Dynamic Ultralong Organic Phosphorescence by Photoactivation

Abstract

Smart materials with ultralong phosphorescence are rarely investigated and reported. Herein we report on a series of molecules with unique dynamic ultralong organic phosphorescence (UOP) features, enabled by manipulating intermolecular interactions through UV light irradiation. Our experimental data reveal that prolonged irradiation of single-component organic phosphors of PCzT, BCzT, and FCzT under ambient conditions can activate UOP with emission lifetimes spanning from 1.8 to 1330 ms. These phosphors can also be deactivated back to their original states with short-lived phosphorescence by UV irradiation for 3 h at room temperature or through thermal treatment. Additionally, the dynamic UOP was applied successfully for a visual anti-counterfeiting application. These findings may provide unique insight into dynamic molecular motion for optical processing and expand the scope of smart-response materials for broader applications.

Keywords: crystal engineering; dynamic ultralong phosphorescence; multilevel anti-counterfeiting; photoactivation; photophysics.