Programmable wavelength- and time-dependent multicolor afterglow in polyvinyl alcohol via synergistic ion-bridging and crosslinking interactions

Abstract

Time-dependent multicolor afterglow (TDMA) introduces a temporal dimension to optical encoding, enabling dynamically distinguishable visual outputs beyond the capability of static emission or single-color persistent luminescence. Nevertheless, the rational construction of TDMA systems remains highly challenging because it requires the simultaneous generation and precise regulation of multiple long-lived emissive states within one material. Herein, we propose a strategy of introducing ion-bridging interactions into a covalently crosslinked monochromatic persistent luminescence system. The ion-induced interactions partially reorganize the original covalent/hydrogen-bonding network and generate new rigid microenvironments; these Na⁺-associated microdomains, together with the pre-existing crosslinked domains, cooperatively generate emissive centers to form dynamic phosphorescent polymers. As a result, the initially static single-color afterglow evolves into wavelength- and time-dependent dynamic multicolor afterglow maintaining an ultralong RTP lifetime of 1.06 s. Notably, by tuning the excitation wavelengths within a narrow 15 nm window (385–400 nm), the afterglow can be modulated over more than 100 nm (460–563 nm), affording a distinct color evolution from yellow-green to cyan to blue. This work provides a practical framework for achieving wavelength/time regulation of dynamic multicolor afterglow in host–guest systems and offers a visual platform for accurate energy discrimination, with promising potential in multilevel information encryption and optoelectronic applications.