The well-known, robust and relatively lightweight silicon-based solar cell is simply not suitable for use in space. Constant exposure to protons interrupts the flow of electrons, leading to a rapid decline in efficiency.
On Earth, these protons carry less energy and radiation, making them virtually harmless and posing no problem for solar panels. Indeed, the magnetic field and our atmosphere intercept these protons. And if they don’t, we can admire magnificent polar, boreal and southern lights.
But why protons? These are more precisely hydrogen nuclei, the main component of the sun. Without their electrons, they are simply protons.
The current standard for powering satellites and the ISS uses indium and gallium. These solar cells are extremely robust, but also heavy, rigid and expensive. That’s pretty much the opposite of what you’d want to put in a launch vehicle for a new satellite.
Surprisingly stable organic molecules
Researchers at the University of Michigan ( ) conducted experiments simulating three years of exposure to proton radiation. In these tests, organic solar cells based on hydrocarbon chains proved to be remarkably robust. However, robustness is not the only factor to consider.
-Their high reliability requires short alkyl chains. With longer alkyl chains, with four or more carbon atoms, protons and their solar radiation remove individual hydrogen atoms and form charged H2 molecules.
Because these longer molecules are more efficient, other research has shown that organic solar cells can be thermally restored. As the required temperatures of 370 kelvins or almost 100 degrees Celsius can be achieved in sunlight, the use of this technology in space would be possible. That said, this approach involves higher maintenance.
Basically, researchers see potential in both methods of energy production. As the number of communications and observation satellites will continue to increase and new manned missions are planned, progress in this area could be very beneficial. In the long term, this technology could also make its way to regular residential solar panels on your roof.
