Investigation of MAl2−xSixO4−xNx:Eu2+ phosphor for improving luminescence properties of white LEDs

Abstract

<span lang="EN-US">We implement a solid-state reaction technique to make MAl<sub>2−x</sub>Si<sub>x</sub>O<sub>4−x</sub>N<sub>x</sub> (M = Ca, Sr, Ba) as well as its variant doped with Eu at 1300 – 1400°C in a nitrogen hydrogen environment. Then, we measure the solubility of (SiN)<sup>+</sup> in MAl<sub>2</sub>O<sub>4</sub>. By replacing (AlO)<sup>+</sup> with (SiN)<sup>+</sup>, whose solubility is dependent on M cations, nitrogen may be integrated into MAl<sub>2</sub>O<sub>4</sub>. (SiN)<sup>+ </sup>has poor solubility in CaAl<sub>2</sub>O<sub>4 </sub>(x ≈ 0.025) and SrAl2O4 lattices (x ≈ 0.045) but a considerable integrated quantity of (SiN)<sup>+ </sup>against BaAl<sub>2</sub>O<sub>4</sub> (x ≈ 0.6). Because of the low solubility of (SiN)<sup>+</sup>, incorporation of (SiN)<sup>+ </sup>barely affects the luminescence characteristics of MAl<sub>2</sub>O<sub>4</sub> when doped with Eu<sup>2+</sup> (M = Ca, Sr), resulting in discharges in green as well as blue at nearly constant wavelengths measured at 440 as well as 515 nm, respectively. With certain concentrations of (SiN)<sup>+ </sup>as well as Eu<sup>2+</sup>, Eu<sup>2+</sup>-doped BaAl<sub>2−x</sub>Si<sub>x</sub>O<sub>4−x</sub>N<sub>x</sub> emits one wide green discharge line under a maximum within the region 500 – 526 nm. Furthermore, once we add nitrogen, both the excitation as well as discharge lines for Eu2+ exhibit one substantial redshift. BaAl<sub>2−x</sub>Si<sub>x</sub>O<sub>4−x</sub>N<sub>x</sub>: Eu<sup>2+ </sup>is a compelling transmuting phosphor that can be utilized for WLED devices because of its efficient stimulation in the range of 390–440 nm radiation.</span>