Li Yungui, Kovačič Milan, Westphalen Jasper, Oswald Steffen, Ma Zaifei, Hänisch Christian, Will Paul-Anton, Jiang Lihui, Junghaehnel Manuela, Scholz Reinhard, Lenk Simone, Reineke Sebastian
Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, Nöthnitzer Str. 61, 01062, Dresden, Germany.
University of Ljubljana, Faculty of Electrical Engineering, Tržaška 25, 1000, Ljubljana, Slovenia.
Nat Commun. 2019 Jul 5;10(1):2972. doi: 10.1038/s41467-019-11032-z.
Organic light-emitting diodes (OLEDs) suffer from notorious light trapping, resulting in only moderate external quantum efficiencies. Here, we report a facile, scalable, lithography-free method to generate controllable nanostructures with directional randomness and dimensional order, significantly boosting the efficiency of white OLEDs. Mechanical deformations form on the surface of poly(dimethylsiloxane) in response to compressive stress release, initialized by reactive ions etching with periodicity and depth distribution ranging from dozens of nanometers to micrometers. We demonstrate the possibility of independently tuning the average depth and the dominant periodicity. Integrating these nanostructures into a two-unit tandem white organic light-emitting diode, a maximum external quantum efficiency of 76.3% and a luminous efficacy of 95.7 lm W are achieved with extracted substrate modes. The enhancement factor of 1.53 ± 0.12 at 10,000 cd m is obtained. An optical model is built by considering the dipole orientation, emitting wavelength, and the dipole position on the sinusoidal nanotexture.
有机发光二极管（OLED）存在严重的光陷获问题，导致外部量子效率仅处于中等水平。在此，我们报告了一种简便、可扩展且无需光刻的方法，用于生成具有定向随机性和尺寸有序性的可控纳米结构，显著提高了白色OLED的效率。聚二甲基硅氧烷表面因反应离子蚀刻引发的压应力释放而形成机械变形，蚀刻的周期性和深度分布范围从几十纳米到微米不等。我们展示了独立调节平均深度和主导周期性的可能性。将这些纳米结构集成到双单元串联白色有机发光二极管中，通过提取衬底模式实现了76.3%的最大外部量子效率和95.7 lm W的发光效率。在10,000 cd m时获得了1.53±0.12的增强因子。通过考虑偶极子取向、发射波长以及正弦纳米纹理上的偶极子位置建立了光学模型。
