Discovering and Dissecting Mechanically Excited Luminescence of Mn²⁺ Activators via Matrix Microstructure Evolution

Mechanoluminescent (ML) materials featuring renewable mechanical-to-optical conversion have shown promising prospects in stress sensing, lighting, and display. However, the advancement in ML applications is being restrained by the obstacles in developing efficient ML materials and understanding the underlying ML mechanisms. Herein, a matrix evolution strategy to modulate the local microstructure and electronic environment around the luminescent activators is proposed, which not only supports the batch development of new ML materials but also provides a well-connected platform for systematically revealing the mechanism of achieving efficient ML performance. The feasibility of the strategy is proved by constructing and evaluating a series of ML materials with matrix-dependent luminescent properties in experimental-theoretical collaboration. It is demonstrated that the construction of piezoluminescence is available in both non-centrosymmetric and centrosymmetric matrices without being restricted by lattice symmetry. The inter-electronic-levels and shallow electron traps formed by activator doping enhance the electron recombination efficiency through tunneling and conduction band transfer pathways. The results are expected to accelerate the exploitation of ML material systems and to deepen the comprehensive apprehending of ML mechanisms, thereby guiding the rational design and widespread use of efficient ML materials. © 2021 Wiley-VCH GmbH