Highly efficient and tunable broadband UV excitable Ba9Lu2Si6O24:Eu2+, Mn2+ single-phase white-light-emitting phosphors

Abstract

Based on crystal site engineering, a series of inorganic Ba9Lu2Si6O24: Eu2+ (BLSO: Eu2+) and Ba9Lu2Si6O24:Eu2+, Mn2+ phosphors were synthesized. These phosphors exhibit broad emission throughout the whole visible spectrum range. More specifically, a systematic cation substitution favored efficient energy transfer. Hence, the produced Ba9Lu2−zSczSi6O24: 0.2Eu2+, 0.4Mn2+ (BLSSO: 0.2Eu2+, 0.4Mn4+) were effective single-phase white-light-emitting phosphors. Particularly, Ba9Lu2Si6O24: Eu2+ phosphors emit a broadband blue emission peaking at 462 nm with a long tail. The results of the emission spectrum's Gaussian fitting (and deconvolution), low-temperature photoluminescence, and decay time observations point to the existence of many luminescence centers in the host lattice of BLSO. Partial cation substitution favors the occupation of Eu2+ ions in other available crystallographic sites, i.e., Ba(2) and Ba(3), resulting in the emission spectrum broadening in the green spectral region. The energy transfer from the doped Eu2+ to the co-doped Mn2+ ions broadens the emission in the red spectral region (618 nm). Accordingly, the broadband emission covers the entire visible spectral region. Furthermore, the make-up of these phosphors provides a powerful method for obtaining continuous tuning throughout the whole visible spectrum. The above features, in conjunction with the color coordinates and the remarkable thermal stability, qualify the optimized Ba9Lu2−zSczSi6O24: 0.2Eu2+, 0.4Mn2+ phosphor for potential use in single-phase white-light-emitting phosphors.