Peacock-Inspired Janus Structural Color Materials for Multi-Level Encryption and Anti-Counterfeiting

Area of Science:

• Materials Science
• Nanotechnology
• Optics

Background:

• Nature exhibits diverse structural colors, but fabrication limitations hinder applications.
• Existing methods for structural color materials suffer from low efficiency, small areas, and poor control.

Purpose of the Study:

• To develop an efficient, one-step strategy for manufacturing Janus structural color materials (JSCMs).
• To mimic the multi-level structural color of peacock feathers.
• To overcome limitations of existing fabrication techniques.

Main Methods:

• Utilized surface tension-regulated self-assembly of SiO2 nanoparticles in polyethylene glycol (PEG) solution at 80°C.
• Employed a one-step strategy for rapid manufacturing (minutes).
• Adjusted PEG molecular weight to control nanoparticle assembly and domain positioning.

Main Results:

• Successfully fabricated JSCMs with distinct photonic crystal (PC) and photonic glass (PG) structures on opposing sides.
• Achieved bright iridescent colors from the ordered PC side and muted, less angle-dependent colors from the disordered PG side.
• Demonstrated control over fluorescence intensity for diverse optical signals.

Conclusions:

• The developed one-step method significantly improves the efficiency of structural color material fabrication.
• JSCMs exhibit tunable optical properties with potential for multi-level information encryption and anti-counterfeiting.
• The Janus structure offers a versatile platform for advanced optical applications.