THIN, FLEXIBLE NEW SOLAR CELLS COULD SOON LINE YOUR SHIRT

The general rule when developing a new kind of solar technology is to expect progress to be slow. Take silicon solar cells, the most ubiquitous and recognizable form of photovoltaic generations today. When silicon panels were first built in the early 1950s, they could only turn about 6 percent of the light that hit them into electricity. More than 30 years later, that number had inched up to 20 percent, and today—30 years after that—they regularly perform in the mid 20s.

So when, in 2017, a new material jumped from 3.8 percent to 22.7 percent efficiency after less than 8 years of development, it got people’s attention.

The new material is called perovskite, after a naturally occurring mineral found abundantly throughout the Earth’s crust. Perovskite photovoltaics are made out of a different material with a similar crystal structure, which gives them semiconductor properties. They are sometimes referred to as “hybrid perovskite cells” because they exhibit characteristics of various existing photovoltaics.

Unlike typical solar panels where silicon must be smelted in high-temperature furnaces and then carved into perfect wafers and soldered together, perovskites can be printed like ink, which means they take much less energy to manufacture. The perovskite structure is also less rigid than silicon, so they can be made into flexible, thin-film panels and installed on office building windows, vehicles, electronics, or even clothing. Other kinds of thin-film solar cells have been around for awhile, but they haven’t shows the kind of performance and rapid improvement that perovskite films achieve. The theoretical maximum efficiency for perovskite is 33 percent—at the current rate of improvement, they could be getting close within decade.