Regensburg 2019 – scientific programme

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O: Fachverband Oberflächenphysik

O 11: Frontiers of Electronic-Structure Theory: Focus on the Interface Challenge II (joint session O/CPP/DS/TT)

O 11.9: Talk

Monday, April 1, 2019, 17:00–17:15, H9

Luminescence of β-SiAlON:Eu²⁺ phosphors: DFT study — •Saleem Ayaz Khan¹, Ondrej Sipr¹, Robin Niklaus², Wolfgang Schnick², and Jan Minar¹ — ¹University of West Bohemia, Pilsen, Czech Republic — ²LMU Munich, Germany

Highly efficient phosphor-converted light-emitting diodes (pc-LEDs)are popular in lighting and high-tech electronics applications[1]. Among them β-SiAlON:Eu²⁺ stands out as a promising narrow-band green phosphor for white-LEDs applications exhibiting good thermal and chemical stabilities. Photoluminescent properties of this material can be tuned by introducing the disorder at various sublattices. To understand the mechanism behind this effect, we performed a systematic study of electronic structure and photoluminescence properties of β-SiAlON:Eu²⁺. The calculations were done within the ab-initio fully relativistic full-potential framework. The disorder was treated by employing both the supercell approach and the coherent potential approximation (CPA). The Stokes shifts were calculated from differences of total energies of the ground and excited states of β-SiAlON:Eu²⁺. The main focus is on monitoring how the Al and O content and Eu²⁺ activator concentrations influence the local β-Si3N4 electronic structure and how this may be used to tune photoluminescence properties.

[1] Z. Wang, W. Ye, Iek-H. Chu, and S. P. Ong, Chem. Mater., 28, 8622 (2016).