Effective Repeatable Mechanoluminescence in Heterostructured Li_{1- x} Na_x NbO₃ : Pr³

Mechanoluminescence (ML) is a striking optical phenomenon that is achieved through mechanical to optical energy conversion. Here, a series of Li_{1 -x} Na_x NbO₃ : Pr³⁺ (x = 0, 0.2, 0.5, 0.8, 1.0) ML materials have been developed. In particular, due to the formation of heterostructure, the synthesized Li_0.5 Na_0.5 NbO₃ : Pr³⁺ effectively couples the trap structures and piezoelectric property to realize the highly repeatable ML performance without traditional preirradiation process. Furthermore, the ML performances measured under sunlight irradiation and preheating confirm that the ML properties of Li_0.5 Na_0.5 NbO₃ : Pr³⁺ can be ascribed to the dual modes of luminescence mechanism, including both trap-controllable and self-recoverable modes. In addition, DFT calculations further confirm that the doping of Na⁺ ions in LiNbO₃ leads to electronic modulations by the formation of the heterostructures, which optimizes the trap distributions and concentrations. These modulations improve the electron transfer efficiency to promote ML performances. This work has supplied significant references for future design and synthesis of efficient ML materials for broad applications.