Multi-Biomimetic Structural Colors Inspired by Pearls and Bird Feathers.

One-dimensional photonic crystals (1D PCs) enable precise control of light-matter interactions and display stable structural colors. However, their optical performance critically depends on strict periodicity and nanometer-scale control of thickness, necessitating complex fabrication processes. In this work, we present a bio-inspired structural coloration strategy that avoids these limitations by mimicking the structures of pearls and bird feathers. Specifically, a pearl-like inorganic multilayer architecture lacking strict periodicity was synthesized via a facile solution-based method. Distinct from traditional 1D PCs, this structure does not rely on precise periodicity, yet preserves the alternating refractive index modulation characteristic of 1D PCs. This disordered multilayer structure causes multiple reflections and partially coherent interference at internal interfaces, resulting in vivid and stable structural colors. Furthermore, inspired by the broadband-absorbing melanin in bird feathers, surface-integrated absorbing materials were introduced to selectively suppress non-target interference. By tuning the absorbing materials, a continuous structural color spectrum covering the visible range can be achieved. The resulting biomimetic optical materials are readily processable and compatible with paints, plastics, coatings, and cosmetic applications.