The effect of flux addition to Eu2+-doped Ca-α-SiAlON phosphor

Abstract

A yellow-emitting Eu2+-doped Ca-α-SiAlON phosphor is a promising candidate to make white LEDs by combining with blue LED. In the current research, the effect of flux (NH4Cl or NH4F) addition on the Ca-α-SiAlON:Eu2+ phosphor was investigated. The formation of both the compound and liquid phase between the flux and raw materials resulted in the decreased photoluminescence (PL) intensity in the early stage. However, the subsequent melting of second phases and retarded crystallization enhanced the PL intensity with increasing the synthesis temperature and time. The increased PL intensity for the flux-added compositions is attributed to the less surface damages due to grinding of as-synthesized agglomerate-like phosphors. Further, the flux addition enhanced the particle growth by forming agglomerates in the early stage and it also influenced the particle morphology from the typical acicular shape to pseudo-equiaxed shape. © 2013 The Ceramic Society of Japan. All rights reserved.