Tailor-made nanostructures bridging chaos and order for highly efficient white organic light-emitting diodes.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31278271.
- Also identified by DOI 10.1038/s41467-019-11032-z and PMC identifier 6611821.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Organic light-emitting diodes (OLEDs) suffer from notorious light trapping, resulting in only moderate external quantum efficiencies. Here, we report a facile, scalable, lithography-free method to generate controllable nanostructures with directional randomness and dimensional order, significantly boosting the efficiency of white OLEDs. Mechanical deformations form on the surface of poly(dimethylsiloxane) in response to compressive stress release, initialized by reactive ions etching with periodicity and depth distribution ranging from dozens of nanometers to micrometers. We demonstrate the possibility of independently tuning the average depth and the dominant periodicity. Integrating these nanostructures into a two-unit tandem white organic light-emitting diode, a maximum external quantum efficiency of 76.3% and a luminous efficacy of 95.7 lm W<sup>-1</sup> are achieved with extracted substrate modes. The enhancement factor of 1.53 ± 0.12 at 10,000 cd m<sup>-2</sup> is obtained. An optical model is built by considering the dipole orientation, emitting wavelength, and the dipole position on the sinusoidal nanotexture.