Amoah Stephen, Fu Xiangyu, Yin Shichen, Dong Qi, Dong Chen, So Franky
Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7907, United States.
ACS Appl Mater Interfaces. 2022 Feb 23;14(7):9377-9385. doi: 10.1021/acsami.1c21128. Epub 2022 Feb 15.
The light outcoupling efficiency of a top-emitting organic light-emitting diode (OLED) is only about 20%, and the majority of the light is trapped in the waveguide modes and surface plasmon polariton (SPP) modes. Extracting the trapped modes can reduce the device power consumption and improve the operating lifetime. In this study, we demonstrate a top-emitting OLED structure with a dielectric spacer to suppress the SPP mode and with a patterned back mirror to extract the waveguide modes. We examine and compare several curved mirror arrays and conclude that a micromirror array (μMA) can efficiently extract the waveguide modes while minimizing the absorption loss. The optimized μMA device with a semi-transparent top electrode shows a 36% external quantum efficiency, 2 times higher than the referenced device. This optical design can be easily incorporated into a top-emitting device and has a great potential for displays and lighting applications.
顶部发射有机发光二极管（OLED）的光出射效率仅约为20%，且大部分光被困在波导模式和表面等离激元极化激元（SPP）模式中。提取被困模式可以降低器件功耗并提高工作寿命。在本研究中，我们展示了一种顶部发射OLED结构，其具有介电间隔层以抑制SPP模式，并具有图案化后镜以提取波导模式。我们研究并比较了几种曲面镜阵列，得出微镜阵列（μMA）可以在将吸收损耗降至最低的同时有效提取波导模式的结论。具有半透明顶部电极的优化μMA器件显示出36%的外量子效率，比参考器件高2倍。这种光学设计可以很容易地集成到顶部发射器件中，在显示和照明应用方面具有巨大潜力。
