A team of scientists in China has discovered a new way to power nano-sized LEDs, paving the path for more compact, energy-efficient, and high-resolution displays in virtual reality (VR) headsets, augmented reality (AR) glasses, and even medical devices.
The breakthrough, led by researchers at Nanjing University and published in Applied Physics Letters, shows that using alternating current (AC) instead of the usual direct current (DC) can simplify how these microscopic LEDs are built—while also improving their performance.
LEDs, or light-emitting diodes, are tiny devices that convert electricity into light.
They are the heart of display technologies—from smartphones to televisions—and are now being miniaturized for next-generation headsets and optical equipment.
But shrinking LEDs down to the nanometer scale introduces major manufacturing challenges.
Traditional LEDs run on DC power, which means each tiny LED needs two electrical contacts—a positive and a negative—just like the terminals on a battery.
When you try to make hundreds or thousands of these microscopic LEDs on one chip, aligning both contacts for each one becomes an engineering nightmare.
To solve this, the Nanjing University team took a bold step: they powered their nano-LEDs with AC instead of DC, allowing the devices to function with only one electrical contact instead of two.
“Using AC was absolutely essential for our design,” said Dr. Tao Tao, the study’s lead author. “It allowed us to explore a new regime of LED behavior.”
This approach not only simplifies the fabrication process but also opens new possibilities for fine-tuning LED performance.
The researchers found that by adjusting the frequency of the AC current—the rate at which it switches direction—they could precisely control how electrons transform into photons, the particles of light.
“It’s just like tuning a dial,” Tao explained. “For a near-eye display, you’d select a frequency high enough so that any flicker is invisible to the human eye, but not so high that the light can’t be generated efficiently.”
The prototype nano-LEDs were made by layering semiconductor materials and then etching them into an array of nanorods only 300 nanometers thick—hundreds of times thinner than a human hair.
These smooth, uniform nanorods ensure that electrons flow cleanly, maximizing the device’s quantum efficiency, or how effectively it turns electrical energy into light.
“This is where the nano size really changes everything,” Tao said. “You simply can’t reach the pixel density needed for advanced AR glasses using traditional LEDs.”
While the research was driven by display applications, the implications reach much further. The same technology could enhance optical communication systems, where light carries information, and biomedical devices that use LEDs for sensing or therapy.
“This work is both academic and practical,” Tao added.
“By rethinking something as basic as how we power an LED, we can create devices that are smaller, brighter, and capable of delivering visual experiences far beyond what’s possible today.”
