Transparent and conductive metallic electrodes fabricated by using nanosphere lithography

Nanosphere lithography is used to pattern metallic thin films to form hexagonal nanohole arrays with both high conductivity and good transparency. We fabricated a silver thin film with a transparency of up to 85% and a sheet resistance lower than 35 Omega/square, which is comparable to the commercial ITO electrode. The nanohole array not only increased the transparency but also helped extracting the guided light trapped in organic layers. Compared to the reference device with ITO anodes, Alq(3)-based organic light-emitting devices with the silver nanohole arrays reduced the turn-on voltage by 0.82 V and improved the current efficiency by up to 68.8% due to extraction enhancement. (C) 2011 Elsevier B.V. All rights reserved.