Phase relationships in the Sr-Si-O-N system

Wu, Zhu; Wang, P. L.; Sun, Weiying; Yan, D.S.

doi:10.1007/bf00592608

Cited by 19 publications

(21 citation statements)

References 9 publications

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“…This indicated that the starting phosphor materials were prone to the low temperature type of SrSi 2 O 2 N 2 when the sintered temperature was below 1550 °C, whereas the high temperature type of SrSi 2 O 2 N 2 was attained at a sintered temperature of above 1550 °C. This result is consistent with that reported in the literature [20]. This lower phase transformation temperature may be due to that NH 4 Cl has a decomposition reaction at a much lower temperature than that for the sample synthesis and could be flushed out of the system by the gas flow.…”

Section: Resultssupporting

confidence: 92%

Role of Fluxes in Optimizing the Optical Properties of Sr0.95Si2O2N2:0.05Eu2+ Green-Emitting Phosphor

et al. 2013

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Chlorides of NH4Cl and SrCl2 and fluorides of AlF3 and SrF2 were added to raw materials acting as the flux for preparing the SrSi2O2N2:Eu2+ phosphor. The effects of the fluxes on the phase formation, particle morphology, particle size, and photoluminescence properties were investigated. The results revealed that particle size, particle morphology and photoluminescence intensity were largely dominated by the type of the flux material and its adding amount. The chloride-based flux was found to favor the formation of the SrSi2O2N2:Eu2+ phase. Among the chloride-based fluxes, the sample added with the SrCl2 flux presented the narrow particle distribution and cleaner surface, with enhanced emission intensity and an increased external quantum efficiency by 68% and 22%, respectively, compared with those of the sample without any flux adding.

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Section: Resultssupporting

confidence: 92%

Role of Fluxes in Optimizing the Optical Properties of Sr0.95Si2O2N2:0.05Eu2+ Green-Emitting Phosphor

et al. 2013

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“…The XRD patterns of the SrSi 2 O 2 N 2 phases described in this paper show similarities to the pattern assigned to a high temperature (HT) phase of SrSi 2 O 2 N 2 in Ref. [19].…”

Section: Crystal Structuresupporting

confidence: 80%

Luminescence properties of SrSi2O2N2 doped with divalent rare earth ions

Bachmann

Jüstel

Meijerink

et al. 2006

Journal of Luminescence

222

158

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The optical properties of SrSi 2 O 2 N 2 doped with divalent Eu 2+ and Yb 2+ are investigated. The Eu 2+ doped material shows efficient green emission peaking at around 540 nm that is consistent with 4f 7 -4f 6 5d transitions of Eu 2+ . Due to the high quantum yield (90%) and high quenching temperature (4500 K) of luminescence, SrSi 2 O 2 N 2 :Eu 2+ is a promising material for application in phosphor conversion LEDs. The Yb 2+ luminescence is markedly different from Eu 2+ and is characterized by a larger Stokes shift and a lower quenching temperature. The anomalous luminescence properties are ascribed to impurity trapped exciton emission. Based on temperature and time dependent luminescence measurements, a schematic energy level diagram is derived for both Eu 2+ and Yb 2+ relative to the valence and conduction bands of the oxonitridosilicate host material. r

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“…It is probable that the reaction of nanocrystalline grains can occur at a lower temperature, leading to the appearance of the low-temperature phase. 43 However, a pure product of low-temperature phase cannot be obtained up to now. The low-temperature phase is probably harmful to luminescent properties but no such work has been reported before to the best of our knowledge.…”

Section: Resultsmentioning

confidence: 99%

Reaction Mechanism of SrSi2O2N2:Eu2+ Phosphor Prepared by a Direct Silicon Nitridation Method

Yang

Song

Yang

et al. 2010

Journal of the American Ceramic Society

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Highly efficient yellow-green-emitting SrSi 2 O 2 N 2 :0.02Eu 21 phosphor with a well-dispersed and uniform morphology was synthesized by a direct silicon nitridation method. The related synthesis parameters including soaking temperature, holding time, silicon source, gas species, and flow rate, have been studied, respectively, in terms of phase compositions and luminescent properties. The possible reaction mechanism was also proposed based on the results obtained. Silicon is assumed to be transported to the surface of decomposed SrO particles in the form of SiO or Si vapor, and nitridation reaction occurs here to form SrSi 2 O 2 N 2 :0.02Eu 21 phosphor directly. The particle size and morphology of phosphors obtained are controlled by the raw oxide materials instead of silicon. CO 2 from the decomposition of SrCO 3 plays an important role in the transportation of Si, which reacts with Si to form SiO vapor and introduces excessive oxygen into the phosphor obtained, resulting in an O/N ratio close to SrSi 2 O 2 N 2 . Direct silicon nitridation is proved to be a simple, cost-effective, facile, and potential morphology-controlling method to synthesize (oxo)nitridosilicate phosphors of excellent properties.

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Phase relationships in the Sr-Si-O-N system

Cited by 19 publications

References 9 publications

Role of Fluxes in Optimizing the Optical Properties of Sr0.95Si2O2N2:0.05Eu2+ Green-Emitting Phosphor

Role of Fluxes in Optimizing the Optical Properties of Sr0.95Si2O2N2:0.05Eu2+ Green-Emitting Phosphor

Luminescence properties of SrSi2O2N2 doped with divalent rare earth ions

Reaction Mechanism of SrSi2O2N2:Eu2+ Phosphor Prepared by a Direct Silicon Nitridation Method

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