Multicolor-Luminescence Including White Light by Photomodulation of Supramolecular Assemblies in Aqueous Media.

Photo-responsive supramolecular systems offer intriguing functional aspects which have led to their applications in diverse fields such as optoelectronics and biomedicine. However, the modulation of the luminescence output in a spatiotemporal fashion by photo-controlled transformation still remains a challenging task. Herein, we report the controlled regulation of the emission color of supramolecular assemblies of amphiphilic cyanostilbenes (CSs) in water through in situ photomodulation employing UV and sunlight. Due to their aggregation-induced emission (AIE) features, the CS chromophores in the supramolecular assemblies exhibited bright greenish-yellow emission. Photoirradiation predominantly led to the formation of a cyclized product exhibiting aggregation-caused quenching (ACQ) features and having efficient cyan-blue emission in water but severely quenched emission in the solid state. Hence, starting from a unicomponent scaffold, photomodulation provided tunable emission ranging from greenish-yellow to cyan-blue including white light in water. Furthermore, using the contrasting AIE and ACQ behavior of the components in the photoirradiated mixtures, we were able to design rewritable fluorescent inks and encryption in solid films indicating the practical utility of these systems.