Metallic Bragg-gratings for light management in organic light-emitting devices

We used laser interference lithography to fabricate organic light-emitting diodes (OLEDs) with gold Bragg gratings on top of the indium-tin-oxide layer for efficient light management. We built polymer OLEDs with 15 and 30 nm gold grating thickness as well as reference devices with continuous gold layers and without gold layer. Electrical and optical device characterization was performed and compared to optical simulations. The gratings extract waveguide and substrate modes and change the angular and spectral emission characteristics by cavity effects. The combination of light extraction and cavity effects leads to 25-30% enhancement in power efficiency compared to reference devices. (C) 2011 American Institute of Physics. [doi:10.1063/1.3631728]