LAUSR

Self-powered smart windows are desirable with the expectations of their energy-saving, weather-independent, user-controllable and miniature performance. However, the recently developed solar or thermal powered smart windows largely depends on the weather conditions and response extremely slow, besides, a certain saved energy will be utilized by the external circuit for mode conversion. In this work, a self-powered normally-transparent smart window was developed by the conjunction of a rotary freestanding sliding triboelectric nanogenerator (RFS-TENG) and a polymer-network liquid crystal (PNLC) cell. To fabricate the PNLC cell, the alignment layer with randomly distributed micro-domains was constructed to encapsulate a mixture of LC polymer and nematic LC. The opacity of the smart window exposed to an alternating electric field was considerably improved owing to the embedded micro-domains and a dense web of LC polymer. The ultra-high haziness greatly alleviates the charge density required for the LC actuation, and thus enables the driving by the TENG where the charge amount is usually limited. The RFS-TENG was elaborately designed with 6 periodic bended triboelectric films and Ag electrodes, which presented an ultralow friction wear and met the frequency requirement to achieve the steady opacity. By harvesting the mechanical energies from ambient environments, the tribo-induced smart window can benefit a wide variety of fields, such as self-powered sunroofs, wind-driven smart farming systems etc.