Dual Mode Circularly Polarized Luminescence Enabled by Spray Deposition Quantum Dots on a Porous Cholesteric Liquid Crystal Template.

Circularly polarized luminescence (CPL) materials show great potential for applications in sensing, detection, information storage, 3D displays, and beyond. For practical use, mechanical robustness and long-term stability are essential. In this study, a porous cholesteric liquid crystal polymer network (porous CLCN) is fabricated as a chiral template. The porous structure allows for the infusion of fluorescent quantum dots (QDs). By selectively spraying a QD dispersion onto the template surface, arbitrary fluorescent patterns can be encoded into the CLCN film. The combination of the chiral polymer network template and fluorescent QDs enables the fabrication of a CPL film with on-demand information encryption capability. Since the QDs are deposited on only one side of the CLCN film, the resulting composite exhibits distinct CPL signals when observed from the front and rear, functioning as a "Janus" CPL film with dual-mode information encryption. As a result, the dissymmetry factor (glum) values for the front and rear sides of a single film are opposite, measuring -0.484 and 0.350, respectively. More importantly, the CPL film composed of a densely cross-linked polymer network and inorganic QDs demonstrates superior stability and mechanical strength, highlighting its advantages for real-world applications.