Novel Eu(2+)-activated thiogallate phosphors for white LED applications: structural and spectroscopic analysis

Novel Eu(2+)-activated BaGa(2)SiS(6) and Ba(2)Ga(8)SiS(16) thiogallate phosphors were prepared by solid-state reaction route. The BaGa(2)SiS(6):Eu(2+) phosphor generated a green emission upon excitation at 405 nm, whereas the Ba(2)Ga(8)SiS(16):xEu(2+) phosphor could be tuned from cyan to green range with increasing Eu(2+) concentration upon excitation at 365 nm. Additionally, the thermal luminescence properties of the thiogallate phosphors were investigated in the temperature range of 25 to 250 °C. A warm-white LED is fabricated using the combination of a 405 nm blue InGaN-based LED chip with the green-emitting BaGa(2)SiS(6):0.01Eu(2+) phosphor, and red-emitting Sr(2)Si(5)N(8):Eu(2+) commercial phosphor with the CRI value of ∼88 and the CCT of 4213 K.