Perovskite and organic solar cells have proven promising alternatives to the widespread silicon-based devices, and now they’ve been tested in space for the first time. Not only did these solar cells perform well, but they’re much thinner and lighter than those currently used and were found to absorb even diffuse light reflected back from Earth.
Silicon has been the solar cell material of choice for decades, and it’s served us well so far. But it may soon be usurped by perovskite, which has advanced so quickly in the last decade or so that its efficiency is already approaching that of silicon.
Organic solar cells are another increasingly attractive option. They may not quite compete with silicon in terms of efficiency, but they’re much thinner, more flexible, and far cheaper to produce in bulk.
And now both perovskite and organic solar cells have been tested in space for the first time. In a new study by researchers from the Technical University of Munich (TUM), two versions of each type of these solar cells were attached to a sounding rocket launched from northern Sweden, which made a short suborbital round trip to a maximum altitude of 240 km (149 mi).
The solar cells withstood the extreme conditions of the launch and flight, and successfully harvested sunlight during their seven minutes in space. They might not have been as plainly efficient as silicon, but they did the job in much less bulky packages. And in spaceflight, size and weight need to be kept to a minimum.
"What counts in this business is not the efficiency, but the produced electric power per weight, which is called specific power," says Peter Müller-Buschbaum, senior author of the study. "The new type of solar cells reached values between 7 and 14 milliwatts per square centimeter during the rocket flight."
Even more interesting is that these solar cells managed to soak up energy even when they were turned away from the Sun. It seems that they were able to harvest the weak light reflected back from the surface of the Earth – something that traditional solar cells usually don’t do.
"This is a good hint and confirms that the technology can go into what is called deep space missions, where you would send them far out in space, far away from the Sun, where standard solar cells wouldn't work in," says Müller-Buschbaum. "There's [a] really exciting future for this sort of technology, bringing these solar cells into more space missions in the future.”
Of course, a seven-minute test run in space isn’t very long, so in future the researchers hope to trial perovskite and organic solar cells on satellites.
The research was published in the journal Joule.
Source: Cell Press via Tech Xplore
