scholarly journals CaSnO 3: Yb 3+, Er 3+, Ho 3+ system synthesis and study of its luminescence under IR excitation

2018 ◽  
Vol 4 (2) ◽  
pp. 71-75
Author(s):  
Ul’ana A. Mar’ina ◽  
Viktor A. Vorob’ev ◽  
Alexandr P. Mar’in
Keyword(s):  
Laser Excitation ◽  
Earth Metal ◽  
Luminescent Properties ◽  
Ion Concentration ◽  
Semiconductor Diode ◽  
Luminescence Spectra ◽  
Energy Transfer Mechanism ◽  
Absorbed Energy ◽  
Ir Radiation ◽  
Synthesis Conditions

Solid state synthesis of Perovskite-like calcium stannate structure activated with three rare-Earth metal ions Yb3+,Er3+,Но3+ has been studied. The formation of the CaSnO3 : Yb3+,Er3+,Но3+ luminescent structure requires the following synthesis conditions: anneal temperature 1250 °C and duration at least 18 h. The luminescent properties of the specimens have been studied under 960 nm semiconductor diode laser excitation. The luminescence spectra contain bands in the visible and IR spectral regions. Yb3+ ions have been shown to act predominantly as sensibilizers capable of transferring part of absorbed energy to Er3+ and Но3+ ions thus intensifying their respective luminescence peaks. Er3+ ions also transfer part of absorbed energy to Но3+ ions leading to an increase in the intensity of the 1194 and 1950 nm IR luminescence bands. A schematic of possible energy transitions in the CaSnO3 : Yb3+,Er3+,Но3+ system under 960 nm laser excitation has been suggested. The energy transfer mechanism between Yb3+,Er3+ and Но3+ions has been described in detail. The luminescence intensity of the luminophore has been studied at 994, 1194, 1550 and 1950 nm as a function of Но3+ion concentration. The peak intensity of the 1194 and 1950 nm bands is the highest at a Но3+ion concentration of 0.007 at.fr. It has been suggested to use the CaSnO3 : Yb3+,Er3+,Но3+ luminescent structure for radiation sources capable of converting 960 nm IR radiation to ~2000 nm IR radiation.

scholarly journals Люминесцентные свойства боросиликатного стекла, легированного церием

2019 ◽  
Vol 61 (10) ◽  
pp. 1879
Author(s):  
Д.Т. Валиев ◽  
С.А. Степанов ◽  
G. Yao ◽  
Y. Zhou
Keyword(s):  
Slow Component ◽  
Glass Melting ◽  
Luminescent Properties ◽  
Luminescence Decay ◽  
Ion Concentration ◽  
Luminescence Spectra ◽  
Decay Kinetics ◽  
Melting Method ◽  
Cerium Ion ◽  
Luminescence Decay Kinetics

ABS – BGP (Al2O3 – B2O3 – SiO2 – BaCO3 – Gd2O43 – P2O5) glasses doped with different Ce3+ concentrations were prepared by glass melting method. Optical, structural and luminescent properties have been characterized. Emission in the spectral range of 350–550 nm, associated with radiation transitions of Ce3+ ions was recorded. The luminescence decay kinetics is characterized by two components. The fast component is 45–90 ns. For the slow component, a decrease in the decay time from 4 to 0.9 us with increasing cerium ion concentration is shown. Based on the luminescence spectra, an assumption about the existence of various emitting states of the Ce3 + ion in borosilicate glass was made.

scholarly journals Neutron Rietveld Analysis for Optimized CaMgSi2O6:Eu2+ and its Luminescent Properties

2005 ◽  
Vol 20 (8) ◽  
pp. 2061-2066 ◽  
Author(s):  
Won Bin Im ◽  
Yong-Il Kim ◽  
Jong Hyuk Kang ◽  
Duk Young Jeon ◽  
Ha Kyun Jung ◽  
...  
Keyword(s):  
Rietveld Refinement ◽  
Goodness Of Fit ◽  
Luminescent Properties ◽  
Energy Transfer Mechanism ◽  
Activator Concentration ◽  
Conventional Solid State Reaction ◽  
Multipolar Interaction ◽  
Synthesis Conditions ◽  
Transfer Distance ◽  
Critical Transfer Distance

We optimized synthesis conditions of blue-emitting CaMgSi2O6:Eu2+ (CMS:Eu2+) with conventional solid-state reaction and successfully determined structure parameters by Rietveld refinement method with neutron powder diffraction data. The final weighted R-factor Rwp was 6.42% and the goodness-of-fit indicator S (= Rwp/Re) was 1.34. The refined lattice parameters of CMS:Eu2+ were a = 9.7472(3) Å, b = 8.9394(2) Å, and c = 5.2484(1) Å. The β angle was 105.87(1)°. The concentration quenching process was observed, and the critical quenching concentration of Eu2+ in CMS:Eu2+ was about 0.01 mol and critical transfer distance was calculated as 12 Å. With the help of the Rietveld refinement and Dexter theory, the critical transfer distance was also calculated as 27 Å. In addition, the dominant multipolar interaction of CMS:Eu2+ was investigated from the relationship between the emission intensity per activator concentration and activator concentration. The dipole–dipole interaction was a dominant energy transfer mechanism of electric multipolar character of CMS:Eu2+.

Study of Luminescent Properties of CaNb2O6:Yb, Er, Tm

2020 ◽  
pp. 78-87
Author(s):  
E.A. Moskvitina ◽  
V.A. Vorobiev ◽  
B.M. Bolotin
Keyword(s):  
Luminescence Spectrum ◽  
Solid Phase ◽  
Luminescent Properties ◽  
Luminescence Spectra ◽  
Energy Transfer Mechanism ◽  
X Ray ◽  
Luminescence Efficiency ◽  
Intermediate Phases ◽  
Diffraction Patterns ◽  
Calcium Niobate

We used solid phase synthesis at 1200 °C to create a luminophore based on CaNb2O6 and activated by ytterbium, erbium, and thulium ions. We present X-ray phase analysis results for the CaNb2O6:Yb, Er, Tm compound. The X-ray diffraction patterns obtained do not contain reflexes belonging to the intermediate phases. We investigated spectral properties of a calcium niobate-based luminophore upon excitation by a 940 nm laser. There are bands in the visible and IR regions to be found in the luminescence spectra. The up-conversion (anti-Stokes emission) luminescence spectrum comprises three bands peaking at 560, 676 and 807 nm. In the IR range, there are three peaks to be detected in the luminescence spectrum at 1010, 1540 and 1812 nm. We established the luminescence variation patterns for compounds based on CaNb2O6:Yb, Er, Tm. We determined the optimum Tm3+ concentration in the system that makes it possible to achieve the highest luminescence efficiency in the 1640--2000 nm range peaking at 1812 nm. We considered an energy transfer mechanism involving Yb3+ and Er3+ as luminescence stabilisers in a thulium ion. Employing erbium as an additional sensitiser allowed the luminescence intensity in the 1812 nm band to be increased by 1.5 time

scholarly journals Luminescence in lanthanum-gallium tantalate

2018 ◽  
Vol 4 (3) ◽  
pp. 97-101
Author(s):  
Oleg A. Buzanov ◽  
Nina S. Kozlova ◽  
Nikita A. Siminel ◽  
Evgeniya V. Zabelina
Keyword(s):  
Stokes Shift ◽  
Luminescent Properties ◽  
Luminescence Spectra ◽  
Absorption Bands ◽  
Argon Gas ◽  
Complex Process ◽  
Growth Atmosphere ◽  
Luminescence Peak ◽  
Integral Absorption ◽  
20 Nm

The optical and luminescent properties of undoped La3Ga5.5Ta0.5O14 lanthanum- gallium tantalate crystals grown in different atmospheres of pure argon gas and argon gas with different oxygen percentages have been studied. The optical absorption α(λ) spectra that characterize integral absorption and reflection have been measured in the 250–700 nm region. The spectral absorption functions have been calculated from the measured α(λ) spectra using the Kubelka–Munk formula. Luminescence has been observed in all the test specimens over a wide spectral region (375 to 650 nm) at 95 and 300 K. The luminescence spectra of the test crystals have a fine dispersed pattern represented by low-intensity discrete luminescence peaks. The 95 K luminescence peak maxima are more pronounced and shifted towards shorter wavelengths by ~16 nm (~0.1 eV) relative to the respective room temperature peaks. The crystal growth atmosphere has been demonstrated to largely affect the luminescent properties of the crystals: the higher the oxygen concentration in the growth atmosphere, the lower the luminescence intensity due to concentration quenching, the luminescence peak maxima shifting towards longer wavelengths. The positions of discrete luminescence peaks have been shown to correlate with the main 420 and 480 nm absorption bands with the respective ~20 nm (~0.2 eV) Stokes shift for crystals grown in different atmospheres. The luminescence in lanthanum-gallium tantalate crystals is a complex process involving several luminescence mechanisms.

Luminescence Properties of Transition-Metal Ions in Double Complex Salts

1990 ◽  
Vol 45 (6) ◽  
pp. 771-778
Author(s):  
Hans-Herbert Schmidtke ◽  
Hans J. Mink
Keyword(s):  
Energy Transfer ◽  
Transition Metal Ions ◽  
Complex Compounds ◽  
Luminescence Spectra ◽  
Energy Transfer Mechanism ◽  
No Emission ◽  
Double Complex ◽  
Decay Channels ◽  
Double Complex Compounds ◽  
Complex Salts

AbstractThe luminescence spectra and radiative lifetimes of a series of d3 and d6 double complex compounds with bipyridine (bip), phenanthroline (phen), ammonia and ethylenediamine (en) ligands in the cations and chloride, cyanide, thiocyanide and oxalate (ox) ligands in the anions have been investigated at temperatures down to 2 K. Although energy transfer between the component ions is predicted from the Förster and Dexter theory to be effective due to the finite overlap of the donor emission and the acceptor absorption spectra, no emission could be detected for most of the double complexes. Only [Ru(bip)3]tr-[Cr(NH3)2(NCS)4]2, [Ru(bip)3][PtCl6] and [Cr(d4-en)3] [Rh(SCN)6] exhibit characteristic luminescence spectra which in part are enhanced compared to their component emissions. For rationalizing the results, radiationless deactivation by various decay channels which compete with the energy transfer mechanism must be considered.

Preparation and Luminescent Properties of the La3+ Doped Tb3+-Hydroxyapatite

2014 ◽  
Vol 716-717 ◽  
pp. 32-35
Author(s):  
Wen Bin Liu ◽  
Adu ◽  
Yu Guang Lv ◽  
Li Li Yu ◽  
Yong Xiang Du ◽  
...  
Keyword(s):  
Rare Earth ◽  
Metal Ion ◽  
Chemical Properties ◽  
Earth Metal ◽  
Luminescent Properties ◽  
Central Metal ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
Terbium Ion ◽  
The Stability

In this paper, a rare earth metal terbium ion as the central metal ion, a nanohydroxyapatite powder of the lanthanum doped terbium was synthesis by precipitation with hydroxyapatite as ligand. The sample was characterized by infrared spectrum, fluorescence spectrum and X ray diffraction instrument, and the thermal properties and fluorescence properties, structure of powderes were discussed. A nanohydroxyapatite powder of the lanthanum doped terbium achieves the maximum luminous intensity, when the La3+ doping concentration of Tb3+ was HAP 5% (La3+ and Tb3+ mole fraction ratio) devices. Rare earth powder of the lanthanum doped terbium hydroxyapatite has the stability chemical properties, the luminescence properties and good biological activity, the rare earth powder has good luminescent properties can be used in preparation of a good light emitting device. At the same time a nanohydroxyapatite powder of the lanthanum doped terbium has good antibacterial property, can be used as antibacterial materials.

scholarly journals An Nd3+-Sensitized Upconversion Fluorescent Sensor for Epirubicin Detection

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1700
Author(s):  
Jingwen Mo ◽  
Long Shen ◽  
Qian Xu ◽  
Jiaying Zeng ◽  
Jingjie Sha ◽  
...  
Keyword(s):  
Laser Excitation ◽  
Fluorescent Sensor ◽  
Low Cost ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Fluorometric Detection ◽  
Energy Transfer Mechanism ◽  
Dynamic Quenching ◽  
Light Penetration

We describe here an Nd3+-sensitized upconversion fluorescent sensor for epirubicin (EPI) detection in aqueous solutions under 808 nm laser excitation. The upconversion fluorescence of nanoparticles is effectively quenched in the presence of EPI via a fluorescence resonance energy transfer mechanism. The dynamic quenching constant was 2.10 × 104 M−1. Normalized fluorescence intensity increased linearly as the EPI concentration was raised from 0.09 μM to 189.66 μM and the fluorometric detection limit was 0.05 μM. The sensing method was simple, fast, and low-cost and was able to be applied to determine the levels of EPI in urine with spike recoveries from 97.5% to 102.6%. Another important feature of the proposed fluorescent sensor is that it holds a promising potential for in vivo imaging and detection due to its distinctive properties such as weak autofluorescence, low heating effect, and high light penetration depth.

Interaction of Alkaline Earth Metal Ions with Acetic and Lactic Acid in Aqueous Solutions Studied by 13C NMR Spectroscopy

1997 ◽  
Vol 52 (4) ◽  
pp. 351-357 ◽  
Author(s):  
A. Kondoh ◽  
T. Oi
Keyword(s):  
Lactic Acid ◽  
Nmr Spectroscopy ◽  
Metal Ion ◽  
Alkaline Earth ◽  
Isotope Effects ◽  
Earth Metal ◽  
Ion Concentration ◽  
Alkaline Earth Metal ◽  
Hydroxyl Groups ◽  
Alkaline Earth Metal Ions

Abstract Interaction of alkaline earth metal (magnesium, calcium, strontium and barium) ions with acetic and lactic acid in aqueous media was investigated by 13C NMR spectroscopy. In the acetate systems, signals whose chemical shifts were the averages of those of the free and bound acetate ions were observed. Downfield shifts of the carboxylate carbon signals with increasing metal ion concentration indicated that the acetate ion acted as a monodentate ligand coordinating to the metal ion using the carboxylate group. The metal ion concentration dependence of the peak positions of the methine and carboxylate carbon signals of the lactate ion in the lactate systems suggested that the lactate ion coordinated to a metal ion using the carboxylate and hydroxyl groups. Unique upfield shifts upon complexation in the magnesium lactate systems suggested that the lactate ion coordinated to the magnesium ion from outside the primary hydration sphere.The present results were consistent with the isotope effects of the alkaline earth metals observed in cation exchange chromatography.

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