Structural Colors by Synergistic Birefringence and Surface Plasmon Resonance

Area of Science:

• Materials Science
• Optics
• Nanotechnology

Background:

• One-dimensional nanomaterials like cellulose nanocrystals (CNCs) and gold nanorods (GNRs) possess unique optical properties.
• CNCs exhibit birefringence and light retardation, while GNRs show surface plasmon resonance (SPR).

Purpose of the Study:

• To combine the optical properties of CNCs and GNRs to generate synergistic and tunable structural colors.
• To explore the potential of hybrid composite polymer films for advanced optical materials.

Main Methods:

• Unidirectional alignment of CNCs and GNRs in dynamic hydrogels to form polymer films.
• Embedding CNCs and GNRs in the same or separate films.
• Stacking and rotating films with aligned CNCs and GNRs to manipulate structural colors.

Main Results:

• Achieved a wide range of tunable structural colors by synergistically combining CNCs and GNRs, surpassing colors from individual components.
• Demonstrated that higher GNR content enhances absorption at 520 nm, promoting magenta colors.
• Showed that CNCs influence phase retardation and light absorption across the visible spectrum (400-700 nm).
• Manipulated colors by adjusting the angles between stacked CNC and GNR films, with GNR film rotation tuning absorption from 500 to 650 nm.

Conclusions:

• The tunable synergism between CNC birefringence and GNR SPR offers significant potential for creating structural colors.
• This approach provides inspiration for the design of novel functional optical materials.