Stabilization of Eu3+ under a reductive atmosphere by the Al3+ co-doping of Sr2SiO4:Eu2+/Eu3+

RSC Advances ◽  
2016 ◽  
Vol 6 (53) ◽  
pp. 48001-48008 ◽  
Author(s):  
Karol Szczodrowski ◽  
Justyna Barzowska ◽  
Natalia Górecka ◽  
Marek Grinberg
Keyword(s):  
Concentration Ratio ◽  
Oxidation States ◽  
Co Doping ◽  
Aluminum Ions ◽  
Reductive Atmosphere ◽  
The Eu

The incorporation of aluminum ions into the Sr2SiO4:Eu causes the stabilization of the Eu3+ ions under reductive atmosphere and concentration ratio of europium in both oxidation states ([Eu3+]/[Eu2+]) can be controlled by changing the Al3+ content.

Synergistic Effect of Eu3+ and Sm3+ Co-Doping on Photocatalytic Activity of TiO2 Nanoparticles

2011 ◽  
Vol 197-198 ◽  
pp. 891-894 ◽  
Author(s):  
Cheng Zhi Jiang ◽  
Xu Dong Lu
Keyword(s):  
Photocatalytic Activity ◽  
Synergistic Effect ◽  
Sol Gel ◽  
Blue Shift ◽  
Nano Particles ◽  
Absorption Profile ◽  
Co Doping ◽  
The Matrix ◽  
Co Doped ◽  
The Eu

Pure TiO2, Eu3+and Sm3+co-doping TiO2composite nanoparticles have been prepared by sol-gel method and characterized by the techniques such as XRD, SEM and DRS. The photocatalytic degradation of methylene blue (MB) in aqueous solution was used as a probe reaction to evaluate their photocatalytic activity. The matrix distortion of TiO2nano-particles increases after co-doping of Eu3+and Sm3+and a blue-shift of the absorption profile are clearly observed. The results show that co-doping of Eu3+and Sm3+inhibits the phase transformation of TiO2from anatase to rutile, decreases the diameter of TiO2nano-particles and significantly enhance the photocatalytic activity of TiO2. The Eu3+and Sm3+co-doped into TiO2nano-particles exert a synergistic effect on their photocatalytic activity.

Understanding Persistent Luminescence: Rare-Earth- and Eu2+-doped Sr2MgSi2O7

2014 ◽  
Vol 69 (2) ◽  
pp. 171-182 ◽  
Author(s):  
Mika Lastusaari ◽  
Högne Jungner ◽  
Aleksei Kotlov ◽  
Taneli Laamanen ◽  
Lucas C. V. Rodrigues ◽  
...  
Keyword(s):  
Rare Earth ◽  
Band Gap ◽  
Charge Compensation ◽  
Band Gap Energy ◽  
Persistent Luminescence ◽  
Excitation Spectra ◽  
Co Doping ◽  
The Individual ◽  
Initial Intensity ◽  
The Eu

Similar to many other Eu2+,RE3+-co-doped persistent luminescence materials, for Sr2MgSi2O7:Eu2+,RE3+ the initial intensity and duration of persistent luminescence was also found to depend critically on the rare-earth (RE) co-doping. An enhancement of 1 - 2 orders of magnitude in these properties could be obtained by Dy3+ co-doping whereas total quenching of persistent luminescence resulted from the use of Sm3+ and Yb3+. To solve this drastic disparity, the effects of the individual RE3+ ions were studied with thermoluminescence (TL) spectroscopy to derive information about the formation of traps storing the excitation energy. The charge compensation defects were concluded to be the origin of the complex TL glow curve structure. The tuning of the band gap of the Sr2MgSi2O7 host and especially the position of the bottom of the conduction band due to the Eu2+,RE3+ co-doping was measured with the synchrotron radiation vacuum UV (VUV) excitation spectra of the Eu2+ dopant. The model based on the evolution of the band gap energy with RE3+ co-doping was found to explain the intensity and duration of the persistent luminescence.

scholarly journals Influence of Al3+ co-doping on the spectral properties of europium doped Ca9Y(PO4)7

RSC Advances ◽  
2020 ◽  
Vol 10 (68) ◽  
pp. 41821-41829
Author(s):  
Karol Szczodrowski ◽  
Natalia Górecka ◽  
Marek Grinberg
Keyword(s):  
Spectral Properties ◽  
Pechini Method ◽  
Luminescent Materials ◽  
Co Doping ◽  
Aluminum Ions

A series of luminescent materials based on a calcium yttrium phosphate matrix doped with europium and different concentrations of aluminum ions (0, 5, 10% of mole) was synthesized using the Pechini method.

Emission Spectra of Zinc Oxychloride Tellurite Glass: Effects of Eu3+/Sm3+ Co-Doping

2011 ◽  
Vol 181-182 ◽  
pp. 451-454
Author(s):  
M.R. Sahar ◽  
R. Arifin ◽  
S.K. Ghoshal
Keyword(s):  
Tellurite Glass ◽  
Emission Spectra ◽  
Excitation Wavelength ◽  
Co Doping ◽  
Absorption Energy ◽  
Doped Glasses ◽  
Doped Glass ◽  
Co Doped ◽  
Resonance Transfer ◽  
The Eu

Eu3+or/and Sm3+co-doped glasses based on TeO2-ZnO-ZnCl2-Li2O are prepared using the melt quenching technique and the effects of co-doping on the emission spectra of these glasses are examined. The Sm3+doped glass under 403 nm excitations show emission bands around 561, 598 and 642 nm corresponding to the transitions of4G5/2→6H5/2,4G5/2→6H7/2and4G5/2→6H9/2respectively. Whereas, in Eu3+doped glass under 397 nm excitation emission bands appear around 553, 586, 613, 650 and 699 nm that corresponds to the transitions of5D1→7F2,5D0→7F1,5D0→7F2,5D0→7F3and5D0→7F4. In addition, the emission spectra of the Eu3+/Sm3+co-doped glass under 482 nm excitation consists of five bands in which three are contributed by Sm3+at 561, 598 and 642 nm and two by Eu3+at 613 nm and 699 nm respectively. Surprisingly, the emission bands of Eu3+are still observed in the emission spectra of Sm3+for the Eu3+/Sm3+co-doped glasses despite the absence of the excitation wavelength 482 nm in the absorption and excitation domain of Eu3+. This observation is attributed to the partial resonance transfer of the absorption energy from Sm3+to the Eu3+ions.

scholarly journals Revealing the substitution mechanism in Eu3+:CaMoO4 and Eu3+,Na+:CaMoO4 phosphors

2018 ◽  
Vol 6 (47) ◽  
pp. 12830-12840 ◽  
Author(s):  
Ana Isabel Becerro ◽  
Mathieu Allix ◽  
Mariano Laguna ◽  
Daniel González-Mancebo ◽  
Cecile Genevois ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Unit Cell ◽  
Co Doping ◽  
Substitution Mechanism ◽  
The Eu

Why is the Eu3+:CaMoO4 unit cell bigger than that of CaMoO4? Does Na+ co-doping improve the quantum yield of Eu3+:CaMoO4 phosphors?

Tunable blue-green emission and energy transfer properties in β-Ca3(PO4)2:Eu2+, Tb3+ phosphors with high quantum efficiencies for UV-LEDs

2015 ◽  
Vol 44 (10) ◽  
pp. 4683-4692 ◽  
Author(s):  
Kai Li ◽  
Yang Zhang ◽  
Xuejiao Li ◽  
Mengmeng Shang ◽  
Hongzhou Lian ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Concentration Ratio ◽  
Green Emission ◽  
High Quantum ◽  
Emission Color ◽  
Potential Applications ◽  
Uv Leds ◽  
Transfer Properties ◽  
Co Doped ◽  
The Eu

A series of Eu2+ and Tb3+ singly-doped and co-doped β-Ca3(PO4)2 phosphors have been synthesized. The emission color can be tuned from blue to green by adjusting the Eu2+/Tb3+ concentration ratio, showing their potential applications in UV-pumped wLEDs.

scholarly journals Luminescent characteristics of Eu2+/Li+ doped (La-Al)2O3 phosphors and PMMA films activated with them

2018 ◽  
Vol 64 (5) ◽  
pp. 447 ◽  
Author(s):  
Roberto Vázquez Arreguín
Keyword(s):  
Solid State ◽  
Methyl Methacrylate ◽  
Luminescence Intensity ◽  
Solid State Reaction ◽  
Broad Band ◽  
Step Process ◽  
Co Doping ◽  
Broad Band Emission ◽  
Band Emission ◽  
Reductive Atmosphere

The effect of Li co-doping on the blue luminescence of Eu2+ doped (La-Al)2O3 phosphors and its incorporation into poly (methyl methacrylate) PMMA films are reported. The phosphors were synthesized by a simple two-step process in which the (La-Al)2O3 powders were obtained by an evaporation method, and the subsequent co-doping with Li+ and Eu2 were made through a solid state reaction in a reductive atmosphere at 1250 0C. The incorporation of those phosphors into PMMA matrix and the synthesis of films with thicknesses between 6 and 12 μm was made by drop-casting. The characteristic blue broad band emission centered at 440 nm associated with the 4f65d1→ 4F7 transition of Eu2+ ions (CIE coordinates 0.6731, 0.3343) was observed when these powders were excited with 297nm light. These luminescence intensity was enhanced when Li was incorporated as co-dopant up to 320% with respect to those phosphors without Li. The luminescent characteristics of these phosphors were preserved when they were embedded into the PMMA films.

scholarly journals 27Al MAS NMR spectroscopy study of Eu2+-doped and Dy3+-co-doped SrAl4O7

2020 ◽  
Vol 60 (2) ◽  
Author(s):  
Martynas Misevičius ◽  
Laurynas Dagys ◽  
Arūnas Maršalka ◽  
Kristina Kristinaitytė ◽  
Vytautas Balevičius
Keyword(s):  
Solid State ◽  
Pulse Sequences ◽  
Single Pulse ◽  
Local Environment ◽  
Mas Nmr ◽  
Strontium Aluminate ◽  
Co Doping ◽  
27Al Mas Nmr ◽  
Co Doped ◽  
The Eu

The Eu2+-doped strontium aluminate SrAl4O7 samples have shown the blue-green persistent luminescence at 490 nm while the co-doping with Dy3+ shifts the maximum of emission to 475 nm. Undoped, 3% Eu-doped and 6% Dy-co-doped SrAl4O7 samples were prepared by the solid state-reaction method and studied by the solid-state 27Al MAS NMR applying the single pulse-acquire and Hahn-echo pulse sequences. It was shown that the Eu2+ with Dy3+ ion doping did not affect the bulk structure as well as the local Al environment in SrAl4O7. This means that large shifts of the emission maximum cannot be caused by changes in the local environment upon the co-doping of SrAl4O7:Eu2+ with Dy3+. However, the spectral features observed in the range between the signals of 4- and 6-coordinated Al (20–40 ppm) indicate that certain phase imperfections are present in all studied samples, and most probably amorphous/glassy domains were formed. Note that such amount of phase impurities was not detected by standard XRD or FTIR methods. This has revealed the 27Al MAS NMR technique to be a very effective tool monitoring the phase perfectness in series of strontium aluminate samples.

A Novel Green-Emitting Phosphor: LiLa2BO5:Ce3+,Tb3+ with High Luminescence Efficiency

2013 ◽  
Vol 800 ◽  
pp. 260-264
Author(s):  
Yin Rong Fu
Keyword(s):  
Emission Spectra ◽  
Luminescent Properties ◽  
Experimental Result ◽  
Green Phosphor ◽  
Co Doping ◽  
Luminescence Efficiency ◽  
Reductive Atmosphere ◽  
Xrd Patterns ◽  
Sintering Condition ◽  
Dominant Peak

Novel Ce3+ and Tb3+ co-doped LiLa2BO5 phosphor, synthesized by a solid state reaction in reductive atmosphere, exhibits enriched emission spectrum in the green region .The XRD patterns, photoluminescence spectra and SEM were recorded and the effects of Tb3+ and Ce3+ concentration, sintering condition on the luminescent properties of as-synthesized phosphors were investigated. The emission spectra under ultraviolet (200--350 nm) radiation showed a dominant peak at 544 nm attributed to the 5D47FJ(J=0,1,2...6) transition of Tb3+, which was greatly enhanced by the co-doping of Ce3+, indicating that there occurred an efficient nonradioactive energy transfer from Ce3+ to Tb3+. The experimental result shows that the optimum Ce3+ and Tb3+ doping concentrations are 15 at% and 10 at% respectively.Keywords: Green phosphor; High luminescence efficiency; LiLa2BO5:Ce3+,Tb3+ ; Rare earths

Controllable Luminescent Properties of Phosphors Sr2.97-XCaxMgSi2O8: Eu0.012+, Dy0.023+ by Adjusting Sr/Ca Ratio

2010 ◽  
Vol 663-665 ◽  
pp. 118-124
Author(s):  
Jun Fu Chu ◽  
Yi Hua Hu ◽  
Hai Wang Yin ◽  
Yi Wu Hao
Keyword(s):  
Size Variation ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Crystal Defects ◽  
Co Doping ◽  
Long Afterglow ◽  
Ion Doping ◽  
Ca Ions ◽  
Small Change ◽  
Reductive Atmosphere

Divalent europium and trivalent dysprosium co-doping in the compounds Sr2.97-xCaxMgSi2O8 (x=0, 0.5, 1.5, 2, 2.5, 2.97) produces phosphors of high luminescence yield. These phosphors were prepared at high temperature and weak reductive atmosphere. The ratio of Eu/Dy is 1/2. The phosphors were characterized for their crystal phases by x-ray powder diffraction. Slight shifts of the peaks in the structure, which indicate a small change of the interplanar crystal spacing, were observed for each different x’s. The interplanar spacing becomes narrow as increasing the value of x. These phosphors respond well to the ultraviolet excitation. The peak of the emission band occurs at progressively longer wavelength and widens as the ratio of alkaline earth Sr/Ca ions is decreased. The emission peaks of the phosphors indicated on the emission spectra range from 463nm to 490nm. It is probably due to the influence of 5d electron states of Eu2+ in the crystal field because of atomic size variation causing crystal defects. Dy3+ ion doping in the phosphor generates deep traps, which results in long afterglow phosphorescence. As the proportion of Ca in the composition increases, the attenuation time of the phosphors becomes short.

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