Influence of amines and alkanethiols on the spectral and luminescent properties of InP@ZnS colloidal quantum dots

It has been shown that the precursors (long-chain amines and alkanethiols) used in liquid-phase colloidal synthesis of InP@ZnS quantum dots exert a significant influence on their spectral and luminescent properties. It has been found that dodecylamine and 1-dodecanethiol facilitate obtaining the particles with a narrow luminescence band and a low quantum yield, whereas oleylamine, 1-octanethiol, and 1,6-hexanedithiol stimulate the formation of the quantum dots with broad and intense luminescence. Conditions have been found under which the narrowing of the emission band to 46.3 nm becomes possible.     

Nonradiative resonance energy transfer in systems containing quantum dots and its application

A brief review is presented considering modern literature data on the principles and specific features of nonradiative resonance energy transfer in systems containing semiconductor quantum dots and prospects for using such systems in advanced materials.     

Phenylmethylene as intermediate in acid-catalyzed oxidation of styrene epoxide

Russian Chemical Bulletin - The absorption spectrum of iminium ylide (λmax = 450 nm) has been registered under the conditions of acid-catalyzed consumption of styrene epoxide under the...     

Long-lived localized magnetic polarons in ZnMnSe/ZnSSe type-II superlattices

The kinetics and polarized spectra of low-temperature photoluminescence in semiconductor type-II superlattices based on ZnMnSe/ZnSSe structures have been studied in detail. Processes responsible for the formation of short-lived (about 1 ns) and long-lived (above 10 ns) localized exciton-type magnetic polarons (EMPs) in these systems are determined, and the relative contributions due to magnetic and nonmagnetic localization of heavy holes to the formation of such polarons are evaluated. A phenomenological model is constructed that takes into account the energy distribution of charge-carrier traps with respect to their level depths and employs the EMP parameters determined for ZnMnSe quantum wells. Within the proposed model, all spectral, temporal, and temperature-dependent features in the behavior of magnetophotoluminescence observed for the system under consideration can be consistently and quantitatively described.     

Changes in luminescence of semiconductor colloidal quantum dots CdSe@CdS by replacement of hydrophobic ligands with 1-thioglycerol

Luminescent properties of CdSe@CdS colloidal quantum dots upon replacement of hydrophobic stabilizing ligands with water-soluble 1-thioglycerol have been studied. The data obtained have made it possible to optimize the ligand replacement procedure and significantly decrease the loss of the fluorescence quantum yield of the resulting hydrophilic quantum dots.     

Gold clusters and nanoparticles in reverse micelles formed by tritons X-100, X-114, and X-45

The formation of gold nanoparticles and clusters in solutions of reverse micelles formed by Tritons X-45, X-114, and X-100 (polyoxyethylene isooctylphenyl ethers with degrees of polymerization n = 5, 7–8 and 9–10, respectively) in the presence of sodium sulfite is studied. The stability of these particles is shown to depend on the length of ethylene oxide chains in surfactant molecules, water content in micelles, and the presence of special additives. It is found that, on one hand, L-ascorbic acid favors a reduction of HAuCl₄ and, on the other hand, affects the stability of resultant particles.     

Effect of Photo-and Thermoactivation of CdSe Cores on the Luminescent Properties of CdSe@CdS Colloidal Quantum Dots

The effect of photo-and thermoactivation of the CdSe cores of colloidal quantum dots (CQDs) on the luminescent properties of the CdSe@CdS CQDs formed on them has been studied. It has been established that an optimum combination of the action of UV light and heat on the CdSe cores has a favorable effect on the luminescent characteristics of the CdSe@CdS CQDs formed on them, noticeably increasing the quantum yield of luminescence, narrowing the spectral emission band, and enhancing their stability.     

Luminescence of Hybrid Nanostructures of InP@ZnS Colloidal Quantum Dots and <Emphasis Type="Italic">meso</Emphasis>-Tetra(3-pyridyl)porphyrin Molecules

The formation of hybrid nanostructures consisting of InP@ZnS colloidal quantum dots and mesotetra(3-pyridyl)porphyrin molecules adsorbed on the quantum dots has been studied. In such nanostructures, strong quenching of quantum dot luminescence and an increase in the emission intensity of porphyrin are observed due to nonradiative resonance energy transfer from colloidal quantum dots to porphyrin.     

Growth kinetics for AgI nanoparticles in AOT reverse micelles: effect of molecular length of hydrocarbon solvents

The growth kinetics for AgI nanoparticles formed in the solutions of water/AOT reverse micelles in n-hexane, n-octane, n-decane, and n-dodecane were investigated. In small micelles, the rate of nanoparticles growth was found to be independent of the type of solvent, while in large micelles the growth rate grew with increasing length of solvent molecules. The effect was explained by a different amount of free water in the micelle pools of the same size.