Enhanced light extraction efficiency and viewing angle characteristics of microcavity OLEDs by using a diffusion layer

Cheol Hwee Park, Shin Woo Kang, Sun Gyu Jung, Dong Jun Lee, Young Wook Park, Byeong Kwon Ju

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22 Citations (Scopus)


The viewing angle characteristics and light extraction efficiency of organic light-emitting diodes (OLEDs) with a micro-cavity structure were enhanced. This was accomplished by inserting a diffusion layer composed of nano-sized structures of a transparent polymer poly(methyl methacrylate) (PMMA) combined with a zinc oxide (ZnO) semi-planarization layer with a high refractive index (n = 2.1) into the devices. The PMMA nanostructures were fabricated by employing a reactive ion etching (RIE) process. The height and density of the PMMA nanostructures were controlled by varying the speed at which the PMMA was spin-coated onto the substrate. The insertion of the diffusion layer into the micro-cavity OLEDs (MC-OLEDs) improved the external quantum efficiency (EQE) by as much as 17% when compared to that of a MC-OLED without a diffusion layer. Furthermore, adjustment of the viewing angle from 0° to 60° halved the peak shift distance of the electroluminescence (EL) spectra from 42 to 20 nm. Additionally, changing the viewing angle from 0° to 60° changed the color coordinate movement distance of the MC-OLED with the diffusion layer to 0.078, less than half of the distance of the MC-OLED without the diffusion layer (0.165).

Original languageEnglish
Article number3430
JournalScientific reports
Issue number1
Publication statusPublished - 2021 Dec

Bibliographical note

Funding Information:
This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean Government (MSIT) (No. NRF-2020R1C1C1013567 and 2019R1A2B5B01070286), and the Brain Korea 21 Project in 2020. We thank the Center for Next Generation Semiconductor Technology at SUNMOON University for analysis support.

Publisher Copyright:
© 2021, The Author(s).

ASJC Scopus subject areas

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