RESUMEN
Two light-driven chiral fluorescent molecular switches, (R,S,R)-switch 1 and (R,S,R)-switch 2, are prepared by means of hydrogen-bonded (H-bonded) assembly of a photoresponsive (S) chiral fluorescent molecule, respectively with a cyano substitution at different positions as an H-bond acceptor and an opposite (R) chiral molecule as an H-bond donor. The resulting two switches exhibit tunable and reversible Z/E photoisomerization irradiated with 450â nm blue and 365â nm UV light. When doped into an achiral liquid crystal, both switches are found to be able to form a CPL tunable luminescent helical superstructure. In contrast to the tunable CPL characteristics of the system incorporating switch 2, exposure of the system incorporating switch 1 to 365â nm and 450â nm radiation can lead to controllable different photostationary CPL behavior, including switching-off and polarization inversion. In addition, optical information coding is demonstrated using the system containing switch 1.
RESUMEN
A near-infrared light-driven self-organized emissive helical superstructure was constructed by doping a new chiral fluorescent photoswitch and upconversion nanoparticles (UCNPs) into a nematic LC. The reversible switching of circularly polarized luminescence (CPL) can be achieved by modulating the power intensity of the 980 nm NIR excitation light.
RESUMEN
A photo-invertible helical cholesteric superstructure was constructed by doping a novel chiral fluorescence photoswitch and a static dopant with opposite handedness into a nematic host. The handedness of circularly polarized luminescence can be reversibly inverted accompanied by a positive-negative change of luminescence dissymmetry factor values upon alternate light irradiations.