Satoshi Shimooka

New Green Phosphor Ba3Si6O12N2:Eu for White LED: Crystal Structure and Optical Properties

A new oxynitride, Ba3Si6O12N2, has been synthesized. The crystal structure has been successfully determined by close collaboration between experiment and first-principles calculation. This compound doped with Eu exhibits intense green photoluminescence with high color purity under near-ultraviolet to blue light excitation; in particular, it has much less thermal quenching than (Ba,Sr,Eu)2SiO4. Thus (Ba,Eu)3Si6O12N2 appears promising green phosphor for white LED backlight for display. The atomic/electronic structure is discussed in comparison with Ba3Si6O9N4, which could not become efficient phosphor by doping Eu due to strong thermal quenching at room temperature.

New phosphors for white LEDs: Material Design Concepts

Efficient phosphors for white LEDs have been successfully developed, wherein some Material Design Concepts were utilized to promote our research and development effectively and efficiently. Useful ideas for the development of our red and green phosphors, Sr-rich (Sr,Ca,Eu)AlSiN3, (Ba,Eu)3Si6O12N2 and (Ca,Ce)3(Sc,Mg)2Si3O12, are reviewed.