Enhancement of Luminescence Dissymmetry Factor in Nano-Segregated Phase Generated by Phase Separation between Helical Nanofilaments and Liquid-Crystalline Smectic A Phase

Abstract

Although several methods exist for the synthesis of circularly polarized luminescent (CPL) materials, the methods are extremely complex and tedious. In recent years, the chiral host-achiral luminescent guest method and the achiral host-achiral luminescent guest method have been employed to fabricate CPL materials; however, the main disadvantage of the latter is the small luminescence dissymmetry factor (glum) that limits the practical applications of the method. Therefore, this study reports on the enhancement of glum in a nano-segregated phase system, generated by the phase separation between helical nanofilaments (HNFs; originating from an achiral bent-core molecule) and a liquid-crystalline (LC) smectic A (SmA) phase (originating from an achiral rod-like mesogen). The observed glum value in the nano-segregated phase between the HNFs and LC SmA phase was larger than that in the nano-segregated phase between the HNFs and LC nematic (N) phase. The enhancement of the glum value was attributed to the order parameter (S) of the dye molecules in the SmA phase being larger than that in the N phase. Therefore, we concluded that the S value of the fluorescent dye molecules, doped into the embedded LC phase between the HNFs, strongly influenced the glum value.

Effect of Nematogen Doping in Bent-Core Molecular Systems with a Helical Nanofilament and Dark Conglomerate

“…The two enantiomeric domains in M1 had grown to a few millimeters in size. This is a well-known feature of mixtures composed of HNFs and rod-like nematogens [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. This state is the nanoseparated phase between the HNF and rod-like nematogen.…”

Control of the Induced Handedness of Helical Nanofilaments Employing Cholesteric Liquid Crystal Fields

“…Ever since the enantiomers of tartaric acid were resolved by Pasteur [ 1 ], chirality has been a remarkable subject in the fields of chemistry, physics, biology, pharmacy, and material science. In the field of liquid crystal (LC) science, chirality is also a fascinating research topic [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ] because unique LC phases (such as cholesteric and blue phases) appear by introducing chirality.…”

Organic Optoelectronic Materials

“…The small luminescence dissymmetry factor (glum) in a nano-segregated phase system, generated by the phase separation between helical nanofilaments (HNFs; originating from an achiral bent-core molecule) and a liquid-crystalline (LC) smectic A (SmA) phase (originating from an achiral rod-like mesogen), was enhanced by Lee et al [5]. The glum value in the nano-segregated phase between the HNFs and LC SmA phase was larger than that between the HNFs and LC nematic phase.…”