Stability

Australian scientists have announced what could be an important step towards commercial viability of perovskite solar cells when their solar cells passed strict International Electrotechnical Commission testing standards for heat and humidity.

"Perovskites are a really promising prospect for solar energy systems," said Professor Anita Ho-Baillie, the inaugural John Hooke Chair of Nanoscience at the University of Sydney. "They are a very inexpensive, 500 times thinner than silicon and are therefore flexible and ultra-lightweight. They also have tremendous energy enabling properties and high solar conversion rates." However, unprotected perovskite cells do not have the durability of silicon-based cells, which is one of the reasons they are not yet commercially viable.

A Purdue University-led research team discovered that adding a rigid bulky molecule – bithiophenylethylammonium – to the surface of a perovskite stabilizes the movement of ions, preventing chemical bonds from breaking easily. The researchers also demonstrated that adding this molecule makes a perovskite stable enough to form clean atomic junctions with other perovskites, allowing them to stack and integrate.

“If an engineer wanted to combine the best parts about perovskite A with the best parts about perovskite B, that typically can’t happen because the perovskites would just mix together,” said Brett Savoie, a Purdue assistant professor of chemical engineering. “In this case, you really can get the best of A and B in a single material. That is completely unheard of.”