In Situ Secondary Growth Method for Dual-Chiral Blue Phase Liquid Crystal Films with Broadly Tunable Hyper-Reflective Photonic Bandgaps

Blue-phase liquid crystals (BPLCs) have shown great potential in hyper-reflective display technology due to their narrow bandgap, high color saturation, and fast response characteristics. However, there remains a significant challenge for achieving open-patternable dual-chiral BPLC films (DH-BP) and precise tuning for efficient hyper-reflection due to the packaging limitations of liquid crystal cells and the complexities of the dynamic bandgap matching principle. In this study, an in situ secondary growth strategy was proposed to successfully fabricate structurally continuous and uniform DH-BP films. Key factors affecting color uniformity were thoroughly analyzed, including the optimization of material structure, surface modification of the polymer template, and control of thickness. Subsequently, inkjet printing and ink diffusion swelling techniques were employed to achieve hyper-reflection in DH-BP films, with a tunable bandgap range of approximately 109 nm (from 576 to 467 nm), and a maximum reflectivity of up to 97%. Finally, a tunable dynamic multi-information encryption strategy was proposed by integrating color, polarization, and hyper-reflection. The method provides new insights into the design of high-saturation, high-reflection displays and has broad application prospects in energy-efficient displays and security technologies.