Intense Mechanoluminescence in Undoped LiGa5O8 with Persistent and Recoverable Behaviors

The distinctive crystal characteristics of undoped LiGa 5 O 8 allow the production of abundant defects and traps in the structure, contributing to attractive luminescent properties. In this work, the mechanoluminescent pathways of LiGa 5 O 8 are demonstrated in terms of the defect induced localized energy levels and trap levels, which are further optimized by adjusting the synthesis atmosphere. The results suggest that the LiGa 5 O 8 synthesized under a reducing atmosphere exhibits an extremely intense mechanoluminescence, which is even better than that of commercial ZnS:Cu. Because of the existence of shallow trap with the spontaneous transfer activity at room temperature, the mechanoluminescence of LiGa 5 O 8 can also exhibit a persistent behavior, overcoming the transient emitting problem in most of the previous mechanoluminescent materials. In addition, the mechanoluminescence of LiGa 5 O 8 can be easily and quickly recovered by refilling the energy in traps. As a result, the undoped LiGa 5 O 8 is confirmed to be an efficient material with intense, persistent, and recoverable mechanoluminescence, which is promising to substitute the doped ones for various applications.