20.500.12556/RUL-144743 Analysis and optimization of light outcoupling in OLEDs with external hierarchical textures Hierarchical textures (combining 2D periodic large and small micro textures) as an external outcoupling solution for OLEDs have been researched, both experimentally and by optical simulations. For the case of a red bottom emitting OLED, different hierarchical textures were fabricated using laser-based methods and a replication step and applied to the OLED substrate, resulting in an increased light outcoupling. Laboratory-size OLED devices with applied textured foils show a smaller increase in efficiency compared to the final large area devices. The results show that the full exploitation of textured foils in laboratory-size samples is mainly limited by the lateral size of the thin film stack area and by limited light collection area of the measuring equipment. Modeling and simulations are used to further evaluate the full prospective of hierarchical textures in large area OLED devices. Optimization of hierarchical textures is done by simultaneously changing the aspect ratios of the small and large textures and a potential of 57% improvement in EQE compared to devices without applied textures is predicted by simulations. Optimized hierarchical textures show similar outcoupling efficiencies compared to optimized single textures, while on the other hand hierarchical textures require less pronounced features, lower aspect ratios, compared to single textures to achieve the same efficiencies. Hierarchical textures also help in eliminating flat parts that limit outcoupling efficiency. Finally, the limiting factors that prevent higher outcoupling are addressed. We show that the dominant factor is non-ideal reflection from the organic thin film stack due to parasitic absorption. In addition, possible ways to further increase the outcoupling from a thick substrate are indicated. optoelectronics OLED performance optoelektronika OLED zmogljivost true false true Angleški jezik Slovenski jezik "© 2021 Optical Society of America. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reserved." (Datum opombe: 10. 3. 2023) Članek v reviji 2023-03-10 08:27:54 2023-03-10 08:27:55 2023-05-29 11:15:41 0000-00-00 00:00:00 2021 0 0 Str. 23701-23716 no. 15, art. 428021 Vol. 29 19 Jul. 2021 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 621.383.51 1094-4087 10.1364/OE.428021 73817859 oe-29-15-23701.pdf oe-29-15-23701.pdf 1 F20F5B212ED530CE1BC0783354527C99 cf0c26bb07d984ae9217d15dc875464b7c6c2dc47871139286e929590f5419a7 2d79e7f4-bf15-11ed-a314-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=167227 https://opg.optica.org/oe/fulltext.cfm?uri=oe-29-15-23701&id=453214 0 4244fc2e-bf15-11ed-a314-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=167228 Fakulteta za elektrotehniko 0 0 0