Turn-On Mode Circularly Polarized Luminescence in Self-Organized Cholesteric Superstructure for Active Photonic Applications.

Developing circularly polarized luminescence (CPL)-active materials with a large luminescence dissymmetry factor () or stimulus responses has evoked a lot of interest in the past few years; however, the light-controllable "on/off" CPL still remains a challenge. Here, a novel diarylethene-based chiral fluorescent photoswitch featuring "turn-on" CPL characteristic is developed, designated as (,)-switch , which can undergo reversible photocyclization/cycloreversion upon irradiation with UV and visible light. (,)-Switch shows completely reversible "off-on-off"-responsive CPL behavior in solution. By doping (,)-switch into nematic liquid crystals (LCs), the consequent luminescent cholesteric LCs (CLCs) exhibit a larger value enhanced 2 orders of magnitude when irradiated with UV light, which can be attributed to the highly ordered helical arrangement of CLCs. The potentials of this turn-on type CPL material for anticounterfeiting and information encryption are illustrated. Furthermore, the visualization of circularly polarized (CP) fluorescent patterns can be successfully achieved by constructing the double-layer CPL system consisting of a CP luminescent layer and a polymer cholesteric reflective layer. The proposed concept establishes a light-controlled off-on-off CPL platform that is of tremendous potential for applications in multi-informational data storage and encryption devices.