How space solar cells respond to high-energy electron exposure
Space has become the new frontier for photovoltaic technologies. Although solar panels have been powering satellites since 1958, interest in space solar cells is rising again as major space agencies, including ESA, explore the idea of deploying massive power stations in orbit. Finding the right solar module is becoming increasingly crucial.
Until the early 2000s, research in this field focused on silicon. Over time, attention shifted toward group III-V semiconductors such as gallium arsenide. Today, advances in commercial silicon solar cells, combined with lower production costs, have brought the historic semiconductor back to the center of scientific interest. Yet comprehensive data on how high-energy electrons affect current commercial architectures is still missing.
A new study conducted at the University of New South Wales helps fill this gap. A team of engineers examined the impact of electron irradiation, a key degradation factor in orbit, on the electrical performance of silicon wafers and high-efficiency photovoltaic cells, including p-PERC, n-TOPCon, and p-TOPCon designs.
The researchers analyzed defects induced by 1 MeV electron beams using Defect Parameterisation Solution Space (DPSS) and spectroscopy.
They also assessed short-circuit current density, open-circuit voltage, integrated external quantum efficiency, and the effective minority carrier lifetime after exposure to different doses and energy levels. The results indicate that, without further mitigation strategies, silicon solar cells are not yet suitable for space applications. The team recorded a drop in minority carrier lifetime from roughly 75,000 µs to 240 µs after exposure to a dose of 1012 e/cm2 at 1 MeV.
At the maximum dose of 1015 e/cm2, lifetime fell to just 0.2 µs.
This decline directly translated into a loss of efficiency, measured through the integrated external quantum efficiency (EQE), relative to initial values:
- 27.5 percent loss for p-PERC cells
- 33.3 percent loss for n-TOPCon cells
The comparative analysis suggests that the degradation observed after exposure to high-energy electron flux is equivalent to 3–5 years of space conditions in low Earth orbit (LEO), a major limiting factor for the use of silicon-based solar cells in space. This underscores the need for commercial architectures with stronger radiation tolerance.
Read the full study, “Electron radiation-induced degradation of silicon solar cells,” in Solar Energy Materials and Solar Cells.