Employing a 2D surface grating to improve light out coupling of a substrate emitting organic LED

We present simulation and experimental results to achieve increased light extraction of a substrate emitting OLED. We present a comparison between a grating surface on the OLED and an array of microlenses at the interface between substrate and air. This experimentally gives -in both cases- a relative improvement of approx. 30 %. We also demonstrate the concept of a (RCLED)-L-2, applied to an OLED. The (RCLED)-L-2 is composed by adding a high, low and high index layers between ITO and glass, i.e. the interface between organic layers and glass. These extra layers create a cavity which numerically gives a relative improvement of over 60% at the resonance wavelength of the cavity over a wavelength range of 50-100 nm. The influence of an array of micro lenses in addition to the RC2 layers is also investigated in this paper.