Structure elucidation of luminescent centers in green emitting Eu2+ doped Si6-zAlzOzN8-z phosphors

Eu2+ doped Si6-zAlzOzN8-z (β-sialon) is a common green emitting phosphor used in white light emitting diodes. Due to its narrowband emission, a wide color gamut is realized in the liquid crystal display. Despite its importance in commercialized phosphors, the position of the luminescent center Eu2+ in the β-sialon crystal structure is not fully clarified. Herein we elucidate the position of the luminescent center Eu2+ by the single crystal X-ray diffraction technique. Eu is positioned at the interstitial site of (0, 0, 1/4) of the β-sialon crystal structure and coordinated by nine anions. Structural and elemental analyses show that almost all of the incorporated Eu are situated at the interstitial channel position.