Optical outcoupling in monochromatic top-emitting organic light-emitting diodes with an Au/Ag semi-transparent electrode

Top-emitting organic light-emitting diodes can achieve high efficiencies due to the strong cavity effect resulting from the relatively thick semi-transparent metallic top electrode. The strong cavity resonance, however, simultaneously brings along negative side effects such as pronounced angular-dependent emission and spectral narrowing. In this work, through numerical simulations, we demonstrate that top-emitting organic light-emitting diodes using a thin Au(2 nm)/Ag(7 nm) top electrode can achieve light-outcoupling efficiency comparable to a thick silver electrode, while reducing spectral narrowing. This can be realized by tuning the organic capping layer thickness without affecting the electrical properties, which can be applied to diodes based on either intrinsic or efficiently doped charge transport layers. (c) 2021 The Japan Society of Applied Physics

Automated summary

This study demonstrates that top-emitting organic light-emitting diodes using a thin Au/Ag top electrode can achieve high light-outcoupling efficiency and reduce spectral narrowing compared to thick silver electrodes. Tuning the organic capping layer thickness can achieve this without affecting the electrical properties, and can be applied to both intrinsic and doped charge transport layers.