Photoluminescence of Rare‐Earth‐Doped Ca‐α‐SiAlON Phosphors: Composition and Concentration Dependence

Rare‐earth‐doped Ca‐α‐SiAlON phosphors, with the compositions of (Ca 1−3/2 x RE x ) m /2 Si 12− m − n Al m+n O n N 16− n (RE=Ce, Sm, and Dy, 0.5≤ m =2 n ≤3.0), were prepared by sintering at 1700°C for 2 h under 10 atm N 2 . The concentration of rare earths varied from 3 to 30 at.% with respect to Ca. The photoluminescence (PL) properties were investigated as functions of the composition of the host matrix (i.e., m ) and the concentration of rare earths (i.e., x ). The results show that the emission properties can be optimized by tailoring m and x . The Ce 3+ luminescence originating from the 4 f –5 d interconfigurational transitions is greatly affected by the environment surrounding the Ce 3+ ions, which differs from the Sm 3+ or Dy 3+ luminescence arising from the 4 f –4 f intraconfigurational transitions. X‐ray diffraction and scanning electron microscopy were used to explain the composition and concentration dependence of PL properties.