Individually Addressable Nanoscale OLEDs

TL;DR

This paper presents a novel nanoscale OLED design with individually addressable pixels, overcoming charge imbalance and filament growth issues through nanoelectrode insulation, enabling stable, efficient, and high-density AR/VR displays.

Contribution

It introduces a new nanoscale OLED architecture with controlled charge injection and suppression of filament growth, advancing high-density display technology.

Findings

Achieved stable hole injection with >90% pixel yield

Demonstrated a 300x300 nm$^{2}$ pixel with long-term stability

Showcased potential for plasmonic nanoantenna enhancement

Abstract

Augmented Reality (AR) and Virtual Reality (VR), require miniaturized displays with ultrahigh pixel densities. Here, we demonstrate an individually addressable subwavelength OLED pixel based on a nanoscale electrode capable of supporting plasmonic modes. Our approach is based on the notion that when scaling down pixel size, the 2D planar geometry of conventional organic light-emitting diodes (OLEDs) evolves into a significantly more complex 3D geometry governed by sharp nanoelectrode contours. These cause (i) spatially imbalanced charge carrier transport and recombination, resulting in a low quantum efficiency, and (ii) filament growth, leading to rapid device failure. Here, we circumvent such effects by selectively covering sharp electrode contours with an insulating layer, while utilizing a nano-aperture in flat areas of the electrode. We thereby ensure controlled charge carrier injection and recombination at the nanoscale and suppress filament growth. As a proof of principle, we first demonstrate stable and efficient hole injection from Au nanoelectrodes in hole-only devices with above 90 % pixel yield and longtime operation stability and then a complete vertical OLED pixel with an individually addressable nanoelectrode (300 x 300 nm$^{2}$), highlighting the potential to further leverage plasmonic nanoantenna effects to enhance the performance and functionality of nano-OLEDs.