Synthesis, crystal structure, and luminescence properties of a new nitride polymorph, β-Sr0.98Eu0.02AlSi4N7

Synthesis, Crystal Structure, and Photoluminescence of the Boron–Aluminum–Silicon Nitride Phosphor Sr3BAl5Si9N20:Eu

“…As shown in Figure , the emission peak wavelengths decrease with increasing volume and Sr-site-number-weighted average volumes of the N polyhedra, which is consistent with the emission wavelength shift explained by the crystal-field theory . The wavelength (565 nm) and average volume of N polyhedra (46.8 Å 3 ) for Sr 3 BAl 5 Si 9 N 20 are between 541 and 583 nm and between 47.3 and 43.3 Å 3 reported for β-SrAlSi 4 N 7 :Eu and Sr 0.31 Al 0.62 Si 11.38 N 16 :Eu, respectively, while the coordination numbers of all Sr sites in the structures of these nitrides are 10. The combination of the B–N 3 triangles and (Al,Si)–N 4 tetrahedra in the framework of Eu 2+ -doped Sr 3 BAl 5 Si 9 N 20 may have realized N coordination environments around the Sr/Eu 2+ atoms, with the volumes of the N polyhedra appropriate for the yellow emission with the unique wavelength.…”

“…The ranges and averages of the Sr–N distances and the volumes of Sr-centered N polyhedra for Sr 3 BAl 5 Si 9 N 20 and previously reported strontium silicon nitrides (SrSiN 2 , Sr 2 Si 5 N 8 , and SrSi 6 N 8 ) and strontium aluminum silicon nitrides (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 Al 6 Si 24 N 40 ), as well as emission peak wavelengths for 1–3% Eu 2+ -doped ones, − are summarized in Table S5. The volumes of the N polyhedra were calculated based on the reported coordination numbers.…”

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

“…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 . The average distances of these nitridosilicates were calculated with the CNs determined in the same manner as those shown in Figure (Figures S5 and S6).…”

“…Recently, we synthesized a sample containing single crystals of the previously known orthorhombic SrAlSi 4 N 7 (α phase) as a main phase at 2030 °C and a nitrogen gas pressure of 0.85 MPa by adding Mg 3 N 2 to a starting mixture of binary nitrides and found a new polymorph of SrAlSi 4 N 7 (β phase) single crystals on and near the surface of the product. 38 β-SrAlSi 4 N 7 crystallized in a monoclinic cell [a = 8.1062(1) Å, b = 9.0953(1) Å, c = 8.9802(1) Å, β = 111.6550(5)°, and space group P2 1 ]. The β phase did not appear without Mg 3 N 2 in the starting mixture, while magnesium was completely evaporated from the sample during heating and was not included in the product.…”