Hot charge carrier ultra-thin space based solar cells

Imagine tomorrow on your way to work your GPS stopped working and as attempt to call your boss to inform them of your problems, you discover your phone no longer works and you can’t even google what is going on, this is what could happen if all satellites disappeared today. As society evolves, we become more dependent on satellites for duties ranging from communications, GPS, scientific research, weather forecasting and imaging of earth. With around 10,000 satellites currently in operation and double that number is projected to be launched into orbit by the end of the decade.

 These satellites must be self-sufficient over the course of their lifetime and therefore need a method to harvest energy, luckily, they are in the prime position to utilise the energy of the sun. However, these solar cells are in the harsh environment of space where they are bombarded by all sorts of radiation which could damage the active absorber of light reducing its efficiency and could even remove its ability to provide energy. This would require larger solar cells to compensate for this reduction in efficiency meaning a more expensive launch and could even reduce the lifetime of the satellite itself. Thankfully ultrathin solar cells (about 100 nanometers) solve this problem by being radiation tolerant, however they pose a different problem in that by being ultrathin they don’t absorb much light to convert into electricity, so are more inefficient than conventional solar cells.

Good news, my current research group has done work on these type of radiation tolerant ultrathin solar cells showing it is possible to increase their efficiency by using special devices called photonic structures which essentially manipulate light in a way that ensures these ultrathin solar cells absorb more light, this leads to the efficiency of these devices rivalling that of conventional solar cells. Other work in my research group has also discovered evidence of “hot charge carriers” in ultrathin solar cells. These “hot charge carriers” have the potential to allow ultrathin solar cells to be much more efficient than conventional solar cells.

The focus of my project is to investigate these “hot charge carriers” and learn how to replicate them for use in new generations of ultrathin solar cells. Also, my project involves integrating these special photonic structures into the new generation of solar cells to enhance these “hot charge carriers” and how to extract the “hot charge carriers” from the solar cells.

Toluwalase Agoro

NanoDTC PhD Student, c2023