Battery‐Free and Instantaneous Colorimetric Wind Speed Indicator Based on Triboelectric‐Responsive Oblique Helical Cholesteric Liquid Crystals

The integration of energy harvesters with electro‐responsive materials offers a promising pathway toward self‐sustaining functional systems. Triboelectric nanogenerators (TENGs), distinguished by their inherently high‐voltage outputs, are particularly well suited for coupling with materials that require strong electric fields. Here, we report a self‐powered electro‐optical platform that combines a rotational TENG with an oblique helicoidal cholesteric liquid crystal (Ch OH LC). The rotational TENG efficiently converts wind‐induced motion into alternating electrical signals, providing field strengths in the range of 30–54 V (1–1.8 V/µm) at frequencies above 50 Hz. Under these conditions, the Ch OH LC exhibits smooth and reversible tuning of its selective reflection, enabling dynamic color modulation across the red, green, and blue regions of the visible spectrum. Unlike previous TENG–LC systems limited to binary transparent–opaque switching, the present platform demonstrates continuous and real‐time spectral control. This work highlights the strong material compatibility between high‐voltage TENGs and electro‐responsive LCs, establishing a new foundation for sustainable, multifunctional optoelectronic devices with applications in smart windows, adaptive optics, and environmental sensing.