Shin Chur-Hyun, Huseynova Gunel, Kim Eunhye, Lee Jonghee, Yoo Seunghyup, Choi Yoonseuk, Lee Jae-Hyun
Opt Express. 2020 Aug 31;28(18):26170-26179. doi: 10.1364/OE.400687.
Random AlO nanoparticle-based polymer composite films are investigated as external scattering layers to enhance light extraction from flexible organic light-emitting diodes (OLEDs). We found that the size and concentration of the nanoparticles (NPs) in the polymer film play a crucial role in improving light extraction. It turned out that their increase has a favorable impact on the light output of the devices, as the high concentration of the NPs leads to the formation of large nanoparticle clusters, which, in turn, yield pore-containing films. As a result, light extraction efficiency of the flexible OLEDs on PEN substrates was enhanced by a factor of 1.65 by the incorporation of the scattering layer, with the highest AlO NP concentration of 99 wt%. This outcome is attributed to the reduction of the waveguide mode and total internal reflection at the substrate/air interface induced by the randomly distributed NPs in the flexible scattering layer. Our work demonstrates an efficient, solution-processable, and low-cost light-outcoupling structure for large-area and flexible OLED applications.
研究了基于随机AlO纳米颗粒的聚合物复合薄膜作为外部散射层，以增强柔性有机发光二极管（OLED）的光提取。我们发现聚合物薄膜中纳米颗粒（NP）的尺寸和浓度在改善光提取方面起着关键作用。结果表明，它们的增加对器件的光输出有有利影响，因为高浓度的NP会导致形成大的纳米颗粒簇，进而产生含孔薄膜。因此，通过掺入散射层，PEN基板上的柔性OLED的光提取效率提高了1.65倍，AlO NP的最高浓度为99 wt%。这一结果归因于柔性散射层中随机分布的NP引起的波导模式的减少以及基板/空气界面处的全内反射的减少。我们的工作展示了一种用于大面积和柔性OLED应用的高效、可溶液加工且低成本的光出耦合结构。
