long-term fluorescence imaging is gaining more interest. Thus far, (pre)clinical QDots remains limited, which primarily caused by the potential toxicity QDots. Most consist Cd2+ ions, are known to cause high levels toxicity. In order overcome this problem, several strategies have been tested, such generation cadmium-free present study, two types QDots, composed ZnSe/ZnS (QDotZnSe) InP/ZnS (QDotInP), were studied with...

We report on the synthesis of core–shell CuInS2/ZnS quantum dots (QDs) in organic solution, their encapsulation with a PEG-containing amphiphilic polymer, and application resulting water-soluble QDs as fluorescent label quantitative immunoassay. By optimizing methods for core shell growth, were obtained yield 50% average after hydrophilization. After conjugation an aflatoxin B1-protein derivative, used labels microplate immunoassay determination mycotoxin B1. QDs-based showed higher...

Colloidal quantum dots (QDs) are highly attractive as the active material for optical amplifiers and lasers. Here, we address relation between structure of CdSe/CdS core/shell QDs, gain they can deliver, threshold needed to attain net stimulated emission by pumping. On basis an initial model, predict that reducing thickness CdS shell grown around a given CdSe core will increase maximal gain, while increasing lower threshold. We assess this trade-off means transient absorption spectroscopy....

We report on the synthesis of luminescent CdSe/CdS@SiO2 nanoparticles and their application to cell labeling. The main novelty these is use newly developed "flash" CdSe/CdS quantum dots (QDs), which are obtained through a new fast efficient method recently reported. These core-shell QDs encapsulated in silica water-in-oil microemulsion process, resulting with good morphology controlled architecture. asset high photoluminescent yield, equal that original remains unchanged even after several...

Functional silica nanoparticles and in particular luminescent constitute very promising candidates for many applications the field of biotechnology, theranostics, photonics. However, optimizing design such materials requires a deep understanding their physicochemical properties. In this article are reported extended investigations on Cs2[Mo6Br14]@SiO2 prepared by water-in-oil microemulsion technique. We bring here new insights into structure its interplay with optical The structural...

The synthesis of metal selenide nanocrystals based on the injection selenium powder in a hot mixture containing cation precursor complexed by carboxylic acid is demonstrated means formation CdSe and ZnSe nanocrystals. In both cases, can reach reaction yields 80–85% within 5 min. case nanocrystals, more extensive study shows that even without protective atmosphere, leads to state-of-the-art with low size dispersion. Importantly, at close full yield be changed varying chain length, whereas...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTHomogeneously Alloyed CdSe1–xSx Quantum Dots (0 ≤ x 1): An Efficient Synthesis for Full Optical TunabilityTangi Aubert*†‡, Marco Cirillo†‡, Stijn Flamee†‡, Rik Van Deun§, Holger Lange∥, Christian Thomsen∥, and Zeger Hens*†‡View Author Information† ‡ †Physics Chemistry of Nanostructures, ‡Center Nano- Biophotonics (NB-Photonics), §L3 − Luminescent Lanthanide Lab, f-element coordination chemistry, Ghent University, Krijgslaan 281-S3, 9000...

Using an optimized lift-off process we develop a technique for both nanoscale and single-dot patterning of colloidal quantum dot films, demonstrating feature sizes down to ∼30 nm uniform films yield 40% positioning, which is in good agreement with newly developed theoretical model. While first all presenting unique tool studying physics single dots, the also provides pathway toward practical dot-based optoelectronic devices.

Quantum dot core–shell structures are essential to superior optical properties. However, Cd-based quantum dots grown from wurtzite CdSe cores still suffer irreproducibility due gel formation during the core synthesis. Moreover, state-of-the-art shelling procedures often remain time-consuming. We report here (1) a new procedure of synthesis which eliminates phosphonic anhydride contamination and (2) improvement generalization flash for growth highly luminescent multishell heterostructures....

A system comprising an aluminum nanoantenna array on top of a luminescent colloidal quantum dot waveguide and covered by thermotropic liquid crystal (LC) is introduced. By heating the LC above its critical temperature, we demonstrate that concomitant refractive index change modifies hybrid plasmonic–photonic resonances in system. This enables active control spectrum directionality narrow-band (∼6 nm) enhancement photoluminescence metallic nanoantennas.

We report on a hybrid integrated distributed feedback (DFB) laser fabricated using the colloidal quantum dots (QDs)/silicon nitride (SiN) integration platform. The DFB is with CMOS-compatible process and consists of waveguide stack in which QD layer embedded between two SiN layers to enhance coupling optical mode. Following characterization intrinsic properties CdSe/CdS core/shell QDs transient absorption spectroscopy, we demonstrate single-mode lasing upon nanosecond pumping. With 7 ns pump...

Metal atom clusters constitute very promising candidates as luminophores for applications in biotechnology because they are nanosized entities offering robust luminescence the near-infrared field (NIR). However, cannot be used prepared biological of potential toxic effects and quenching clusters' aqueous media, therefore need to dispersed a biocompatible matrix. We describe herein encapsulation octahedral rhenium clusters, denoted A(4)[Re(6)Q(8)L(6)] (A = Cs or K, Q S Se, L OH CN), silica...

We demonstrate the fabrication of a large-scale device allowing for electrical switching polarized light with polarization ratio 0.45 over 1.5 cm2 area. To achieve this, silica-coated semiconductor nanorods were embedded in polymeric nanofibers by electrospinning. The uniaxial extensional flow experienced particles induces alignment within nanofibers. A subsequent parallel themselves results large and flexible film massively aligned that can conveniently be processed further. this...

Silicon nitride waveguides with a monolayer of colloidal quantum dots embedded inside were fabricated using low-temperature deposition process and an optimized dry etching step for the composite layers. We experimentally demonstrated luminescence is preserved loss these hybrid waveguide wires as low 2.69dB/cm at 900nm wavelength. This integration silicon photonics active emitters offers opportunities optical sources operating over very broad wavelength range.

Despite extensive studies on mesoporous silica since the early 1990s, synthesis of two-dimensional (2D) nanostructures remains challenging. Here, is synthesized at an interface between two immiscible solvents under conditions leading to formation 2D superstructures cages, thinnest films date. Orientational correlations cage units increase with increasing layer number controlled via pH, while swelling oil and mixed surfactants micelle size dispersity, complex clathrate type structures in...

The exciton spin dynamics and polarization properties of the related emission are investigated in colloidal CdSe/CdS dot-in-rod (DiR) spherical core/shell nanocrystal (NC) ensembles by magneto-optical photoluminescence (PL) spectroscopy magnetic fields up to 15 T. It is shown that degree circular (DCP) induced field affected NC geometry as well fine structure can provide information on nanorod orientation. A theory describe linear a developed. takes into account phonon mediated coupling...