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Materials exhibiting mechanoluminescence (ML) are a class of smart materials capable of mechanical-to-light energy conversion. Thus, ML materials have been widely used in various electronic applications such as smart sensors, security systems, human–machine interfaces, and energy harvesting systems. Herein, we report a centrosymmetric ML semiconductor host material family MGa2S4 (M = Ca, Sr), which features in-layered structures constructed with unique distorted bi-tetrahedral [Ga2S2S4/2] lattice units. It exhibited similar structural characteristics to the well-known ML semiconductor host ZnS. Remarkably, the lanthanide ions of 5d → 4f transition-activated hosts showed sensitive and high ML luminance under natural lighting upon mechanical stimulation; thus, an efficient mechanical-to-light energy conversion of a self-powered display was achieved. Moreover, because of structural distortion and strain-gradient-induced electrical polarization in the ML host material upon mechanical stimulation, a ML mechanism based on the synergy effect between local electronic polarization and flexoelectricity was proposed. This study facilitates a deeper understanding of the relationship between the structure and underlying ML, and promotes further development of ML-material-based products and technologies. [ABSTRACT FROM AUTHOR]

Lanthanide–organic frameworks (LnOFs) have been brought into focus due to their unique structure–function relevance, and have shown good application prospects in many fields. According to the characteristics of scintillating materials, we synthesized two isomorphic LnOFs with the lanthanides terbium and europium as emission centers: Tb(bmb)3·H2O (LnOF-1) and Eu(bmb)3·H2O (LnOF-2). Tb3+ and Eu3+ were used as X-ray absorption centers, and large conjugated organic ligands were used as energy transfer bridges, which can effectively convert X-rays into visible light. LnOF-1 and LnOF-2 show good X-ray scintillation performance and anti-radiation stability. At the same time, we prepared a LnOF-1 mixed matrix scintillating film by the physical deposition method for X-ray imaging experiments, and its spatial resolution can reach 9.5 lp mm−1@MTF20%. The excellent imaging application effect prospect makes the lanthanide–organic frameworks show development potential in the field of scintillating materials. [ABSTRACT FROM AUTHOR]