Pushing OLEDs beyond the diffraction limit

– Ananth Govind Rajan and Abhijit Gogoi

Organic light-emitting diodes 100 times smaller than a human cell (Image: Manas Sharma and Abhijit Gogoi)

A recent study published in Nature Photonics by scientists at IISc and ETH Zürich demonstrates a major advance in miniaturising organic light-emitting diodes (OLEDs) beyond the diffraction limit, achieving pixel densities up to 100,000 pixels per inch. While the experimental work at ETH Zürich – led by Chih-Jen Shih – focused on developing a resist-free nanostencil lithography process, researchers at IISc provided critical insights into the underlying molecular-level phenomena through advanced modelling.

The IISc team, involving Ananth Govind Rajan and Abhijit Gogoi from the Department of Chemical Engineering, developed theoretical and computational models to predict how the employed organic semiconductors behave when confined at the nanoscale. Using large-scale molecular dynamics simulations, they examined nanodroplets of the emissive blend and discovered that the light-emitting molecules used preferentially migrate toward the surface in a thermodynamically favourable process. This surface activity enhances light emission and alters molecular coordination and dipole orientations, influencing device efficiency and light polarisation.

These findings offer a fundamental understanding of how nanoscale confinement impacts device performance and open avenues for tailoring emission properties through molecular design. By bridging fabrication and molecular-scale theory, IISc’s contribution ensures that future OLED technologies can be engineered with precision. More broadly, this work paves the way for exciting applications in visible-light communication, lasing, and ultra-high-resolution displays.

REFERENCE:
Marcato T, Oh J, Lin Z-H, Tian T, Gogoi A, Shivarudraiah SB, Kumar S, Rajan AG, Zeng S, Shih C-J, Scalable nanopatterning of organic light-emitting diodes beyond the diffraction limit, Nature Photonics (2025).
https://www.nature.com/articles/s41566-025-01785-z

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