Dual functional anode for organic light-emitting devices by directly imprinted nanostructured ultrathin Au film

Abstract

The ultrathin metal film with excellent electrical conductivity and high visible-band transmittance has attracted considerable attention as a transparent electrode for the organic light-emitting devices (OLEDs). However, the deficient surface morphology and poor continuity of low thickness evaporated metal films and the surface plasmon-polaritons (SPPs) mode induced energy loss still seriously limit the actual efficiency of OLEDs. In this work, the thermal nanoimprint lithography has been further modified and directly applied to fabricate nanostructures onto the ultrathin Au film. During the imprinting process, the surface smoothness and conductivity of the Au film are obviously optimized with the formation of nanostructures. After integrating proper nanostructures into OLEDs, the photons that trapped by SPPs mode within the device were effectively out-coupled. The current efficiency and luminance have been enhanced 45.3% and 18.1%, respectively. Furthermore, the emitting properties of the OLEDs were also modified by the nanostructures, and the directional transmission capability of output light was significantly improved.