Dependence of luminescence properties on composition of rare-earth activated (oxy)nitrides phosphors for white-LEDs applications

Rare-earth-activated nitride and oxynitride phosphors are attractive converter materials for white-LEDs applications due to their efficient luminescent characteristics, high thermal and chemical stabilities because their basic crystal structure is built on rigid tetrahedral networks, either of the Si-(O,N) or Al-(O,N) type. Recent progress in fluorescence properties of silicon-aluminum-(oxy)nitride-based luminescent materials with broad excitation bands activated by Eu2+, Ce3+, and Yb2+ for phosphor-converted white-LEDs are reviewed in this article, with the emphasis on the dependence of luminescence properties on composition. We elaborate on these composition-dependent properties in three sections: (i) Eu2+-activated nitride and oxynitride phosphors; (ii) Ce3+-activated nitride and oxynitride phosphors; and (iii) Yb2+-doped alpha-SiAlON phosphor. Eu2+- or Ce3+-activated nitride and oxynitride phosphors are categorized into four parts following the structural and/or composition characteristics, i.e., alpha-SiAlON, beta-SiAlON, oxonitridosilicates, nitridoalumosilicates, and nitridosilicates. Some involving aspects for designing and the trends of research and development of these phosphors are addressed at the end of this article.