High-performance flexible oleds on outcoupling enhanced plastics

摘要

Flexible organic light-emitting diodes (OLEDs) hold great promise for future bendable display and curved lighting applications. One key challenge of high-performance flexible OLEDs is to develop new flexible transparent conductive electrodes with superior mechanical, electrical and optical properties. Herein, we demonstrate a new strategy to achieve a powerful transparent conductive electrode on plastic substrate that combines a quasi-random nanostructured optical coupling layer and an ultrathin metal alloy conduction layer. The optimum electrical conductivity, optical manipulation capability, and high tolerance to mechanical bending are realized in this composite electrode, which is favorable for the fabrication of ITO-free flexible OLEDs with state-of-the-art performance on low-refractive-index plastic substrate. The angularly and spectrally independent boost in light outcoupling of white emission is obtained by minimizing the waveguide mode, metallic electrode-related microcavity effect and surface plasmonic loss due to the integrated quasi-random outcoupling structure in the composite electrode. The resulting white flexible OLED exhibits the high enhancement in efficiency, e.g., external quantum efficiency of 47.2% and power efficiency of 112.4 lm/W. In addition, this composite electrode has a scalable manufacturing potential in large-area flexible electronic systems.