World’s First Solid-State Far-UVC Light Emitter Shows How “Light Can Be Part of the Solution to COVID-19”

November 04, 2020 by Jake Hertz

On the heels of new academic research showing the safety and efficacy of far-UVC light as a germicide, NS Nanotech has created a product to bring this technology to market. We interviewed CEO Seth Coe-Sullivan to hear the details.

As soon as the global pandemic hit, many electrical engineers sought to apply their skills to help stop the spread of the disease. One of the ways EEs have been blazing the trail in prevention is by designing devices with UVC light, a well-known and well-studied disinfectant. While UVC is one of the most effective ways to purify one's immediate area, this technology is by no means the perfect solution.


The UVC spectrum

The UVC spectrum. Image used courtesy of the Atlantic Ultraviolet Corporation


UVC disinfectant utilizes EM waves of up to 280 nanometers, which has the potential to cause skin cancer, cataracts, and other ailments in humans. For this reason, UVC-disseminating devices are only mandated to operate when people are not around—which isn't the most effective solution when trying to protect people directly from airborne and contact transmission. 

Now, leveraging new optoelectronics research and novel techniques in semiconductor physics, startup NS Nanotech claims to have found the solution—a far-UVC chip. We interviewed CEO Seth Coe-Sullivan to get a better understanding of this big news.


Far-UVC Light as a Safe Germicide

"As electrical engineers—as optoelectronics engineers—we've been asking ourselves, 'How can we help?'" said Seth Coe-Sullivan, CEO of NS Nanotech. "How can light be a part of the solution to COVID-19?"

Recent independent research from both the University of Kobe in Japan and Columbia University in New York answers this question in part, demonstrating the efficacy of what is called “far-UVC light." Far-UVC is UVC light at the 200–220nm wavelength as opposed to traditional 280nm wavelengths.


Far-UVC has been proven safe for human exposure

Far-UVC has been proven safe for human exposure because it is absorbed in the dead cells of the skin and eyes. Image used courtesy of Columbia University Irving Medical Center


Researchers have found that, importantly, far-UVC is both safe for human exposure while safely deactivating human coronaviruses and other viruses and diseases. This technology opens up a new world of use cases for UVC, particularly applications where a person can remain in an environment that is actively being disinfected. 


Current Far UVCs: A Hot Issue

While it may appear that the easy solution is to push far-UVC light into public spaces, the realities of implementing this technology warrant more considerations. 

"To make a light-emitting semiconductor, you have to move away from materials like silicon or other so-called indirect bandgap semiconductors and make something that has a direct bandgap," Coe-Sullivan explains. The trick, then, is to create photons with very high energy. 

According to Coe-Sullivan, up until now, the only known source of far-UVC light is what is known as a Krypton-Chlorine Excimer Lamp—a very high voltage AC device that is extremely hot to the touch and can become a fire/explosion hazard. While the whole point is to keep people safe, these drawbacks seem to defeat the purpose of using far-UVC. 

NS Nanotech has created up a solution that eliminates these heat risks while maintaining the germicidal properties of far-UVC. 


The World's First Solid-State Far-UVC Light Emitter

Coe-Sullivan explains that his company has developed the first-ever solid-state far-UVC light emitter. The new device works on similar principles to a blue LED, for example, which exploits the 2.7 eV bandgap of indium gallium nitride to efficiently emit blue light.

"We've gone from silicon at 1 eV to red LEDs that were 2 eV to blue LEDs that were 2.7 eV. That jump from 2 to 2.7 eV was worth the Nobel Prize, by the way," Coe-Sullivan notes. "And now I want to go to 6 eV with this far-UVC light chip."

According to the entrepreneur, the challenge here is that a device with a 6 eV bandgap is no longer considered a semiconductor—at this point, it's an insulator.

The NS Nanotech chip itself is a DC-driven device that behaves similarly to an LED, where light output is proportional to the current input above the turn-on voltage. This structural familiarity will hopefully make this device intuitive for engineers to integrate into designs. 


Prototype of the new far-UVC chip

Prototype of the new far-UVC chip. Image used courtesy of NS Nanotech

In regard to long-term safety for human exposure, Coe-Sullivan assures that "we can very easily measure the spectrum of the device before it leaves the factory and verify that it's emitting at the right wavelength."

"We're quite confident that it's not going to shift out of those wavebands over time," he adds.

Since NS Nanotech has successfully devised a way to emit this far-UVC light from a solid-state device, the company is now working to bring this technology to market fast.


What are the Next Steps for the Far-UVC Chip?

The first thing that NS Nanotech is doing with this new technology is producing a new tabletop air purifier. At the size of a coffee mug, this device disinfects the area (air and surfaces) around the user—at up to three feet around the device. 

"This is something that can sit on your desk at work or on your airplane tray table. It purifies enough air at those distances that it keeps you surrounded by a purified air source," Coe-Sullivan remarks. 


Concept image for the tabletop purifier

Concept image for the tabletop air purifier. Image used courtesy of NS Nanotech


Because the air purifier will be on at all times, this device will (at least initially) be wall powered. However, according to Coe-Sullivan, future generations of this technology may also be portable and battery-powered.

NS Nanotech's far-UVC chip holds promise in a plethora of fields, garnering interest not only from the air purifier industry but also from educational institutions, food processing facilities, ridesharing, and public transportation, to name a few. 


Another Testament to EEs' Impact on the Pandemic

NS Nanotech's novel technology illustrates the impact that electrical engineers have on promoting public health in the era of COVID-19. With more designers pushing disinfecting robots and pathogen testing into shared spaces, this chip seems to be yet another step to returning society—safely—to some semblance of normalcy. 

"This wavelength region is very effective at controlling and mitigating the spread of COVID-19, the flu, and the common cold. But it's something that you can actually use around people where you actually need it," Coe-Sullivan says.  

"And so we looked at our knowledge of semiconductors and the need of the market—the lack of compelling light sources in this space. We put one and one together and made three."

NS Nanotech reports that potential partners can get their hands on prototypes of the far-UVC chip at the end of this year and can expect volume production to launch in 2021. 


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