Dependence of Phase Composition and Luminescence of Sr[sub 6]BP[sub 5]O[sub 20] on Eu Concentration

Laubach, Sonja; Mishra, K. C.; Hofmann, Kathrin; Albert, Barbara; Larsen, Patrick; Wickleder, Claudia; McSweeney, Robert T.; Schmidt, Peter

doi:10.1149/1.2919561

Cited by 4 publications

(3 citation statements)

References 11 publications

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“…First, the electrons are available from the matrix or synthetic atmosphere to enable the reduction from Eu 3+ to Eu 2+ ; second, the matrix should have a capability to offer a stable lattice environment for the Eu 2+ . Therefore it is considered that the special structure [ ] tetrahedral unit in silicate glasses, and form three-dimensional network which plays an important role in the stability of rare earth ions [13,14] . When the ratio of B/P exceeds 1.4, however, the glass structure tends to deviate from the suitable structure, resulting in a decrease in the intensity of blue emission.…”

Section: Fig1 Pl Spectra Of the Glass Samples With Different Glass Cmentioning

confidence: 99%

“…As to where the Eu ions exist in the multiphase and multi-component system of borophosphate glass ceramics, we propose that the Eu ions in the glass-ceramics can exist in the sites of the glassy phase, the sites inside the nanocrystals and the sites localized at the interface between the crystal particles and the glassy phase [13][14][15][16][17] . With the amount of B 2 O 3 increases, the amount of Sr(PO 3 ) 2 crystal increases, which indicates the increase of Eu 2+ to substitute the more sites of Sr 2+ in the crystalline phase to intensify the blue emission.…”

Section: Fig4 Pl Spectra Of Blue-light and Red-light Borophosphate Gmentioning

confidence: 99%

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Composition-induced valence variation of europium and the photoluminescence properties for Eu2+ doped borophosphate luminous glass in air

Qiu

Tian

et al. 2011

Optoelectron. Lett.

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A simultaneous blue-light and red-light emitting glass of SrO-B 2 O 3 -P 2 O 5 doped with Eu 2 O 3 is prepared in air, and then heat-treated without any reductive reagent. A transition combination is found to consist of a band emission peaked around 430 nm and a series of line emission from 593 nm to 611 nm, corresponding to the typical 4f 6 5d 4f 7 transition of Eu 2+ and 5 D 0 7 F J (J = 0, 1, 2, 3, 4) transitions of Eu 3+ , respectively. Some unidentified crystals such as Sr (PO 3 ) 2 and SrB 2 O 4 as hosts for Eu 2+ with more stronger crystal field lead to this enhancement of photoluminescence (PL) intensity superior to the asprepared parent glass.Luminous glass and glass-ceramics doped with rare earth (RE) ions have drawn much interest in a lot of applications. The borophosphate glasses doped with Eu 2+ can be applied in packaging light emitting diodes (LEDs) using GaN or InGaN chip [1,2] . Generally, a suitable reduction atmosphere of H 2 , H 2 /N 2 or CO is needed to obtain the broad band emission materials doped with the low valence stat REs.Fortunately, an abnormal phenomenon of low valence state of REs stabilized by some hosts has been widely observed in the absence of any reduction atmosphere [3][4][5][6][7] , But little attention is paid to the effect of crystallization on the photoluminescence (PL) in the variarle composition.As regards the rare-earth Eu doped SrO-B 2 O 3 -P 2 O 5 borophosphate glass prepared in air, we also observed abnormal valence state of Eu 2+ . We will concentrate our contents on the effect of crystallization on the PL of this glass ceramics with variable composition in comparison with the parent glass.The rare earth doped Sr-B-P-O glass samples are prepared by melting a mixture of high-purity oxides or salts including SrCO 3 , NH

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Section: Fig1 Pl Spectra Of the Glass Samples With Different Glass Cmentioning

confidence: 99%

Section: Fig4 Pl Spectra Of Blue-light and Red-light Borophosphate Gmentioning

confidence: 99%

Composition-induced valence variation of europium and the photoluminescence properties for Eu2+ doped borophosphate luminous glass in air

Qiu

Tian

et al. 2011

Optoelectron. Lett.

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“…For example, EuCaAl 3 O 7 appears as a secondary phase at above 6 mol % of the Eu 2+ concentration in the CaAl 2 O 4 :Eu 2+ phosphor synthesis using Eu 2 O 3 even in a reducing atmosphere. 14 Laubach et al 15 also reported that Sr 3 Eu͑PO 4 ͒ 3 , as well as SrBPO 5 and Sr 2 P 2 O 7 , are formed as a secondary phase at above 2 mol % of the Eu 2+ concentration in the Sr 6 BP 5 O 20 :Eu 2+ phosphor synthesis using Eu 2 O 3 . These reports suggest that the influence of the increased oxygen content by using Eu 2 O 3 on the phosphor synthesis cannot be negligible at the high Eu concentration range.…”

mentioning

confidence: 97%

Effect of Oxygen Content in Raw Materials on the Synthesis of a Single-Phase EuSi[sub 2]O[sub 2]N[sub 2]

Yun

Horikawa

Hanzawa

et al. 2010

J. Electrochem. Soc.

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The formation behavior of EuSi 2 O 2 N 2 prepared with various starting compositions and different methods from the Eu 2 O 3 -SiO 2 -Si 3 N 4 -Si system was investigated to demonstrate the effect of the oxygen content in raw materials on the synthesis of MSi 2 O 2 N 2 :Eu 2+ ͑M = Ca, Sr, Ba͒ phosphors for white light-emitting diodes. It was found that Eu 2 O 3 cannot be reduced by H 2 gas but can be reduced by a reaction with Si 3 N 4 in the synthesis process of EuSi 2 O 2 N 2 ; as a result, EuSi 2 O 2 N 2 was not obtained from the starting composition containing the excess oxygen content such as 1/2Eu 2 O 3 − 1/2SiO 2 − 1/2Si 3 N 4 even in H 2 gas flow because the extra oxygen causes the formation of secondary phases. A nearly single-phase EuSi 2 O 2 N 2 was obtained from the starting composition having a stoichiometric oxygen amount. The present study indicates that the extra oxygen induced by the use of Eu 2 O 3 should be controlled to synthesize MSi 2 O 2 N 2 :Eu 2+ phosphors as a single phase when Eu 2 O 3 is used as the Eu source material.White light-emitting diodes ͑LEDs͒ have recently been widespread as a solid-state lighting source for general illumination instead of mercury-containing fluorescent lamps owing to their low energy consumption, long lifetime, small size, and a mercury-free structure. 1,2 For practical applications as general illumination, white LEDs, having a high color-rendering index as well as a high luminous efficiency, have to be realized. General white LEDs are fabricated by the combination of phosphors with blue LEDs or UV LEDs. In either case, the development of suitable phosphors is essential.MSi 2 O 2 N 2 :Eu 2+ ͑M = Ca, Sr, Ba͒ oxynitride compounds have attracted attention as promising phosphors for white LEDs due to their excellent luminescence properties and chemical stability. [3][4][5] The emission color of the MSi 2 O 2 N 2 :Eu 2+ phosphor can be tuned by the incorporation of different M 2+ cations into the M 2+ ion site and by changing the concentrations of Eu 2+ , which can make it possible to produce high color-rendering white LEDs. [6][7][8] These phosphors are expected to have a small concentration quenching of the Eu 2+ emission due to their layered crystal structure in which the probability of energy migration between twodimensionally arranged Eu 2+ ions can be suppressed to a low level. 6,[9][10][11] However, with increasing concentrations of Eu 2+ , secondary phases are easily formed and the single phase of MSi 2 O 2 N 2 :Eu 2+ phosphors become hard to be formed. [6][7][8]12,13 For the SrSi 2 O 2 N 2 :Eu 2+ phosphor, Bachmann et al. 8 and Song et al. 12 concluded that the concentration quenching of Eu 2+ emission occurs at around 2 mol % from the observation of the luminescence decay times and quantum efficiency with varying concentrations of Eu 2+ . In addition, Wang et al. 13 reported that the critical quenching concentration of Eu 2+ in CaSi 2 O 2 N 2 :Eu 2+ phosphor is 8 mol %. However, they did not check the influence of the phase purity and crystallinity of ...

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Cyan emission of phosphor Sr6BP5O20:Eu2+ under low-voltage cathode ray excitation

Hou

Xie

et al. 2014

Journal of Luminescence

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Dependence of Phase Composition and Luminescence of Sr[sub 6]BP[sub 5]O[sub 20] on Eu Concentration

Cited by 4 publications

References 11 publications

Composition-induced valence variation of europium and the photoluminescence properties for Eu2+ doped borophosphate luminous glass in air

Composition-induced valence variation of europium and the photoluminescence properties for Eu2+ doped borophosphate luminous glass in air

Effect of Oxygen Content in Raw Materials on the Synthesis of a Single-Phase EuSi[sub 2]O[sub 2]N[sub 2]

Cyan emission of phosphor Sr6BP5O20:Eu2+ under low-voltage cathode ray excitation

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