Spectral characteristics of chromium-activated yttrium aluminum garnet in theR-line range

The variety of applications of yttrium-aluminum garnet (YAG)-based luminescent materials and the morphology necessary for these purposes required the development of many technologies for their synthesis. All synthesis technologies used are complex. The structural phase of yttrium-aluminum garnet is formed with any technology, at temperatures exceeding 1,500 °C. The starting materials for the synthesis are metal oxides of aluminum, yttrium and other oxides for activation and modification. It seems possible to use hard radiation to form a new phase. Radiation synthesis of ceramics is realized in less than 1 s, without the use of any additives and influences. The synthesis was carried out at the electron accelerator of the Institute of Nuclear Physics (Novosibirsk). In this work, we studied the spectral-kinetic and quantitative characteristics of luminescence for the first time obtained by the method of radiation synthesis of ceramic samples of yttrium-aluminum garnet doped with cerium with statistical processing of their values. The dependences of the reproducibility of the spectral characteristics of the luminescence of the samples on the preliminary preparation of the charge for synthesis have been investigated. Several cycles of luminophore brightness studies have been performed. It is shown that the obtained ceramics based on yttrium-aluminum garnet doped with cerium possesses the required spectral-kinetic properties, and the efficiency of conversion of the chip radiation into luminescence is achieved, which is comparable to that available in commercial phosphors. The maximum measured values of the position of the bands are from 553.5 to 559.6 nm. Brightness values range from 4,720 to 1,960 cd/m2. It was found that the main reason for the scatter in the characteristics of the luminescent properties of ceramics of yttrium-aluminum garnet, activated by cerium obtained by radiation assisted synthesis is the high rate of synthesis and, especially, the high rate of cooling of the samples.

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LUMINESCENCE OF YAG:Ce DOPED WITH SILVER NANOPARTICLES

Physical and Chemical Aspects of the Study of Clusters Nanostructures and Nanomaterials ◽

10.26456/pcascnn/2021.13.220 ◽

2021 ◽

pp. 220-227

Author(s):

Александр Александрович Кравцов ◽

Ирина Сергеевна Чикулина ◽

Дмитрий Сергеевич Вакалов ◽

Олег Михайлович Чапура ◽

Святослав Олегович Крандиевский ◽

...

Keyword(s):

Silver Nanoparticles ◽

Yttrium Aluminum Garnet ◽

Chemical Reduction ◽

Spectral Characteristics ◽

Ceramic Powder ◽

Precursor Powder ◽

Precipitation Method ◽

Photoluminescence Intensity ◽

Two Stage ◽

Yttrium Aluminum

В работе впервые было исследовано влияние наночастиц серебра на люминесценцию иттрий-алюминиевого граната, легированного церием. С помощью метода химического восстановления был синтезирован золь с размером наночастиц серебра ≈100 нм. Керамический порошок люминофора иттрий-алюминиевого граната, легированного церием, был получен методом двухстадийного осаждения в уротропин. Золь наночастиц серебра в концентрациях от 0,125 до 0,1 мл вводили в порошок-прекурсор перед прокаливанием. Было показано, что при данном способе введения наночастиц серебра интенсивность фотолюминесценции возрастала по сравнению с эталоном. Оптимальной концентрацией в рамках исследования являлась концентрация 0,25 мл. При данной концентрации увеличение интенсивности фотолюминесценции на длине волны 540 нм составило порядка 10%. Проведенные исследования показали, что наночастицы серебра могут с успехом применяться для увеличения яркости люминофора иттрий-алюминиевого граната, легированного церием, без искажения и ухудшения спектральных характеристик. This work was the first to study the effect of silver nanoparticles on the luminescence of cerium doped yttrium-aluminum garnet. A sol with the size of silver nanoparticles of ≈100 nm was synthesized using the method of chemical reduction. Phosphor ceramic powder of the yttrium-aluminum garnet doped with cerium was obtained by the two-stage precipitation method. The silver nanoparticles sol was introduced into the precursor powder before calcination in concentrations from 0,125 to 0,1 ml. It was shown that the photoluminescence intensity increased in comparison with the reference when we used this method of introducing silver nanoparticles. The optimal concentration within the study was 0,25 ml. At this concentration, the increase in the photoluminescence intensity at a wavelength of 540 nm was about 10 %. Studies have shown that silver nanoparticles can be successfully used to increase the brightness of the phosphor of the yttrium-aluminum garnet doped with cerium without distortion and deterioration of spectral characteristics.

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Inorganic Composites Luminophors in Lithium-Borate Glasses with Rare-Earth Elements for White-Emitting Diodes

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.410.764 ◽

2021 ◽

Vol 410 ◽

pp. 764-769

Author(s):

Anna V. Tepikina ◽

Svetlana G. Vlasova

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Composite System ◽

Yttrium Aluminum Garnet ◽

Spectral Characteristics ◽

Lithium Borate ◽

Radiation Spectra ◽

Inorganic Composites ◽

Yttrium Aluminum ◽

Lithium Borate Glass

The paper describes the synthesis of novel luminescent composite system, based on lithium-borate glass matrix with addition of rare-earth elements and yttrium-aluminum garnet finely divided powder. The new chemical composition of glass has been selected, composite’s fabrication technology was developed, the temperature conditions of glass and luminophore sintering as well. The spectral characteristics of the obtained luminescent composites are measured, and chromaticity diagrams are considered. The radiation spectra showed a maximum of about 560 nm, the maximum spectral intensity of the radiation is about 90 μw/cm2/nm. Powerful energy saving source of white light was produced.

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Yag Single Crystals for Scintillators of Stem

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100179580 ◽

1990 ◽

Vol 48 (1) ◽

pp. 166-167

Author(s):

M. Hibino ◽

K. Irie ◽

R. Autrata ◽

P. schauer

Keyword(s):

Single Crystals ◽

Yttrium Aluminum Garnet ◽

Light Guide ◽

Detection System ◽

Polished Surface ◽

Detective Quantum Efficiency ◽

Backscattered Electrons ◽

Electron Detection ◽

Yttrium Aluminum ◽

Phosphor Screens

Although powdered phosphor screens are usually used for scintillators of STEM, it has been found that the phosphor screen of appropriate thickness should be used depending on the accelerating voltage, in order to keep high detective quantum efficiency. 1 It has been also found that the variation in sensitivity, due to granularity of phosphor screens, makes the measurement of fine electron probe difficult and that the sensitivity reduces with electron irradiation specially at high voltages.In order to find out a preferable scintillator for STEM, single crystals of YAG (yttrium aluminum garnet), which are used for detecting secondary and backscattered electrons in SEM were investigated and compared with powdered phosphor screens, at the accelerating voltages of 100kV and 1 MV. A conventional electron detection system, consisting of scintillator, light guide and PMT (Hamamatsu Photonics R268) was used for measurements. Scintillators used are YAG single crystals of 1.0 to 3.2mm thicknesses (with surfaces matted for good interface to the light guide) and of 0.8mm thickness (with polished surface), and powdered P-46 phosphor screens of 0.07mm and 1.0mm thicknesses for 100kV and 1MV, respectively. Surfaces on electron-incidence side of all scintillators are coated with reflecting layers.

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