Nanomolecular OLED Pixelization Enabling Electroluminescent Metasurfaces

TL;DR

This paper reports the scalable fabrication of ultra-high-density nano-OLED arrays with sub-100 nm pixels, enabling electroluminescent metasurfaces for advanced optical applications like super-resolution imaging and integrated photonics.

Contribution

It introduces a novel self-aligned evaporation technique for patterning organic semiconductors at nanoscale, achieving record pixel density and efficiency in nano-OLEDs.

Findings

Achieved >84,000 pixels per inch in nano-OLED arrays.

Demonstrated control over emission directionality and polarization.

Realized surface light sources smaller than the diffraction limit.

Abstract

Miniaturization of light-emitting diodes (LEDs) can enable high-resolution augmented and virtual reality displays and on-chip light sources for ultra-broadband chiplet communication. However, unlike silicon scaling in electronic integrated circuits, patterning of inorganic III-V semiconductors in LEDs considerably compromises device efficiencies at submicrometer scales. Here, we present the scalable fabrication of nanoscale organic LEDs (nano-OLEDs), with the highest array density (>84,000 pixels per inch) and the smallest pixel size (~100 nm) ever reported to date. Direct nanomolecular patterning of organic semiconductors is realized by self-aligned evaporation through nanoapertures fabricated on a free-standing silicon nitride film adhering to the substrate. The average external quantum efficiencies (EQEs) extracted from a nano-OLED device of more than 4 megapixels reach up to 10%. At the subwavelength scale, individual pixels act as electroluminescent meta-atoms forming metasurfaces that directly convert electricity into modulated light. The diffractive coupling between nano-pixels enables control over the far-field emission properties, including directionality and polarization. The results presented here lay the foundation for bright surface light sources of dimension smaller than the Abbe diffraction limit, offering new technological platforms for super-resolution imaging, spectroscopy, sensing, and hybrid integrated photonics.