Prototype All-Solid Lithiated Smart Window Devices

The optical transmissivity (and especially the reflectivity) of a ultilayer electrochvomic smart windowTM glass structure can be reversibly modulated by an electrical current pulse; and the modulation is spectrally selective. This is important for building and vehicle windows and for other electro-optical applications. Discussed is the state of development of each of the layers for, and the state of development of, prototype all-solid electrochemically reversible, 5-layer smart window devices. These devices employ: a lithium-insertable rf sputter-deposited polycrystalline WO3 film that exhibits reflection modulation as the electrochromic layer; a lithium-insertable rf sputter deposited In203 film or a thermally deposited V205 film as the counterelectrode layer; an rf sputter deposited LiNbO3 film as the ion conducting (solid electrolyte) layer; and rf sputter deposited ITO (Sn-doped In203) or undoped In203 films as the transparent conducting layers. The devices exhibit useful operating characteristics and indicate that robust and economical practical smart windowTM glass could soon become a commercial reality.