Paving the Way for High-Efficiency UVC LEDs

NS Nanotech founder focuses on UV disinfection with LED efficiency breakthrough....

University of Michigan Professor Zetian Mi, co-founder of NS Nanotech, has spent more than a decade developing new ways to develop more efficient light-emitting diodes (LEDs). His lab’s patented research is already providing a foundation for NS Nanotech’s next-generation solid-state far-UVC ShortWaveLight™ Emitters and future LEDs that will be used for disinfection applications. And his latest breakthrough is paving the way for higher-efficiency UV LEDs that may be capable of a multitude of new air-, surface-, and water disinfection applications.

In a paper published by Photonics Research, “High-Efficiency AlGaN/GaN/AlGaN Tunnel Junction Ultraviolet Light-Emitting Diodes,” Professor Mi and his colleagues describe a new approach to LED fabrication resulting in maximum external quantum efficiency of approximately 11% and wall-plug efficiency of approximately 7.6%, new records that demonstrate a viable path to overcome current efficiency limits of UVC LEDs.

“Sterilization of pathogens by UV light works on all kinds of cells, making it effective against new variants of the coronavirus and other diseases,” says Dr. Mi. “Mercury lamps are currently used to generate UV light for disinfection in hospitals, water purifiers, air purifiers, and many other applications, but they are bulky, contain toxic chemicals, and are not as versatile as semiconductor light sources.”

UV LEDs, on the other hand, offer advantages in size, usability, and safety that make them an attractive alternative. But their efficiency has been too low to be effective for many disinfection applications—especially at the critical wavelength of 265 nm. “The record-high efficiencies demonstrated in our research enable the performance required for many new sterilization applications, where a solid-state solution can provide a smaller form factor and safer, easier handling than mercury lamps,” says Professor Mi.

The paper based on his team’s research won the 2020 Editors in Chief Award from Photonics Research, and articles in Laser Focus World and the University of Michigan Department of Electrical and Computer Engineering website describe the breakthrough in more detail.