On the relations between the bandgap, structure and composition of the M–Si–N (M = alkali, alkaline earth or rare-earth metal) nitridosilicates

Recent progress in Ce3+/Eu2+-activated LEDs and persistent phosphors: focusing on the local structure and the electronic structure

“…Since high chemical stability and minimal thermal degradation are the prerequisites for practical applications, it is revealed that a higher degree of cross-linking between Si(O,N) 4 tetrahedral enhances the chemical stability of M-Si-N compounds and the oxidation resistance of Ln-Si-O-N and Ce-Si-O compounds. 279,280 It has been demonstrated that the degradation stability of Sr 2 Si 5 N 8 :Eu 2+ can be enhanced by deposition of an ultra-thin Al 2 O 3 coating using atomic layer deposition in a fluidized bed reactor. 281 The PersL performance of M 2 Si 5 N 8 (M = Ca, Sr, Ba):Eu 2+ was first discovered in Ba 2 Si 5 N 8 :Eu 2+ , but its PersL duration is pretty short of about 15 min under the naked eye.…”

Synthesis, Crystal Structure, and Luminescence Properties of a White-Light-Emitting Nitride Phosphor, Ca0.99Eu0.01AlSi4N7

“…Xie et al have compiled emission maxima of Eu 2+ -doped nitrides and oxynitrides by adopting the empirical equation proposed by van Uitert with some parameters including the ionic sizes of the host ions and CNs . Recently, ten Kate et al studied the relationship between the band gap and degree of condensation (Si/N ratio) for nitridosilicates and revealed the relationships between the Si/N ratio or average Eu–N distance and crystal-field splitting and between the Si/N ratio or average Eu–N distance and Stokes shift of Eu 2+ -doped nitridosilicates Figure just plots the Eu 2+ 5d–4f emission wavelength against the Ca/Eu–N average distances for the Eu sites of Ca 0.99 Eu 0.01 AlSi 4 N 7 , as well as for the Ca–N and Sr–N average distances for the Eu 2+ -doped sites of the nitridosilicates Ca 2 Si 5 N 8 , Ca 16 Si 17 N 34 , CaAlSiN 3 , Ca 5 Al 2 Si 2 N 8 , , SrSi 6 N 8 , , Sr 0.31 Al 0.62 Si 11.38 N 16 , SrAlSiN 3 , α-SrAlSi 4 N 7 , β-SrAlSi 4 N 7 , and Sr 3 BAl 5 Si 9 N 20 .…”

Progress of M2Si5N8:Eu series in industrial LED phosphors

“…Then, the trapped electron is thermally released to the excited Eu 2+ -state, causing a delayed emission with the transition of 5d -4f. 54 When the Si/N ratio is increases, the structures consist of a network of interconnected SiN 4 tetrahedra through NSi 2 bonds (two-fold coordination), NSi 3 bonds (three-fold coordination), and even NSi 4 bonds (four-fold coordination) rather than SiN bonds (onefold coordination), which provides chemically stable host crystals. The degree of contribution of the interconnection to the stability of the host crystals follows the order of NSi 4 bonds 4 NSi 3 bonds 4 NSi 2 bonds 4 NSi bond.…”