Electrically‐Tunable Scattering‐Reflection‐Transparency State Transition in Polymer Dispersed Oblique Helicoidal Cholesterics for Smart Window Application

Smart windows capable of electrically regulating light and heat offer an effective approach to reducing energy consumption while maintaining visual privacy. However, conventional smart windows are typically limited to binary switching between transparent and opaque states. Here, we develop a polymer‐dispersed oblique helicoidal cholesteric liquid crystal (PD‐Ch OH ‐LC) system that enables electrically driven and reversible switching among transmission, reflection, and scattering modes. The device is fabricated by doping a Ch OH ‐LC mixture with ultraviolet (UV) polymerizable monomers, which undergo polymerization and phase separation under irradiation with 365 nm UV light, endowing the system with mechanical stability. Particularly, the PD‐Ch OH ‐LC device exhibits electrically tunable reflection within a wide temperature range including room temperature, allowing dynamic modulation of color across the full visible spectrum. The multifunctional state switching and flexibility of this smart window demonstrate great potential for applications in smart building and automotive windows.