Lensfree OLEDs with over 50% external quantum efficiency via external scattering and horizontally oriented emitters

• DOI: 10.1038/s41467-018-05671-x
• Publication Date: 2018-08-06T13:49:05Z
• Authors: Jinouk Song; Kwon-Hyeon Kim; Eunhye Kim; Chang-Ki Moon; Yun-Hi Kim; Jang-Joo Kim; Seunghyup Yoo
• Keywords: Science; Q; 02 engineering and technology; 0210 nano-technology; 7. Clean energy; Article

AbstractHigh efficiency is important for successful deployment of any light sources. Continued efforts have recently made it possible to demonstrate organic light-emitting diodes with efficiency comparable to that of inorganic light-emitting diodes. However, such achievements were possible only with the help of a macroscopic lens or complex internal nanostructures, both of which undermine the key benefits of organic light-emitting diodes as an affordable planar light source. Here we present a systematic way to achieve organic light-emitting diodes with ultrahigh efficiency even only with an external scattering film, one of the simplest low-cost outcoupling structures. Through a global, multivariable analysis, we show that scattering with a high degree of forwardness has a potential to play a critical role in realizing ultimate efficiency. Combined with horizontally oriented emitters, organic light-emitting diodes equipped with particle-embedded films tailored for forward-intensive scattering achieve a maximum external quantum efficiency of 56%.