Effective electrically tunable infrared reflectors based on polymer stabilised cholesteric liquid crystals

Electrically tunable infrared (IR) reflectors based on polymer stabilised cholesteric liquid crystals (PSCLC) have been fabricated. The influence of polymerisation time on bandwidth broadening and response time of the IR reflector was investigated. Such IR reflector can reflect broad band of infrared light from 725 to 1435 nm upon application of a DC electric field, while remaining predominantly transparent in the visible region, with the transmittance in the region of 400–700 nm being above 90%. Bandwidth broadening was induced using low operational power with acceptable switching speeds. Model tests reveal that this IR reflector can effectively control the indoor temperature. The distinct properties of such IR reflector make it a good candidate for smart windows of automobiles and buildings to control interior temperature and save energy.