Comparative luminescence study of terbium-exchanged zeolites silylated with alkoxysilanes

Tiseanu, Carmen; Lórenz-Fonfrı́a, Vı́ctor A.; Geßner, André; Kumke, Michael U.; Gagea, Bogdan C.

doi:10.1007/s10854-008-9597-1

Cited by 5 publications

(3 citation statements)

References 14 publications

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“…strongest emission peak was located at 545 nm. The decay time for all the glasses was estimated around 1.8 ms. [7] reports that in terbium-exchanged zeolites decay times were about 610-650 .…”

Section: Introductionmentioning

confidence: 99%

Rare Earth Activated Oxyfluoride Glasses and Glass-Ceramics for Scintillation Applications

Rogulis

Elsts

Jansons

et al. 2012

IEEE Trans. Nucl. Sci.

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Oxyfluoride glasses activated with Tb, Ce, Eu have been synthesized and studied. After heating at 580 and 750 crystalline phases were obtained. The samples were studied by DTA (Differential thermal analyzer), CL (cathodoluminescence), XRD (X-ray diffraction), SEM (scanning electron microscope), EDS (energy dispersive x-ray spectroscopy) methods. We found out that presence of crystalline phase enhances the CL of Tb activated samples significantly; whereas, the shortest decay time of 0.29 has been observed for less intense Ce doped glass sample.

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Section: Introductionmentioning

confidence: 99%

Rare Earth Activated Oxyfluoride Glasses and Glass-Ceramics for Scintillation Applications

Rogulis

Elsts

Jansons

et al. 2012

IEEE Trans. Nucl. Sci.

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“…Uncertainty for the short components is ± 5 μs, and for the long ones − ± 20 μs. For more convenient comparison of the exponential functions of different samples we have calculated the average exponents of each pair (see Table 4) For this purpose the following formula was used [8]:…”

Section: Cathodoluminescence Measurementsmentioning

confidence: 99%

Cathodoluminescence of Terbium- and Ytterbium-Activated Oxyfluoride Glasses and Glass Ceramics

Elsts¹,

Rogulis²,

Jansons³

et al. 2010

Latvian Journal of Physics and Technical Sciences

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Cathodoluminescence (CL) spectra and decay times have been studied for oxyfluoride glasses and glass ceramics of the system: SiO 2 -Al 2 0 3 -Na 2 O -LaF 3 -NaF, activated by terbium and ytterbium.The CL spectra of the glasses and glass ceramics show characteristic Tb 3+ luminescence bands: blue ( 5 D 3 → 7 F J ) and green ( 5 D 4 → 7 F J ) groups. With increasing terbium concentration the blue-to green-group ratio decreases.The CL decay curves can be sufficiently well approximated by two exponents − fast and slow. Decay times for the blue-group CL bands are faster than for those of green group.As the terbium concentration increases, the lifetimes for the lines of the blue group shorten, while for the green group they remain unchanged. This could be explained by the cross-relaxation between the transitions 5 D 3 → 5 D 4 and 7 F 6 → 7 F 0 of two terbium ions.

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“…However, upon exposure to moist atmosphere, the PL properties characteristic for the hydrated state will be partially restored. [37][38][39][40] Current work on terbium-exchanged zeolites showed that following the silylation of the calcined terbium-exchanged BEA, USY, MOR, and ZSM-5 zeolites [41][42][43] with hexadecyl-, phenyl-, and vinyltrimethoxysilanes, luminescence properties were preserved more or less at the values measured after the calcination. The characterization of these materials indicated a significant reduction of the chemisorbed water due to silylation.…”

Section: Introductionmentioning

confidence: 99%

Europium(3+): An Efficient Luminescence Probe for the Si to Al Ratio and Silylation Effects in the Microporous−Mesoporous Zeogrid Materials

et al. 2008

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The optical response of europium ions in the parent (non-silylated) and silylated microporous-mesoporous Zeogrid materials was investigated in detail in relation to Zeogrid structure. All materials were characterized using nitrogen adsorption isotherms, powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry, and time-resolved photoluminescence spectroscopy. A two europium species distribution with distinct luminescence spectra and lifetimes was found for both parent and silylated Zeogrid. In the parent Zeogrid, the short-lived europium species is characterized by the intensity ratio R=I(5D0-(7)F2)/I(5D0-(7)F1) or asymmetry values of approximately 0.4-0.7 and photoluminescence (PL) lifetimes of 110-125 micros and therefore is assigned to an almost fully hydrated europium species. In the silylated Zeogrid, the short-lived europium species is characterized by asymmetry values of 1.0-2.4 and lifetimes of 160-180 micros suggesting a relatively distorted europium environment. The long-lived europium species exhibits similar asymmetry ratios in the parent and silylated Zeogrid, which vary between 5.0 and 6.2 with increasing Si to Al ratio from 25 to 150 and slightly different PL lifetimes. The mechanism responsible for the intensity of the electric and magnetic forbidden 5D0-(7)F0 transition was determined to be J-mixing of the 7F2 into the 7F0 state through the axial second-order crystal-field potential. The comparison between the photoluminescence properties of europium in the parent and silylated Zeogrid demonstrates that the effects of rehydration were strongly suppressed following silylation.

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Comparative luminescence study of terbium-exchanged zeolites silylated with alkoxysilanes

Cited by 5 publications

References 14 publications

Rare Earth Activated Oxyfluoride Glasses and Glass-Ceramics for Scintillation Applications

Rare Earth Activated Oxyfluoride Glasses and Glass-Ceramics for Scintillation Applications

Cathodoluminescence of Terbium- and Ytterbium-Activated Oxyfluoride Glasses and Glass Ceramics

Europium(3+): An Efficient Luminescence Probe for the Si to Al Ratio and Silylation Effects in the Microporous−Mesoporous Zeogrid Materials

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