corona virus-Covid19

Penn State Discovery Paves Way for Environmentally Friendly Disinfecting UV LED Devices Interview with:
Joseph Roth
Graduate Student
Dr. Roman Engel-Herbert PhD
Assoc. Prof. of Materials Science & Engineering, Chemistry and Physics
The Pennsylvania State University
University Park, PA 16802 What is the background for this study?  

Response: UV disinfection is currently a hot topic as there have been many studies on its effectiveness against COVID-19. Typically, this disinfection is done with expensive, mercury containing gas discharge lamps that have major downsides including high power requirements, short lifetimes, and bulky form factors.

Ideally these disinfection devices would be replaced with high performance UV LEDs that are far more energy efficient, long lasting, and compact. Currently the development of these LEDs is limited by a lack of effective UV transparent electrode materials. The introduction of an effective UV transparent electrode will greatly expedite the process of making UV disinfection devices widely available. What are the main findings? Is this wavelength considered UVC?

Response: In this study we have identified SrNbO3 as an effective UV transparent electrode. UVC is typically designated as 100-280nm; however, the germicidal effectiveness is maximized for most viruses and bacteria between 200-300nm. We found that this material in thin film form is very conducting, similar to a metal, in addition to an optical transmission of over 90% at a wavelength of 280nm and even maintains a transmission of 60% at a wavelength of 250nm. This is remarkable because at wavelengths of 250nm competing transparent conductor materials have nearly zero transmission. This exceptional performance marks a dramatic improvement over the currently used UV semi-transparent electrodes. What should readers take away from your report?

Response: The discovery of this high-performance UV transparent electrode allows to build high performance UV LED devices. This means we can replace the existing solution, a mercury containing gas discharge lamp, by a much more environmentally benign, longer lasting and more energy efficient solution. The drastic improvement that has been witnessed recently from replacing conventional light sources, such as headlamps and ambient lighting in cars, home lighting by replacing incandescent light bulbs, fluorescent and halogen lights etc, with LEDs can now be expanded to the ultraviolet light. What recommendations do you have for future research as a result of this work?

Response: This study has characterized the performance of the material as a UV transparent electrode. While this is a first important step in the right direction, marking the discovery of a suitable material for the application, still work needs to be done to mature, simplify and optimize the film deposition process. Specifically the integration of the material into existing UV LED devices is a next step to examine its performance as a COVID-19 disinfection method.

Any disclosures? A provisional patent has been filed. 


  Yoonsang Park, Joseph Roth, Daichi Oka, Yasushi Hirose, Tetsuya Hasegawa, Arpita Paul, Alexej Pogrebnyakov, Venkatraman Gopalan, Turan Birol, Roman Engel-Herbert. SrNbO3 as a transparent conductor in the visible and ultraviolet spectra. Communications Physics, 2020; 3 (1) DOI: 10.1038/s42005-020-0372-9

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Jun 4, 2020 @ 10:16 am

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