Low-Refractive Index Layers in Organic Light-Emitting Diodes via Electrospray Deposition for Enhanced Outcoupling Efficiencies

Abstract

Organic light-emitting diodes (OLEDs) still suffer from limited outcoupling efficiencies. Herein, a novel technology for the enhancement of the outcoupling efficiency of OLED devices is presented. By means of electrospray deposition (ESD), the active hole-transport layer (HTL) is modified to have a reduced effective refractive index due to its porosity. A green-emitting stack is tailored to demonstrate this effect, whereas additional haze effects are to be prevented. The introduction of a low-index HTL results in a more efficient light extraction by a factor of 1.05 showing excellent agreement between experiment and simulation.