For the most part, the universe tends from order to disorder. Scientists call this entropy. Unfortunately for humanity, order really tickles our fancy. For example, humans put up tall buildings; gravity eventually brings them down. People clean their houses; they get dirty again. So, we’ve come to see disorder as a bad thing. However, that isn’t always the case.
Researchers from the University of Cambridge have discovered that materials made from perovskite—which is used to make solar cells and flexible LEDs—become more efficient when their chemical compositions are less ordered. So, why does this matter?
Cost is one of the major reasons that solar cell technology isn’t more widespread. The Cambridge breakthrough could lead to much simpler production of solar devices and substantially lower costs. Furthermore, the technology could lead to cool developments like solar cell smartphone screens. Dr. Felix Deschler and Dr. Sam Stranks led the study, which is published in the journal Nature Photonics.
Next-Gen Solar Cells
The conventional technique for producing solar cells involves crystalline silicon. This technology has worked for decades. The problem with crystalline silicon, though, is that it requires a costly and time-consuming process to achieve efficient energy conversion. This is because the silicon must have a very ordered wafer structure. Moreover, crystalline silicon is vulnerable to impurities like dust. Therefore, it has to be made in an incredibly clean room.
In the past decade, however, materials made from perovskite have come to the forefront as possible alternatives to crystalline silicon for making solar cells. It’s cheaper to produce, but that’s not really the coolest thing about it.
For instance, perovskite materials can mix with liquid ink. They can then be printed to produce a film. Researchers can also change their color by altering the components used to create the material. Being able to change the color is important as different colors collect sunlight differently.
Solar Cell Revolution
Perhaps the coolest thing about perovskite is that the film can be extremely thin (1000 times thinner than a human hair) and still clock efficiencies similar to the much thicker crystalline silicon cells. This opens up the possibility of futuristic-sounding things like solar cell windows or super-flexible solar cell smartphone screens.
“This is the new class of semiconductors that could actually revolutionise all these technologies,” doctoral student at Cambridge’s Cavendish Laboratory Sascha Feldmann said. “These materials show very efficient emission when you excite them with energy sources like light, or apply a voltage to run an LED.”
“The beauty of the study really lies in the counterintuitive discovery that easy to make does not mean the material will be worse, but can actually be better,” Feldmann added. Perovskite film seems like a supermaterial. However, there are a few downsides.
The most notable is a sensitivity to moisture. Putting a solar cell on a phone is cool, but one of the most practical places to put solar panels is on a roof. “There’s still work to do to make them last on rooftops the way silicon can,” Dr. Stranks said. “But I’m optimistic.”