Mechanically robust antireflective coatings

Mechanical strength is an essential parameter that influences and limits the lifetime performance of antireflective (AR) coatings in optical devices. Specifically, amphiphobic AR coatings with reduced reflectance are of great significance as they considerably enlarge the range of fundamental applications. Herein, we describe the design and fabrication of amphiphobic AR coatings with reduced reflectance and enhanced mechanical resilience. Introducing a thin polytetrafluoroethylene (PTFE) layer on top of the bilayer SiO₂ coating via vapor deposition method makes it highly liquid repellent. We achieved reduced reflectance (< 1%) over the entire visible wavelength range, as well as tunability according to the desired wavelength region. The fabricated film showed better thermal stability (up to 300 ℃) with stable AR efficiency, when an ultrathin dense coat of Al₂O₃ was deposited via atomic layer deposition (ALD) on the polymer-based bilayer SiO₂ antireflective coating (P-BSAR). The experimental results prove that the omnidirectional AR coating in this study exhibits multifunctional properties and should be suitable for the production of protective optical equipment and biocompatible polymer films for the displays of portable electronic devices.