The inactivation (killing) of viruses and other pathogens using UV light rather than chemical disinfectants has drawn greater attention with the COVID-19 pandemic. Nevertheless, it has been necessary to prevent light from conventional mercury UV lamps (254 nm) and UVC LEDs (260–280 nm) from directly irradiating human skin due to risk of harmful effects. In contrast, UV excimer lamps with a wavelength of 222 nm were introduced last year showing negligible effect on the human body. However, LEDs are more compact and allow greater flexibility in design, have less risk of breaking, and have a quicker startup time than traditional lamps, opening up new potential for smaller, safer, and more responsive applications of UVC light.

Crystal IS, Inc., an Asahi Kasei company, has commercialized Klaran™ UVC LEDs in the 260–270 nm wavelength range, and is now supporting the advanced research by Asahi Kasei to reach shorter wavelengths. Recently, Asahi Kasei’s Corporate Research & Development was able to create 226 nm UVC LED prototypes, and tests with both 226 nm and 270 nm UVC LEDs were conducted regarding their efficacy for inactivating SARS-CoV-2 as well as their effects on animal skin cells. The test results showed that in approximately 6 seconds, 99.9% of COVID-19 was inactivated by both 226 nm and 270 nm UVC LEDs. In addition, the tests confirmed that the 226 nm UVC LED had significantly less of an effect on animal cells than 270 nm LEDs.

These results suggest the possibility that 226 nm UVC LEDs may be safely used to disinfect hands or objects where there are people nearby. Moving forward, further advancements in technology will be necessary before the power of the light emitted from 226 nm UVC LEDs can be improved enough for commercialization. Continued research development by Asahi Kasei is progressing to make this possible.

About Crystal IS

Crystal IS, an Asahi Kasei company, is a pioneer in the development and commercialization of UVC LEDs based on its proprietary Aluminum Nitride substrate technology. Devices grown on Aluminum Nitride can more effectively (technically and economically) emit at deeper ultraviolet (UVC) wavelengths than devices grown on sapphire. Crystal IS products are used to produce high performance UVC LEDs for disinfection and environmental monitoring in a variety of applications that enhance and sustain life and living around the world. www.cisuvc.com