A powerful LED can effectively disinfect surfaces while keeping people safe. Physicists from the Institute of Physical Chemistry in Japan have designed an efficient LED that is lethal to microorganisms and viruses, but safe for humans. One day, it can help countries overcome the shadow of pandemics by killing pathogens in rooms filled with people.

Most LEDs emit visible light, but physicists at the Institute of Physical and Chemical Sciences have created an LED that emits light in a narrow area of far ultraviolet light, which is safe for humans but deadly to viruses and bacteria

UV sterilization lamps are extremely effective in eliminating bacteria and viruses. In fact, they are often used in hospitals to disinfect surfaces and medical equipment. This type of lamp can be constructed with LED to make it energy-efficient. However, the ultraviolet rays generated by these LEDs can damage DNA within a certain range, so they cannot be used around humans. People are looking to develop efficient LEDs that emit light within a narrow far ultraviolet band, seemingly capable of both effective disinfection and human safety.

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

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To solve this problem, three physicists from the Quantum Optical Device Laboratory at the Institute of Physical Chemistry, Masafumi Jo (Masayoshi Sadamasa), Yuri Itokazu (Hiroshi Ito), and Hideki Hirayama (Hideki Hirayama), created a more complex LED design. They sandwiched multiple layers of aluminum together, with slightly different proportions for each layer. In addition, in some layers, they also added trace amounts of silicon or magnesium.

This effectively creates an obstacle for electrons, hindering their movement on the material and keeping them stuck in certain areas for longer periods of time. This leads to an increase in the amount of light emitted by the device and a decrease in the amount of light absorbed.

The team uses computer simulations to simulate all possible impacts to help determine the ideal design. Accurately controlling the thickness of each layer is the biggest experimental challenge. They ultimately obtained an LED that operates under far ultraviolet light, with an output power almost ten times higher than their previous optimal value.

The COVID-19 pandemic has brought a new awareness of the importance of eradicating surface viruses and microorganisms. Ding Changshi said, 'We believe that our discoveries and technologies will be very useful in safeguarding society from the impact of this and future pandemics.'. "

He added that the three person team will strive to further improve the performance of their LED, and there is still a lot of room for improvement in terms of output power and power efficiency of this product.