China's researchers create world's smallest light-emitting diodes

Researchers from Zhejiang University in China and the University of Cambridge have developed the smallest light-emitting diodes (LEDs) in the world. These tiny LEDs, called nano-PeLEDs, measure just 90 nanometers, which is similar in size to a virus. Their study was published in the journal Nature. Nano-PeLEDs are made from halide perovskites, a type of semiconductor known for its efficient light emission. Unlike traditional micro-LEDs that use costly materials like gallium nitride, perovskite LEDs remain effective even at very small sizes. The new LEDs have an impressive pixel density of 127,000 pixels per inch, outperforming current technologies. They showed a light output efficiency of about 20% across a range of sizes. Creating these tiny LEDs was challenging. Standard manufacturing methods could harm the delicate perovskites. To overcome this, the research team designed a new technique called "localized contact fabrication." This method involves adding an insulating layer to protect the perovskite while creating electrical contacts, allowing the LEDs to work well at such a small scale. The high pixel density of nano-PeLEDs makes them ideal for future augmented reality (AR) and virtual reality (VR) displays, where sharp images are essential. Researchers teamed up with a semiconductor company to create a prototype display that successfully showed detailed images and videos. While micro-LEDs are advanced, they have issues with cost and manufacturing. Perovskite LEDs could be a more affordable solution. Experts believe these LEDs may overcome efficiency challenges in very small pixels, which is important for high-quality AR and VR experiences. Although the prototype is a significant step forward, more work is needed before it can be commercially available. The researchers also see potential for this technology in areas such as new lighting solutions and optical communications. They are looking to partner with industry to bring their innovations into practical use. The findings suggest that perovskite materials could transform miniaturized electronics and lead to better visual technologies.