We demonstrate an approach for the fabrication of one-dimensional magnetophotonic crystals (1D MPCs) that are composed of electron beam evaporation-deposited Bragg mirrors (BMs) and a bismuth-substituted yttrium iron garnet layer made by metal-organic decomposition. Since such a garnet layer is crystallized at high temperatures, changes in structural and optical properties of BMs caused by annealing are studied. By subjecting single layers of SiO2, HfO2, ZrO2, and Ta2O5 to annealing, we found changes in their optical constants and thicknesses and interpreted stop band shifts in spectra of BMs. The ZrO2/SiO2 pair was found to be resistant to annealing and was used for 1D MPC fabrication. The resulting 1D MPCs were shown to exhibit Faraday rotation enhancement by an order of magnitude at a wavelength of the Fabry-Perot resonance.

We studied the efficiency of energy transfer in systems composed of TPD organic semiconductor and CdSe/CdS/ZnS nanocrystals passivated with different organic ligands. It was demonstrated that increasing the thickness of the nanocrystal capping layer results in reduction of energy transfer rates from TPD to the nanocrystals as well as inter-nanocrystal energy transfer rates. The Förster mechanism was suggested to be responsible for the energy transfer observed.

This paper demonstrates the possibilities of a method of depositing uniform layers of colloidal CdSe/CdS/ZnS quantum dots with a hydrophobic shell made from fatty acids and aliphatic amines onto planar substrates. Using centrifugation onto flat substrates, separate thin layers of polymethyl methacrylate and quantum dots are deposited with good adhesion, with the quantum dots being dispersed in the polymethyl methacrylate. The topology of the fabricated layers is investigated by means of atomic-force microscopy and luminescence mapping, and the processes of aggregation and segregation of the quantum dots into a separate phase is studied. The deposited layers can be structured by means of electron-beam lithography in order to create quantum-dot-based nanostructures. (C) 2018 Optical Society of America

Исследована эффективность передачи энергии электронного возбуждения от органического полупроводникового материала TPD к полупроводниковым нанокристаллам CdSe/CdS/ZnS, пассивированным различными органическими лигандами. Показано, что с увеличением толщины слоя пассиватора скорость передачи возбуждения от TPD к нанокристаллам уменьшается. Высказано предположение о ферстеровском механизме передачи возбуждения. DOI: 10.21883/FTP.2017.05.44424.8475

The efficiency of electronic-excitation energy transfer from organic semiconductor TPD to CdSe/CdS/ZnS nanocrystals passivated with different organic ligands is investigated. It is shown that the rate of energy transfer from TPD to nanocrystals decreases with increasing thickness of the passivation coating. It is suggested that the Förster mechanism is responsible for the excitation transfer.

In this work, we present experimental study on structural peculiarities and optical properties of single silver, gold and bilayer films of these metals. We illustrate that the treatment of substrate defines structural quality and roughness of the fabricated films. Considering the problem of radiation (temperature) resistances of plasmonic/active material systems, films covered by a layer of PMMA and a monolayer of quantum dots were under study in the presence of cw laser radiation. We demonstrate an irreversible effect of cw laser pumping radiation of a moderate power density on the properties of the studied plasmonic/active material system.

Experimental samples of organic light-emitting diodes with transport layers based on polythienothiophenes and using CdSe/CdS/ZnS semiconductor quantum dots with an internal quantum efficiency up to 85% in the emitting layer are investigated. It is shown that solubility and film-forming properties are key for using polythienothiophenes in light-emitting diodes. The most promising polythienothiophenes are identified on the basis of the results obtained.

The electrooptical characteristics of organic light-emitting diodes with quantum dots passivated with organic ligands of different lengths as emitting centers are investigated. It is established that the thickness of the ligand coating covering the quantum dots has little effect on the Förster energy transfer in the diodes, but significantly affects the direct injection of charge carriers into the quantum-dot layer. It is shown that the thickness of the passivation coating covering the quantum dots in a close-packed nanoparticle layer is deter- mined both by the length of passivating ligands and the degree of quantum-dot coverage with ligands.

The results of an experimental study of organic light-emitting diodes with poly-2,5-(3,4-diamino thieno[2,3-b]thiophene)-4,4’-amidoarylene transport layers and CdSe/CdS/ZnS quantum dots, the CdSe core of which has an average diameter of 4.1 nm, are presented. A suggestion is made regarding the possible conjugation of quantum dots and polythiophenes, which would substantially improve the characteristics of the light-emitting diodes in the case of optimization of their structure.

The results are reported of an experimental study of samples of organic light-emitting diodes (OLEDs) with luminescent layers fabricated on the basis of two types of CdSe/CdS/ZnS semiconductor quantum dots (QDs) with average CdSe core diameters of 3.2 and 4.1 nm and the same overall diameters of 6.5 nm. The dependences of the LED efficiency on the applied voltage are determined. Assumptions are made about ways of optimizing the design of high-efficiency LEDs.

L'invention porte sur des dispositifs optoelectroniques, a savoir, sur des dispositifs optoelectroniques bases sur des diodes electroluminescentes organiques, qui comprennent la couche electroluminescente active contenant des points quantiques avec la surface modifiee. Une couche electroluminescente active de dispositif optoelectronique comprend la premiere couche de transport de trous organique soluble dans un solvant non polaire, la seconde couche de transport d'electrons organique soluble dans un solvant non polaire, entre lesquelles la couche de points quantiques de semi-conducteur est situee, deposee a partir d'une solution dans le solvant polaire. La surface de points quantiques etait prealablement modifiee par un polymere conducteur amphiphile, cette surface de points quantiques de semi-conducteur avant modification etait hydrophobe et contenait sur sa zone entiere une couche du surfactant, dont l'epaisseur etait de 0,7 nm a 3 nm.

Sols of stabilized copper-doped CdSe nanocrystals in a nonpolar high-boiling solvent have been synthesized using cadmium oleate, copper stearate, and trioctylphosphine selenide as starting reagents. The average size of the nanocrystals is 2.8–2.9 nm, with a 10% variance, as evaluated from their absorption spectra. The samples show excitonic luminescence and bright near-IR (700–900 nm) luminescence with a lifetime on the order of 0.5–1 μs. The luminescence spectroscopy data are consistent with the assumption that the copper distribution over the nanocrystals follows Poisson’s law. The average copper content of the samples is 0.1–2 atoms per nanocrystal.

Vapor growth of In-doped PbTe crystals by the sublimation–condensation and vapor–liquid–solid (VLS) processes is examined. Well-faceted Pb 1 – x In x Te crystals with x = 0.04–0.06 are prepared by the sublimation method. The effects of the charge composition on the facial development and growth rate in the range 0 ≤ x ≤ 0.02 are discussed. The growth process at x ≥ 0.02 is shown to follow the VLS mechanism. Bulk Pb 1 – x In x Te crystals with x ≤ 0.05 are grown by a vertical VLS process. The crystal composition is shown to depend significantly on the rate of ampule translation through the temperature field of the furnace and the separation between the evaporation and condensation zones. The longitudinal indium profiles in the crystals are correlated with growth kinetics.

Supplementary information on optical characterization of single-photon emitters based on hybrid structures consisting of Nd(III) coordination compounds and CdSe/CdS/ZnS single nanocrystals.