Optical and Thermal Switching of Liquid Crystals for Self-Shading Windows

A liquid crystal light shutter whose transmittance can be controlled by ambient conditions, such as incident solar UV intensity and outdoor temperature, is demonstrated. Self-shading by optical or thermal switching between transparent and opaque states is achieved by liquid crystals doped with push-pull azobenzene and can be used for energy-saving smart windows. The self-shading light shutter is transparent during cool weather or under weak sunlight, which could save the energy used for heating and lighting, and can be switched from transparent to opaque during warm weather or under strong sunlight, saving energy used for cooling.