Abstract
One of the main efficiency-limiting factors for organic light-emitting diodes (OLEDs) is poor light extraction, which typically reaches only 20% (in best cases up to 30%) in flat standard devices. Optical modeling and simulations play an important role in improving light extraction and optimizing outcoupling efficiency. Using FEM modeling approach, the effect of dipole positions and orientations for red OLEDs on periodically corrugated substrate is evaluated and used to enhance the outcoupling efficiency. It is shown that with only 3 carefully selected dipole positions, the outcoupling efficiency over the whole area can be predicted with very reasonable accuracy, which greatly reduces the number of simulations required. The presented modelling approach is used for optimization of the sine texture as a substrate corrugation structure. OLEDs with optimized simulated texture show a relative improvement of light outcoupling from the thin film stack to the substrate by more than 25% compared to the flat plane devices.
Highlights
Organic light-emitting diodes (OLEDs) have in recent years achieved a commercial widespread in display technology, especially in mobile and television displays
The outcoupling of light in OLEDs, which is the focus of this paper, can be presented by combined opto-electrical parameter called external quantum efficiency (EQE), which defines the ratio between the number of photons reaching the far field as useful light to the number of injected charge carriers
2.1 Modelling of light in thin film OLED stack In OLEDs light is generated in the emission layer (EML) inside a thin film structure (e.g., see thin film structure used in this paper – Figure 1(a)) by electroluminescence emission of emitter material molecules
Summary
Organic light-emitting diodes (OLEDs) have in recent years achieved a commercial widespread in display technology, especially in mobile and television displays. Solutions to waveguide and SPP losses exists, like micro-lens arrays [20], introducing scattering particles [21], corrugations [22], [23] and others [24], [25], but remain less researched and non-optimized. This is mainly because internal solutions are more challenging to fabricate and to integrate with OLED thin film stack, without having negative impact on electrical efficiency [26]. Outcoupling efficiency and outcoupling trends of differently oriented dipoles for different positions on corrugated substrate are evaluated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Informacije MIDEM - Journal of Microelectronics, Electronic Components and Materials
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
