Highly Efficient Color Tuning of Lithium Niobate Nanostructures on Flexible Substrate

Nanostructures based on flexible material are essential for modulating reflected colors by actively changing the unit structure. However, current nanostructures face challenges in achieving active and efficient modulation across a broader spectral range. Here, we propose a stretchable color management method. The structure consists of a polydimethylsiloxane (PDMS) flexible substrate and cross-shaped lithium niobate (LiNbO₃). This study achieves reflection color changes, continuous adjustment, and automatic switching of solar spectrum reflectance by optimizing the geometric structure. It shows that the spectral tuning range is larger, benefiting from the special nanostructures and the stretchability of PDMS, which result in a larger tunable period range and a maximum wavelength shift of nearly 180 nm. Moreover, this unique design has been effectively balanced and optimized to respond to different polarization waves. Finally, the sensing characteristics of the nanostructure are studied through its response to changes in the refractive index (RI). The results demonstrate a method with implications for flexible electronic devices, color generation, and biochemical sensing, contributing to progress in flexible wearable technology and green building.