Self-Assembled Hierarchical Nanostructures for Above 100k DPI Resolution and Wide-Gamut Structural Coloration on Both Rigid and Flexible Substrates

Technologies on structural coloration attract significant research interests in diversified areas ranging from displaying, bioimaging, security, holographic data storage, and integrated optoelectronics. Current structural colors with resolution above 100k dots per inch (DPI) rely on e-beam writing, which has a limited manufacturing size of 4.37 cm². Other scalable technologies, however, report low resolution or narrow color gamut. In this work, we engineer hierarchical nanostructures for structural coloration by employing self-assembled polystyrene (PS) spheres as soft templates followed by reactive ion etching. By changing the size of PS spheres for the self-assembly process and tuning the parameters of the reaction ion etching, we manufacture fully three-dimensional nanostructures with varying profiles. This nanostructured platform reports a high resolution of 101 600 DPI and a wide color gamut exceeding the standard red, green, and blue (RGB) spectrum on both rigid and flexible substrates, with a printing area of entire 4-inch wafers. Taking these hierarchical nanostructured substrates as a platform, we investigate the previously unexplored color generation mechanism, which leverages the complex light-matter interactions combining the scattering and strong optical resonance in fully 3D dielectric nanostructures, varying in both horizontal and longitudinal directions. With this technology, we print various artworks with constant resolution above 100k DPI and multiple colors. This wet-chemistry-based structural coloration technology simultaneously addresses scalability, low-cost, high-resolution printing, and wide color gamut requirements, and the manufacturing process is also complementary metal–oxide–semiconductor (CMOS) compatible, supporting the development of wearable electronics and flexible devices.