Large-scale structural color on transparent plexiglass by nanosphere lithography combined with reactive-ion etching

Structural color due to unique optical response are of much interest both for their fundamental properties and applications in photonic integrate circuits, optical biomaterials and camouflage. Nanosphere lithography combined with reactive-ion etching demonstrates a feasible strategy to achieve large-scale photonic crystals with structural color. In this work, polymethyl methacrylate (PMMA), namely plexiglass, was firstly used as photonic crystals substrate to fabricate large-area and novel nanopillar arrays via reactive-ion etching monolayer polystyrene (PS) sphere arrays. The height and diameter of plexiglass’ nanopillars can be controlled by adjusting PS size and etching time. In addition, PS sphere arrays exhibited charming structures like chrysanthemum after O2 plasma etching with higher intensity. The nanopillar arrays exhibited the tuned band-gap of such structures with different sizes and tunable resonance peaks from 350 nm to 600 nm. The fabricated nanopillar arrays have potential applications in solar cells, self-cleaning materials, photonic crystals and nonlinear optics.