Near-infrared long-lasting phosphorescence in transparent glass ceramics embedding Cr3+-doped LiGa5O8 nanocrystals

Abstract

Abstract Cr 3+ doped transparent glass ceramics of SiO 2 –Ga 2 O 3 –Li 2 O were fabricated by melt-quenching and subsequent crystallization. X-ray diffraction and transmission electron microscopy analyses evidenced that cubic LiGa 5 O 8 nanocrystals were homogeneously precipitated among the silicate glass matrix. The incorporation of Cr 3+ ions into LiGa 5 O 8 nanocrystals was evidenced by absorption, emission and time-resolved luminescence spectra. Impressively, the present Cr 3+ doped glass ceramics were demonstrated to be a new near-infrared (∼720 nm) long-lasting bulk phosphor whose luminescence can last for more than 2 h after stoppage of UV (250–350 nm) irradiation. The occurring of Cr 3+ long-lasting phosphorescence in the glass ceramics was confirmed to be mainly due to the precipitation of Cr 3+ :LiGa 5 O 8 nanocrystals from glass matrix. The filling/releasing of electrons into/from the intrinsic traps of LiGa 5 O 8 nanocrystals through the conduction band of host were proposed to be responsible for the realization of the long-lasting phosphorescence of the investigated Cr 3+ doped glass ceramics.