Photoluminescence properties of rare earth doped α-Si3N4

Dopant Concentration Induced Optical Changes in Ca,Eu-α-Sialon

“…This effect could be expected since the ionic radius of Eu 2+ (1.2 Å) is larger than that of Ca 2+ in 7-fold coordination (1.06 Å) [50]. However, previous works indicated that the size of M(II) in α-sialon solid solution does not affect the lattice parameters since the radius of the cage in the parent α-Si 3 N 4 crystal structure (~2.8 Å) is large enough to accommodate optical activator [22]. The unexpected reduction of the unit cell volume after introducing more than 6 mol % of Eu could be related to formation of Si 4+ vacancies (higher amount of AlN) or to the shift of α-sialon chemical composition into the nitrogen rich corner.…”

A novel polymer-derived method to prepare Eu-doped Si3N4 yellow phosphor

“…Among them, Eu-doped nitridosilicate phosphors such as the redemitting M 2 Si 2 N 8 :Eu 2 þ (M¼ Ca, Sr, Ba) [1,2] and yellowemitting Si 3 N 4 (α and β):Eu 2 þ [3], blue-emitting α-Si 3 N 4 :Eu 2 þ [4], and green-emitting β-sialon:Eu 2 þ [5] have shown great prospects with a broad excitation and emission in UV-Visible spectral region. However, the conventional methods to prepare Eu-doped nitridosilicate phosphors commonly start from Eu nitrides/oxides and silicon nitrides as raw materials.…”

“…For instance, the doping from Eu nitrides required the reaction of Eu(NH 2 ) 2 obtained by dissolution of Eu in supercritical ammonia (NH 3 ) at 150 1C and 300 bar pressure with Si(NH) 2 precursor prepared separately [1]. In the case of doping from Eu oxides, the mixture of Eu 2 O 3 and α-Si 3 N 4 powders was wet milled with high purity Si 3 N 4 balls in anhydrous ethanol for 12 h [3] or the mixed powders were placed into a BN crucible and fired at 1600 1C for 5 h under N 2 -H 2 (5%) atmosphere [4]. The low efficient Eu doping by a solid-state reaction also made the preparation method very complex.…”

Synthesis and photoluminescence of a novel Sr-SiAlON:Eu2+ blue-green phosphor (Sr14Si68−sAl6+sOsN106−s:Eu2+ (s≈7))

“…Typical examples are red-emitting M 2 Si 5 N 8 :Eu 2+ (M = Ca, Sr, and Ba) [5,6], CaAlSiN 3 :Eu 2+ [7,8], Sr x Ca 1−x AlSiN 3 :Eu 2+ [9], orange-red SrSiAl 4 N 7 :Eu 2+ [10], yellowemitting Ca-␣-SiAlON:Eu 2+ [11][12][13][14], Ba 2 AlSi 5 N 9 :Eu 2+ [15] and Ce-melilite [16], green-emitting ␤-SiAlON:Eu 2+ [17], and blue emitting BaSi 7 N 10 :Eu 2+ [18], BaSi 6 N 8 O:Eu 2+ [19], and ␣-Si 3 N 4 :Eu 2+ [20]. Among these (oxy)nitride luminescence materials, ␤-SiAlON:Eu 2+ phosphor has a strong absorption in the range of UV to blue * Corresponding author.…”