Far-Ultraviolet LED Kills Bacteria and Viruses Without Harming People

RIKEN physicists have engineered an exceptionally efficient LED that is lethal to microorganisms and viruses while being safe for humans. Someday it may help nations overcome pandemics by eliminating microorganisms in spaces filled with people.

Ultraviolet germicidal lights are significantly efficient at eradicating microorganisms and viruses. They are consistently used in medical facilities to sterilize surfaces and clinical instruments.

Lights of this kind can be built with LEDs, making them energy efficient. However, these LEDs generate ultraviolet light in a range that affects DNA and consequently can not be employed around people. The search is on to establish effective LEDs that beam light within a specific band of far-ultraviolet light that seems both an efficient disinfectant while staying harmless for people.

Germicidal LED lights that function in the absence of humans are commonly made from gallium, aluminum, and nitrogen. By raising the quantity of aluminum, these LEDs can be customized to operate in a wavelength that is harmless for humans. This strategy has been utilized previously yet has led to significantly reduced power.

To overcome this problem, three physicists at RIKEN Quantum Optodevice Laboratory, Yuri Itokazu, Masafumi Jo, and Hideki Hirayama, developed an LED with a more intricate design. They combined several layers, each containing slightly different proportions of aluminum. Additionally, some layers included tiny quantities of silicon or magnesium.

Developing an effective pandemic killing LED

This successfully produced a challenge for electrons, preventing their movement throughout the product and trapping them for longer in specific locations. This led to a raised quantity of light emitted by the device and a decreased quantity absorbed by it.

The group utilized computer simulations to model all feasible outcomes to help determine the optimal design. “We then grew samples to see if it was effective or not,” Jo says. Accurately managing the thickness of each layer was the greatest experimental obstacle. They ended up with an LED operating in the far ultraviolet, with an output power nearly ten times greater than their previous best.

The COVID-19 pandemic brought a new awareness of the significance of being able to eliminate viruses and microorganisms on surfaces. “We trust that our findings and technologies will be very useful for safeguarding society against this and future pandemics,” states Jo.

Jo includes that the trio will aim to enhance their LED’s efficiency further. “There’s still much room for improvement in the output power and the power efficiency,” he mentions.

Originally published by: ScitechDaily

Reference: “Milliwatt-power far-UVC AlGaN LEDs on sapphire substrates” by Masafumi Jo, Yuri Itokazu and Hideki Hirayama, 25 May 2022, Applied Physics Letters.
DOI: 10.1063/5.0088454