A simple methodology is developed to realize chiroptical function induced through superstructural chirality of a matrix of helical nanofilaments formed by achiral molecules. In this work, circularly polarized luminescence is demonstrated in nanosegregated mesophase comprising only achiral molecules. An achiral molecular mixture of a bent-core host and a rod-like guest blended with a fluorescent dye is prepared. Circularly polarized luminescence confirms that the chiral superstructure consisting only of achiral molecules may serve as a chiral super nanospace for inducing chiral emissions from the fluorescent dye that exhibits rod-like molecular ordering. In other words, the formation of a chiral superstructure by the segregated rod-like molecules embedded in helical nanofilaments (bent-core molecules) is confirmed. The results provide a novel strategy for constructing dissymmetric circularly polarized luminescence materials based on achiral molecules, which is potentially applicable in future information and display technologies.
Herein,
an epoch-making method based on bottom-up templating is
proposed for the fabrication of a chiral nanoporous film that provides
a chiral environment in which to confine nematic liquid crystals.
A helical nanofilamental network of bent-core molecules was utilized
as a three-dimensional mold, and thus the fabricated chiral nanoporous
film has an inverse nanohelical structure. The presence of a chiral
superstructure was confirmed by the observation of circular dichroism
signals. Upon refilling this chiral nanoporous film with an achiral
nematic liquid crystal, distinct circular dichroism signals appeared
due to the transfer of chirality from the inverse helical nanofilaments
to the achiral nematic liquid crystal. The circular dichroism signals
can be readily modulated by external stimuli, such as the application
of heat or an electric field. In addition, by refilling the chiral
nanoporous film with a nematic liquid crystal doped with fluorescent
dye, it exhibits stimuli-responsive circularly polarized luminescence.
The proposed approach has huge potential for practical applications,
such as for chiroptical modulators and switches and biological sensors.
A liquid crystal laser using a polymer-stabilized simple cubic blue phase (BPII) platform has been scarcely reported because the polymer stabilization of a BPII is relatively difficult compared to that of a bodycentered-cubic BP (BPI). In this study, we succeeded in fabricating a dye-doped polymer-stabilized BPII laser with wide operating-temperature ranges over 15 C including room temperature. A narrow and sharp single laser peak with a full width at half maximum of approximately 2 nm was derived from the photonic band edge effect of the BPII-distributed feedback optical resonator. As a result, the laser emission was a circularly polarized light, which matched the chirality of the proposed pure BPII.
In article number 1903246, Fumito Araoka, Suk‐Won Choi, and co‐workers demonstrate circularly polarized luminescence (CPL) from a nanosegregated mesophase consisting only of achiral molecules. CPL is induced through self‐assembled chiral aggregates (in the chiral super nanospace) formed only by achiral molecules. The results introduce the possibility of developing a novel technique for constructing practical CPL active materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.