Light‐Driven Sign Inversion of Circularly Polarized Luminescence Enabled by Dichroism Modulation in Cholesteric Liquid Crystals

Abstract

Stimuli‐responsive circularly polarized luminescence (CPL) materials show great promise in applying information encryption and anticounterfeiting. Herein, light‐driven CPL sign inversion is achieved by combining a photoresponsive achiral negative dichroic dye (KG) and a static achiral positive dichroic dye (NR) as dopants at the 0.5:0.5 weight ratio into the cholesteric liquid crystal (CLC) host. The side chains of KG undergo trans/cis isomerization after 365 nm UV light irradiation, leading to the dichroism (SF) decrease. The |glum| value of CLC doping with KG (CLC‐KG) weakens from 0.67 to 0.28 in response to the order degree change. Taking advantage of its unique CPL response property, the light‐driven CPL sign inversion is achieved (from −0.20/0.14 to 0.02/−0.04) by incorporating NR (0.5:0.5) into the CLC‐KG with helical superstructure static. Based on the synergistic use of circular polarization and responsiveness state as cryptographic primitives, the multidimensional information encryption CLC system can be realized.

Stimuli-responsive luminescence from polar cyano/isocyano-derived luminophores via structural tailoring and self-assembly

“…95 Very recently, this same group also realized the light-driven sign inversion of CPL by the dichroism modulation. 96 These chiral binaphthyl partners were popular in the stimuli-responsive CPL-type LLC fields, which supported many similar works ( 4-4 , 4-6 , 4-8 , 4-14 ). 97–100 Among them, the maximal g lum was found in 4-6 (−0.83 and +0.86 in Fig.…”

Ultrastrong Circularly Polarized Luminescence Triggered by the Synergistic Effect of Chiral Coassembly and Selective Reflective Cholesteric Liquid Crystal Film

“…Note that the new mirror-image Cotton peaks emerged in the long-wavelength range from 400 to 600 nm. This band can correspond well to the absorption of achiral IrPA, 48 which indicates intermolecular chirality induction from chiral inducers R/S-1 to achiral IrPA within the SLC1717 host. This process involves chiral supramolecular coassembly, including the helical arrangement of the achiral IrPA dye.…”

Helical columnar phase of mesogen-jacketed liquid crystal polymers for efficient circularly polarized luminescence

“…20–24 Some employed a host–guest doping method to induce chiral alignment of luminescent liquid crystals or enable luminescence in chiral liquid crystals. 25–27 Others established covalent bonds between chiral and luminescent components to directly construct a non-doped chiral luminescent liquid crystal system. 28–31 Regardless of the method used to construct CPL-activated liquid crystal materials, they can be divided into two categories based on molecular weight: 32 CPL-active small molecule liquid crystals and CPL-active liquid crystal polymers.…”