Optimizing OLED performance on polyimide substrates: Evaluation of ITO and organic layer thicknesses with different encapsulation materials
H. Cho, G. H. Kim, W.-j. Lee, and Y.-H. Kim, Optimizing OLED performance on polyimide substrates: Evaluation of ITO and organic layer thicknesses with different encapsulation materials, ETRI Journal (2025), 1–10, DOI 10.4218/etrij.2024-0319
The goal of this study was to optimize OLED device performance on flexible polyimide (PI) substrates by evaluating the effects of indium tin oxide (ITO) and electron transporting layer (ETL) thicknesses, as well as different thin-film encapsulation (TFE) materials.
Key findings revealed that OLEDs on PI substrates exhibited different optical behavior compared to glass, due to the similar refractive indices between PI and organic layers. While glass substrates showed higher luminance overall, PI-based OLEDs were more sensitive to ETL thickness rather than ITO thickness. Furthermore, replacing SiNx with SiO₂ in the TFE structure enhanced luminance by 10.1%, optimizing the optical microcavity without introducing significant losses.
Fluxim’s Setfos simulation software was critical for modeling the optical behavior of the multilayer OLED stacks, including variations in ITO and ETL thicknesses and encapsulation material properties. Setfos enabled precise prediction of luminance trends and guided experimental optimizations, saving time and reducing costly fabrication iterations.
These findings are important because they provide practical design strategies for boosting the performance of flexible OLEDs, crucial for next-generation foldable and wearable display technologies. Tailoring substrate and encapsulation choices is key to achieving high luminance and efficiency.