Enhancement of the photoluminescence properties of Ba1.98SiO4-delta N2/3 delta:Eu-0.02 phosphors and their application to green LEDs

Abstract

A green emitting Ba(1.98)Sia(4-delta)N(2/3 delta):EU0.02 phosphor with an appreciable intensity was synthesized using the gas-reduction nitridation (GRN) method. SEM revealed agglomerated Ba1.98SiO4-delta N2/36:Eu0.02 particles with irregular morphologies and a primary particle size of 1-2.5 mu m. The phosphor showed emission lines of Eu2+ corresponding to the 4f(6)5d(1) -˃ ˃ (4)f(7) transition under 370 nm excitation. As the GRN process was conducted to incorporate N3- into the lattice, both the excitation and emission intensity of Ba1.98SiO4-delta N2/36:EU0.02 were enhanced greatly compared to Ba(1.98S)ia(4):Eu-0.02. The decay time of Ba1.98SiO4-delta N2/36:Eu-0.02 showed that N entered the Ba(1.98)Sia(4):Eu-0.02 lattices to replace 0 to form a No point defect. The electroluminescence intensity of Ba-1.98-SiO(4-delta)N(2/3)6:EU0.02 at 503 nm increased with increasing forward bias current. Intense green LEDs were fabricated by coating the synthesized phosphors on the cap of the near -ultraviolet InGaN LEDs (lambda(em) = 375 nm). Overall, this phosphor appears to be a promising candidate for solid-state lighting applications.