Synthesis of a Novel Bluish-Green Emitting Oxynitride Ca<sub>3</sub>Al<sub>8</sub>Si<sub>4</sub>O<sub>17</sub>N<sub>4</sub>:Eu<sup>2+</sup> Phosphor in a CaAl<sub>4-x</sub>Si<sub>x</sub>O<sub>7-x</sub>N<sub>x</sub> Solid Solution S

Abstract

Synthesis of oxynitride solid solutions CaAl 4−x Si x O 7−x N x :Eu 2+ (x = 0-4) was attempted by the solid state reaction (SSR) methods using Si 3 N 4 and AlN as nitrogen sources. The Ca 3 Al 8 Si 4 O 17 N 4 (x = 4/3) sample with the high phase purity was obtained when AlN was used as a nitrogen source whereas the sample synthesized using Si 3 N 4 as another nitrogen source contained a Ca 2 Al 2 SiO 7 impurity. Thus, it was revealed that AlN was a preferable nitrogen source for the synthesis of Ca 3 Al 8 Si 4 O 17 N 4 by the SSR method. The solid solutions around x = 4/3 activated with Eu 2+ exhibited bluish-green luminescence with emission maxima at 480 nm by the excitation at 250-450 nm. Thus, the CaAl 4-x Si x O 7-x N x : Eu 2+ solid solutions especially for Ca 3 Al 8 Si 4 O 17 N 4 :Eu 2+ (x = 4/3) were developed as novel Eu 2+-activated oxynitride phosphors capable of the excitation by the near ultraviolet (NUV) LEDs.

Photoluminescence and Thermoluminescence Properties of Eu²⁺ and Ce³⁺Activated BaAlSi₅O₂N₇ Phosphors

“…x Si x O 12-x N x :Ce [15], Y 5 Si 3 O 12 N:Ce 3+ [16],CaSi 2 O 2 N 2 :Tb 3+ [17], Al 5 O 6 N:Ce 3+ , Tb 3+ [18] , Ba 0.93 Eu 0.07 Al 2 O 4 [19], Eu,Si co-doped AlN [20], SiAlON [21] , Ca 3 Al 8 Si 4 O 17 N 4 :Eu 2+ [22]. Most importantly, these phosphors emit visible light efficiently under near-ultraviolet or blue light irradiation allowing them to be used as down-conversion luminescent materials for white lightemitting diodes (LEDs).…”