A self-regulating liquid crystal (LC) smart window whose reflectance changes with ambient conditions is demonstrated. Thermally or optically induced switching between the transparent state and a near-infrared (NIR) reflective state can be used for energy-saving windows. Reflection of NIR can reduce the energy used for cooling, while remaining transparent to visible light. By changing the initial alignment of LCs, the window can be switched between hazy-opaque and IR-reflective states to be used for privacy windows.
Keywords: IR reflection; cholesteric liquid crystals; energy-cost reduction; phase transition; privacy.