Extracting internal modes of top emission organic light emitting diodes by using internal random mesoscopic wrinkles

Abstract

Angular electroluminescence spectra stabilized and efficiency enhanced top-emitting organic light-emitting devices (TOLEDs) were demonstrated using randomly distributed mesoscopic internal wrinkles. Compared to planar TOLEDs, wrinkled TOLEDs showed a faster exciton decay rate in the emissive layer and high rate of radiative recombination, which leads to enhanced efficiency. Our wrinkled TOLEDs showed angular spectral dependency (u'v'(theta)) of 0.0032, which is low enough to be imperceptible to the human eyes, and 38.7 % enhanced external quantum efficiency relative to the planar counterpart. The approach described here provides an effective scheme for improving TOLEDs and obviating the necessity of modifying the stack structure of the device. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.