Efficient structural color from pigment-loaded nanostructures
Abstract
Color can originate from wavelength-dependence in the absorption of pigments or the scattering of nanostructures. While synthetic colors are dominated by the former, vivid structural colors found in nature have inspired much research on the latter. However, many of the most vibrant colors in nature involve the interactions of structure and pigment. Here, we demonstrate that pigment can be exploited to efficiently create bright structural color at wavelengths outside its absorption band.
Summary
This paper demonstrates how combining pigments with photonic nanostructures can enhance structural color efficiency. Key findings:
Fabrication Method:
- Sequential spin-coating of alternating layers
- Poly-vinyl alcohol (PVA) and polystyrene (PS) layers loaded with beta-carotene pigment
- Creates Bragg reflector structures
Performance Results:
- Peak reflectance over 0.8 at 550 nm with only 10 double layers
- Equivalent pigment-free structure requires 25 double layers for same reflectance
- Suppressed iridescence (angle-dependent color shift)
- Expanded gamut of non-iridescent colors achievable
Key Insights:
- Pigment absorption enhances structural color at wavelengths outside its absorption band
- Hybrid pigment-structure approach mirrors natural systems (many butterfly colors combine pigment with nanostructure)
- Photonic glasses with pigment loading can achieve broader color gamut
This work is relevant for understanding how natural butterfly coloration combines structural and pigment effects, and provides a practical spin-coating fabrication approach.