Supramolecular Chiral Assembly Films with Dynamic Handedness and Emitting-Color Afterglow

This work presents a strategy for the fabrication of multicolor-emitting circularly polarized afterglow (CPA) films by assembling achiral phosphorescent donors and fluorescent emitters in a photonic crystal matrix. Achiral positively charged phosphors and fluorophores with good spectral overlap are selected as the donor and sequential receptors, which are then coassembled with poly(vinyl alcohol) and cellulose nanocrystals. CPA can be achieved in the blue to near-infrared (NIR) range with stepwise amplification of the dissymmetry factor (lifetime up to 4.52 s and dissymmetry factor up to −0.038) through synergistic chirality and energy transfer processes. Notably, the handedness of the CPA signal can be amplified or reversed by altering the receptor types or the direction of incident light. With the flexibility in manipulating emission and handedness, these materials show potential applications in multidimensional anticounterfeiting and high-definition noctilucent displays.

Supramolecular assembly with chiral cellulose nanocrystal template and Förster resonance energy transfer cascade enables direction-switchable circularly polarized afterglow and NIR emission.