Fabrication of broadband antireflective plasmonic gold nanocone arrays on flexible polymer films.

Flexible broadband antireflective and light-absorbing nanostructured gold thin films are fabricated by gold vapor deposition onto Teflon films modified with nanocone arrays. The nanostructures are created by the oxygen plasma etching of polystyrene bead monolayers on Teflon surfaces. The periodicity and height of the nanocone arrays are controlled by the bead diameter and the overall etching time. The gold nanocone arrays exhibit a reflectivity of less than 1% over a wide spectral range (450-900 nm) and a wide range of incident angles (0-70°); this unique optical response is attributed to a combination of diffractive scattering loss and localized plasmonic absorption. In addition to nanocones, periodic nanostructures of nanocups, nanopyramids, and nanocavities can be created by the plasma etching of colloidal bilayers. This fabrication method can be used to create flexible nanocone-structured gold thin films over large surface areas (cm(2)) and should be rapidly incorporated into new technological applications that require wide-angle and broadband antireflective coatings.