Real structure and diffuse scattering of Sr0.5Ba0.5Si2O2N2:Eu2+ - A highly efficient yellow phosphor for pc-LEDs

Seibald, Markus; Celinski, Vinicius R.; Schmidt, Peter J.; Tücks, Andreas; Schnick, Wolfgang

doi:10.1016/j.solidstatesciences.2011.07.006

Cited by 35 publications

(49 citation statements)

References 32 publications

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“…A clear difference in the diffraction patterns is observed for those recorded from the rGO (edges) as well as from the phosphor regions (inner region) of the rGO wrapped phosphor particles. The SAED pattern recorded from the inner regions correspond to the phosphor21 while the SAED pattern recorded from edges correspond to rGO222324.…”

Section: Resultsmentioning

confidence: 99%

Reduced graphene oxide enwrapped phosphors for long-term thermally stable phosphor converted white light emitting diodes

Anoop

Rani

Lim

et al. 2016

Sci Rep

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The long-term instability of the presently available best commercial phosphor-converted light-emitting diodes (pcLEDs) is the most serious obstacle for the realization of low-cost and energy-saving lighting applications. Emission from pcLEDs starts to degrade after approximately 200 h of operation because of thermal degradation of the phosphors. We propose a new strategy to overcome this thermal degradation problem of phosphors by wrapping the phosphor particles with reduced graphene oxide (rGO). Through the rGO wrapping, we have succeeded in controlling the thermal degradation of phosphors and improving the stability of fabricated pcLEDs. We have fabricated pcLEDs with long-term stability that maintain nearly 98% of their initial luminescence emission intensity even after 800 h of continuous operation at 85 °C and 85% relative humidity. The pcLEDs fabricated using SrBaSi2O2N2:Eu2+ phosphor particles wrapped with reduced graphene oxide are thermally stable because of enhanced heat dissipation that prevents the ionization of Eu2+ to Eu3+. We believe that this technique can be applied to other rare-earth doped phosphors for the realization of highly efficient and stable white LEDs.

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Section: Resultsmentioning

confidence: 99%

Reduced graphene oxide enwrapped phosphors for long-term thermally stable phosphor converted white light emitting diodes

Anoop

Rani

Lim

et al. 2016

Sci Rep

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“…In order to emit light in the visible region of electromagnetic spectrum, synthesized phosphors have to absorb in near UV to blue spectral range thereby limiting the activators to Eu 2+ and Ce 3+ that can be used in phosphors. Among these silicon oxynitrides, Eu doped MSi 2 O 2 N 2 (M = Sr, Ba, Ca) is found to be excellent candidates owing to better thermal and chemical stability with a broad absorption band spanning from UV to blue region of the electromagnetic spectrum 13–21. SrSi 2 O 2 N 2 is isotypic with EuSi 2 O 2 N 2 and crystallizes in triclinic structure and has P1(1) space group symmetry 13.…”

Section: Introductionmentioning

confidence: 99%

Luminescence characteristics of Sr_1−xBa_xSi₂O₂N₂:Eu²⁺ phosphors for white light emitting diodes

Anoop

Cho

Suh

et al. 2012

Physica Status Solidi (a)

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Sr1−xBaxSi2O2N2:Eu2+ phosphors were synthesized using high temperature solid state reaction. The effect of Ba incorporation on the structural and luminescence characteristics of SrSi2O2N2:Eu2+ phosphors were studied. The phosphors were crystallized in triclinic crystal structure and the cell volume increases monotonically with Ba addition. The PL emission peak wavelength red shifts with Ba up to x = 0.50 beyond which no red shift is observed. The XPS analysis shows that nitrogen is being incorporated into the host lattice along with Ba addition up to x = 0.50. The as synthesized phosphors show high thermal stability. Phosphor converted light emitting diodes were realized using Sr1−xBaxSi2O2N2:Eu2+ phosphors (x = 0 and x = 0.40) showing luminance efficacies of 108 and 101 lm W−1. The CIE chromaticity coordinates of Sr1−xBaxSi2O2N2:Eu (x = 0 and x = 0.40) phosphors.

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“…Reported structural data for α and β SrSi 2 O 2 N 2 phases 15,18,33,39,[43][44][45] are quoted in Table II. Equation of state describes fundamental physicochemical properties of a substance.…”

Section: Introductionmentioning

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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Real structure and diffuse scattering of Sr0.5Ba0.5Si2O2N2:Eu2+ - A highly efficient yellow phosphor for pc-LEDs

Cited by 35 publications

References 32 publications

Reduced graphene oxide enwrapped phosphors for long-term thermally stable phosphor converted white light emitting diodes

Reduced graphene oxide enwrapped phosphors for long-term thermally stable phosphor converted white light emitting diodes

Luminescence characteristics of Sr_1−xBa_xSi₂O₂N₂:Eu²⁺ phosphors for white light emitting diodes

Equation of state for Eu-doped SrSi2O2N2

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Real structure and diffuse scattering of Sr0.5Ba0.5Si2O2N2:Eu2+ - A highly efficient yellow phosphor for pc-LEDs

Cited by 35 publications

References 32 publications

Reduced graphene oxide enwrapped phosphors for long-term thermally stable phosphor converted white light emitting diodes

Reduced graphene oxide enwrapped phosphors for long-term thermally stable phosphor converted white light emitting diodes

Luminescence characteristics of Sr1−xBaxSi2O2N2:Eu2+ phosphors for white light emitting diodes

Equation of state for Eu-doped SrSi2O2N2

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Luminescence characteristics of Sr_1−xBa_xSi₂O₂N₂:Eu²⁺ phosphors for white light emitting diodes