Open AccessRandom Al2O3 nanoparticle-based polymer composite films as outcoupling layers for flexible organic light-emitting diodes
Author(s) -
Chur-Hyun Shin,
Gunel Huseynova,
Eunhye Kim,
Jonghee Lee,
Seunghyup Yoo,
Yoonseuk Choi,
Jae-Hyun Lee
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.400687
Subject(s) - oled , materials science , nanoparticle , light scattering , optoelectronics , polymer , scattering , composite number , diode , layer (electronics) , light emitting diode , total internal reflection , optics , substrate (aquarium) , nanotechnology , composite material , oceanography , physics , geology
Random Al 2 O 3 nanoparticle-based polymer composite films are investigated as external scattering layers to enhance light extraction from flexible organic light-emitting diodes (OLEDs). We found that the size and concentration of the nanoparticles (NPs) in the polymer film play a crucial role in improving light extraction. It turned out that their increase has a favorable impact on the light output of the devices, as the high concentration of the NPs leads to the formation of large nanoparticle clusters, which, in turn, yield pore-containing films. As a result, light extraction efficiency of the flexible OLEDs on PEN substrates was enhanced by a factor of 1.65 by the incorporation of the scattering layer, with the highest Al 2 O 3 NP concentration of 99 wt%. This outcome is attributed to the reduction of the waveguide mode and total internal reflection at the substrate/air interface induced by the randomly distributed NPs in the flexible scattering layer. Our work demonstrates an efficient, solution-processable, and low-cost light-outcoupling structure for large-area and flexible OLED applications.