Self-organized Chiral Liquid Crystalline Nanostructures for Energy-Saving Devices

Abstract

Energy saving, as important as energy harvesting and storage in sustainable energy endeavor, would greatly decrease the energy production and will help in alleviating the increasing pressure on nonrenewable energy sources, which will not only lengthen their exhaustion but also would provide sufficient time to explore alternative potential sources of sustainable energy. Hitherto, extensive efforts have been devoted to developing energy saving technology to meet environmental and economic restrictions. In this context, liquid crystal (LC) based energy-saving devices employing chiral LC phases as the active materials have been demonstrated. As unique LCs, chiral LC phases possess many excellent characteristics on molecular arrangement and optical properties due to their periodic modulated structure, which enables their promising applications in energy-saving devices. Here we discuss different approaches adopted to develop LC devices with energy saving characteristics. The devices are based on the chiral LCs, i.e., chiral nematic LCs and blue phase LCs, however the use of chiral nematic LCs is highlighted in this chapter. The bistable states of chiral nematic LCs present different optical properties in absence of external field for potential applications in low energy consumption displays, image storage, and light shutters. Furthermore, their selective reflection exhibits the high efficiency on solar energy tuning as a smart window or adaptor of photovoltaic devices. By doping photosensitive chiral switches or motors into the LC, light tunability on reflection band of chiral LCs has been achieved. In this sense, recent developments of delicate light driven energy-saving photonic devices will be also discussed.