Highly Efficient pc-LED Phosphors Sr1-xBaxSi2O2N2:Eu2+(0 x 1) - Crystal Structures and Luminescence Properties Revisited

Seibald, Markus; Rosenthal, Tobias; Oeckler, Oliver; Schnick, Wolfgang

doi:10.1080/10408436.2013.863175

Cited by 58 publications

(61 citation statements)

References 88 publications

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“…This is no surprise since it was shown by Seibald et al by a combination of TEM/ HRTEM/TEM-EDX that a domain structure is present at a nanometer length scale, impossible to resolve with SEM-EDX. The yellow emission is originating from domains with a Sr-richer content, composed of the SrSi 2 O 2 N 2 structure [14,19].…”

Section: Sem-edx-clmentioning

confidence: 99%

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Evaluating the use of blue phosphors in white LEDs: the case of Sr0.25Ba0.75Si2O2N2:Eu2+

2014

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The luminescence properties of the blue emitting phosphor Sr 0.25 Ba 0.75 Si 2 O 2 N 2 :Eu 2+ are extensively investigated. This oxonitridosilicate phosphor features strong 4f 6 5d 1 -4f 7 luminescence originating from the Eu 2+ ion, with a narrow emission band peaking at 467 nm and a full width at half maximum of only 41 nm. Thermal quenching of the blue luminescence only sets in above 450 K, making this material an interesting candidate as LED conversion phosphor. The fast decay of the luminescence prevents the phosphor to be susceptible to saturation effects at high excitation fluxes. Furthermore it is proven to be chemically stable against moisture. The only drawback is the relatively low quantum efficiency of the synthesized powder, provisionally preventing this material to be used in applications. In addition, the phosphor features a weak yellow emission band, originating from small domains featuring a different crystal structure. It is shown that the majority of the powder grains only exhibit blue emission. Finally, the spectrum of a white LED, based on a UV pumping LED and three (oxy)nitride phosphors is simulated in order to assess the usefulness of blue phosphors in LEDs for lighting. Only a marginal improvement in terms of color quality can be achieved with a narrow banded phosphor, at the expense of a decrease in luminous efficacy and overall electrical to optical power efficiency.

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Section: Sem-edx-clmentioning

confidence: 99%

“…The MSi 2 O 2 N 2 :Eu 2+ (M = Ca, Sr, Ba) system has already been the subject of extensive and detailed studies [7][8][9][10][11][12][13][14]. All three basic compounds (i.e.…”

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confidence: 99%

Evaluating the use of blue phosphors in white LEDs: the case of Sr0.25Ba0.75Si2O2N2:Eu2+

2014

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“…The dashed line shows, based on points reported by different groups (Refs. 15,17,33,45,39, and this work), that the volume does not vary with Eu substitution. The scatter of the experimental points (especially that for Ce and Yb points added to the figure) can be attributed to differences in technology leading to compositional differences (such as a deviation in N/(N+O) ratio).…”

Section: A Phase Analysis and Rietveld Refinementmentioning

confidence: 90%

“…• (hkl = 110, intensity of 0.3%), 17 those of the α phase. Judging after the intensity of the −102 reflection, the amount of β phase is here distinctly smaller than in the sample studied in Ref.…”

Section: A Phase Analysis and Rietveld Refinementmentioning

confidence: 99%

Equation of state for Eu-doped SrSi2O2N2

Ermakova

Paszkowicz

Kamińska

et al. 2014

The Journal of Chemical Physics

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α-SrSi2O2N2 is one of the recently studied oxonitridosilicates applicable in optoelectronics, in particular in white LEDs. Its elastic properties remain unknown. A survey of literature shows that, up to now, nine oxonitridosilicate materials have been identified. For most of these compounds, doped with rare earths and manganese, a luminescence has been reported at a wavelength characteristic for the given material; all together cover a broad spectral range. The present study focuses on the elastic properties of one of these oxonitridosilicates, the Eu-doped triclinic α-SrSi2O2N2. High-pressure powder diffraction experiments are used in order to experimentally determine, for the first time, the equation of state of this compound. The in situ experiment was performed for pressures ranging up to 9.65 GPa, for Eu-doped α-SrSi2O2N2 sample mounted in a diamond anvil cell ascertaining the hydrostatic compression conditions. The obtained experimental variation of volume of the triclinic unit cell of α-SrSi2O2N2:Eu with rising pressure served for determination of the Birch-Murnaghan equation of state. The determined above quoted bulk modulus is 103(5) GPa, its first derivative is 4.5(1.1). The above quoted bulk modulus value is found to be comparable to that of earlier reported oxynitrides of different composition.

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“…5). As the BaSi 2 O 2 N 2 host can form domains with different stacking order for the silicate layers [39,63,64], it is not unlikely that the size of the codopants incorporated into the material can influence the crystallographic structure. As a consequence, the defect structure can change, affecting the number and depth of traps.…”

Section: Overview Of Oxynitride Phosphorsmentioning

confidence: 99%

Persistent luminescence in nitride and oxynitride phosphors: A review

et al. 2014

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The research field of persistent luminescence has experienced a strong growth in the past two decades, with a steady development of new materials and applications. Here we give an overview of the recent progress in a specific class of host materials, namely oxynitride and nitride persistent phosphors. These are interesting hosts to explore because of their unique characteristics, such as chemical stability and tunability of the emission over the entire visible range upon doping with divalent europium. To yield persistent luminescence however, codopants have to be added or the synthesis conditions have to be adjusted. Specific materials, such as Ca 2 Si 5 N 8 :Eu,Tm and BaSi 2 O 2 N 2 :Eu, are highlighted and their properties are put into the context of emerging applications such as in vivo imaging and pressure sensing via mechanoluminescence. Finally, directions for future research are given.

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Highly Efficient pc-LED Phosphors Sr_1-xBa_xSi₂O₂N₂:Eu²⁺(0 x 1) - Crystal Structures and Luminescence Properties Revisited

Cited by 58 publications

References 88 publications

Evaluating the use of blue phosphors in white LEDs: the case of Sr0.25Ba0.75Si2O2N2:Eu2+

Evaluating the use of blue phosphors in white LEDs: the case of Sr0.25Ba0.75Si2O2N2:Eu2+

Equation of state for Eu-doped SrSi2O2N2

Persistent luminescence in nitride and oxynitride phosphors: A review

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