Photoresponsive chiral vesicles as a light harvesting matrix with tunable chiroptical properties.

Abstract

A chiral vesicle system with photo-regulated chiroptical properties including Cotton effects and circularly polarized luminescence (CPL) was reported. Photoresponsive cyanostilbene was conjugated to the cholesteryl group, which provides chiral centers and lipophilic domain for the flexible vesicle membrane formation. The building block self-assembled into vesicles with exciton Cotton effects and CPL. The high dissymmetry g-factor of CPL at 10-2 order of magnitude was achieved. Upon UV light irradiation, Cotton effects were enhanced with an elevated g-factor by 3-fold, while the CPL dissymmetry factor showed a light irradiation resistance. A hydrophobic fluorescent dye (Nile Red) was loaded into vesicle membranes to allow energy transfer and chirality transfer to give red color CPL with retained high g-factor, while resistance to the UV light irradiation of vesicles was enhanced after loading the fluorescent dye. This study highlights the fabrication of the chiral vesicle system with noninvasively stimulus-responsive chiroptical properties, which may provide new thoughts for the fabrication of smart chiroptical materials in aqueous media.