Scientists have developed a new far-UV LED that can kill bacteria and viruses while being harmless to humans.

A powerful LED can effectively disinfect surfaces while remaining safe for people. Physicists at the RIKEN Institute in Japan designed an efficient LED that is lethal to microorganisms and viruses but safe for humans. One day, it could help countries emerge from the shadow of pandemics by killing pathogens in rooms full of people.

Most LEDs emit visible light, but physicists at the RIKEN Institute have created an LED that emits in a narrow band of far ultraviolet, which is safe for humans but lethal to viruses and bacteria.

UV sterilization lamps are extremely effective against bacteria and viruses. In fact, they are often used in hospitals to disinfect surfaces and medical instruments. This type of lamp can be built using LEDs, making it energy-efficient. However, the UV produced by these LEDs within a certain range damages DNA and therefore cannot be used around people. Researchers are seeking to develop efficient LEDs that emit in a narrow far-ultraviolet band, appearing to offer both good disinfection and human safety.

LED sterilization lamps that operate without people are typically made of aluminum, gallium, and nitrogen. By increasing the amount of aluminum contained in them, these LEDs can be modified to work in wavelength regions safe for humans. This method has been used before, but it resulted in a significant drop in power.

为了解决这个问题，理化学研究所量子光学装置实验室的三位物理学家Masafumi Jo（定昌史）、Yuri Itokazu（糸数雄吏）和Hideki Hirayama（平山秀樹）创造了一种设计更复杂的LED。他们将多层铝夹在一起，每层铝的比例略有不同。此外，在一些层中，他们还添加了微量的硅或镁。

This effectively creates an obstacle for electrons, hindering their movement across the material and keeping them trapped in certain areas for longer periods. This results in increased light emission from the device and reduced light absorption.

The team used computer simulations to model all possible effects to help determine the ideal design. The precise control of each layer's thickness was the greatest experimental challenge. They ultimately obtained an LED that operates in the far ultraviolet range, with an output power nearly ten times higher than their previous best value.

The COVID-19 pandemic has brought a new awareness of the importance of being able to eradicate viruses and microbes on surfaces. "Dingchang Shi said: "We believe that our discoveries and technologies will be very useful in protecting society from this and future pandemics."

He added that the three-person team will strive to further improve the performance of their LED, which still has significant room for improvement in terms of output power and power efficiency.

Source: cnBeta