Germans Created World’s Smallest Pixel
Credit: Pixabay
Scientists from the Julius-Maximilians-University of Würzburg (Germany) have created an orange pixel measuring just 300 by 300 nanometers. A display with a resolution of 1920 x 1080 pixels could fit within 1 square millimeter.
The development is based on the creation of an optical antenna made of gold, which simultaneously serves as a conductive electrode and amplifies light emission. The results, published in the journal Science Advances, pave the way for ultra-compact displays for wearable devices—for example, those built into eyeglass frames or even contact lenses.
A major challenge in reducing pixel size was the resulting unevenness in the current supplied to the pixel’s light-emitting area. Simply scaling the electrode would have resulted in a rectangular antenna electrode. Under such a geometry, stronger currents would flow from the antenna’s corners, where the electromagnetic field concentration would be highest. This would have caused uneven pixel emission and quickly destroyed it—specifically, due to the electrochemical transfer of gold atoms, which would quickly grow into filaments and short-circuit the structure.
To ensure uniform current flow to the gold antenna, the scientists coated the electrode with an insulating material and left a 200-nm-diameter circle free in the center. Above this circle are several layers of organic material. This is where the glow occurs: electrons in the stack recombine with holes, producing photons. Another electrode is located above it, ensuring the flow of electrons through the pixel’s stack to the gold antenna.
In the future, scientists plan to increase the efficiency of their invention and expand its color gamut to the RGB spectral range.
