Solar cells made from perovskite materials have the potential for use in powering electronics in space. Before considering them for space applications, it is crucial to understand how resilient they would be in such a high radiation environment. In previous experiments by other groups, the effect of high-energy protons and electrons has been tested, with the results suggesting that this type of solar cell is particularly resilient to radiation effects. This experiment, on VESUVIO at ISIS, is the first to test cells in operando while being exposed to high-energy neutrons, and found that the cells suffered minimal irreversible damage during the process.
Solar cells made from metal-halide perovskite materials have recently seen huge improvements in efficiency, after a high level of research interest and activity. They have a high power-to-weight ratio, which gives them great potential for applications where weight is important, such as space and aviation.
To test the behaviour of such solar cells under the high radiation conditions that they would experience in space, the group from UCL brought their solar cell to the VESUVIO beamline at ISIS. At ISIS, neutrons are produced by spallation reactions caused by high energy proton bunches colliding with a tungsten target. This produces a neutron spectrum similar to that in a space environment, but at a much higher intensity. One hour of neutron irradiation at ISIS is equivalent to approximately ten years of exposure on the International Space Station.
They recorded the current and voltage across the cells every 15 minutes for over seven hours both under light, and under light whilst being irradiated with neutrons. By comparing these two experiments, the scientists were able to quantify the effect of the neutron irradiation on the performance of the solar cell.
Both light and neutron irradiation caused damage to the cell, but the damage caused by light was reversible, whereas the neutron-induced effects were not. The group propose that this irreversible damage is caused by permanent defects forming in the structure of the perovskite layer, although further investigations are needed to investigate this idea.
Although neutron irradiation reduced the efficiency of the cells, the effects were only small. This experiment therefore shows that perovskite solar cells can be highly resilient to this kind of environment, maintaining their position as potential devices for use in space and aviation applications.
The full paper can be found at DOI: 10.1039/C9SE00102F
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