Structural correlation between Ba3Si6O12N2 and Ba3Si6O9N4 and the luminescent properties Eu2+ doped Ba3Si6O9N4

Powder samples of Ba 3 Si 6 O 12 N 2 and Ba 3 Si 6 O 9 N 4 were synthesized by solid state reaction method at 1300–1400 °C in H 2 /N 2 (6:94) reductive atmosphere. The structural correlations between the two phases were analyzed based on X-ray diffraction data and neutron diffraction data. The results indicate that Ba 3 Si 6 O 12 N 2 can be converted into Ba 3 Si 6 O 9 N 4 when three O 2− are replaced by two N 3− , meanwhile, one trigeminal N(SiO 3 ) 3 group of two in the unit cell is transformed into (SiO 2 N) 3 ring. The luminescent properties of Eu 2+ doped Ba 3 Si 6 O 9 N 4 were investigated. Ba 3 Si 6 O 9 N 4 :Eu 2+ gives wide excitation and emission spectra since the dopant occupy three different Ba sites. The phosphor shows green luminescence color with three emission peaks at 370 nm, 405 nm and 520 nm excited in the range of 210 nm–470 nm. Both luminescence spectra and decay curves indicate that in the Eu 2+ doped Ba 3 Si 6 O 9 N 4 , the energy transfer occurs from the luminescence centers for the shorter wavelength emissions (Eu1 at 370 nm and Eu2 at 405 nm) to the center for the longer wavelength emissions (Eu3 at 520 nm). The Eu 2+ doped sample has potential application in white LEDs.