Ultra-thin solar cells help boost satellite performance
Source：Econess Energy Co., Ltd. Release time：2022-11-14 09:01:28 Author：4334
Photo of solar cells on ultra-thin sheets. The cells are green squares that include an ultrathin layer of light-absorbing GaAs, the key to their radiation resistance. The surface of each green square is only 120 nanometers, about one-thousandth the thickness of a human hair, and higher than the surrounding gray area. The gold grids are conductive metal contacts. Credit: Armin Battelle
The satellites are powered by photovoltaic cells that convert sunlight into electricity. But the sun also emits radiation that causes these solar cells to degrade. Solar cells absorb light and emit photon energy, which is then transferred to negatively charged electrons. These electrons act as charge carriers.
The problem occurs when these electrons are affected by radiation. Irradiation in space causes damage and reduces efficiency by displacing atoms in solar cell materials and shortening the lifetime of charge carriers.
To eliminate this degradation, the researchers designed a thinner layer of photovoltaic cells. This can increase the lifetime of the flow as the charge carriers travel further during their shortened lifetime. The researchers fabricated two types of photovoltaic devices using the semiconductor gallium arsenide. One is an on-chip design built by stacking several substances in layers. Another design involves a silver rear mirror to enhance light absorption.
The amount of radiation damage to the performance of photovoltaic devices before and after irradiation was studied using a technique called cathodoluminescence. A second set of tests was conducted using a compact solar simulator to determine how the devices convert sunlight into electricity after being bombarded with protons.
"Our ultrathin solar cells outperform previously studied thicker devices in proton emission above a certain threshold. The ultrathin geometry provides two orders of magnitude better performance than previous observations," said the new device. Nearly 3.5 times fewer coverslips are required than thicker cells. This would translate into lighter loads and significantly lower launch costs, as they would still provide the same amount of power even after 20 years of operation.
The satellites are powered by photovoltaic cells that convert sunlight into electricity. But the sun also emits radiation that causes these solar cells to degrade. Solar cells absorb light and emit photon energy, which is then transferred to negatively charged electrons. These electrons act as charge carriers.
The problem occurs when these electrons are affected by radiation. Irradiation in space causes damage and reduces efficiency by displacing atoms in solar cell materials and shortening the lifetime of charge carriers.
To eliminate this degradation, the researchers designed a thinner layer of photovoltaic cells. This can increase the lifetime of the flow as the charge carriers travel further during their shortened lifetime. The researchers fabricated two types of photovoltaic devices using the semiconductor gallium arsenide. One is an on-chip design built by stacking several substances in layers. Another design involves a silver rear mirror to enhance light absorption.
The amount of radiation damage to the performance of photovoltaic devices before and after irradiation was studied using a technique called cathodoluminescence. A second set of tests was conducted using a compact solar simulator to determine how the devices convert sunlight into electricity after being bombarded with protons.
"Our ultrathin solar cells outperform previously studied thicker devices in proton emission above a certain threshold. The ultrathin geometry provides two orders of magnitude better performance than previous observations," said the new device. Nearly 3.5 times fewer coverslips are required than thicker cells. This would translate into lighter loads and significantly lower launch costs, as they would still provide the same amount of power even after 20 years of operation.