Enhancing and reducing chirality by opposite circularly-polarized light irradiation on crystalline chiral domains consisting of nonchiral photoresponsive W-shaped liquid crystal molecules

Abstract

We found possible chirality enhancement and reduction in chiral domains formed by photoresponsive W-shaped molecules by irradiation with circularly polarized light (CPL). The W-shaped molecules exhibit a unique smectic phase with spontaneously segregated chiral domains, although the molecules are nonchiral. The chirality control was generated in the crystalline phase, which shows chiral segregation as in the upper smectic phase, and the result appeared to be as follows: for a certain chiral domain, right-CPL stimuli enhanced the chirality, while left-CPL stimuli reduced the chirality, and vice versa for another chiral domain. Interestingly, no domain-size change could be observed after CPL irradiation, suggesting some changes in the causes of chirality. In this way, the present system can recognize the handedness of the applied chiral stimuli. In other words, the present material can be used as a sensitive chiral-stimuli-recognizing material and should find invaluable applications, including in chiroptical switches, sensors, and memories as well as in chiral recognition.

Circularly Polarized Luminescence in Nanoassemblies: Generation, Amplification, and Application

“…In addition, compared with excitation by unpolarized light (g lum = 3.3 × 10 −3 ), the l-CG/ ThT system achieved amplified g lum (1.89 × 10 −2 ) when using circularly polarized light to excite it. [12,141] These results indirectly suggested that the helicity in the donor fluorescence can be transferred to the acceptor and subsequently amplifies the g lum . [35] It is understandable that when energy transfer results in manifestations of chirality by an acceptor, cognate with effects in the donor, that it might seem that chirality, in some sense, accompanies the energy-transfer process.…”

Chiral Superstructure Mesophases of Achiral Bent‐Shaped Molecules – Hierarchical Chirality Amplification and Physical Properties

“…Reversible photoinduced CD was observed with sign relevant to the handedness of the CPL. Recently, it was found that even the Cr phase of the W‐shaped molecule shows enhancement and reduction of CD by CPL irradiation . Detailed studies remain as a future problem.…”

Cooperative Chirality and Sequential Energy Transfer in a Supramolecular Light‐Harvesting Nanotube

“…As shown in Figure S11, 12, when using unpolarized light to excite ThT in l ‐CG/ThT system ( λ ex =400 nm), a g lum =3.3×10 −3 was obtained. However, if left‐handed circularly polarized light was used, an amplified g lum value=1.89×10 −2 was achieved . These results indirectly indicated that the helicity in the donor fluorescence could be transferred to the acceptor and subsequently amplified the g lum .…”