Electronic and Luminescence Properties of LiSiON: Eu2+, Eu2+/Mn2+ as a Potential Phosphor for UV-Based White LEDs

LiSiON:Eu2+, Eu2+/Mn2+ phosphors with compositions of Li1-2x-2yEuxMnySiON (x = 0-0.006, y = 0-0.006) were successfully fabricated using Li4-2x-2ySiO4:xEu(2+), yMn(2+) and Si3N4 as starting materials. The crystal and electronic structures, as well as the luminescence properties of Li1-2x-2ySiON:xEu(2+), yMn(2+) were reported. First-principles calculations indicated that LiSiON host was an insulator with indirect band gap about 5.4 eV, which was in good agreement with the experimental data obtained from the diffuse reflection spectrum. The value of x in Li1-2xEuxSiON gave rise to obvious differences in the emission profiles and peak wavelength which might result from the different crystal environments around Eu2+ ions. The mechanism of energy transfer from a sensitizer Eu2+ ion to an activator Mn2+ ion in LiSiON:Eu2+, Mn2+ phosphors were demonstrated to be electric dipole-quadrupole interaction. The emission hue of Li1-2x-2ySiON:xEu(2+), yMn(2+) varied from blue (0.232, 0.296) (x = 0.001, y = 0) to white-light (0.329, 0.316) (x = 0.001, y = 0.004) by tuning the Eu2+/Mn2+ ratio. Preliminary studies showed that the LiSiON: Eu2+, Eu2+/Mn2+ might be a promising white-light-emitting phosphor for ultraviolet (UV) based white Light Emitting Diodes (LEDs). (C) 2012 The Electrochemical Society. All rights reserved.