Self-assembled coffee-ring colloidal crystal arrays with periodical structural colours utilizing porous polydimethylsiloxane film as a template

Microscale coffee-ring photonic crystal arrays with periodical structure colours were fabricated by evaporation of a colloidal solution in the confined porous polydimethylsiloxane (PDMS) film. The self-assembled concentric rings with various colours were formed by repetition of the deposition and recession cycle of the contact lines. Furthermore, the change in the temperature was found to be crucial for the structure colours of photonic crystal arrays. The present work provides valuable insights into the preparation of intriguing photonic crystal patterns, which may develop potential for applications in electronic devices, biosensors, and disease diagnosis.