Design of external microtextures for efficient light outcoupling in OLEDs with different preferential orientation of emission dipoles

Kovačič, Milan (author)

External light outcoupling structures provide a cost-effective and highly efficient solution for light extraction in organic light-emitting diodes. Among them, different microtextures, mainly optimized for devices with isotopically oriented emission dipoles, have been proposed as an efficient light extraction solution. In the paper, the outcoupling for a preferential orientation of emission dipoles is studied for the case of a red bottom-emitting organic light-emitting diode. Optical simulations are used to analyse the preferential orientation of dipoles in combination with three different textures, namely hexagonal array of sine-textures, three-sided pyramids, and random pyramids. It is shown that while there are minimal differences between the optimized textures, the highest external quantum efficiency of 51% is predicted by using the three-sided pyramid texture. Further improvements, by employing highly oriented dipole sources, are examined. In this case, the results show that the top outcoupling efficiencies can be achieved with the same texture shape and size, regardless of the preferred orientation of the emission dipoles. Using an optimized three-sided pyramid in combination with ideally parallel oriented dipoles, an efficiency of 62% is achievable. A detailed analysis of the optical situation inside the glass substrate, dominating external light outcoupling, is presented. Depicted results and their analysis offer a simplified further research and development of external light extraction for organic light-emitting devices with highly oriented dipole emission sources.

• Language: English
• Keywords: organic light emitting diodes, OLED, outcoupling, ray tracing, optical modelling
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FE - Faculty of Electrical Engineering
• Publication status: Published
• Publication version: Version of Record
• Publication date: 01.01.2022
• Year: 2022
• Number of pages: Str. 1-13
• Numbering: iss. 2, e141542
• PID: 20.500.12556/RUL-142383
• UDC: 621.383.51
• ISSN on article: 1896-3757
• DOI: 10.24425/opelre.2022.141542
• COBISS.SI-ID: 108555011
• Publication date in RUL: 04.11.2022

Record is a part of a journal

• Title: Opto-electronics review
• Shortened title: Opto-Electron. Rev.
• Publisher: Stowarzyszenie Elektryków Polskich
• ISSN: 1896-3757
• COBISS.SI-ID: 513715737

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 20.05.2022

Secondary language

• Language: Slovenian
• Keywords: organske svetleče diode, OLED, izstop svetlobe, sledenje žarkom, optično modeliranje

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0415
• Name: Fotovoltaika in elektronika

• Funder: ARRS - Slovenian Research Agency
• Project number: J2-1727
• Name: Napredno modeliranje in karakterizacija visokoučinkovitih sončnih celic in fotonapetostnih modulov