CdS(Se) and PbS(Se) Quantum Dots with High Room Temperature Quantum Efficiency in the Fluorine-Phosphate Glasses

In this study, the luminescent properties of the CdS(Se) quantum dots (QDs) with the mean size of 2–4 nm, the (PbS)n/(PbSe)n molecular clusters (MCs) and PbS(Se) quantum dots (QDs) with the mean size of 2–5 nm embedded in the fluorine-phosphate glass are investigated. The dependence of the photo luminescence absolute quantum yield (PL AQY) on the sizes of the CdS(Se) QDs are studied. It is found that the PL AQY of the CdSe QDs increases monotonically to its maximum height and then falls down. The PL AQY of the CdS(Se) QDs can reach 50–65%. Luminescence of (PbS)n/(PbSe)n MCs embedded in fluorine-phosphate matrix and excited by UV radiation is obtained in the visible spectral region and its absolute quantum yield was up to 10%. The PbSe QDs have broadband photoluminescence with quantum efficiency about five times more than MCs (~50%) in the spectral range of 1–1.7 µm. Glasses doped with PbS(Se) QDs provide potential application as infrared fluorophores, which are both efficient and possess short life times. The glass matrix protects the QDs from external influence and their optical properties remain unchanged for a long time

Electrochromic Film Based on a-WO3 Obtained by Sol-gel

The influence of changes in the conditions of sol-gel method on the thermal characteristics and the structure electrochromic (EC) а-WO3 films. DSC data showed greater sensitivity of the structure to the pe-culiarities of the drying of the product poliperoxo-tungstic acid. The Films were transparent over a wide range (Eg 2,5 eV). All compositions were amorphous as measured by X-rays diffraction. Based on the IR and Raman spectroscopy dates was concluded the presence in the structure of amorphous transparent glassy semiconductor a-WO3 predominantly tetrahedral [WO4] groups. The precursor product and EC-films are glass material, obtained by the sol-gel process, with the composition WO3* H2O. Synthesis peculiari-ties of mesoporous a-WO3. affects both the pore structure, which determines the concentration of the aqueous components and the ratio of the bridging W-O-W and unbridged W O bonds, defining characte-ristics of the electrochromic materials. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3538

LOGISTICS IN THE CONTEMPORARY WORLD: PECULIARITIES IN RUSSIA AND KEY PROBLEMS

In the article the urgency majorof logistics in modern заключениconditions, theoretical логистическиbases of the потребителямterm «Logistics» is процессconsidered. The логистикиtasks of logistics магистратурыare defined, озданиlogistics infrastructure логисти analysis is carried стремятся out and промышленностиthe necessary услугmeasures are компанийproposed to improve развитыхthe development эффективностиof the logistics сценариindustry

Optical Properties of PbSe Qantum Dots Doped in Fluorophosphate Glasses

PbSe quantum dots (QDs) were synthesed in fluorophosphate glass and their absorption and lumines-cence properties were investigated. The effect of the duration of the heat treatment on the spectral-luminescent properties was considered. The average diameter of the synthesized quantum dots has been calculated. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3536

FEATURES PROMOTION OF HOTEL SERVICES WITH THE USING MODERN MARKETING METHODS

The arguments proving necessity of promotion of hotel services with the using innovative marketing trends. The carrying out of evaluation key marketing strategies in hospitality industry. The most creative approaches in the marketing policy of the hotel enterprise are allocated

FEATURES PROMOTION OF HOTEL SERVICES WITH THE USING MODERN MARKETING METHODS

The arguments proving necessity of promotion of hotel services with the using innovative marketing trends. The carrying out of evaluation key marketing strategies in hospitality industry. The most creative approaches in the marketing policy of the hotel enterprise are allocated

LOGISTICS IN THE CONTEMPORARY WORLD: PECULIARITIES IN RUSSIA AND KEY PROBLEMS

In the article the urgency majorof logistics in modern заключениconditions, theoretical логистическиbases of the потребителямterm «Logistics» is процессconsidered. The логистикиtasks of logistics магистратурыare defined, озданиlogistics infrastructure логисти analysis is carried стремятся out and промышленностиthe necessary услугmeasures are компанийproposed to improve развитыхthe development эффективностиof the logistics сценариindustry

Red Emitting Phosphors Doped with Mn and Eu Ions for pc-WLEDs

A new red emitting phosphors based on oxyfluoride glass and glassceramics doped with europium and manganese ions were synthesized and their optical properties and structure were studied. The transparent ceramic matrices for phosphors were selected because they overcome traditional powder phosphors due to high chemical and thermal stability and low temperature sensitivity. The fluoride based red emitting phosphors combined with green one and blue emitting chip used to fabricate phosphor converted white LEDs with warm color temperature and improved color rendering indexes. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3537