High thermal stability and color purity of red-emitting phosphor Y2SiWO8: Eu3+ for w-LEDs: Synthesis and photoluminescence properties

Abstract

A series of Eu3+-activated Y2SiWO8 red phosphors were prepared using the sol-gel process. The as-synthesized phosphors were characterized by X-ray diffraction, crystal structure, morphology as well as photoluminescence spectra. Observed from the excitation spectrum, Y2SiWO8: Eu3+ phosphor exhibits the highest excitation peak situated at ∼395 nm. Excited by 395 nm, this phosphor presents the dominant red emission band (∼619 nm), arising from the electric dipole transition 5D0→7F2 of Eu3+. The optimum Eu3+ dopant concentration is 6 mol%, beyond which the concentration quenching happens. The energy immigration mechanism among Eu3+ ions is extensively studied, which further proves to be the dipole-dipole interaction. More importantly, this phosphor is found to emit a bright red light with the excellent color coordinate (0.665, 0.335) and color purity (96.61%) under the excitation of n-UV light. The phosphor exhibits remarkable thermal stability and its emission intensity remains above 80% at 473 K, as compared to that at room temperature. Furthermore, the structural and optical properties of as-obtained microcrystal phosphors are thoroughly investigated as a function of the [MoO4] content. It can be concluded that Y2SiWO8: Eu3+ phosphors have a great promising in the field of n-UV pumped w-LEDs.