Helix-induced full-color circularly polarized luminescence films with multiple information encryption and multi-stimuli responsiveness.

The development of full-color circularly polarized luminescence (CPL) materials is of great significance in the field of luminescent materials; however, it is difficult due to the limitations in the synthesis and preparation methods. Helical polymers, with their high optical activity and easy processability, offer a promising solution for the construction of high-performance CPL materials. In this study, we successfully prepared full-color CPL composite films using precisely synthesized polyisocyanide (PI) as chiral source, poly(methyl methacrylate) as the matrix, and commercially available fluorescein as fluorescence source. The introduction of PI not only improves the mechanical properties and fluorescence lifetime of the composite films but also facilitates recyclability through centrifugation after dissolving the composite films with the poor solvent of PI. Moreover, the use of spiropyran as a red fluorescein allows for dynamic responsiveness to light, heat, and acid-base stimuli, broadening the functionality of the CPL materials and constructs a multiple information encryption system. This work presents a low-cost, easily processable, and multi-stimuli responsive strategy for full-color fabrication of CPL materials based on helical PI.