Making OLED pixels for future microdisplays

Organic light-emitting diodes (OLEDs) have become the industry standard for high-resolution displays in cell phones and TV screens. But future augmented reality (AR) and virtual reality (VR) devices will require OLED microdisplays with smaller, more densely packed pixels than current manufacturing methods can produce.

Researchers recently found a way to fabricate these nanopixels using photolithography, which is the method currently used to print computer chips. The new process produces high-resolution OLED pixels small enough for next-generation devices (Nature 2026, DOI: 10.1038/s41586-026-11042-0).

Traditionally, photolithography is a lot like using a stencil to trace patterns. Here, the stencil is called a photoresist, a material that undergoes a chemical change when light shines on it. Laser light draws a fine pattern into the photoresist. Typically, a solvent then washes away the parts of the photoresist that the laser transformed, and the material acts as a stencil to pattern the desired electronic components into the gaps. But photolithographic processing tends to destroy OLED molecules and makes them lose their glow.

A team led by Chih-Jen Shih and Yinyin Bao at the Swiss Federal Institute of Technology (ETH), Zurich, overcame this challenge. “Our method solves this by turning the light-emitting organic material itself into a photoresist,” Shih says.

The team designed a star-shaped polymer by positioning a light-emitting unit at the polymer’s center and connecting it to multiple radial arms. Each arm features two segments: an inner part that insulates the light emitter from the outer part—a photoreactive tip. This configuration ensures that the light-emitting segment never makes contact with the photoreactive tip, preserving the OLED’s glow throughout the process. By tailoring the central unit, the team made red, green, and blue OLEDs.

“This allows us to use the exact same scalable, high-resolution lithography tools that the semiconductor industry uses to print silicon chips,” Shih says.

“Researchers have tried in the past to do this type of patterning, with varying success,” says Max Shtein, a chemical engineer at the University of Michigan, who was not involved in the work. But he thinks the authors seem to have solved a lot of problems. “They achieved good performance and a pretty good patterning resolution,” he says.

Using this method, the team was able to make a fluorescent image of a macaw with red and green pixels just 200 nm wide, which is at least 10 times as small as the smallest pixels used in microdisplays today.

But the macaw is a fluorescent image and not a working display, which means it is not electrically powered but reflects light that is shone on it. The team created it to showcase the precision that the photolithography could achieve.

The team was unable to achieve the same nanoscale precision in a working display model that spells out ETH. The display grid consists of red, green, and blue pixels 30 µm in diameter. The pixels reached an efficiency of 13.3%, lower than the 20–30% typical of today’s commercial OLED screens.

The proof-of-concept devices also fade quickly. The best pixels lost half their glow within 146 min of continuous use. “This is our most critical challenge,” Shih says. The team found that this degradation partly results from trace metal impurities, including residual copper catalysts. “To make this commercially viable, we need to transition to metal-free polymerization methods,” he says.

Another limitation to commercialization is that “the OLED industry has more or less standardized small-molecule emitters,” Shtein says. Their performance has been improved and optimized over the last couple of decades. Shtein believes it would be difficult to change that.

“Bringing a fundamentally new materials platform to commercial foundries is a major engineering effort,” Shih says. He thinks it would take 5–10 years of concentrated effort to get there.