Nanostructured, ultrathin silver-based transparent electrode with broadband near-infrared plasmonic resonance

A nanostructured transparent electrode with high average visible transmittance of 76%, low sheet resistance of 7.0 Ω/sq and steep transmittance drop in the near-infrared (NIR) range is investigated by simulations and experiments. The electrode is composed of a nanostructured substrate, on which a trilayer, consisting of an ultrathin 14 nm thick silver film embedded between thin films of TiO₂ and Al-doped ZnO, is deposited. Directional silver deposition results in the formation of a disk-hole array without additional lift-off or etching steps. While the trilayer approach enables increased visible transmittance, the transmittance in the NIR regime is decreased by a broadband plasmonic dipole excitation in the disk-hole array. Moreover, a rich mode spectrum of weaker multipole surface plasmon excitations is observed in the nanodisk- and nanohole array. The presented electrode holds great potential for applications in optoelectronic devices, solar control coatings and solar cells.