Efficient Light Extraction of Organic Light‐Emitting Diodes on a Fully Solution‐Processed Flexible Substrate

A flexible, nanocomposite substrate for maximizing light outcoupling efficiencies of organic light‐emitting diodes (OLEDs) is introduced. In depth investigation is performed on designing the integrated strategy based on considerations of surface conductivity, microcavity tuning, and internal light scattering. The resulting nanocomposite substrate consists of silver nanowires as the electrode and a high‐index polymer layer and a light‐scattering layer for light extraction. It is able to outcouple both the waveguide and the substrate modes, two modes accounting for significant losses in OLED device efficiency. With enhanced light outcoupling, white OLEDs subsequently fabricated on the nanocomposite substrates demonstrate performance metrics of 107 lm W⁻¹ power efficiency and 49% external quantum efficiency at 1000 cd m⁻². The nanocomposite substrate is fabricated by solution processes at low temperatures for potentially low manufacturing cost.