A highly efficient, eco-friendly method for antireflection nanostructures on poly (ethylene terephthalate)

Antireflection surfaces are widely used in optical devices (such as vehicle display, solar cells, and architectural glass) to reduce the reflection and increase transmittance. Plasma etching shows great potential in making subwavelength antireflection structures for its advantage of scalable, low-cost, and applicable in flexible substrates. Here, we demonstrate an antireflection nanostructure by O-2 plasma etching on poly (ethylene terephthalate) (PET) substrate without additional corrosive gas species or antireflective coatings. Nanopores on the surface were formed due to the different etching rates of the organic region and silica region of the surface. The solar weighted average transmittance was improved from 91.6% to 94.8% for single-side treated PET with silica antiblocking layer. The transmission increment was attributed to the gradient refractive index of the nanostructured surface due to the elimination of step discontinuity in refractive index. The result shows a highly efficient, eco-friendly, solvent-free, economical, and sputtering target-free method for reducing the reflection and increasing the transmittance of the substrates.