YAG glass-ceramic phosphor for white LED (II): luminescence characteristics

Setsuhisa Tanabe; Shunsuke Fujita; Satoru Yoshihara; Akihiko Sakamoto; Shigeru Yamamoto

doi:10.1117/12.614681

13 September 2005 YAG glass-ceramic phosphor for white LED (II): luminescence characteristics

Setsuhisa Tanabe, Shunsuke Fujita, Satoru Yoshihara, Akihiko Sakamoto, Shigeru Yamamoto

Proceedings Volume 5941, Fifth International Conference on Solid State Lighting; 594112 (2005) https://doi.org/10.1117/12.614681
Event: Optics and Photonics 2005, 2005, San Diego, California, United States

Abstract

Optical properties of the Ce:YAG glass-ceramic (GC) phosphor for the white LED were investigated. Concentration dependence of fluorescence intensity of Ce³⁺:5d→4f transition in the GC showed a maximum at 0.5mol%Ce₂O₃. Quantum efficiency (QE) of Ce³⁺ fluorescence in the GC materials, the color coordinate and luminous flux of electroluminescence of LED composite were evaluated with an integrating sphere. QE increased with increasing ceramming temperature of the as-made glass. The color coordinates (x,y) of the composite were increased with increasing thickness of the GC mounted on a blue LED chip. The effect of Gd₂O₃ substitution on the optical properties of the GC materials was also investigated. The excitation and emission wavelength shifted to longer side up to Gd/(Y+Gd)=0.40 in molar composition. As a result, the color coordinate locus of the LED with various thickness of the GdYAG-GC shifted to closer to the Planckian locus for the blackbody radiation. These results were explained by partial substitution of Gd³⁺ ions in the precipitated YAG micro-crystals, leading to the increase of lattice constant of unit cell, which was confirmed by X-ray diffraction.

Citation Download Citation

Setsuhisa Tanabe, Shunsuke Fujita, Satoru Yoshihara, Akihiko Sakamoto, and Shigeru Yamamoto "YAG glass-ceramic phosphor for white LED (II): luminescence characteristics", Proc. SPIE 5941, Fifth International Conference on Solid State Lighting, 594112 (13 September 2005); https://doi.org/10.1117/12.614681

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