Irradiation‐Wavelength Directing Circularly Polarized Luminescence in Self‐Organized Helical Superstructures Enabled by Hydrogen‐Bonded Chiral Fluorescent Molecular Switches

Abstract

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 450 nm blue and 365 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 365 nm and 450 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.

Chiral Luminescent Liquid Crystal with Multi‐State‐Reversibility: Breakthrough in Advanced Anti‐Counterfeiting Materials

“…[27,28] Meaningfully, the CPL materials with a large g lum value show different fluorescence intensity under the left-and right-handed circular polarized filter (L-CPF and R-CPF). [27,29,30] However, the obtained g lum value of the general CPL materials is very low. [31][32][33][34][35][36] So far, the chiral liquid crystals (N*LC) are recognized as the most effective matrix for fabricating the CPL-active materials with a large g lum value.…”

“…[31][32][33][34][35][36] So far, the chiral liquid crystals (N*LC) are recognized as the most effective matrix for fabricating the CPL-active materials with a large g lum value. [30,37,38] Particularly, the N*LC system can be prepared by simply doping the chiral compounds into the achiral nematic liquid crystal. To obtain the CPL-active materials with a large g lum value, the emission of doped emitters is generally located in the center of the photonic bandgap.…”

Dynamic Circularly Polarized Luminescence with Tunable Handedness and Intensity Enabled by Achiral Dichroic Dyes in Cholesteric Liquid Crystal Medium

“…[7] There are still two major at different wavelengths. [37] To date, tunable CPL handedness and intensity regulated by the achiral molecular structures are rarely reported. [38] As an optically functionalized organic material, a rod-like dichroic dye can exhibit fluorescence anisotropy along the long and short molecular axes under polarized light due to the difference in the transition dipole moment (TDM) vectors.…”

A photoswitchable circularly polarized luminescent cholesteric superstructure: direct visualization and dynamic modulation of the amplified luminescence dissymmetry factor

“…Among them, optically-tunable CPL as well as g em in the luminescent CLCs have received more attention due to the non-contact, non-intrusive, and environmentally friendly properties of the light sources. [17][18][19][20][21] In recent years, our group reported several optically-switchable CPLs in the emissive CLCs induced by a-cyanodiarylethene-based chiral fluorescence photoswitches. [18][19][20][21] For instance, the intensity and helical sense of the CPL signals could be switched by visible, UV, and NIR light in luminescent cholesteric superstructures.…”