Tailor-made tuneable dielectric and optical characteristics of inorganic electro-chromic materials

Electro-chromic materials (EC) have the ability to reversibly change their optical properties by charge insertion/extraction and have, since their discovery by Deb, been chiefly used in applications related to display technology. Examples are many - smart windows and mirrors and active optical filters being some of them. Owing to their bi-stable nature and relatively fast switching times of the order of 100 ms, EC-based devices have low power consumption and, have begun to challenge the Liquid Crystal (LC) dominance of display technologies. In this sense, a variety of studies related to the tuneable optical characteristics of EC materials have been reported, however, their microwave tuneable dielectric characteristics have been left somewhat unexplored. Recently, it was shown that dc bias voltage induced modulation of the optical characteristics of an inorganic Conductor/WO3/LiNbO3/NiO/Conductor EC cell is accompanied by the modulation of its high frequency dielectric characteristics. In general, to produce tailor-made dielectric characteristics suitable for various applications, EC cells of different material composition are needed. Here, we report that microwave dielectric and optical characteristics of an EC cell can be tailor made to suit a variety of applications without changing their material composition. These results indicate the potential of producing novel, tuneable and tailor-engineered materials that can support a new family of future devices.