Ultrathin, lightweight and flexible organic light-emitting devices with a high light outcoupling efficiency

摘要

High-efficiency, flexible organic light-emitting diodes (OLEDs) are of interest for display and lighting applications. However, they often suffer from inefficient light extraction, and many outcoupling schemes are incompatible with flexible OLEDs. Here, we demonstrate a corrugated, ultrathin (10 mu m), light-weight (20 g/m(2)), and flexible OLED on a polychloro-p-xylylene (parylene) substrate. A visible-wavelength-scale random corrugation pattern is imprinted on both surfaces of the parylene substrate that efficiently outcouples trapped substrate, waveguide and surface plasmon modes. A green phosphorescent OLED fabricated on a corrugated parylene substrate (CP-OLED) has an external quantum efficiency of 28 +/- 2% compared with 21 +/- 1% for devices on a conventional flat glass substrate. The CP-OLED shows a Lambertian intensity profile whose spectra are unchanged at different viewing angles. The very thin and flexible substrates offer a solution for foldable displays over very small radii for use in mobile devices and medical applications.