High Color Gamut Top-Emitting Organic Light-Emitting Diode Based on Metal/Transparent Conductive Oxide Composite Electrode

Abstract

Top-emitting organic light-emitting diodes (TEOLEDs) based on metal/transparent conductive oxide composite anodes, which were Al/ITO and Ag/ITO, were studied. The microcavity effect was optimized by adjusting the microcavity thickness and microcavity order to achieve high color gamut RGB monochromatic light display. Through mathematical modeling and spectral simulation, TEOLEDs with different microcavity structures were designed. The results showed that the full width at half maximum and the color purity of the light of the TEOLED based on the second-order microcavity were significantly optimized compared to those of the TEOLED based on the first-order microcavity. Meanwhile, the TEOLEDs based on the Ag/ITO composite electrode exhibited better optoelectronic performance, with the significantly enhanced external quantum efficiency of up to 19.40%, narrower full width at half maximum of down to 20 nm, and improved color purity. The corresponding red, green, and blue TEOLEDs had achieved excellent color coordinates of (0.697, 0.301), (0.154, 0.769), and (0.139, 0.050), and the color gamut area of the device had reached 172.4% of the color gamut area of the bottom-emitting OLED, 125.6% of the National Television System Committee standard color gamut, and 93.8% of the ITU-R Recommendation BT.2020 standard color gamut.

Keywords: High color gamut, top-emitting organic light-emitting diodes, metal/transparent conductive oxide composite electrode, RGB display