An article in Nature magazine has reported on a project that has created the smallest LED displays ever. The display has pixels less than 100 micrometres across, about the width of a human hair.
image: Nature
Baodan Zhao at Zhejiang University in Hangzhou, China, and her collaborators were also able to create an even tinier LED, whose pixels were 90 nanometres wide — the size of a typical virus, and too small to be resolved even by the most powerful optical microscopes.
The researchers created a semiconductor from a perovskite, a class of materials that includes not only common minerals from the Earth’s mantle, but also ones that are used in advanced solar panels.
The perovskite enabled the team’s LEDs to stay bright, even as the pixels were scaled down to microscopic sizes. “Apart from our scientific curiosity, such experiments show that at extremely small sizes, the perovskite LEDs can still hold reasonable efficiencies,” says Zhao. That gives them an advantage over conventional LEDs.
“Making electronic devices smaller is an everlasting pursuit for scientists and engineers”, said Prof. DI Dawei, Deputy Director of the International Research Center for Advanced Photonics of Zhejiang University. “Perovskite LEDs are an emerging technology for display and lighting applications. Several years ago, we thought it might be a good idea to make perovskite LEDs smaller, similar to what has been done for micro-LEDs and micro-OLEDs. In 2021, we introduced the concept of ‘micro-perovskite LEDs (micro-PeLEDs)’. Since then, we wanted to make the devices even smaller, and explore the downscaling limits for the LEDs”, said Di.
“Currently, the most advanced technology for display applications is micro-LEDs”, said Prof. ZHAO Baodan of Zhejiang University. “Micro-LEDs are based on III-V semiconductors. They are the best light source for AR and VR applications. However, the efficiency of micro-LEDs drops rapidly when the pixel sizes are smaller than 10 micrometers, which are the desirable pixel sizes for high-end AR/VR applications with ultra-high resolutions. Halide perovskites are a new class of semiconductors. It would be interesting to see how perovskite LEDs perform when they are made extremely small,” said Zhao.