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ECE 443 Course Project Highlights: Improved Solar Cells for Low Earth Orbit Constellation Satellites and the Fight Against COVID-19

5/26/2020

Joseph Park, Illinois ECE

Brian D Li
Brian D Li

Every spring, the ECE 443 LEDs and Solar Cells course encourages the class to address a grand societal challenge by putting the students’ semester-long learnings into the creation of a project. This semester was no different but with an adjustment. With the COVID-19 pandemic, the final exam was replaced with a final project to inspire photonic engineering solutions including help to fight against COVID-19. With support from Microlink Devices and Crosslight, the class thus competed for two distinct project competitions: MicroLink Devices Best Project Award (sponsored by MicroLink Devices with an honorarium of $1,000) and Crosslight Best Technological Solution Award (addressing the COVID-19 pandemic) (sponsored by Crosslight with an honorarium of $2,000).

MicroLink Devices Best Project Award was given to a project exploring the GaAsP solar cells with distributed bragg reflectors for space applications. As space applications shift towards the use of low earth orbit constellations with less expensive satellites in the coming years, the cost of solar cells is becoming a more important consideration for space PV than in the past. The awardee, Illinois ECE graduate student Brian D Li, took on exploring the GaAsP/Si tandem solar cell technology to meet this need for a high-efficiency low-cost PV solution. One of the unique challenges of space solar cells is degradation due to irradiation by high-energy particles. Li demonstrated how the combination of a back reflector with a thinner solar cell can be a promising approach to minimize the damaging effects of irradiation.

Sketch of LEO constellations (Photo credit: Universe Today)
Sketch of LEO constellations (Photo credit: Universe Today)

The final project was also open-ended, asking the class to design a self-sustained solar-powered photonic disinfection system. The project titled "A Sustainable, UV-LED Disinfection System for N95 masks in Haiti" stood out clearly to claim the Crosslight Best Technological Solution Award. The awardee, Mr. Brian Li, provided a design of a UV disinfection system based on AlGaN LEDs and Si solar cells to disinfect N95 masks in Port-au-Prince, Haiti. He found that for a requirement of 40 masks per day to supply 40 medical personnel, serving a population of ~100,000 people, a single Si solar panel and battery were greatly over-sized to fulfill the power needs for mask disinfection. In addition, a 0.19 m2 LED array was sufficient to disinfect all 40 masks on both sides in a combined span of ~9 hours, well within the daily requirements. The over-sizing of the system was an unexpected if welcomed result, and suggests that the availability of medical personnel and medical supplies could be a greater bottleneck to usage rather than disinfection capabilities.

ECE 443 Best Projects can be found here.