Solar panel technology has made significant progress in recent years, making solar energy the fastest growing renewable energy source. The solar cells we have today are a byproduct of the solar cells used in space.
If you want to power a satellite or manned craft, there are only two options: solar power or nuclear power. Of the two, only solar is not limited by the amount of fuel it can carry. When we think about traveling to other star systems, the question arises: Do solar panels work near other stars?
Solar modules generate electrical voltage through something called the photovoltaic effect. This effect was first discovered in the 19th century, when scientists realized that charged metallic planets could release electrons when exposed to ultraviolet light. This led to the discovery that light is made up of quantum particles called photons. Several examples of the use of this effect to produce electricity soon appeared, but the first solar panels did not appear on the market until the middle of the twentieth century.
Since then, research has focused on making solar cells lighter, cheaper and more efficient. Modern solar panels can use not only ultraviolet light, but also visible light, and in some cases infrared light. However, all of these designs are designed to take advantage of the sun, which emits most of its light in the green range and also emits a lot of ultraviolet rays. But most exoplanets orbit red dwarf stars, which have a red or infrared maximum and emit little ultraviolet light.
If we want to see nearby planetary systems like Proxima Centauri, we need solar panels that can use light from red dwarf stars.
This is the subject of a recent study in Scientific Reports . The researchers studied the characteristics of solar panels in the lower part of the stellar spectrum, especially compared to the Sun and Proxima Centauri. Their research focused on organic photovoltaics (OPV), which are lightweight and flexible. This would allow the solar panels to be attached to the large solar sails that were a common design element of early interstellar probes.
OPV is a newer technology, but it has the advantage over better-known silicon-based cells that it can be tuned to different wavelengths. The efficiency of a solar cell depends on the wavelength that produces the most energy, known as the band gap.
Essentially, the electrons bound to the cell material must capture enough energy from the photon to jump through the band gap into the conduction band, where they can flow as an electric current. By using different organic materials, we can optimally adapt the gap to the available light.
The team found that a wider band gap works well with sunlight, but light from Proxima Centauri requires a narrower band gap. For example, a simulated broadband solar cell has a theoretical efficiency of 18.9% for sunlight, but only 0.9% for Proxima Centauri. In contrast, the narrowband model of Proxima Centauri has a theoretical efficiency of 12.6%.
Solar panels can generate electricity from red dwarf stars. But there is still a big drawback. Because red dwarfs produce much less light than the Sun, solar cells, even with good efficiency, will not produce as much energy as we can get from the Sun.
Interstellar solar panels would need to be much larger, which would increase their weight and cost. However, it is possible, and further research into materials may reveal more efficient ways to generate electricity from light.
More information: Nora Shoup et al., Interstellar Photovoltaics, Scientific Reports (2023). doi: 10.1038/s41598-023-43224-5
Quote : Do solar panels work on Proxima Centauri? (2023, October 6), retrieved October 7, 2023, from https://phys.org/news/2023-10-solar-panels-proxima-centauri.html
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