ABSTRACT Circularly polarized luminescence (CPL) has attracted considerable attention owing to its wide range of potential applications. Cholesteric liquid crystals (CLCs) are promising candidates for CPL‐active materials because of their ease of fabrication, stimulus responsiveness, and ability to achieve high dissymmetry factors (|glum|). In most studies on CPL‐active CLCs, non‐mesogenic luminophores are doped into commercially available liquid crystals (LCs). However, their low solubility in LCs (typically only a few wt%) and their tendency to disrupt LC alignment present challenges in achieving high |glum| values—particularly in thin cells—and in broadening the CPL spectra. Here, we report a new LC mixture comprising our previously designed mesogenic fluorophore and a commercially available LC. This strategy enables a markedly increased luminophore loading (up to ∼50 wt%) and enhances the birefringence of the LC matrix. As a result, we achieved a notably high |glum| value of 1.25 even in thin cells (2 µm), together with significantly broadened CPL spectra. Furthermore, the emission wavelength was successfully tuned via Förster resonance energy transfer. This work demonstrates a rational design strategy for LC mixtures that yield CPL materials with high |glum|, advances the fundamental understanding of CPL generation in photoluminescent CLCs, and highlights their potential for future photonic and optoelectronic applications.
Iida et al. (Sun,) studied this question.