ABSTRACT Organic light–emitting diodes (OLEDs) suffer from low light outcoupling efficiency, with much of the generated light trapped within the device. To address this issue, we present a scalable, maskless, polymer‐free strategy for fabricating quasi‐random external nanowire (ENW) and internal nanocorrugation (INC) structures directly on glass substrates using reactive ion etching (RIE) and combined RIE–wet etching. This simple approach avoids deformation, delamination, and environmental instability associated with polymer scattering layers, requires no planarization layer, and offers compatibility with large‐area processing. We examine how surface characteristics, specifically root mean square roughness and correlation length, influence light outcoupling, with simulations providing additional insight. Fabricated ENW OLEDs reach an external quantum efficiency (EQE) of up to 33.4% compared to 23.0% for the control device, representing a 45.2% enhancement. Similarly, INC structures reach EQE values up to 33.2%, corresponding to a 44.5% improvement. For external structures, both high transparency and haze are desired, while for internal structures the situation is more complex. Lower transmission may be beneficial, and larger roughness and shorter correlation length improve outcoupling but also increase the risk of electrical shorts. Overall, this work demonstrates a versatile, experimentally validated approach to OLED light extraction combining simplicity, scalability, and high performance.
Zarei et al. (Mon,) studied this question.