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

Abstract

We implement a solid-state reaction technique to make MAl_2−xSi_xO_4−xN_x (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)⁺ in MAl₂O₄. By replacing (AlO)⁺ with (SiN)⁺, whose solubility is dependent on M cations, nitrogen may be integrated into MAl₂O₄. (SiN)⁺ has poor solubility in CaAl₂O₄ (x ≈ 0.025) and SrAl2O4 lattices (x ≈ 0.045) but a considerable integrated quantity of (SiN)⁺ against BaAl₂O₄ (x ≈ 0.6). Because of the low solubility of (SiN)⁺, incorporation of (SiN)⁺ barely affects the luminescence characteristics of MAl₂O₄ when doped with Eu²⁺ (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)⁺ as well as Eu²⁺, Eu²⁺-doped BaAl_2−xSi_xO_4−xN_x 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_2−xSi_xO_4−xN_x: Eu²⁺ 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.