Pressure-Treated Luminescent and Structural Evolution With Irreversible Control of Emission in Through-Space Charge Transfer Emitter

Through-space charge transfer (TSCT) is gaining prominence for developing solid-state luminophores, owing to its tunable and dynamically regulable luminescence. In this work, a novel TSCT emitter with a spatially segregated donor–acceptor (D–A) architecture is designed and synthesized, which exhibits high-efficiency blue-violet emission at 410 nm with a narrow 37 nm FWHM and minimal Stokes shift due to molecular rigidity and suppressed structural reorganization. DMAC-CBO crystal demonstrates remarkable mechanochromism through grinding-induced amorphization and a pronounced piezochromic response showing a 156 nm redshift in the range of 14.0 GPa due to the decreased distance between D and A units. As a result, pressure-induced the enhancement of intramolecular and intermolecular interactions promote excimer formation, leading to redshifted emission and enabling the modulation of the dominant emissive state from a local excited (LE) state to an excimer. Impressively, upon decompression from high pressure, DMAC-CBO retains a metastable phase, resulting in irreversibly shifted and broadened luminescence derived from excimers. These findings not only demonstrate that pressure can continuously regulate the distance between D and A units of TSCT-based materials, but also effectively establish a structure-property framework for TSCT-based smart materials with tunable and persistent emission, offering promising applications in data storage, sensing, and optoelectronics.