High-contrast top-emitting organic light-emitting diodes with AlO1.086 dark-and-conductive electrodes

To improve the poor contrast of conventional organic light-emitting diodes (OLEDs) resulting from highly reflective metal electrode, a dark-and-conductive electrode with an average reflectance of 28.1% and a resistivity of 4.6 x 10(-4) Omega/cm was fabricated by fine-tuning O-2/Ar flow ratio on aluminum electrode sputtering. X-ray photoelectron spectroscopy analysis indicates pure aluminum and aluminum oxide coexist in the fabricated dark-and-conductive electrodes. With the proposed dark-and-conductive AlO1.086 electrodes, top-emitting OLEDs exhibit significantly improved contrast, whereas maintain moderate luminous efficiency. The demonstrated AlO1.086 dark-and-conductive electrodes can potentially replace the circular polarizers for high-contrast OLED display applications. (C) 2014 Elsevier B.V. All rights reserved.