White-light-excited multicolour room-temperature phosphorescence: Mg2+-coordinated metal-organic amorphous composites for anti-counterfeiting and information encryption.

The development of white-light-excited room-temperature phosphorescent (RTP) materials with tunable emission remains a significant challenge for practical applications. Herein, we report a novel strategy to achieve this goal using amorphous metal-organic amorphous composites (MOACs) based on Mg2+ coordination. Mechanistic studies reveal that the MgO coordination bonds not only broaden the visible-light absorption but also suppress non-radiative decay by restricting molecular motion and blocking O2 permeation within the rigid MOACs matrix. By rationally redesigning the luminescent centers, we successfully tuned the phosphorescence emission from green to orange. Notably, the optimized yellow-emitting material exhibits a naked-eye-visible afterglow lasting up to 8 s under white-light (300 W Xe lamp) excitation and achieves a prolonged lifetime of 768 ms upon 400 nm excitation. This approach not only obviates the need for high-melting-point processing but also demonstrating considerable potential for applications in dynamic 3D artworks and information encryption.