Nanoscale Pixels to Advance Compact Augmented Reality Eyewear

A newly developed pixel, only 300 nanometers wide, could soon make it possible to embed vivid, high-resolution displays directly into wearable devices like AR glasses and contact lenses. 

Smart glasses that present information directly within the user's line of sight are regarded as a pivotal technology for the future. But their implementation has frequently been hindered by inconvenient technology.

Now, physicists at Julius-Maximilians-Universität Würzburg (JMU) have made a significant advancement in the development of luminous miniature displays. Using optical antennae, they have created the world's smallest pixel to date.

The study, led by Professors Jens Pflaum and Bert Hecht, was published in Science Advances.

A Display on a Square Millimeter

With the help of a metallic contact that allows current injection into an organic light-emitting diode while simultaneously amplifying and emitting the generated light, we have created a pixel for orange light on an area measuring just 300 by 300 nm. This pixel is just as bright as a conventional OLED pixel with normal dimensions of five by five µm.

Bert Hecht, Professor and Study Lead, Julius-Maximilians-Universität Würzburg

These findings make it possible for a display or projector boasting a resolution of 1920 × 1080 pixels to be accommodated within just one square millimeter. This capability could allow for the integration of the display into the arms of a pair of glasses, from which the produced light would be projected onto the lenses.

An organic light-emitting diode (OLED) is composed of multiple ultra-thin organic layers situated between two electrodes. When an electric current passes through, electrons and holes recombine, thereby electrically exciting the organic molecules in the active layer. This process releases energy in the form of light quanta.

Each pixel emits light independently, meaning backlighting is not necessary. This allows particularly deep blacks and vibrant colors to be displayed. Therefore, efficient energy management is possible for portable devices used in augmented and virtual reality (AR and VR).

Simple Miniaturization Does Not Work

The researchers in Würzburg encountered a significant challenge when attempting to miniaturize the pixels: the inconsistent distribution of currents within these small dimensions.

As with a lightning rod, simply reducing the size of the established OLED concept would cause the currents to emit mainly from the corners of the antenna.

Jens Pflaum, Professor and Study Lead, Julius-Maximilians-Universität Würzburg

This antenna, made from gold, would take the form of a cuboid with edge dimensions measuring 300 by 300 by 50 nm.

“The resulting electric fields would generate such strong forces that the gold atoms becoming mobile would gradually grow into the optically active material,” continued Pflaum.

These ultra-thin structures, also known as 'filaments,' would then continue to grow until a short circuit destroys the pixel.

Next Step: Increasing Efficiency

The new tech features a custom-made insulation layer positioned atop the optical antenna. This layer permits only a circular aperture with a diameter of 200 nm at the center of the antenna.

This configuration prevents currents from being injected from the edges and corners, facilitating the reliable and long-lasting operation of the nano light-emitting diode. Under these conditions, filament formation is no longer possible.

Even the first nanopixels were stable for two weeks under ambient conditions.

Bert Hecht, Professor and Study Lead, Julius-Maximilians-Universität Würzburg

In future iterations, the physicists aim to enhance efficiency beyond the current level of one percent and broaden the color resolution to encompass the RGB spectral range.

With this advancement, displays and projectors could potentially shrink to a size that they can be seamlessly integrated into wearable devices, ranging from eyeglass frames to contact lenses.

Journal Reference:

Zhang, C., et al. (2025). Individually addressable nanoscale OLEDs. Science Advances. doi.org/10.1126/sciadv.adz8579.