scholarly journals IR luminescence of CaGa 2O 4 : Yb 3+ excited by 940 and 980 nm radiation

2020 ◽  
Vol 6 (1) ◽  
pp. 31-36
Author(s):  
Ul’ana A. Mar’ina ◽  
Viktor A. Vorob’ev ◽  
Alexandr P. Mar’in
Keyword(s):  
Luminescence Intensity ◽  
Level Structure ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Luminescence Spectra ◽  
Practical Implementation ◽  
Luminescent Materials ◽  
Solid State Method ◽  
Region Data

Existing calcium gallate CaGa2O4 based luminescent materials radiating in visible IR region have been reviewed. IR luminophores have been studied but slightly but their practical implementation is of interest. CaGa2O4 specimens activated with Yb3+ rare-earth ions have been synthesized using the solid-state method. The structure and luminescent properties of CaGa2O4 : Yb3+ have been studied. CaGa2O4 : Yb3+ excitation with 940 and 980 nm radiation generates luminescence in the 980–1100 nm region. Data on the electron level structure in Yb3+ ions suggest that the excitation and luminescence occur directly in the Yb3+ ions with only a passive role of the base lattice. The luminescence spectra contain three peaks at 993, 1025 and 1080 nm. These luminescence peaks are caused by electron optical transitions from excited to main state in Yb3+ ions. 993 nm band luminescence intensity has been studied as a function of Yb3+ activator ions concentration. Introduction of Na+ ions into the luminophore increases IR luminescence intensity. Optimum (Ca1-x-yYbxNay)Ga2O4 luminophore composition has been suggested at which the 993 nm luminescence intensity is the highest.

scholarly journals Synthesis and Luminescent Properties of Eu3+/Tb3+ Rare Earth Ions Doped Li2SrSiO4 Phosphors

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Kaitao Yu ◽  
Lifang Wei ◽  
Jiaqi Shen
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Band ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Luminescent Materials ◽  
Excitation Spectra ◽  
Solid State Method ◽  
X Ray ◽  
Uv Visible

The series of luminescent materials of Eu3 +, Tb3 + doped Li2SrSiO4 were synthesized by a high-temperature solid-state method. The phase purity of the samples was measured by X-ray powder diffraction (XRD). The luminescent properties of the samples were studied by UV-visible excitation spectra and emission spectra The It is found that the strong absorption of Eu3 + doped Li2-xSr1-xEuxSiO4 is from the 250 ~ 290 nm charge transfer band of Eu3 + and the 7F0 → 5L6 absorption transition of 393 nm. The strongest emission of the emission spectra at 393 nm is 614 nm and 701 nm, respectively, from the 5D0 → 7F2 and 5D0 → 7F4 transitions of Eu3 +. Tb3 + doped sample Li2-xSr1-xTb xSiO4 excitation spectrum is mainly composed of Tb3 + ion fd transition and charge transfer band composed of broadband, the strongest absorption at 269 nm, the emission of the main emission of 5D4 → 7F5 transition (542 nm).

scholarly journals Kinetics of luminescence calcium gallate activated by Yb3+, Er3+ ions

2020 ◽  
Vol 23 (3) ◽  
pp. 213-221
Author(s):  
A. P. Mar`in ◽  
U. A. Mar`ina ◽  
V. A. Vorob`ev ◽  
R. V. Pigulev
Keyword(s):  
Rare Earth ◽  
Luminescence Intensity ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Luminescence Spectra ◽  
Excitation Spectra ◽  
Semiconductor Laser Diode ◽  
Intracenter Luminescence ◽  
Trivalent Rare Earth ◽  
Kinetics Of

The paper presents the results of a study of the luminescent properties of calcium gallate activated by trivalent rare earth ions Yb3+ and Er3+. IR luminescence spectra of samples with a single activator Ca1‑хYbxGa2O4,Ca1‑хErxGa2O4 were studied when excited by radiation sources with a wavelength of 940 and 790 nm, respectively. The dependence of the luminescence intensity of samples on the concentration of rare earth ions is obtained. When the two-activator composition of Ca1‑х‑yYbxEryGa2O4 is excited by a semiconductor laser diode with a wavelength of 940 nm, IR luminescence is registered in the regions of 980-1100 nm and 1450-1670 nm. The radiation in these bands corresponds to electronic transitions in Yb3+ and Er3+ ions, respectively. For a luminescence band with a maximum at a wavelength of 1540 nm, the excitation spectra were measured, the maximum intensity is at the wavelengths: 930, 941, 970, 980 nm. The dependence of the IR luminescence intensity of a solid solution of Ca1‑х‑yYbxEryGa2O4 on the concentration of Er3+ ions was studied. With an increase in the concentration of Er3+ ions in the luminescence spectra, there is a redistribution in the intensity of the bands belonging to Yb3+ and Er3+ ions, which indicates the presence of energy transfer processes between these ions. The kinetics of IR luminescence attenuation was studied for series with one and two activators: Ca1‑хYbxGa2O4,Ca1‑хErxGa2O4, Ca1‑х‑yYbxEryGa2O4. It is established that the luminescence attenuation occurs mainly according to the exponential law, which indicates the predominance of the intracenter luminescence mechanism in the studied structures. Based on the analysis of the excitation and luminescence spectra of experimental samples, conclusions are made about the interaction of Yb3+ and Er3+ activator ions in the crystal lattice of calcium gallate.

scholarly journals Promoting luminescence of Yb/Er codoped ferroelectric composite by polarization engineering for optoelectronic applications

Nanophotonics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 2215-2223 ◽  
Author(s):  
Er Pan ◽  
Gongxun Bai ◽  
Yutao Peng ◽  
Liang Chen ◽  
Shiqing Xu
Keyword(s):  
Rare Earth ◽  
Electric Field ◽  
Electrical Resistance ◽  
Near Infrared ◽  
Optoelectronic Devices ◽  
Glass Ceramics ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Luminescent Materials ◽  
Crystal Structural

AbstractFerroelectric oxide nanocrystals, in combination with the robust coupling of an electric field with crystal structure symmetry, makes such systems agreeable to field-induced crystal structural transformation. The luminescent properties of rare earth ions are sensitive to the symmetry of the surrounding crystal field. The luminescence tuning of rare earth ions is an important assignment in the research of luminescent materials. However, the current conditional feasibility and reversibility in the exploration of luminescence modification remain major challenges. In this article, the luminescence modulation of rare earth ions has been developed in Yb3+/Er3+ codoped ferroelectrics glass ceramics containing Bi4Ti3O12 nanocrystals through an electric field. The inclusion of nanocrystals in the glass matrix greatly enhances the electrical resistance. Both upconversion and near-infrared emissions of rare earth ions are effectively enhanced more than twice via polarization engineering. The electric field regulates the photonic properties of rare earth ions with excellent reversibility and nonvolatility in ferroelectrics. The effective modification by electric field provides a new scheme for optical storage and optoelectronic devices.

Preparation and Properties of CdSiO3: Mn2+, Er3+ Phosphor

2013 ◽  
Vol 873 ◽  
pp. 831-836
Author(s):  
Xiao Fei Qu ◽  
Fang Lin Du ◽  
Li Xin Cao
Keyword(s):  
Uv Light ◽  
Luminescent Properties ◽  
Solid State Method ◽  
Naked Eye ◽  
Afterglow Time ◽  
Method Effects ◽  
State Method ◽  
Intensity Decay ◽  
Co Doped

CdSiO3: Mn2+, Er3+long-lasting phosphor was prepared by the conventional high temperature solid-state method. Effects of the concentration of Mn2+and Er3+on the luminescent properties of phosphor CdSiO3: Mn2+, Er3+were investigated by means of photoluminescence (PL) spectra and the afterglow intensity decay curves. It was found that when the Mn2+and Er3+dopant-concentrations were 0.2 mol% and 0.8 mol% of Cd2+ions in CdSiO3, respectively, the luminescence of phosphor prepared had better luminescent property and longer afterglow time. The phosphorescence for it could be seen with the naked eye for more than 60 min in the dark after the removal of the 254 nm UV light. Role of Er3+co-doped into CdSiO3: Mn2+matrix was discussed in this paper.

Dy3+ Doping Blue-Green Sr4Al14O25:Eu2+ Phosphor for Enhancing Luminescent Properties and the Mechanism Study

2014 ◽  
Vol 936 ◽  
pp. 562-570 ◽  
Author(s):  
Zhe Kong ◽  
Hong Bo Wang ◽  
Er Pan Zhang ◽  
Tao Qiu ◽  
Jun Zhang ◽  
...  
Keyword(s):  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Strontium Aluminate ◽  
Mechanism Study ◽  
X Ray Diffraction ◽  
Doping Amount ◽  
Solid State Method ◽  
Characterization Methods ◽  
Aluminate Phosphor ◽  
Afterglow Time

Dy3+ doped blue-green Eu2+ doped strontium aluminate (Sr4Al14O25:Eu2+) phosphor was prepared using a high temperature solid state method and the influence of the doped Dy3+ on the luminescent properties was studied using X-ray diffraction, scanning electron microscopy, fluorescence spectroscopy and a series of other characterization methods. It is found that Dy3+ doping can enhance the luminescent intensity and extend the afterglow time. The luminescent mechanism of rare earth ions doped strontium aluminate phosphor was also discussed deeply, the effects of the doping amount on the luminescent properties has been made detailed explanation and description. This work has important theoretical significance for the development of higher brightness and longer afterglow blue-green phosphors.

scholarly journals Structural Investigation of Crystalline Host Phosphor Cadmium Tellurite Systems

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Rosli Hussin ◽  
Ng Siang Leong ◽  
Nur Shahira Alias
Keyword(s):  
Crystal Structure ◽  
Luminescent Properties ◽  
Transition Metal Ions ◽  
Rare Earth Ions ◽  
Molar Ratio ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
X Ray ◽  
Physical And Chemical

Generally, the luminescent properties of phosphors are strongly dependent on the crystal structure of the host materials. Finding a stable crystal structure, high physical and chemical stability of crystalline matrix is still a critical step to obtain rare-earth ions or transition metal ions-doped persistent phosphor with excellent properties. The glassceramic materials based on cadmium tellurite developed for stable host phosphor is reported in this paper. The structure of TeO2 and CdO-TeO2 system has been investigated by means of FT-Raman, Infrared (IR) spectroscopy and x-ray diffraction (XRD) spectroscopies. Cadmium tellurite system were prepared with the compositions of xCdO-(1-x)TeO2 with 0.1 x 0.5 in percent molar ratio, doped with 1% mol MnO2, using solid state method. The x-ray diffraction measurement results showed that the phase in the cadmium tellurite system matched quite well with the standard ICDD files, indicating that the phases present in this sample appeared to be a phase of -TeO4 trigional bipyramid (tbp), CdTe2O5 and CdTeO3. The Raman and Infrared spectra show that the structures are mainly builds by TeO4 (tbp) groups,TeO3+1 trigional pyramid (tp) and TeO3 (tp), while Cd2+ ions play as network modifiers. As addition concentration of CdO increases, TeO4 (tbp) groups progressively change polymerized framework structure in TeO4 (tbp) into TeO3+1 trigional pyramid (tp) and TeO3 (tp). On the contrary, the addition of 1 mol % MnO2 into the sample did not giving any effect on the structural of the final samples.

Hydrothermal Synthesis and Luminescent Properties of Eu3+ Doped Sr3Al2O6 Phosphor for White LED

2016 ◽  
Vol 16 (4) ◽  
pp. 3474-3479 ◽  
Author(s):  
Xu Li ◽  
Heng Pan ◽  
Aiwei Tang ◽  
Jinping Zhang ◽  
Li Guan ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Single Phase ◽  
Luminescent Properties ◽  
Synthesis Temperature ◽  
Rare Earth Ions ◽  
Light Sources ◽  
Luminescent Materials ◽  
Facile Hydrothermal Method ◽  
Optimal Value ◽  
New Generation

Eu3+ ions doped Sr3Al2O6 phosphors were successfully synthesized via a hydrothermal method. The precursor was prepared by low temperature hydrothermal method using ammonia as both alkaline source and precipitator. Then the final product was obtained by high temperature sintering. In addition, the structures, morphologies, and luminescent properties of as-prepared products were thoroughly characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Fluorescence spectroscopy (PL). XRD shown a single phase Sr3Al2O6 prepared by a facile hydrothermal method at 250 °C for 10 h. In the PL spectra of as-prepared samples, the optimal value of Eu3+ concentration is 2 mol%. From the fluorescent spectra, the emission peaks of Sr3Al2O6: Eu3+ phosphors are centered at around 591 nm, and the excitation peaks are centered at around 233 nm, 323 nm, 394 nm, and 468 nm, respectively, which were assigned to the characteristic transition of Eu3+ ions. The influence of ammonia, and the synthesis temperature on the luminescent properties of Sr3Al2O6: Eu3+ phosphors were studied in detail. The alkaline earth aluminates luminescent materials activated by rare earth ions have good prospects in the field of new-generation light sources.

OBOLESCENCE AND THE DIFFUSION OF INNOVATIONS

2020 ◽  
pp. 113-130
Author(s):  
A.V. GOLUBEV ◽  
Keyword(s):  
Diffusion Of Innovations ◽  
Time Lag ◽  
Practical Implementation ◽  
Primary Role ◽  
Innovation Development ◽  
Scientific Hypothesis ◽  
Scientific Papers ◽  
The Moment ◽  
Sociological Studies

The diffusion of innovations is described as a process in a number of scientific papers. At the same time, the causes of this process have not been sufficiently studied. The author’s goal is to consider the main regularities, under which the life cycle of innovations begins, and propose measures to enhance diffusion in modern conditions. As a scientific hypothesis, the author accepts the postulate about the primary role of the obolescence of attracted innovations in this process. The analysis revealed not only the economic proportions that initiate the start of innovation promotion, but also the influence on the diffusion rate of the obsolescence degree of innovations and the market share occupied by the new product. Methodological approaches have been developed to determine economic efficiency depending on the moment of technological change-over, as well as to determine the absolute and relative speed of innovation diffusion. Sociological studies were conducted to determine the state of innovation development and the time lag between obtaining information about an innovation and its practical implementation. The author presents his “Agroopyt” information system developed to disseminate knowledge in the agricultural sphere and ensure technology transfer in agriculture. Digital methods provide for significant accelerateion of the diffusion of innovations and expand its scope.

scholarly journals Structure, Luminescence, and Magnetic Properties of Crystalline Manganese Tungstate Doped with Rare Earth Ion

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3717
Author(s):  
Jae-Young Jung ◽  
Soung-Soo Yi ◽  
Dong-Hyun Hwang ◽  
Chang-Sik Son
Keyword(s):  
Magnetic Field ◽  
Rare Earth ◽  
Sintering Temperature ◽  
Luminescent Properties ◽  
Concentration Quenching ◽  
Rare Earth Ions ◽  
Precipitation Method ◽  
Rare Earth Ion ◽  
Co Precipitation ◽  
Quenching Phenomenon

The precursor prepared by co-precipitation method was sintered at various temperatures to synthesize crystalline manganese tungstate (MnWO4). Sintered MnWO4 showed the best crystallinity at a sintering temperature of 800 °C. Rare earth ion (Dysprosium; Dy3+) was added when preparing the precursor to enhance the magnetic and luminescent properties of crystalline MnWO4 based on these sintering temperature conditions. As the amount of rare earth ions was changed, the magnetic and luminescent characteristics were enhanced; however, after 0.1 mol.%, the luminescent characteristics decreased due to the concentration quenching phenomenon. In addition, a composite was prepared by mixing MnWO4 powder, with enhanced magnetism and luminescence properties due to the addition of dysprosium, with epoxy. To one of the two prepared composites a magnetic field was applied to induce alignment of the MnWO4 particles. Aligned particles showed stronger luminescence than the composite sample prepared with unsorted particles. As a result of this, it was suggested that it can be used as phosphor and a photosensitizer by utilizing the magnetic and luminescent properties of the synthesized MnWO4 powder with the addition of rare earth ions.

Luminescent Properties of Rare Earth Ions in One-Dimensional Oxide Nanowires

2005 ◽  
Vol 5 (9) ◽  
pp. 1519-1531 ◽  
Author(s):  
Hongwei Song ◽  
Lixin Yu ◽  
LinMei Yang ◽  
Shaozhe Lu
Keyword(s):  
Rare Earth ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Oxide Nanowires ◽  
One Dimensional
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