强大的 LED 灯可以有效消毒表面，同时确保人员安全。
RIKEN 物理学家设计了一种高效 LED 灯，它具有抗菌和抗病毒作用，但对人类安全。 有一天，它可以通过在人满为患的房间里杀死病原体来帮助各国摆脱流行病的阴影。
紫外线杀菌灯在杀死细菌和病毒方面非常有效。 事实上，它们通常在医院用于对医疗表面和器械进行消毒。
Masafumi Jo 和两位同事设计了一种 LED 灯，有助于保护社会免受流行病的侵害。 信用：理研
这种类型的灯可以使用 LED 制造，这使得它们更加节能。 然而，这些 LED 灯会产生范围内有害的紫外线[{” attribute=””>DNA and therefore cannot be used around people. The search is on to develop efficient LEDs that shine light within a narrow band of far-ultraviolet light that appears to be both good at disinfecting while remaining safe for people.
Germicidal LED lamps that operate in the absence of humans are often made from aluminum, gallium, and nitrogen. By increasing the amount of aluminum they contain, these LEDs can be modified to work in a wavelength region that is safe for humans. This approach has been used before but has resulted in dramatically reduced power.
To work through this issue, three physicists at RIKEN Quantum Optodevice Laboratory, Masafumi Jo, Yuri Itokazu, and Hideki Hirayama, created an LED with a more complex design. They sandwiched together multiple layers, each containing slightly different proportions of aluminum. In addition, in some layers they also added tiny amounts of silicon or magnesium.
This effectively created an obstacle course for electrons, hindering their movement across the material and trapping them for longer in certain areas. This resulted in an increased amount of light emitted by the device and a reduced amount absorbed by it.
The team used computer simulations to model all possible effects to help pin down the ideal design. “We then grew samples to see if it was effective or not,” Jo says. Precisely controlling the thickness of each layer was the biggest experimental challenge. They ended up with an LED operating in the far ultraviolet, with an output power almost ten times higher than their previous best.
The COVID-19 pandemic brought a new consciousness of the importance of being able to eradicate viruses and microbes on surfaces. “We trust that our findings and technologies will be very useful for safeguarding society against this and future pandemics,” says Jo.
Jo adds that the trio will strive to improve their LED’s performance even further. “There’s still much room for improvement in the output power and the power efficiency,” he notes.
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
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