Botterman, Jonas

Joos, Jonas

Poelman, Dirk

Smet, Philippe

English

Ghent University Academic Bibliography

Evaluation of a novel blue oxynitride conversion phosphor  Jonas Botterman, Jonas J. Joos, Dirk Poelman, Philippe F. Smet  LumiLab, Dept. of Solid State Sciences, Ghent University, Krijgslaan 281-S1, 9000 Gent Centre for Nano- and Biophotonics (NB Photonics), Ghent University, Gent   Solid state lighting (SSL) has proven to be the sole viable alternative to replace energy consuming incandescent or mercury based lighting technology. Light-emitting diodes or LEDs are gaining market share every day although improvements in color rendering and luminous efficacy are still desirable. In white LEDs, the intrinsically narrow emission band of the pumping diode is combined with one or multiple phosphor materials which convert a part of the pumping light into light of longer wavelengths. The different colors mix together, yielding white light. Blue phosphors are required for high color rendering white LEDs, in which they are combined with a near-ultraviolet pumping diode. The phosphors have to fulfill several requirements in order to be suitable for the application [1].  Oxonitridosilicates are well known host materials for conversion phosphors. Doped with divalent europium (Eu2+), they are able to convert light with very high conversion efficiencies, up to 90% [2]. Furthermore, this material class is chemically stable. The luminescence is driven by the parity allowed 4f65d1 → 4f7 transition in the optical dopant. In this work, a blue emitting phosphor, Sr0.25Ba0.75Si2O2N2:1%Eu2+ is considered. The crystallographic structure of this specific composition deviates from the structures of the well-known green and bluish green phosphors SrSi2O2N2:Eu2+ and BaSi2O2N2:Eu2+ [3]. First, emphasis is put on the synthesis process. Secondly, important physical properties like photoluminescence, thermal quenching, luminescent decay and quantum efficiency of this new material are evaluated. Thirdly, variations in chemical composition and its influence on the luminescence could be studied by means of cathodoluminescence spectroscopy inside a scanning electron microscope (SEM-CL), giving a deeper insight into the luminescent properties of the powders.  [1] P. F. Smet, A. B. Parmentier, D. Poelman, “Selecting conversion phosphors for white light-emitting diodes”, J. Electrochem. Soc. 3 (2011), R37-R54. [2] V. Bachmann, C. Ronda, O. Oeckler, W. Schnick, A. Meijerink, “Color Point Tuning for (Sr,Ca,Ba)Si2O2N2:Eu2+ for White Light LEDs”, Chem. Mater. 21 (2009), 316-325. [3] M. Seibald, T. Rosenthal, O. Oeckler, F. Fahrnbauer, A. Tücks, P. J. Smidt, W. Schnick, “Unexpected Luminescence Properties of Sr0.25Ba0.75Si2O2N2:Eu2+ - A Narrow Blue Emitting Oxonitridosilicate with Cation Ordering, Chem. Eur. J. 18 (2012), 13446-13452 

Evaluation of a novel blue oxynitride conversion phosphor

https://biblio.ugent.be/publication/4095695/file/4095721

Evaluation of a novel blue oxynitride conversion phosphor

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Ghent University Academic Bibliography