Broadband Reflective Cholesteric Liquid Crystals for Low‐Blue Circularly Polarized Light Generation in the Visible Region

Abstract

ABSTRACT In this work, a polymerizable chiral liquid‐crystal monomer was first synthesized from inexpensive biomass‐derived cholesterol through a simple transformation. Co‐assembling this chiral monomer with a polymerizable achiral liquid‐crystal monomer and followed by initiator‐free photopolymerization, yielded a cholesteric liquid‐crystal (CLC) material YMZ‐5 featuring a broad reflection band in the visible region with blue‐selectivity. After removal of the quartz substrates, the material forms a flexible film with good thermal stability. Due to Bragg reflection, under transmission mode, YMZ‐5 efficiently converts 510–700 nm unpolarized light into right‐handed circularly polarized ( R ‐CP) light with dissymmetry factors ( g lum ) of −1.6 and even reaching up to −2.0. Placed behind achiral zero‐blue aqueous solutions, YMZ‐5 enabled multicolour zero‐blue circularly polarized photoluminescence, generating exclusively R ‐CP light with | g lum | values exceeding 1.6. Additionally, under reflection mode, YMZ‐5 efficiently converts unpolarized ambient light into 510–700 nm low‐blue left‐handed circularly polarized ( L ‐CP) light. Therefore, YMZ‐5 exhibited distinctly different colors under varying backgrounds and circular polarizers. Leveraging these behaviors, molecular logic gate and information encryption–decryption were realized. Furthermore, a conceptual design for a low‐blue circularly polarized display device was also demonstrated.