Chemical engineers at ETH Zurich led by Professor Chih-Jen Shih have reduced OLED pixel size by several orders of magnitude. Jiwoo Oh, a doctoral student, said the smallest pixel diameters are about 100 nanometres, roughly 50 times smaller than the current state of the art. Postdoc Tommaso Marcato added that, in a single step, the maximum pixel density can be around 2,500 times greater than before.
The team demonstrated an ETH Zurich logo made of 2,800 nano-OLEDs; each pixel in the logo is about 200 nanometres, similar in size to a human cell. The researchers used pixel interactions within the visible-light diffraction range to direct emitted light into specific angles rather than in all directions.
They used silicon nitride membranes that are about 3,000 times thinner than older metal masks and can fit standard lithography. The work was developed with a Consolidator Grant awarded to Shih in 2024 by the Swiss National Science Foundation. The team is now optimising the method and aims to control each nano-pixel individually, with future ideas such as phased array optics, mini lasers and grouped "meta-pixels."
Difficult words
- diameter — distance across a circular objectdiameters
- pixel — smallest addressable point in a digital imagepixels, pixel size, pixel diameters, pixel density, pixel interactions, nano-pixel
- nanometre — one billionth of a metrenanometres, 100 nanometres, 200 nanometres
- density — amount per unit area or volumepixel density
- diffraction — bending and spreading of waves around obstacles
- membrane — thin flexible layer that covers somethingmembranes
- lithography — process to create patterns on surfaces
- optimise — make something work better or fasteroptimising
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How could much smaller OLED pixels affect the design of everyday devices like phones or TVs?
- What difficulties do you think scientists might face when they try to control each nano-pixel individually?
- Which of the future ideas mentioned (phased array optics, mini lasers, grouped "meta-pixels") seems most useful to you, and why?
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